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Hitachi Zw220 Zw250 Wheel Loader Service Manual Set

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Contents
Overview
Front ............................................................................................ 1
Side ............................................................................................. 1
Rear............................................................................................. 3
Cab
Cab.............................................................................................. 5
Pedals ......................................................................................... 7
Monitor ...................................................................................... 11
Control Lever............................................................................. 11
Right Console............................................................................ 13
Pilot Valve.................................................................................. 17
Front Control Lock Valve ........................................................... 17
MCF and ICF............................................................................. 19
Fuse Boxes and Relays............................................................. 19
Satellite Terminal ....................................................................... 21
Operator’s Seat ......................................................................... 23
Air Recirculation Filter ............................................................... 25
Fresh Air Filter ........................................................................... 25
Radio and Switch Box ............................................................... 27
Sun Visor................................................................................... 27
Engine
Left View.................................................................................... 29
Cooling Fan Pump..................................................................... 31
Fusible Links and Relays........................................................... 31
Alternator................................................................................... 33
Cooling System ......................................................................... 33
ECM .......................................................................................... 35
Fuel Feed Pump........................................................................ 37
Cooling Fan ............................................................................... 37
Battery ....................................................................................... 39
Right View ................................................................................. 41
Cooling System ......................................................................... 43
Common Rail and Sensors........................................................ 43
Exhaust Gas Recirculation (EGR) ............................................. 45
Contents
Overheat Switch and Coolant Temp. Sensor............................. 47
Fuel Supply Pump ..................................................................... 47
Engine Oil Pressure Sensor ...................................................... 49
A/C Compressor........................................................................ 51
Crank Revolution Sensor........................................................... 53
Fuel Tank................................................................................... 53
Engine Oil Drain ........................................................................ 55
Power Train
Torque Converter....................................................................... 59
ZF Transmission........................................................................ 61
Rear Propeller Shaft .................................................................. 63
Propeller Shaft and Parking Brake ............................................ 65
Front Propeller Shaft and Front Axle ......................................... 65
Service Brake ............................................................................ 67
Front Axle .................................................................................. 69
Tire ............................................................................................ 69
Brake System
Service Brake ............................................................................ 71
Charging Block .......................................................................... 71
Parking Brake Solenoid Valve and Accumulator........................ 73
Parking Brake............................................................................ 75
Steering System
Steering System ........................................................................ 77
Steering Cylinders ..................................................................... 79
Emergency Steering Pump........................................................ 81
Frame
Hinge Points .............................................................................. 83
Tool Box..................................................................................... 85
Hydraulic System
Hydraulic System ...................................................................... 87
Pilot Filter .................................................................................. 89
Main Control Valve .................................................................... 91
Pressure Check Ports................................................................ 91
Proximity Switch ........................................................................ 93
Hydraulic Oil Tank...................................................................... 95
Oil Temperature Sensor............................................................. 99
Contents
Ride Control System.................................................................. 99
Lift Arm Auto Lever
Lift Arm Auto Lever .................................................................. 101
OVERVIEW (FRONT)
Operating Weight : 19690 kg
Engine : Isuzu 6HK1XYWT-04
Engine Max. Output :
179.1 kW/2000 min-1
Engine Max. Torque :
1022 N⋅m/1400 min-1
Max. Traction Force : 177 kN
Bucket Capacity : 3.7 m3
Breakout Force : 162 kN
Tipping Load (Full Turn): 13000 kg
001
OVERVIEW (SIDE)
Transmission : TCM
Max. Forward Speed : 34.5 km/h
Bucket Width : 3050 mm
Dimensions
Length with Bucket
on Ground : 8385 mm
Wheel Base : 3350 mm
Tread : 2200 mm
Tire : 23.5-25-16PR(L3)
Width Over Tire std : 2830 mm
002
-1-
-2-
OVERVIEW (REAR)
Axle Make : TCM
Differential : TPD(std)
LSD(option)
003
-3-
Vehicle Speed (km/h)
ZW220
ZW250
1st (Fwd/Rev)
7.2
7.1
2nd (Fwd/Rev)
12.3
12.3
3rd (Fwd/Rev)
22.0
21.9
4th (Fwd/Rev)
34.5
34.5
-4-
CAB
Hazard Light Switch
Working Light Switch
Rear Wiper Switch
FNR and Shift
Change Lever
004
CAB
Clutch Cut Position Switch
Travel Mode Switch
Work Mode
Selector Switch
Turn Signal Lever
Parking Brake Switch
005
-5-
Work Mode Selection
Mode Selection
Front Speed
L-mode
P-mode
Mode Selection
Traction Force
L-mode
P-mode
Automatic Transmission with Load-Sensing System
Speed Shift Modes
Mode
Gear shift timing
Gear shift
Manual mode
—
L Mode
Fast
1—4
2—4
Jobs
—
N Mode
Slow
H Mode
Slow
1—4
2—4
Automatic shift-down to 1st
gear according to loading
Excavation Loading
Excavation Loading · Dumping
· Hopper dumping
· Dumping
Travel at job sites with many
· Hopper charging
steep slopes
Travel
· Load & carry
· Long travel
3-Mode Clutch Cutoff
3-Mode Clutch Cutoff
Clutch Cutoff Timing Selectable According to
Job Needs and Operator's Preference
• Selectable Clutch Cutoff Timing
• S [short] Mode
The clutch is cut off at fast timing by depressing the pedal
for productive loading on level ground.
• N [Normal] Mode
The clutch is cut off by depressing the pedal midway for
dependable operation on slope.
• D [Deep] Mode
The clutch is cut off by depressing the clutch fully for easy
dumping into hopper on slope.
The clutch does not work when it is turned OFF.
• OFF
The clutch is normally ON.
-6-
PEDALS
Accelerator Pedal
Brake Pedals
006
PEDALS
Brake Lamp Switch
007
-7-
-8-
PEDALS
Accelerator Pedal
008
PEDALS
Accelerator Sensor
009
-9-
-10-
MONITOR
010
CONTROL LEVER
Floating
Down
FNR Switch
Roll Back
DSS Button
Dump
Raise
USS Button
011
-11-
Monitor Panel
1
2
3
4
5
6
7
8
9
10
11
34
12
33
13
14
32
15
31
T4GB-01-02-001
30
29
28
1 - Coolant Temperature
Gauge
2 - Transmission Oil Temperature Gauge
3 - Turn Signal Indicator
(Left)
4 - High Beam Indicator
5 - Working Light Indicator
6 - Turn Signal Indicator
(Right)
7 - Monitor Display
8 - Stop Indicator
9 - Service Indicator
27
26
25
24
23
22
10 - Parking Brake Indicator
21
20
19
18
11 - Clearance Light Indicator
19 - Lever Steering Indicator (Optional)
20 - Monitor Mode Selector
12 - Fuel Gauge
21 - Glow Signal
13 - Brake Low Oil Pressure
Indicator
14 - Brake Low Oil Level Indicator
15 - Emergency Steering Indicator (Optional)
16 - Low Steering Oil Pressure
Indicator
17 - Seat Belt Indicator
22 - Monitor Display Selector (Up)
23 - Maintenance Indicator
24 - Monitor Display selector
(Down)
25 - Forward/Reverse Switch Indicator
26 - Water Separator Indicator
18 - Discharge Warning Indicator
-12-
17
16
27 - Engine Warning Indicator
28 - Overheat Indicator
29 - Engine Low Oil Pressure
Indicator
30 - Air Filter Restriction Indicator
31 - Transmission Warning Indicator
32 - Transmission Oil Filter Restriction Indicator
33 - Hydraulic Oil Temperature
Indicator
34 - Transmission Oil Temperature Indicator
CONTROL LEVERS
DSS
Lift Arm Control Lever
FNR Selector Switch
Hold Switch
Horn Switch
Bucket Control Lever
DSS/USS
012
RIGHT CONSOLE
Front Control Lock Lever
Fan Reverse Switch
Emergency Steering
Check Switch
Lighter
Fwd. Rev. Selector Switch
Ride Control Switch (Option)
013
-13-
Control on Right Console
• Right Console (Front End):
Levers/Switches Layout
1. Forward/reverse switch
Selects forward and reverse travel.
6
2
NOTE: When operating both this switch and Forward/reverse lever at the front console simultaneously, the Forward/reverse lever will
be automatically selected.
1
2. DSS* and DSS/USS**
DSS and seesaw type DSS/USS selector are provided. At the DSS/USS selector, pressing USS allows quick upshift (one gear), and pressing DSS
allows one-gear downshift.
5
2
4
3
3. Lift arm lever (fingertip control type)
4. Bucket lever (fingertip control type)
13
5. Horn switch
6. Hold switch
Holds the speed at the gear selected in the auto
mode.
7
* Down-Shift Switch
** Up-Shift Switch
8
9
• Right Console (Rear End):
7. Lever lock
8. Forward/reverse switch
10
11
12
9. Ride control switch (option)
10. Cooling fan reverse switch
Selects normal rotation and reversing of cooling
fan. This switch functions only when the engine
stops.
11. Emergency steering check switch (option)
Checks the operation of electric pump interacting
with emergency steering.
12. Lift arm kickout switch
Presets the stop position of lift arm, and turns lift
arm kickout system ON and OFF.
13. Auto lift arm leveler switch (option)
Presets the stop position of boom, and turns
ground stop system ON and OFF.
-14-
RIGHT CONSOLE
Lever for Positioning
015
-15-
-16-
PILOT VALVE
Detent for Lift
Arm Floating
Detent for Lift
Arm Kick-out
Tank Port
Detent for Bucket
Positioner
018
PILOT SHUTOFF VALVE
019
-17-
1
2
3
4
5
6
Port T
(Clearance of Part A: 0)
(A)
Port P
Fine Control Hole
7
Output Port
T4GB-03-05-009C
12-
Disc
Push Rod
3 - Piston
4 - Spring Guide
T4GB-03-05-010C
56-
Balance Spring
Return Spring
7 - Spool
T1F3-03-09-004
-18-
MCF AND ICF
ICF
MCF
020
-19-
-20-
FUSE BOXES AND RELAYS
AEB Switch Connector
Dr. ZX Connector
022
SATELLITE TERMINAL
023
-21-
Controller and Relays
6
7
T4GB-01-02-006
11
5
15
1
20
2
16
21
17
22
18
23
19
12
8
13
9
14
10
24
4
3
25
26
27
28
29
30
31
32
33
34
T4GB-01-02-021
T4GB-01-02-022
1 - Flasher Relay
10 - Front Window Heater Relay
2 - Option Controller
(Optional)
3 - TCU
11 - Neutral Relay
12 - Rear Window Heater Relay
4 - MCF
13 - Wiper Relay (Left)
5 - ICF
14 - Wiper Relay (Right)
6 - Dr.ZX Connector
15 - Reverse Light Relay (A-R5)
7 - Fuse Box
16 - Brake Light Relay (A-R4)
8 - Fog Light Relay (Optional)
9 - Auxiliary
17 - High Beam Relay (A-R3)
18 - Head Light Relay (Right)
(A-R2)
19 - Head Light Relay (Left)
(A-R1)
20 - Emergency Steering Relay
(A-R10)
21 - Horn Relay (A-R9)
22 - Turn Signal Relay (Right)
(A-R8)
23 - Working Light Relay (Rear)
(A-R7)
24 - Working Light Relay (Front)
(A-R8)
25 - Front Wiper Relay (B-R5)
26 - Neutral Relay (B-R4)
-22-
27 - Load Dump Relay (B-R3)
28 - Parking Brake Relay
(B-R2)
29 - Parking Brake Relay
(B-R1)
30 - Fuel Pump Relay (B-R10)
31 - Main Relay (B-R9)
32 - Rear Washer Relay (B-R8)
33 - Turn Signal Relay (Left)
(B-R7)
34 - Rear Wiper Relay (B-R6)
OPERATOR’S SEAT
024
SEAT ADJUSTMENT
025
-23-
-24-
AIR RECIRCULATION FILTER
026
FRESH AIR FILTER
027
-25-
-26-
RADIO AND SWITCH BOX
028
SUNVISOR
029
-27-
-28-
ENGINE (LEFT VIEW)
ISUZU
AH-6HK1XYWT-02
179.1 kW/2000 min-1
Air Cleaner
Muffler
Turbocharger
030
ENGINE (LEFT VIEW)
Cam Angle Sensor
031
-29-
ENGINE AND FAN PUMP
1
2
3
6
7
8
9
5
10
11
4
14
13
12
T4GB-01-02-025
1 - Glow Plug
9 - EGR Valve
12 - Crank Revolution Sensor
2 - Injector
5 - Coolant Temperature Sensor
6 - Overheat Switch
10 - Supply Pump
3 - Cam Angle Sensor
7 - Boost Pressure Sensor
11 - Fuel Temperature Sensor
13 - Engine Oil Pressure Sensor
14 - Common Rail Pressure
Sensor
4 - Fan Pump
8 - Boost Temperature Sensor
-30-
COOLING FAN PUMP
Fan Pump
Max. Flow :
60 L/min
Torque Converter
Cooler Check Valve
0.15 MPa
032
FUSIABLE LINKS AND RELAYS
Fusiable Links
Atmospherical
Pressure Sensor
Safety Relay
Glow Relay
Engine Oil : 25 L
033
-31-
ENGINE
ZW220
Manufacturer ............................................ ISUZU
Model........................................................ AH-6HK1XYWT-03 (Wet Type)
Type.......................................................... Diesel, 4 Cycle, Water Cooled, Over Head Valve, Inline,
Direct Injection, Turbo Charged
Cyl. NO. - Bore×Stroke............................. 6-115 mm×125 mm (4.53 in×4.92 in)
3
3
Piston Displacement................................. 7790 cm (475 in )
-1
Rated Output ............................................ 139.3±3 kW/2170 min (189±4 PS/2170 rpm)
Compression Ratio................................... 17.5
Dry Weight................................................ 630 kg (1389 lb)
Firing Order .............................................. 1-5-3-6-2-4
Rotation Direction ..................................... Clock Wise (Viewed from fan side)
ZW250
Manufacturer ............................................ ISUZU
Model........................................................ AH-6HK1XYWT-04 (Wet Type)
Type.......................................................... Diesel, 4 Cycle, Water Cooled, Over Head Valve, Inline,
Direct Injection, Turbo Charged
Cyl. NO. - Bore×Stroke............................. 6-115 mm×125 mm (4.53in×4.92 in)
3
3
Piston Displacement................................. 7790 cm (475 in )
-1
Rated Output ............................................ 163.0±3 kW/2240 min (222±4 PS/2240 rpm)
Compression Ratio................................... 17.5
Dry Weight................................................ 630 kg (1389 lb)
Firing Order .............................................. 1-5-3-6-2-4
Rotation Direction ..................................... Clock Wise (Viewed from fan side)
COOLING SYSTEM
Cooling Fan .............................................. Diameter 850 mm (33.47 in),
6 Blades (N6G-Type Blade, Steel Center), Draw-in Type
Thermostat ............................................... Cracking Temperature at Atmospheric Pressure:
82 °C (180 °F)
Full Open (Stroke: 10 mm (0.39 in) or more) Temperature:
95 °C (203 °F)
Fan Pump................................................. Gear Pump
-1
Engine Speed (min )
ZW220
ZW250
Min. Speed..................................
840 ± 25
840 ± 25
Max. Speed.................................
2240/2230 ± 25
2310/2300 ± 25
Max. Speed (Stall).......................
2010/1920 ± 50
2060/1980 ± 50
Max. Speed (Stall + Relief) .........
1780/1770 ± 50
1800/1790 ± 50
-32-
ALTERNATOR
24 V, 50 A
034
COOLING SYSTEM
Intercooler
T/C Oil Cooler
A/C Condenser
035
-33-
ENGINE ACCESSORIES
RADIATOR ASSEMBLY
Type.......................................................... Radiator and Oil Cooler Tandem Type Assembly
Inter Cooler and Torque Converter Cooler Tandem Type Assembly
Weight ...................................................... 67 kg (148 Ib) (ZW220)
74.5 kg (164 Ib) (ZW250)
ZW220
Radiator
Capacity.................................................... 15 L (4 US gal)
2
Air-Tight Test Pressure ............................. 100 kPa (1.0 kgf/cm , 14.5 psi)
2
Cap Opening Pressure............................. 49 kPa (0.5 kgf/cm , 7 psi)
Oil Cooler
5.1 L (3.3 US gal)
2
1500 kPa (15 kgf/cm , 217 psi))
−
Intercooler
Capacity.................................................... 11.5 L (3 US gal)
2
Air-Tight Test Pressure ............................. 245 kPa (2.5 kgf/cm , 36 psi)
Cap Opening Pressure.............................
−
Torque Converter Cooler
10.2 L (2.7 US gal)
2
1500 kPa (15 kgf/cm , 217 psi)
−
ZW250
Radiator
Capacity.................................................... 18 L (4.8 US gal)
2
Air-Tight Test Pressure ............................. 100 kPa (1.0 kgf/cm ,14.5 psi)
2
Cap Opening Pressure............................. 49 kPa (0.5 kgf/cm , 7 psi)
Oil Cooler
5.1 L (1.3 US gal)
2
1500 kPa (15 kgf/cm ,217 psi))
−
Intercooler
Capacity.................................................... 12.5 L (3.3 US gal)
2
Air-Tight Test Pressure ............................. 245 kPa (2.5 kgf/cm , 36 psi)
Cap Opening Pressure.............................
−
Torque Converter Cooler
10.7 L (2.8 US gal)
2
1500 kPa (15 kgf/cm , 217 psi)
−
BATTERY
Voltage...................................................... 12 V
Capacity.................................................... 108 Ah
-34-
COOLING SYSTEM
Intercooler
Swing Open Type
036
ECM (ENGINE CONTROL MODULE)
ECM
037
-35-
-36-
ELECTROMAGNETIC PUMP
Strainer Built-In
100 µm
038
COOLING FAN HYDRAULICALLY DRIVEN
Cooling Fan
Motor
Relief Press.
Setting :
20.6 MPa
Back-Up Alarm
Fuel Supply Port
039
-37-
Fan Speed Controls
Torque Converter
Temp. Sensor
//
Monitor
Engine Coolant
Temp. Sensor
CAN
MC
//
Flow
Control
Sol. Valve
//
* Not activate if each temp.
above setting
Hydraulic Oil
Temp. Sensor
//
High fan speed
-1
(
min )
A/C Control Panel
//
* Activate if each temp.
below setting
Outside Temp.
Sensor
//
Low fan speed
-1
(
min )
Fan Speed
-1
Speed (min )
Coolant (°C)
Hydraulic Oil (°C)
T/C Oil (°C)
A/C ON (°C)
Solenoid (mA)
500
50
50
50
-
800
500
80
70
80
-
800
1650
90
90
100
30 - 35
0
1650
100
100
110
-
0
-38-
COOLING FAN
Radiator 18 L
Hydraulic Oil
Cooler
Swing Open Type
040
BATTERY
12 V × 2
108 Ah
041
-39-
-40-
ENGINE (RIGHT VIEW)
Common Raid
for Fueling
Main Filter
Pre Filter
Fuel Filters
042
AIR FILTER
043
-41-
OUTLINE
• Supply pump is driven by engine and generates
Signals from sensors and MC (Main Controller) are
input to ECM (Engine Control Module).
ECM calculates and drives two way valves, suction
control valve and EGR motor in order to control supply
pump, injectors and EGR (Exhaust Gas Recirculation).
high pressure fuel.
• Common rail destributes high pressure fuel generated by supply pump to injectors of each engine
cylinder.
• Injector injects high pressure fuel from common
rail.
• Fuel Injection Control
• Engine Start Control
• EGR Control
• Correction of Fuel Injection Volume
• Engine Stop Control (Refer to System/Electric
System)
Crank Revolution Sensor
Cam Angle Sensor
Atmospherical Pressure Sensor
Fuel Temperature Sensor
Coolant Temperature Sensor
Inlet Air Temperature Sensor
Boost Pressure Sensor
Boost Temperature Sensor
Engine Oil Pressure Sensor
EGR Motor Position Sensor
EGR
EGR Motor
ECM
MC
Common Rail
Pressure Sensor
Two Way Valve
Suction Control
Valve
Common Rail
Supply Pump
Injector
Fuel Tank
T4GB-02-02-022
-42-
COOLING SYSTEM
T/M Oil Cooler
A/C Receiver
044
COMMON RAIL AND SENSORS
Boost Pressure
Sensor
Boost Temperature
Sensor
Common Rail
Common Rail
Pressure Sensor
045
-43-
Tier 3 Emission Regulation
ENGINE
CLASS
2003
2004
2005
2006
2007
Tire 2
EPA
130-225 kW
(175-300 hp)
Tire 3
NOx + HC
CO
PM
6.6
3.5
0.2
→
→
→
4.0
3.5
0.2
Stage 2
EC
130-560 kW
Stage 3-A
NOx
HC
CO
PM
6.0
→ 4.0
1.0
3.5 → 3.5
0.2 → 0.2
Tire 2
JPN
130-560 kW
Tire 3
NOx
HC
CO
PM
6.0
1.0
3.5
0.2
→
→
→
→
3.6
0.4
3.5
0.17
Common Rail Pressure Sensor
Boost Pressure Sensor
Output (V)
Output (V)
4.2
4.75
1
0.1
Pressure (MPa)
2008
200
40
-44-
Pressure (kPa)
350
COMMON RAIL AND HIGH PRESSURE PIPING
Glow Plug
Fuel Return
Connection
to Injector
Flow Damper
Pressure Limiter
200 MPa
Fuel Inlet Pipe
046
EXHAUST GAS RECIRCULATION (EGR)
EGR
Reed Valve
EGR Valve
047
-45-
Cooled EGR
EGR stands for ”Exhaust Gas Recirculation”.
This equipment lowers burning temperature by mixing some of the emitted exhaust gas with the intake air to control
oxygen concentration in the combustion chamber slowing down combustion.
This enables reduction of nitrogen oxide or ”NOx” which is produced during high-temperature combustion. Cooled
EGR system is a system which equips cooling system in the EGR gas passages.
This system contributes reduction of NOx by further lowering the burning temperature than normal EGR with
cooling down the heated EGR gas with cooler before mixing with the intake air.
Moreover, by cooling down the high temperature EGR gas, intake air concentration is increased resulting in more
air capacity.
This brings close to the perfect combustion resulting in reduction of PM and other graphite as well as better fuel
consumption.
-46-
OVERHEAT SWITCH AND COOLANT TEMP. SENSOR
Wire for Overheat
Switch 105 °C
Coolant
Temperature
Sensor
048
FUEL SUPPLY PUMP
Fuel
Temperature
Sensor
Fuel Return
Suction
Control Valve
From Electromagnetic Fuel
Pump
Fuel Supply
049
-47-
Engine Coolant Temperature Sensor
Fuel Temperature Sensor
Output (V)
Output (V)
5
4.5195
4
3
2
1
0
0.1973
-40
0
40
80
-30
120
Temperature (°C)
Temperature (°C)
Intake Air Temperature Sensor
Output (V)
4.8691
0.1797
-40
120
120
Temperature (°C)
-48-
FUEL SUPPLY PUMP
Crank Revolution
Sensor
050
ENGINE OIL PRESSURE SENSOR
Engine Oil Pressure
Sensor
051
-49-
Crank Revolution Sensor
Cam Angle Sensor
6HK
No.6 cylinder
G standard pulse
No.1 cylinder
Standard pulse
Cam Angle Sensor
Crank Revolution
Sensor
No.1 cylinder
NE standard pulse
No.6 cylinder
NE standard pulse
-50-
No.1 cylinder
G standard pulse
CRANK REVOLUTION SENSOR
Crank Revolution
Sensor
052
A/C COMPRESSOR
Cooling Ability : 4.65 kW or more
Heating Ability : 5.81 kW or more
Refrigerant Quantity : 1050 g
Compressor Oil Q’ty : 160 cm3
053
-51-
-52-
BELT ADJUSTMENT
054
FUEL TANK
Drain Cock
055
-53-
-54-
FUEL TANK
Fuel Tank Capacity
340 Liters
Fuel Level Sensor
Fuel Supply Line
056
ENGINE OIL DRAIN
Engine Oil Pan
Drain Plug
25 Liters
057
-55-
-56-
COOLANT REPLENISHMENT
Coolant Reservoir
Radiator
18 L
104
-57-
-58-
TORQUE CONVERTER
T/C Inlet
Pressure :
0.84-0.94 MPa
T/C Outlet
Pressure :
0.32-0.42 MPa
106
TORQUE CONVERTER
T/C Input
Speed Sensor
Charge Pump
T/C Output
Speed Sensor
107
-59-
Side View of Transmission
2
1
3
4
3
5
6
9
7
8
10
T4GC-03-09-005C
1 - Converter Inlet Pressure
Port
2 - Regulator Valve
3 - Forward Clutch Pressure
Port
4 - Reverse Clutch Pressure
Port
5 - 1st Speed Clutch Pressure
Port
6 - 2nd Speed Clutch Pressure
Port
7 - 3rd Speed Clutch Pressure
Port
8 - 4th Speed Clutch Pressure
Port
9 - Parking Brake Release
Pressure Inlet
-60-
10 - Parking Brake Pressure
Switch Port
TCM TRANSMISSION
Rotation
Sensor (B)
Vehicle Speed
Sensor
Wet Type
Parking Brake
108
TCM TRANSMISSION
Regulator Valve
Press. Setting :
2.2 – 2.4 MPa
T/C Inlet Press. Port
Fwd. Clutch
Press. Port
Rev. Clutch
Press. Port
Proportional
Solenoid Valves
1st Speed Clutch
Press. Port
2nd Speed Clutch
Press. Port
3rd Speed Clutch
Press. Port
4th Speed Clutch
Press. Port
109
-61-
1
2
3
24
4
5
23
6
7
8
22
9
21
10
11
12
20
13
14
19
15
16
17
18
T4GC-03-09-029C
From
Charging Pump
1 - Solenoid Body
7 - Emergency Reverse Spool
2 - Valve Body
8 - Reverse Modulation Spool
3 - Cover
9 - Reverse Modulation Spring
4 - Emergency Forward Spool
10 - 1st Speed Modulation
Spool
11 - 1st Speed Modulation
Spring
12 - Emergency 2nd Speed
Spool
5 - Forward Modulation Spool
6 - Forward Modulation Spring
13 - 2nd Speed Modulation
Spool
14 - 2nd Speed Modulation
Spring
15 - 3rd Speed Modulation
Spool
16 - 3rd Speed Modulation
Spring
17 - 4th Speed Modulation
Spool
18 - 4th Speed Modulation
Spring
-62-
19 - 4th Speed Proportional
Solenoid Valve
20 - 3rd Speed Proportional
Solenoid Valve
21 - 2nd Speed Proportional
Solenoid Valve
22 - 1st Speed Proportional
Solenoid Valve
23 - Reverse Proportional Solenoid Valve
24 - Forward Proportional Solenoid Valve
TCM TRANSMISSION
Drain Plug
110
REAR PROPELLER SHAFT
111
-63-
Control Valve
4th Speed Clutch
3rd Speed Clutch
2nd Speed Clutch
1st Speed Clutch
Reverse Clutch
Forward Clutch
Regulator 2.2 – 2.4
Valve
MPa
Clutch
Lubrication
Torque
Converter
Cooler
Torque
Converter
Torque
Converter
Safety
Valve
Filter
Charging
Pump
T4GC-03-09-027C
-64-
PROPELLER SHAFT AND PARKING BRAKE
Plug
Pulling Bolt
112
FRONT PROPELLER SHAFT AND FRONT AXLE
066
-65-
OUTLINE
Axle consists of the differential, final drives, axle shafts,
brake and others.
Axle Shaft
Final
Drive
Power from the transmission is transmitted to the front
axle and the rear axle through the propeller shafts.
Inside the axle, power is transmitted to the differential,
and divided into left and right, and drives the axle
shafts and the wheels through the final drives.
Differential
Brake
Brake
T4GB-03-10-001
-66-
SEIVICE BRAKE PIPING
Clutch Cut-off
Pressure Sensor
Brake Pressure
3.9 MPa
067
SERVICE BRAKE
Brake Disk
Check Ports
068
-67-
1
2
2
3
3
2
Brake Oil
Pressure
4
5
6
7
8
T4GB-03-10-005
1 - End Plate
2 - Brake Ring
3 - Brake Disc
4 - Differential Body
5 - Brake Piston
6 - Return Spring
• Operation
1
2
7 - Disc Hub
8 - Shaft
• Release
3
2
3
2
From
Brake Valve
1
5
2
3
2
3
2 To
Brake Valve
5
6
6
T4GB-03-10-007C
T4GB-03-10-008C
-68-
FRONT AXLE
Front 32 L
Rear 34 L
Oil Level
Check Port
069
TIRE
ZW220
ZW250
23.5-25-16PR(L3) 23.5-25-16PR(L3)
325 kPa
375 kPa
070
-69-
FINAL DRIVE / AXLE SHAFT
Final drive is the device for finally decreasing the
speed in the power transmission system, and of the
planetary gear type. As for power transmission, the
power from the differential, transmitted from the shaft,
rotates the three planetary gears in the ring gear, and
transmits rotation of the planetary carrier to the axle
shaft through the planetary carrier.
Final
Drive
Axle Shaft
Ring Gear
Shaft
Housing
Planetary Carrier
Planetary Gear
T4GB-03-10-006C
-70-
SERVICE BRAKE
Outside Temp.
Sensors
Brake Valve
To Front
Service
Brake
To Rear Service
Brake
105
CHARGING BLOCK
Accumulators
Charging Block
Cut-In Press. 11.8 MPa
Cut-Out Press. 14.7 Mpa
Pilot Relief Press. 4.0 MPa
072
-71-
Component Layout
1
2
3
4
Port T
5
6
Port BR1
Port M1
11
7
Port BR2
Port M2
10
8
9
T4GB-03-11-002C
1 - Pedal
2 - Roller
3 - Spool Input
4 - Spring
5 - Spring
6 - Spring
7 - Spool
8 - Spool
9 - Spring
-72-
10 - Plunger
11 - Plunger
CHARGING BLOCK
Accumulator
4.4 MPa
Pump Torque
Proportional
Solenoid Valve
Parking Brake
Solenoid Valve
Charging Pressure
Cut-In : 11.8 MPa
Cut-out : 14.7 MPa
Service Brake Acc. Charging Press. 4.4 MPa
Pilot Acc. Charging Press. 2.0 MPa
Service Brake
Pressure Sensor
ON : 10 MPa
OFF : 8 MPa
073
-73-
Component Layout
1
2
3
4
5
6
7
8
22
9
10
11
21
12
13
14
20
15
16
17
18
4
1 - Service Brake Accumulator
(Rear)
2 - Adaptor
3 - Port M2
(To Rear End of Brake Valve)
4 - Check Valve
5 - Port M1
(To Front End of Brake Valve
and Parking Brake)
6 - Service Brake Accumulator
(Front)
7 - Service Brake Pressure Sensor
19
9 - Priority Valve
10 - Pilot Relief Valve
11 - Port DR (To Hydraulic Oil Tank)
T4GB-03-06-002C
16 - Port BR3 (to be adopted in EU Specification Machines)
17 - Port PS2
(To Main Pump Regulator
and Ride Control Valve (Optional))
18 - Pilot Accumulator
12 - Port DR2 (To Hydraulic Oil Tank)
13 - Port PS1
(To Steering Pilot Valve)
19 - Port PP (To Pilot Shutoff Valve)
20 - Parking Brake Solenoid Valve
14 - Port X
(To Main Pump Regulator)
15 - Port S3 (To be adopted in EU Specification Machines)
21 - Pump Torque Control Proportional
Solenoid Valve
22 - Relief Valve
8 - Port P (From Pilot Pump)
-74-
PARKING BRAKE
Bleeder
113
-75-
Service Brake
Brake
Pedal
Front Brake
Service Brake
Accumulators
Brake
Valve
Rear Brake
Check
Valves
Relief Valve
B
Priority
Valve
A
Charging Block
Pilot Pump
T4GC-02-02-002
NOTE: Illustration shows oil flow when the relief
valve and the priority valve are closed in
response to pressure decrease in the service brake circuit, and also oil flow when
the parking brake is working with the unexcitement of the parking brake solenoid
valve.
-76-
STEERING SYSTEM
Steering Pilot
Valve
076
STEERING SYSTEM
Stopper Bolt
To Tank
To Steering
Valve
From Steering
Pilot Valve
Stop Valve
077
-77-
Steering Stop Circuit
(Refer to COMPONET OPERATION / Steering Valve)
• When either of the left or right cylinder is at the
• As a result, the steering valve spool is shifted at
stroke end, the stop valve spool contacts the
frame, and the stop valve closes to block pressure oil from being supplied to the steering valve
from the steering pilot valve.
neutral, and supply of pressure oil from the main
pump to the steering cylinders is stopped.
Steering Cylinders
Acc. Charging Pressure 8 MPa
Steering Valve
Overload Relief Valve Pressure
34.3 MPa
Spool
Stop
Valve
Stop
Valve
External Force
Applied
Steering
Pilot Valve
Main Pump
Pilot Pump
Hydraulic
Oil Tank
T4GB-02-02-004
NOTE: Illustration shows flow of oil when the
steering valve is turned right.
-78-
STEERING SYSTEM
Overload Relief Pressure
34.3 MPa
To Steering
Cylinders
From Stop
Valve
Steering Valve
078
STEERING CYLINDERS
Steering
Accumulator
8 MPa
079
-79-
-80-
STEERING CYLINDERS
Pressure Check Port
27.4 MPa
080
EMERGENCY STEERING PUMP
Electrical Motor
Max. Flow 17 L/min
081
-81-
-82-
HINGE POINTS
Engine Oil Filter
Main : 120 µm
Bypass : 10 µm
Upper Hinge Points
T/M Oil Level
Gauge
L
Lower Hinge Points
082
HINGE POINTS
Hinge Points
for Lift Arm
Hinge Points
for Lift Arm
Cylinders
083
-83-
-84-
HINGE POINTS (BUCKET)
084
TOOL BOX
085
-85-
-86-
HYDRAULIC SYSTEM
Main Pump
290 L/min
Pump Delivery
Pressure Sensor
Pilot Pump
Priority Valve
Setting Press.
29.4 MPa
114
-87-
PUMP DEVICE
Main Pump
Regulator
Priority Valve
Steering Relief Valve
Pilot Pump
Pump Delivery
Pressure Sensor
T4GB-01-02-009
Oil Flow
L/min
A
B
C
D
MPa (kgf/cm 2)
Operating Pressure
T4GB-04-02-001
ZW220
ZW250
Pressure
2
MPa (kgf/cm )
Flow
L/min
Pressure
2
MPa (kgf/cm )
Flow
L/min
A
4.9(50)
271±3
4.9(50)
291±3
B
19.6(200)
270±3
19.6(200)
290±3
C
24.5(250)
240±6
24.5(250)
275±6
D
27.4(280)
210±6
29.4(300)
225±6
-88-
PILOT FILTER
Pilot Filter
T/M Oil Filter
115
MAIN CONTROL VALVE
Restriction Valve
Main Relief Valve
29.4 MPa
Rear View
Section for
Lift Arm
Section for
Bucket
Overload Relief
Press. 36.8 MPa
Overload Relief
Press. 32.5 MPa
Spare Spool
(Option)
089
-89-
D
10
C
6
7
8
8
A
E
5
4
3
T4GB-03-02-009
1 - Flow Control Valve
(Poppet)
2 - Flow Control Valve
(Changeover Valve)
3 - Negative Control Valve
4-
Overload Relief Valve
(Bucket: Bottom End)
5 - Overload Relief Valve
(Bucket: Rod End)
6 - Overload Relief Valve
(Lift Arm: Bottom End)
7-
Make-up Valve
(Lift Arm: for Rod)
8 - Restriction Valve
9-
-90-
Low-pressure Relief Valve
10 - Main Relief Valve
11 - Load Check Valve
(Lift Arm Circuit)
MAIN CONTROL VALVE
Overload Relief
Valve
Pump Control
Valve Pressure
Rear View
090
PRESSURE CHECK PORTS FOR FRONT ATTACHMENT
Pressure Check Ports
29.4 MPa
091
-91-
Oil Flow
L/min
A
B
C
MPa (kgf/cm 2)
Pump Control Pressure
(Pi1-Pi2)
T4GB-04-02-002
ZW220
Pump Control Pressure
(Pi1-Pi2)
2
MPa (kgf/cm )
A
+0.01
+0.1
-0(4
-0)
0.39
B
1.47±0.05(15±0.5)
C
+0.01
+0.1
0.67
-0(17
-0)
ZW250
Flow
L/min
271±3
Pump Control Pressure
(Pi1-Pi2)
2
MPa (kgf/cm )
+0.01
+0.1
-0(5
-0)
0.49
Flow
L/min
291±3
80±2
1.47±0.05(15±0.5)
100±2
36±3
+0.01
+0.1
0.67
-0(17
-0)
55±3
-92-
PROXIMITY SWITCH
Lift Arm Proximity
Switch
092
PROXIMITY SWITCH
Bucket Proximity
Switch
093
-93-
-94-
HYDRAULIC OIL TANK
Level Gauge
114 L
094
HYDRAULIC OIL TANK
Full Flow Filter
Breather
095
-95-
-96-
HYDRAULIC OIL TANK
Return Hoses
096
HYDRAULIC OIL TANK
Oil Level Switch
097
-97-
-98-
HYDRAULIC OIL TEMPERATURE SENSOR
Temp. Sensor
098
RIDE CONTROL SYSTEM (OPTION)
Cut-Out Press.
11.3 MPa
Manually
Pressure
Release
Valve
Overload Relief Valve
39.2 MPa
Ride Control
Solenoid Valve
Accumulator
2.9 MPa
099
-99-
-100-
LIFT ARM AUTO-LEVELER (OPTION)
Downward
Set Switch
Upward Set
Switch
100
LIFT ARM ANGLE SENSOR
Angle Sensor
Lift Arm
Link
101
-101-
-102-
LIFT ARM ANGLE SENSOR
102
LIFT ARM ANGLE SENSOR
103
-103-
-104-
PART NO.
ZW 220 • 250
Technical Manual
Operational Principle
WHEEL LOADER
TECHNICAL MANUAL
220
250
Wheel Loader
OPERATIONAL PRINCIPLE
URL:http://www.hitachi-c-m.com
TO4GC-E-00
Service Manual consists of the following separate Part No;
Technical Manual (Operational Principle)
: Vol. No. TO4GC-E
Technical Manual (Troubleshooting)
: Vol. No. TT4GC-E
Workshop Manual
: Vol. No. W4GC-E
PRINTED IN SINGAPORE (YS) 2006.03
TO4GC-E-00 ZW.p65
1
1/3/06, 11:23
INTRODUCTION
TO THE READER
• This manual is written for an experienced technician
to provide technical information needed to maintain
and repair this machine.
• Be sure to thoroughly read this manual for correct product information and service procedures.
• If you have any questions or comments, at if you
found any errors regarding the contents of this
manual, please contact using “Service Manual
Revision Request Form” at the end of this manual.
(Note: Do not tear off the form. Copy it for usage.):
Publications Marketing & Product Support
Hitachi Construction Machinery Co. Ltd.
TEL: 81-29-832-7084
FAX: 81-29-831-1162
ADDITIONAL REFERENCES
• Please refer to the materials listed below in addition
to this manual.
• The Operator’s Manual
• The Parts Catalog
• The Engine Manual
• Parts Catalog of the Engine
• Hitachi Training Material
MANUAL COMPOSITION
• This manual consists of three portions: the Technical Manual (Operational Principle), the Technical
Manual (Troubleshooting) and the Workshop Manual.
• Information included in the Technical Manual
(Operational Principle):
technical information needed for redelivery and
delivery, operation and activation of all devices
and systems.
• Information included in the Technical Manual
(Troubleshooting):
technical information needed for operational performance tests, and troubleshooting procedures.
• Information included in the Workshop Manual:
technical information needed for maintenance
and repair of the machine, tools and devices
needed for maintenance and repair, maintenance
standards, and removal/installation and assemble/disassemble procedures.
PAGE NUMBER
• Each page has a number, located on the center
lower part of the page, and each number contains
the following information:
Example : T 1-3-5
Consecutive Page Number for Each Group
Group Number
Section Number
T: Technical Manual
W: Workshop Manual
IN-01
INTRODUCTION
SAFETY ALERT SYMBOL AND HEADLINE
NOTATIONS
In this manual, the following safety alert symbol and
signal words are used to alert the reader to the
potential for personal injury of machine damage.
This is the safety alert symbol. When you see this
symbol, be alert to the potential for personal injury.
Never fail to follow the safety instructions prescribed
along with the safety alert symbol.
The safety alert symbol is also used to draw attention
to component/part weights.
To avoid injury and damage, be sure to use appropriate lifting techniques and equipment when lifting
heavy parts.
•
CAUTION:
Indicated potentially hazardous situation which
could, if not avoided, result in personal injury or
death.
• IMPORTANT:
Indicates a situation which, if not conformed to the
instructions, could result in damage to the machine.
•
NOTE:
Indicates supplementary technical information or
know-how.
UNITS USED
• SI Units (International System of Units) are used in
Example : 24.5 MPa (250 kgf/cm2, 3560 psi)
this manual.
MKSA system units and English units are also
indicated in parenthheses just behind SI units.
Quantity
Length
Volume
Weight
Force
Torque
To Convert
From
mm
mm
L
L
m3
kg
N
N
N⋅m
N⋅m
Into
in
ft
US gal
US qt
yd3
lb
kgf
lbf
kgf⋅m
lbf⋅ft
A table for conversion from SI units to other system
units is shown below for reference purposees.
Quantity
Multiply By
0.03937
0.003281
0.2642
1.057
1.308
2.205
0.10197
0.2248
1.0197
0.7375
Pressure
Power
Temperature
Velocity
Flow rate
IN-02
To Convert
From
MPa
MPa
kW
kW
°C
km/h
min-1
L/min
mL/rev
Into
kgf/cm2
psi
PS
HP
°F
mph
rpm
US gpm
cc/rev
Multiply By
10.197
145.0
1.360
1.341
°C×1.8+32
0.6214
1.0
0.2642
1.0
SECTION AND GROUP
CONTENTS
SECTION 1 GENERAL
Group 1 Specification
Group 2 Component Layout
Group 3 Component Specifications
SECTION 2 SYSTEM
TECHNICAL MANUAL
(Operational Principle)
Group 1 Control System
Group 2 ECM System
Group 3 Hydraulic System
Group 4 Electrical System
SECTION 3 COMPONENT OPERATION
All information, illustrations and specifications in this manual are based on
the latest product information available
at the time of publication. The right is
reserved to make changes at any time
without notice.
COPYRIGHT (C) 2005
Group 1 Pump Device
Group 2 Control Valve
Group 3 Hydraulic Fan Motor
Group 4 Steering Pilot Valve
Group 5 Steering Valve
Group 6 Pilot Valve
Group 7 Charging Block
Group 8 Ride Control Valve
Group 9 Drive Unit
Group 10 Axle
Group 11 Brake Valve
Group 12 Others
TECHNICAL MANUAL (Troubleshooting)
SECTION 4 OPERATIONAL PERFORMANCE TEST
Group 1 Introduction
Group 2 Standard
Group 3 Engine Test
Group 4 Wheel Loader Test
Group 5 Component Test
Group 6 Adjustment
SECTION 5 TROUBLESHOOTING
Group 1 Diagnosing Procedure
Group 2 Dr-ZX
Group 3 e-Whell
Group 4 Component Layout
Group 5 Troubleshooting A
Group 6 Troubleshooting B
Group 7 Troubleshooting C
Group 8 Electrical System Inspection
Hitachi Construction Machinery Co., Ltd.
Tokyo, Japan
All rights reserved
←これ以下
記載しない
WORKSHOP MANUAL
SECTION 1 GENERAL INFORMATION
Group 1 Precautions for Disassembling and Assembling
Group 2 Tightening Torque
Group 3 Painting
Group 4 Bleeding Air from Hydraulic Oil Tank
SECTION 2 BASE MACHINE (UPPER
STRUCTURE)
Group 1 Cab
Group 2 Counterweight
Group 3 Frame
Group 4 Pump Device
Group 5 Control Valve
Group 6 Pilot Valve
Group 7 Ride Control Valve
Group 8 Pilot Shutoff Valve
Group 9 Hydraulic Fan Motor
SECTION 3 BASE MACHINE (TRAVEL
SYSTEM)
Group 1 Tire
Group 2 Drive Unit
Group 3 Axle
Group 4 Propeller Shaft
Group 5 Brake Valve
Group 6 Charging Block
Group 7 Steering Pilot Valve
Group 8 Steering Valve
Group 9 Steering Cylinder
Group 10 Emergency Steering Pump Unit
(Optional)
SECTION 4 FRONT ATTACHMENT
Group 1 Front Attachment
Group 2 Cylinder
SECTION 5 ENGINE
SECTION 1
GENERAL
―CONTENTS―
Group 1 Specifications
Group 3 Component Specifications
Specifications ........................................... T1-1-1
Engine ...................................................... T1-3-1
Engine Accessories .................................. T1-3-6
Group 2 Component Layout
Main Component Layout........................... T1-2-1
Electrical Component Layout.................... T1-2-4
Hydraulic Component ............................... T1-3-8
Electrical Component.............................. T1-3-13
(Overview)
Electrical System (Cab) ............................ T1-2-5
Electrical System .................................... T1-2-6
(Controller and Relays)
Electrical System (Right Console) ............ T1-2-7
Electrical System (Monitor and Switchs)... T1-2-8
Monitor Panel ........................................... T1-2-9
Engine and Fan Pump ............................ T1-2-10
Pump Device and Drive Unit....................T1-2-11
Control Valve .......................................... T1-2-12
Ride Control Valve,Charging Block
and Fan Motor ................................... T1-2-13
Steering Valve and Emergency Steering
Pump (Optional) .................................. T1-2-14
4GCT-1-1
(Blank)
4GCT-1-2
GENERAL / Specification
SPECIFICATIONS
M4GB-12-002
−
ZW220 (Standard)
ZW250 (Standard)
Operating Weight
kg(lb)
3.4 (BOC)
3.7 (BOC)
Static Tipping Load (Full Turn)
kg(lb)
17290
19610
Rated Loading Weight
kg(lb)
5120
5600
−
ISUZU
6HK1
139.3 kW/2170 rpm
(189 PS/2170 rpm)
ISUZU
6HK1
163.0 kW/2240 rpm
(221.5 PS/2240 rpm)
A: Overall Length
mm(ft.in)
8245
8385
B: Overall Width (Bucket)
mm(ft.in)
2910
3050
C: Overall Height
mm(ft.in)
3375
3405
D: Wheel Base
mm(ft.in)
3300
3350
E: Tread
mm(ft.in)
2160
2200
F: Ground Clearance
mm(ft.in)
450
425
G: Height to Bucket Hinge Pin, Fully Raised
mm(ft.in)
4090
4195
H: Dumping Clearance 45 Degree, Full Height
mm(ft.in)
2880
2950
I:
mm(ft.in)
1150
1120
R1: Turning Radius (Centerline of Outside Tire)
mm(ft.in)
5620
5715
R2: Loader Clearance Circle, Bucket in Carry Position
mm(ft.in)
6620
6780
Maximum Travel Speed (Forward/Reverse)
km/h(mph)
34.5/34.5
34.5/34.5
Number of Travel Shift (Forward/Reverse)
−
4/4
4/4
Degree(%)
40
40
−
23.5-25-16PR
23.5-25-16PR
Type
Engine
Dumping Reach, 45 Degree Dump, Full Height
Articulation Angle (Left/Right)
Tire Size
T1-1-1
GENERAL / Specification
(Blank)
T1-1-2
GENERAL / Component Layout
MAIN COMPONENT LAYOUT (OVERVIEW)
1
2
3
4
5
6
12
7
11
10
9
T4GB-01-02-005
8
1 - Bucket
2 - Bell Crank
4 - Head Light
5 - Front Working Light
3 - Bucket Cylinder
6 - Rear Working Light
(Optional)
7 - Rear Working Light
8 - Rear Combination Light
(Turn Signal, Hazard Light
Clearance Light and Brake
Light)
9 - Turn Signal, Hazard Light
and Clearance Light
T1-2-1
10 - Lift Arm Cylinder
11 - Lift Arm
12 - Bucket Link
GENERAL / Component Layout
MAIN COMPONENT LAYOUT (UPPERSTRUCTURE)
1
20
2
3
4
5
21
19
18
17
16
15
6
7
8
9
10
14
13
12
11
T4GB-01-02-002
123456-
Charging Block
Pilot Valve
Brake Valve
Steering Pilot Valve
Steering Valve
Control Valve
78910 11 12 -
Stop Valve
Pilot Shutoff Valve
Engine Oil Filter
Pilot Filter
Engine
Fuel Tank
13 14 15 16 17 18 -
T1-2-2
Torque Converter Cooler
Oil Cooler
Fan Motor
Radiator
Inter Cooler
Reserve Tank
19 - Muffler
20 - Air Cleaner
21 - Hydraulic Tank
GENERAL / Component Layout
MAIN COMPONENT LAYOUT (TRAVEL SYSTEM)
1
2
3
4
5
6
9
8
7
T4GB-01-02-004
1 - Front Axle
2 - Propeller Shaft (Front)
3 - Steering Cylinder
45-
Pump Device
Transmission
5 - Rear Axle
6 - Propeller Shaft (Rear)
T1-2-3
7 - Steering Accumulator
8 - Brake Pressure Sensor
GENERAL / Component Layout
ELECTRIC COMPONENT LAYOUT (OVERVIEW)
14
Cab
(Refer to T1-2-5)
2
1
13
12
Engine and Fan Pump
(Refer to T1-2-10)
11
3
4
5
6
8
Pump Device
(Refer to T1-2-11)
Drive Unit
(Refer to T1-2-11)
10
7
9
T4GB-01-02-019
1 - Hydraulic Oil Level Switch
5-
Battery
2 - Air Filter Restriction Switch
3 - ECM
67-
Boost Pressure Sensor
Fuel Level Sensor
4 - Reverse Buzzer
8-
Hydraulic Oil
Temperature Sensor
7 - Emergency Steering
Pump Delivery Pressure
Switch
8 - Lift Arm Angle Sensor
(Optional)
9 - Bucket Proximity Switch
T1-2-4
10 - Lift Arm Proximity Switch
11 - Implement Pressure Sensor
12 - Out Side Temperature
Sensor
GENERAL / Component Layout
ELECTRICAL SYSTEM (CAB)
1
2
3
Monitor and Switches
(Refer to T1-2-8)
4
Right Consol
(Refer to T1-2-7)
6
5
Controller and Relays
(Refer to T1-2-6)
T4GB-01-02-006
1 - Radio
2 - Auxiliary Switch Panel
(Optional)
3 - Speaker
4 - Rear Wiper Motor
5 - Brake Lamp Switch
T1-2-5
6 - Front Wiper Motor
GENERAL / Component Layout
Controller and Relays
5
6
T4GB-01-02-006
10
4
1
14
15
16
17
18
2
19
20
21
22
23
11
7
12
8
13
9
3
24
25
26
27
28
29
30
31
32
33
T4GC-01-02-002
1-
Flasher Relay
2-
Option Controller
(Optional)
3 - MCF
9-
Front Window Heater
Relay
10 - Neutral Relay
11 - Rear Window Heater Relay
4-
ICF
12 - Wiper Relay (Left)
5-
Dr.ZX Connector
13 - Wiper Relay (Right)
6-
Fuse Box
7-
Fog Light Relay (Optional)
14 - Reverse Light Relay
(A-R5)
15 - Brake Light Relay (A-R4)
8-
Auxiliary
16 - High Beam Relay (A-R3)
17 - Head Light Relay (Right)
(A-R2)
T4GB-01-02-022
18 - Head Light Relay (Left)
(A-R1)
19 - Emergency Steering Relay
(A-R10)
20 - Hone Relay (A-R9)
21 - Turn Signal Relay (Right)
(A-R8)
22 - Working Light Relay (Rear)
(A-R7)
23 - Working Light Relay
(Front) (A-R8)
24 - Front Wiper Relay (B-R5)
25 - Neutral Relay (B-R4)
T1-2-6
26 - Load Dump Relay (B-R3)
27 - Parking Brake Relay
(B-R2)
28 - Parking Brake Relay
(B-R1)
29 - Fuel Pump Relay (B-R10)
30 - Main Relay (B-R9)
31 - Rear Washer Relay (B-R8)
32 - Turn Signal Relay (Left)
(B-R7)
33 - Rear Wiper Relay (B-R6)
GENERAL / Component Layout
Right Console
T4GB-01-02-006
2
3
4
6
5
7
1
8
9
10
18
17
16
15
14
13
12
T4GB-01-02-023
11
1 - Down Shift Switch
2 - Bucket Control Lever
3 - Lift Arm Control Lever
4 - Forward/Reverse Switch
5 - Hone Switch
6 - Auxiliary Control Lever
(Optional)
7 - Quick Coupler Switch (Optional)
8 - Lift Arm Auto Leveler Downward
Set Switch (Optional)
9 - Lift Arm Auto Leveler Upward
Set Switch (Optional)
10 - Front Control Lock Lever
11 - Emergency Steering Check
Switch
12 - Fan Reversing Switch
13 - Fog Light Switch (Optional)
15 - Forward/Reverse Selector
Switch
16 - Cigar Lighter
17 - Up-shift/Down-shift Switch
14 - Ride Control Switch
(Optional)
18 - Hold Switch
T1-2-7
GENERAL / Component Layout
Monitor and Switchs
1
2
T4GB-01-02-006
14
3
13
12
4
5
11
6
7
10
9
8
1 - Monitor Panel
(Refer to T1-2-9)
2 - Driving Mode Switch
3 - Turn Signal Lever /Head Light
Switch/Dimmer Switch
4 - Parking Brake Switch
T4GB-01-02-024
5 - Work Mode Selector Switch
9 - Front Wiper Switch
12 - Rear Wiper Switch
6 - Clutch Cat Position Switch
10 - Forward/Reverse Lever
and Shift Switch
11 - Air Conditioner Switch
Panel
13 - Working Light Switch
7 - Key Switch
8 - Steering Column Tilt
/Telescopic Lever
T1-2-8
14 - Hazard Light Switch
GENERAL / Component Layout
Monitor Panel
1
2
3
4
5
6
7
8
9
10
11
34
12
33
13
14
32
15
31
T4GB-01-02-001
30
29
28
1 - Coolant Temperature
Gauge
2 - Transmission Oil
Temperature Gauge
3 - Turn Signal Indicator
(Left)
4 - High Beam Indicator
5 - Working Light Indicator
6 - Turn Signal Indicator
(Right)
7 - Monitor Display
8 - Stop Indicator
9 - Service Indicator
27
26
25
24 23
22
10 - Parking Brake Indicator
21
20
19
18
11 - Clearance Light Indicator
19 - Lever Steering Indicator
(Optional)
20 - Monitor Mode Selector
12 - Fuel Gauge
21 - Glow Signal
13 - Brake Low Oil Pressure
Indicator
14 - Brake Low Oil Level
Indicator
15 - Emergency Steering
Indicator (Optional)
16 - Low Steering Oil Pressure
Indicator
17 - Seat Belt Indicator
22 - Monitor Display Selector (Up)
23 - Maintenance Indicator
24 - Monitor Display selector
(Down)
25 - Forward/Reverse Switch
Indicator
26 - Water Separator Indicator
18 - Discharge Warning
Indicator
T1-2-9
17
16
27 - Engine Warning Indicator
28 - Overheat Indicator
29 - Engine Low Oil Pressure
Indicator
30 - Air Filter Restriction Indicator
31 - Transmission Warning
Indicator
32 - Transmission Oil Filter
Restriction Indicator
33 - Hydraulic Oil Temperature
Indicator
34 - Transmission Oil
Temperature Indicator
GENERAL / Component Layout
ENGINE AND FAN PUMP
1
2
3
6
7
8
9
5
10
11
4
14
13
12
T4GB-01-02-025
1 - Glow Plug
9 - EGR Valve
12 - Crank Revolution Sensor
2 - Injector
5 - Coolant Temperature
Sensor
6 - Overheat Switch
10 - Supply Pump
3 - Cam Angle Sensor
7 - Boost Pressure Sensor
11 - Fuel Temperature Sensor
13 - Engine Oil Pressure
Sensor
14 - Common Rail Pressure
Sensor
4 - Fan Pump
8 - Boost Temperature Sensor
T1-2-10
GENERAL / Component Layout
PUMP DEVICE
1
2
3
6
5
T4GB-01-02-009
4
DRIVE UNIT
7
21
8
9
13
14
15
16
17
18
20
12
19
11
10
T4GC-01-02-001
1 - Main Pump
7-
2 - Regulator
Torque Converter Input
Speed Sensor
8 - Air Breather
3 - Priority Valve
9-
4 - Pump Delivery Pressure
Switch
5 - Pilot Pump
10 - Vehicle Speed
Sensor
11 - Transmission Output
Speed Sensor
Charge Pump
12 - Transmission Middle Shaft
Sensor
13 - Forward Clutch Solenoid
Valve
14 - Reverse Clutch Solenoid
Valve
15 - 1st Clutch Solenoid Valve
16 - 2nd Clutch Solenoid Valve
6 - Steering Relief Valve
T1-2-11
17 - 3rd Clutch Solenoid Valve
18 - 4th Clutch Solenoid Valve
19 - Transmission Control Valve
20 - Parking Brake Pressure
Switch
21 - Regulator Valve
GENERAL / Component Layout
CONTROL VALVE
ZW220
5
4
1
2
3
T4GB-01-02-027
ZW250
5
1
4
3
2
T4GB-03-02-002
1 - Over Load Relief Valve
(Lift Arm: Bottom)
2 - Over Load Relief Valve
(Bucket: Bottom)
3 - Over Load Relief Valve
(Bucket: Rod)
4 - Make-up Valve
(Lift Arm: Rod)
T1-2-12
5 - Main Relief Valve
GENERAL / Component Layout
RIDE CONTROL VALVE (OPTIONAL)
1
2
CHARGING BLOCK
3
4
5
6
10
T4GB-01-02-014
9
8
7
T4GB-01-02-013
FAN MOTOR
10
11
12
T4GB-01-02-012
1 - Overload Relief Valve
2 - Ride Control Solenoid
Valve
3 - Ride Control Accumulator
5 - Service Brake Accumulator
(Front)
6 - Service Brake Accumulator
(Rear)
7 - Relief Valve
89-
Pilot Relief Valve
Pump Torque Control
Solenoid Valve
10 - Parking Brake Solenoid
Valve
4 - Pilot Accumulator
T1-2-13
11 - Reverse Control Solenoid
Valve
12 - Relief Valve
13 - Flow Control Solenoid
Valve
GENERAL / Component Layout
STEERING VALVE
1
2
T4GB-01-02-020
EMERGENCY STEERING PUMP
(OPTIONAL)
3
4
5
6
T4GB-01-02-010
1 - Overload Relief Valve
2 - Overload Relief Valve
3 - Electric Motor
4 - Gear Pump
5 - Check Valve
T1-2-14
6-
Relief Valve
GENERAL / Component Specifications
ENGINE
ZW220
Manufacturer ............................................ ISUZU
Model........................................................ AH-6HK1XYWT
Type.......................................................... Diesel, 4 Cycle, Water Cooled, Over Head Valve, Inline,
Direct Injection, Turbo Charged
Cyl. NO. - Bore×Stroke............................. 6-115 mm×125 mm (4.53 in×4.92 in)
Piston Displacement................................. 7790 cm3 (475 in3)
Rated Output ............................................ 139.3±3 kW/2170 min-1 (189±4 PS/2170 rpm)
Max. Output.............................................. 164.3±3 kW/2000 min-1 (223.4±4 PS/2000 rpm)
Compression Ratio................................... 17.5
Dry Weight................................................ 630 kg (1389 lb)
Firing Order .............................................. 1-5-3-6-2-4
Rotation Direction..................................... Clock Wise (Viewed from fan side)
ZW250
Manufacturer ............................................ ISUZU
Model........................................................ AH-6HK1XYWT
Type.......................................................... Diesel, 4 Cycle, Water Cooled, Over Head Valve, Inline,
Direct Injection, Turbo Charged
Cyl. NO. - Bore×Stroke............................. 6-115 mm×125 mm (4.53in×4.92 in)
Piston Displacement................................. 7790 cm3 (475 in3)
Rated Output ............................................ 163.0±3 kW/2240 min-1 (222±4 PS/2240 rpm)
Max. Output.............................................. 179.1±3 kW/2000 min-1 (243.5±4 PS/2000 rpm)
Compression Ratio................................... 17.5
Dry Weight................................................ 630 kg (1389 lb)
Firing Order .............................................. 1-5-3-6-2-4
Rotation Direction..................................... Clock Wise (Viewed from fan side)
COOLING SYSTEM
Cooling Fan .............................................. Diameter 850 mm (33.47 in),
6 Blades (N6G-Type Blade, Steel Center), Draw-in Type
Thermostat ............................................... Cracking Temperature at Atmospheric Pressure:
82 °C (180 °F)
Full Open (Stroke: 10 mm (0.39 in) or more) Temperature:
95 °C (203 °F)
Fan Pump................................................. Gear Pump
T1-3-1
GENERAL / Component Specifications
LUBRICATION SYSTEM
Lubrication Pump Type............................. Gear Pump
Oil Filter .................................................... Full-Flow Paper Element Type with Bypass
Oil Cooler ................................................. Water Cooled Integral Type
STARTING SYSTEM
Motor ........................................................ Magnetic Pinion Shift Reduction Type
Voltage/Output.......................................... 24 V⋅5 kW
PREHEAT SYSTEM
Preheating Method ................................... Glow Plug (QOS II Type with After Glow)
ENGINE STOP SYSTEM
Stop Method ............................................. Fuel Shut Off (Electrically Controlled)
ALTERNATOR
Type.......................................................... Regulator Integrated AC Type
Voltage/Output.......................................... 24 V⋅50 A (Brush less)
SUPERCHARGING SYSTEM
Model........................................................ RHG6
Type.......................................................... Exhaust Turbocharger Type
FUEL SYSTEM
Type.......................................................... Common Rail Type (HP4 Model)
Governor .................................................. Electrically Controlled
Injection Nozzle ........................................ Electric Multi Hole Injector (G2 Type)
T1-3-2
GENERAL / Component Specifications
PERFORMANCE
IMPORTANT: This list shows design specifications, which are not servicing standards.
ZW220
Fuel Consumption Ratio........................... 212.0±13.6 g/kW⋅h (156±10 g/PS⋅h) @ 2000 min-1 (rpm)
Maximum Output Torque .......................... 981±60 N⋅m (100±6 kgf⋅m) @ at approx. 1400 min-1 (rpm)
Compression Pressure............................. 3.04 Mpa (31 kgf/cm2) @ 200 min-1 (rpm)
Valve Clearance (Inlet/Exhaust)............... 0.4/0.4 mm (when cool)
No Load Speed......................................... Slow: (at Full Load: 850±20 min-1 (rpm))
Fast: (at Full Load: 2260±20 min-1 (rpm))
ZW250
Fuel Consumption Ratio........................... 212.0±13.6 g/kW⋅h (156±10 g/PS⋅h) @ 2000 min-1(rpm)
Maximum Output Torque .......................... 1022±60 N⋅m (104±6 kgf⋅m) @ at approx 1400 min-1 (rpm)
Compression Pressure............................. 3.04 MPa (31 kgf/cm2) @ 200 min-1 (rpm)
Valve Clearance (Inlet/Exhaust)............... 0.4/0.4 mm (0.016/0.016 in) (when cool)
No load Speed.......................................... Slow: (at Full Load: 850±20 min-1 (rpm))
Fast: (at Full Load: 2330±20 min-1 (rpm))
T1-3-3
GENERAL / Component Specifications
ZW220
Engine Performance Curve (AH-6HK1XYWT)
Test Condition:
1. In conformity with JIS D1005 (Performance Test Method for Diesel Engine Used for Construction Machinery)
under standard atmospheric pressure.
2. Equipped with the fan and alternator.
Torque
(N⋅m)
Output
(kW)
Fuel
Consumption
Ratio
(g/kW⋅h)
Engine Speed min-1 (rpm)
T1-3-4
T4GC-01-03-001
GENERAL / Component Specifications
ZW250
Engine Performance Curve (AH-6HK1XYWT)
Test Condition:
1. In conformity with JIS D1005 (Performance Test Method for Diesel Engine Used for Construction Machinery)
under standard atmospheric pressure.
2. Equipped with the fan and alternator.
Torque
(N⋅m)
Output
(kW)
Fuel
Consumption
Ratio
(g/kW⋅h)
Engine Speed min-1 (rpm)
T1-3-5
T4GC-01-03-002
GENERAL / Component Specifications
ENGINE ACCESSORIES
RADIATOR ASSEMBLY
Type.......................................................... Radiator and Oil Cooler Tandem Type Assembly
Inter Cooler and Torque Converter Cooler Tandem Type Assembly
Weight ...................................................... 67 kg (148 Ib) (ZW220)
74.5 kg (164 Ib) (ZW250)
ZW220
Radiator
Capacity.................................................... 15 L (4 US gal)
Air-Tight Test Pressure ............................. 100 kPa (1.0 kgf/cm2, 14.5 psi)
Cap Opening Pressure............................. 49 kPa (0.5 kgf/cm2, 7 psi)
Oil Cooler
5.1 L (3.3 US gal)
1500 kPa (15 kgf/cm2, 217 psi))
−
Intercooler
Capacity.................................................... 11.5 L (3 US gal)
Air-Tight Test Pressure ............................. 245 kPa (2.5 kgf/cm2, 36 psi)
Cap Opening Pressure.............................
−
Torque Converter Cooler
10.2 L (2.7 US gal)
1500 kPa (15 kgf/cm2, 217 psi)
−
ZW250
Radiator
Capacity.................................................... 18 L (4.8 US gal)
Air-Tight Test Pressure ............................. 100 kPa (1.0 kgf/cm2,14.5 psi)
Cap Opening Pressure............................. 49 kPa (0.5 kgf/cm2, 7 psi)
Oil Cooler
5.1 L (1.3 US gal)
1500 kPa (15 kgf/cm2,217 psi))
−
Intercooler
Capacity.................................................... 12.5 L (3.3 US gal)
Air-Tight Test Pressure ............................. 245 kPa (2.5 kgf/cm2, 36 psi)
Cap Opening Pressure.............................
−
Torque Converter Cooler
10.7 L (2.8 US gal)
1500 kPa (15 kgf/cm2, 217 psi)
−
BATTERY
Voltage...................................................... 12 V
Capacity.................................................... 108 Ah
T1-3-6
GENERAL / Component Specifications
HYDRAULIC FAN PUMP
Model........................................................ SGP1A27D2H1
Type.......................................................... Fixed Displacement Type Gear Pump
Maximum Flow (Theoretical Value).......... 60 L/min (15.85 US gpm)
HYDRAULIC FAN MOTOR
Relief Set Pressure .................................. 20.6 MPa (210 kgf/cm2) @ 5 L/min (1.32 US gpm)
SOLENOID VALVE
Function.................................................... Fan Motor Reverse Control
Fan Motor Speed Control
T1-3-7
GENERAL / Component Specifications
HYDRAULIC COMPONENT
MAIN PUMP
Type.......................................................... Bent Axis Type Variable Displacement Axial Plunger Pump
Maximum Flow (Theoretical Value).......... 270 L/min (71 US gum) (ZW220)
290 L/min (77 US gum) (ZW250)
REGULATOR
Type.......................................................... Hydraulic Pressure Operated Type
PRIORITY VALVE
Relief Set Pressure .................................. 27.4 MPa (280 kgf/cm2) @ 70 L/min (18.5 US gpm) (ZW220)
29.4 MPa (300 kgf/cm2) @ 90 L/min (23.8 US gpm) (ZW250)
PILOT PUMP
Model........................................................ HY/ZFS11/16.8
Type.......................................................... Fixed Displacement Type Gear Pump
Maximum Flow (Theoretical Value).......... 35 L/min (9.3 US gpm)
CONTROL VALVE
ZW220
Type.......................................................... Pilot Pressure Operated Type (2 Spools)
Main Relief Set Pressure.......................... 27.4 MPa (280 kgf/cm2) @ 200 L/min (52.8 US gpm)
Overload Relief Set Pressure................... 34.3 MPa (350 kgf/cm2) @ 35 L/min (9.3 US gpm)
(Lift Arm)
30.4 MPa (310 kgf/cm2) @ 35 L/min (9.3 US gpm)
(Bucket Tilt)
30.4 MPa (310 kgf/cm2) @ 50 L/min (13 US gpm)
(Bucket Dump)
ZW250
Type.......................................................... Pilot Pressure Operated Type (2 Spools)
Main Relief Set Pressure.......................... 29.4 MPa (300 kgf/cm2) @ 220 L/min (58 US gpm)
Overload Relief Set Pressure................... 36.8 MPa (375 kgf/cm2) @ 50 L/min (13 US gpm)
(Lift Arm)
32.5 MPa (330 kgf/cm2) @ 50 L/min (13 US gpm)
(Bucket Tilt, Bucket Dump)
T1-3-8
GENERAL / Component Specifications
RIDE CONTROL VALVE (OPTIONAL)
Type.......................................................... Pilot Pressure Operated Type
Overload Relief Set Pressure................... 39.2 MPa (400 kgf/cm2) @ 50 L/min (13 US gpm)
Charge Cut Pressure................................ 11.3 MPa (115 kgf/cm2)
RIDE CONTROL ACCUMULATOR (OPTIONAL)
Capacity.................................................... 4 L (244 in3)
Charging Pressure ................................... 2.9 MPa (30 kgf/cm2)
CHARGING BLOCK
Charging Pressure ................................... Cut In Pressure: 11.8 MPa (120 kgf/cm2)
Cut Out Pressure: 14.7 MPa (150 kgf/cm2)
Pilot Relief Valve Set Pressure................. 3.7 MPa (38 kgf/cm2) @ 40 L/min (10.6 US gpm)
SOLENOID VALVE (For Charging Block)
Function.................................................... • Main Pump Torque Control
• Parking Brake
SERVICE BRAKE ACCUMULATOR
Capacity.................................................... 1.4 L (85.4 in3)
Charging Pressure ................................... 4.4 MPa (45 kgf/cm2)
PILOT ACCUMULATOR
Capacity.................................................... 0.75 L (45.8 in3)
Charging Pressure ................................... 2.0 MPa (20 kgf/cm2)
PILOT SHUT OFF VALVE
Type.......................................................... Rotary Type
STEERING VALVE
Type.......................................................... Flow Amp Type
Over Load Relief Set Pressure ................ 32.3 MPa (330 kgf/cm2) @50 L/min (13 US gpm) (ZW220)
34.3 MPa (350 kgf/cm2) @50 L/min (13 US gpm) (ZW250)
T1-3-9
GENERAL / Component Specifications
STEERING PILOT VALVE
Type.......................................................... Orbitroll Type
Gerotor Capacity ...................................... 96 cm3/rev (5.9 in3/rev)
STEERING ACCUMULATORv
Capacity.................................................... 0.2 L (12 in3)
Charging Pressure ................................... 8 MPa (82 kgf/cm2)
BRAKE VALVE
Brake Pressure......................................... 3.9 MPa (40 kgf/cm2)
T1-3-10
GENERAL / Component Specifications
• Travel System
TRANSMISSION
Type.......................................................... Counter Shaft Type
Gear Ratio ................................................ Forward 1st : 3.225
Forward 2nd : 1.901
Forward 3rd : 1.026
Forward 4th : 0.605
Reverse 1st : 3.225
Reverse 2nd : 1.901
Reverse 3rd : 1.026
Reverse 4th : 0.605
Parking Brake Release Pressure ............. 2.7 MPa (28 kgf/cm2)
STANDARD AXLE (FRONT/REAR)
ZW220
Model........................................................ Two Stage Transmission
Brake Type ............................................... Wet Multiplate Disk Brake
Brake Pressure......................................... 3.92 MPa (40 kgf/cm2)
Final Reduction Gear Ratio...................... 25.766
ZW250
Model........................................................ Two Stage Transmission
Brake Type ............................................... Wet Multiplate Disk Brake
Brake Pressure......................................... 3.92 MPa (40 kgf/cm2)
Final Reduction Gear Ratio...................... 26.760
STANDARD PROPELLER SHAFT
Type.......................................................... Cruciform Joint Type
Dimension between Pins.......................... Front : 1500 mm (59.06”)
Rear : 367.18 mm (14.46”)
T1-3-11
GENERAL / Component Specifications
• Front Attachment
CYLINDER
ZW220
Lift Arm (Left/Right)
Rod Diameter ........................................... 85 mm (3.35”)
Cylinder Bore............................................ 130 mm (5.12”)
Stroke ....................................................... 880 mm (34.65”)
Fully Retracted Length ............................. 1420 mm (55.91”)
Plating Thickness ..................................... 30 µm (1.2 µin)
Bucket
95 mm (3.74”)
165 mm (6.5”)
510 mm (20.08”)
1060 mm (41.73”)
30 µm (1.2 µin)
Steering
45 mm (1.77”)
70 mm (2.76”)
442 mm (17.40”)
804 mm (31.65”)
30 µm (1.2 µin)
ZW250
Lift Arm (Left/Right)
Rod Diameter ........................................... 85 mm (3.35”)
Cylinder Bore............................................ 130 mm (5.12”)
Stroke ....................................................... 940 mm (37.01”)
Fully Retracted Length ............................. 1481 mm (58.31”)
Plating Thickness ..................................... 30 µm (1.2 µin)
Bucket
100 mm (3.94”)
165 mm (6.5”)
530 mm (20.87”)
1090 mm (42.91”)
30 µm (1.2 µin)
Steering
45 mm (1.77”)
70 mm (2.76”)
542 mm (21.34”)
900 mm (35.43”)
30 µm (1.2 µin)
T1-3-12
GENERAL / Component Specifications
ELECTRIC COMPONENT
ENGINE OIL PRESSURE SENSOR
Operation Pressure .................................. 29.4 kPa (0.3 kgf/cm2)
OVER HEAT SWITCH
Operation Temperature ............................ 105±2 ° C (221±2 °F)
COOLANT TEMPERATURE SENSOR
(For Coolant Temperature Gauge)
Operation Temperature ............................ 25 to 120 °C (77 to 248 °F)
AIR FILTER RESTRICTION SWITCH
Operation Pressure .................................. 6.3±0.6 kPa (635±58 mmH2O)
FUEL LEVEL SENSOR
Resistance Value...................................... Empty: 90+100Ω, Full: 100-4Ω
ENGINE OIL TEMPERATURE SENSOR
Operation Temperature ............................ -30 to 120 °C (-22 to 248 °F)
BATTERY RELAY
Voltage/Current ........................................ 24 V⋅100 A
GLOW RELAY
Voltage...................................................... 24 V
SAFETY RELAY
Voltage...................................................... 24 V
HORN
Voltage/Current ........................................ 24 V⋅3.0±0.5 A
Sound Pressure........................................ 113±5 dB (A) @ 2 m (6’ 7”)
T1-3-13
GENERAL / Component Specifications
ILLUMINATION
Work Light ................................................ : Halogen 24 V, 55/70 W
Cab Light .................................................. : 24 V, 10 W
Head Light ................................................ : Halogen 24 V、75/70 W
Turn Signal Light ...................................... : Front : 24 V, 25 W
:Rear : 24 V, 21 W
Clearance Light ........................................ : 24 V, 5 W
License Light ............................................ : 24 V, 12 W
Reverse Light ........................................... : 24 V, 21 W
Tail Light ................................................... : 24 V, 5 W
Brake Light ............................................... : 24 V, 21 W
AIR CONDITIONER
Refrigerant................................................ 134a
Cooling Ability........................................... 4.65 kW (16.74 MJ, 3999 kcal) or more
Cool Air Volume........................................ 550 m3/h or more
Heating Ability........................................... 5.81 kW (20.92 MJ, 4997 kcal) or more
Warm Air Volume...................................... 400 m3/h or more
Temperature Adjusting System ................ Electronic Type
Refrigerant Quantity ................................. 1050±50 g
Compressor Oil Quantity .......................... 160 cm3
EMERGENCY STEERING PUMP UNIT
Type.......................................................... Electric Motor Operated Type
Maximum Flow ......................................... 17 L/min (4.49 gpm) @10.3 MPa (105 kgf/cm2)
ELECTRIC MOTOR
Voltage...................................................... 24 V, 2.4 kW
T1-3-14
MEMO
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SECTION 2
SYSTEM
—CONTENTS—
Group 1 Control System
Group 4 Electrical System
Outline ...................................................... T2-1-1
Outline ...................................................... T2-4-1
Engine Control.......................................... T2-1-6
Main Circuit............................................... T2-4-2
Pump Control ......................................... T2-1-15
Electric Power Circuit................................ T2-4-3
Transmission Control.............................. T2-1-20
Indicator Light Check Circuit ..................... T2-4-4
Other Controls ........................................ T2-1-41
Accessory Circuit ...................................... T2-4-5
Control by Electric and Hydraulic
Preheat Circuit .......................................... T2-4-6
Combined Circuit .................................. T2-1-51
Starting Circuit .......................................... T2-4-8
Charging Circuit ...................................... T2-4-12
Group 2 ECM System
Serge Voltage Prevention Circuit ............ T2-4-16
Outline ...................................................... T2-2-1
Engine Stop Circuit ................................. T2-4-18
Fuel Injection Control ............................... T2-2-2
Lamplight Circait ..................................... T2-4-19
Compensation of Fuel Injection
Head Light Circuit ................................... T2-4-20
Volume ................................................. T2-2-10
Turn Signal Circuit .................................. T2-4-24
Engine Start Control ................................T2-2-11
Brake Light Circuit .................................. T2-4-25
EGR Control ........................................... T2-2-12
Hazard Light Circuit ................................ T2-4-26
Horn Circuit............................................. T2-4-27
Group 3 Hydraulic System
Outline ...................................................... T2-3-1
Reverse Light/Buzzer Circuit .................. T2-4-28
Main Circuit .............................................. T2-3-2
Parking Brake Circuit .............................. T2-4-30
Pilot Circuit ............................................. T2-3-17
Emergency Steering Check
Steering Circuit ....................................... T2-3-32
Circuit (Optional) ................................... T2-4-32
Hydraulic Drive Fan Circuit ..................... T2-3-38
4GCT-2-1
(Blank)
4GCT-2-2
SYSTEM / Control System
GENERAL
There are four controllers as shown below with MC –
Main Controller – installed at their center.
•
•
•
•
MC: Main Controller
ICF: Information Controller
ECM: Engine Control Module
Monitor Unit
Controllers are mutually connected through CAN, and
each controller uploads analog signals detected by
sensors and switches as well as analog output signals
of solenoid valves on the CAN by converting them into
digital ones.
As the signals are processed into the digital ones, a
large amount of signals detected at each controller can
be transmitted through few wires in a shirt time.
MC, ECM, and monitor unit display indications on
monitors and make various controls of the vehicle
body by using analog signals received by each
controller as well as digital signals detected on the
CAN.
ICF stores machine history, receives digital signals for
various adjustments from Dr-ZX, transmits them to the
CAN, and transmits the vehicle body signal (digital
signal) received by each controller to Dr-ZX.
A GPS-provision (optional) vehicle makes location
arithmetic operation, utilising signals received by
artificial sattelites, and transmits body information to
the e-service host computer through artificial satellites.
(Refer to the TROUBLESHOOTING/ICF)
Receipt and Transmission by
Analog Signal
Monitor
Unit
GPS
S
Dr-ZX
ICF
Receipt and
Transmission by
Digital Signal
ECM
MC
CAN
S
S
T2-1-1
Sensors, Switches and
Solenoid Valves
SYSTEM / Control System
MC, ECM, and Monitor Unit are used for various
operation controls of the body.
• Analog input signals from sensors and switches
attached to devices other than the engine and
monitor unit as well as analog output signals from
solenoid valves are transmitted into the MC, and
converted into digital signals to be uploaded on the
CAN.
• Analog input signals from sensors attached to the
engine are transmitted to the ECM, and converted
into digital signals to be uploaded on the CAN.
• Analog input signals from cabin, and analog input
signals from sensors and switches necessary for
indication of the monitor are transmitted into the
monitor unit, and converted into digital signals to be
uploaded on the CAN.
Each controller detects lacking information necessary
for the control program from among the CAN data.
(digital signals)
Each controller makes various control program
arithmetic operations using the detected data (digital
signals), outputs actuation signals to the solenoid
valves unit and torque control solenoid valve, and
controls the pump, engine, transmission, and valves.
Analog signals from various sensors, switches, and
solenoid valves are periodically transmitted into each
controller, and converted into digital signals to be
uploaded on the CAN.
By repeating the above operations, the vehicle body
movement is watched and controlled.
T2-1-2
SYSTEM / Control System
Injectors
Sensors and Switches
for Vehicle Body
MC
ECM
Engine
Solenoid Valves
for Vehicle Body
Transmission
Sensors and
Switches
Sensor Switches
for Cab and Monitor
Solenoid Valves
Monitor
Unit
Relays for
Cab
Sensors and
Switches
Switches for
Traveling
Light-emitting
Dildes
Dr-ZX
ICF
GPS
T4GC-02-01-001
T2-1-3
SYSTEM / Control System
Sensors and switches to detect signals for various
operation controls and their controllers are as shown
below.
Input Signals
• Accelerator Pedal Sensor
• Driving Mode Switch
•
•
•
•
•
•
•
•
•
•
•
Work Mode Selector Switch
Fan Reversing Switch
Ride Control Switch
Parking Brake Pressure Sensor
Pump Delivery Pressure Switch
Imprement Pressure Sensor
Hydraulic Oil Temperature sensor
Clutch Cut Position Sensor
Lift Arm Kick-out Switch
Lift Arm Angle Sensor (OP)
Lift Arm Auto-leveler Upwards
Set Switch (OP)
• Lift Arm Auto-leveler Downwards
Set Switch (OP)
•
Output Signals
Engine Control
→
→
→Accelerator Pedal Control
→
→
→
→
→
→
→
→
→
→
MC
→Automatic Warming Up Control
→Engine Torque Control
Pump Control
→Standard Torque Control
→Torque Reduction Control
Other Controls
→Hydraulic Fan Cooling Control
→Hydraulic Fan Cleaning Control
→Transmission Alarm Control
→Forward/Reverse Indicator Control
→Reverse Traveling Alarm Control
→Parking Brake Alarm Control
→
→
CAN
(See next chart)
NOTE: OP : Stands for optional.
* : Controls for optional parts provision
machines only
T2-1-4
Control by Electric and Hydraulic
Combined Circuit
→*Ride Control
Bucket Auto-leveler Control
Lift Arm Float Control
→Lift Arm Kick-out Control
→*Lift Arm Auto-leveler Upward Control
→*Lift Arm Auto-leveler Downward Control
SYSTEM / Control System
Input Signal
(See previous chart)
• Forward/Reverse Lever
• Shift Switch
→
→
•
•
•
•
•
Down Shift Switch
Up Shift Switch
Hold Switch
Forward/Reverse Selector Switch
Forward/Reverse Switch
→
→
→
→
→
•
•
•
•
•
Brake Pressure Sensor
→
Torque Converter Input Speed Sensor →
Torque Converter Output Speed Sensor →
Transmission Middle Shaft Sensor
→
Vehicle Speed Sensor
→
(Refer to the SYSTEM/ECM System)
Output Signal
Transmission control
→Neutral Control
→Forward/Reverse Lever Priority Control
→Forward/Reverse Selector Control While
Traveling
CAN
MC
→Manual Speed Shift Control
→Automatic Speed Shift Control
→Down Shift Control
→Up Shift Control
→Clutch Cut Control
→Shift Holding Control
→
ECM
• Engine Coolant Temperature Sensor
→
• Torque Converter Oil Temeperature
Sensor
→
Monitor
Unit
NOTE: ECM controls the engine speed and others
based on the target engine speed
transmitted from the MC and the converted
signal of the torque curve, and on the
signals detected by the sensors installed at
the engine. For details, refer to the
SYSTEM/ECM System.
T2-1-5
→(Refer to the SYSTEM/ECM System)
SYSTEM / Control System
ENGINE CONTROL
Following engine controls are made.
• Accelerator pedal Control
• Automatic warming up control
• Engine torque control
T2-1-6
SYSTEM / Control System
Engine Control System Layout
Work Mode
Selector Switch
L
Accelerator Pedal
Hydraulic Oil
Temperature
Sensor
Accelerator Pedal Sensor
N
P
Main Pump
Delivery
Pressure Switch
Shift Switch
MC
ECM
Transmission
Engine
Torque Converter Output
Speed Sensor
Torque Converter Input
Speed Sensor
Monitor
Unit
Engine Coolant
Temperature Sensor
T2-1-7
T4GC-02-01-002
SYSTEM / Control System
Accelerator Pedal Control
Purpose: Control of the engine speed in response to
stepping amount of accelerator
Engine Actual
Speed
Operation:
1. MC converts the input value into the target engine
speed, and transmits it to the ECM.
Maximum
Speed
2. ECM controls the engine speed in response to the
target engine speed.
NOTE: Output value of the accelerator pedal
sensor is 0.5 V – 4.5 V.
NOTE: In case the accelerator pedal sensor
becomes abnormal, the MC makes
back-up control, and the engine speed is
fixed at about 1000 min-1.
NOTE: In case the MC becomes out of order, or
the CAN fails, the ECM makes back-up
control, and the engine speed is fixed at
about 1000 min-1.
NOTE: In case the MC becomes out of order with
the accelerator remaining normal, control
of the engine speed is possible by
connecting the accelerator pedal sensor
wires directly to the ECM.
T2-1-8
Minimum
Speed
Minimum
Speed
Maximum
Speed
Target
Engine
Speed
SYSTEM / Control System
Accelerator Pedal
Accelerator Pedal Sensor
Transmission
ECM
MC
Engine
Monitor
Unit
T4GC-02-01-003
T2-1-9
SYSTEM / Control System
Automatic Warming Up Control
Purpose: Automatic warming up of the engine in
response to the hydraulic oil temperature
Engine
Actual
Speed
Operation:
1. At start of the engine, if the hydraulic oil
temperature is 0°C (32°F) or below, the MC
transmits signal to the ECM for setting the engine
minimum speed at 1000 min-1.
Maximum
Speed
Automatic
Warming Up
Speed
2. ECM increases the minimum engine speed to
1000 min-1.
3. When the engine coolant temperature or
hydraulic oil temperature is 40°C (104°F) or
above, or when 10 minutes have passed, the MC
stops signals, and the ECM decreases the engine
minimum speed to the idling value.
NOTE: At start of the engine, if the hydraulic oil
temperature is 1°C (34°F) or above,
automatic warming up control is not made.
NOTE: In case the hydraulic oil temperature
sensor becomes abnormal, automatic
warming up control is not made.
NOTE: When the parking brake switch is turned
OFF, automatic warming up control is
released.
NOTE: In case automatic warming up control is
released by Dr. ZX, retrieve the automatic
warming up control effective by Dr. ZX the
moment releasing becomes unnecessary.
(Retrieving is impossible by just turning the
key switch OFF.)
T2-1-10
Speed
Increase
Minimum
Speed
Minimum
Speed
Maximum
Speed
Target Engine
Speed
SYSTEM / Control System
Hydraulic Oil
Temperature Sensor
Transmission
MC
ECM
Engine
Monitor
Unit
Engine
Coolant
Temperature
Sensor
T4GC-02-01-004
T2-1-11
SYSTEM / Control System
Engine Torque Control
Purpose: Improving fuel consumption rate by
changing the torque curve in response to
input signals from the work mode selector
switch, shift switch, and vehicle speed
sensor
Engine
Torque
1
2
Operation:
3
1. When the signal of the selected work mode is
transmitted to the MC, it detects signals from the
main pump delivery pressure switch, shift switch,
torque converter input speed sensor, and torque
converter output speed sensor.
2. MC has programmed torque curves to be
selected in response to the combination of work
mode, speed shift, torque converter speed ratio,
and pump delivery pressure, and outputs to the
ECM the selection command signal most suitable
to each time.
• When the light mode (L) is selected, Torque
Curve 4 or 3 is primarily used, which is
advantageous in making much of low fuel
consumption at light-load work.
• When normal mode (N) is selected, Torque Curve
3 or 2 is primarily used, which is advantageous in
making much of production as well as low fuel
consumption.
• When the power mode (P) is selected, Torque
Curve 1 or 2 is primarily used, which is
advantageous in making much of production
mainly as well as low fuel consumption slightly.
3. ECM controls torque curves in response to the
inputted torque curve selection command signal.
4
Engine
Speed
Conceptual Diagram of
Engine Torque Curve
NOTE: In case the signal from the work mode
selector switch is not transmitted to the MC,
back-up control of fixing the work mode to
the normal mode is made.
NOTE: In case the signal from the torque converter
input speed sensor or the torque converter
output sensor is not transmitted to the MC,
engine torque control is made by setting
the vehicle speed at the back-up speed.
NOTE: In case the signal from the shift switch is
not transmitted to the MC, back-up control
of fixing to Torque Curve 2 is made.
NOTE: Each mode switch of the mode selector
switch is supplied with respectively different
voltages from the monitor unit, and when
the switch selects a mode, the MC judges
which mode has been selected by the input
voltage.
NOTE: Shift switch has two switches, and the
combination of their ON varies depending
on each speed shift. Controller judges
which speed shift has been selected by the
combination of the two input signals.
T2-1-12
SYSTEM / Control System
Work Mode
Selector Switch
L&C
N
P
Main Pump
Delivery
Pressure Switch
Shift Switch
MC
ECM
Transmission
Engine
Torque Converter
Output Speed Sensor
Torque Converter
Input Speed Sensor
Monitor
Unit
T4GC-02-01-005
NOTE: Illustration shows flow of the signal in case
the light mode of the work mode selector
switch and Speed 1 of the speed shift
switch have been selected.
T2-1-13
SYSTEM / Control System
(Blank)
T2-1-14
SYSTEM / Control System
PUMP CONTROL
Following pump controls are made.
• Standard Torque Control
• Torque Reduction Control
Pump Control System Layout
Accelerator Pedal
Accelerator Pedal Sensor
Main Pump Delivery
Pressure Switch
MC
ECM
Engine
Transmission
Main Pump
regulator
Pump Torque Control
Solenoid Valve
Torque Converter
Output Speed Sensor
Monitor
Unit
Torque Converter
Input Speed Sensor
T4GC-02-01-006
T2-1-15
SYSTEM / Control System
Standard Torque Control
Purpose: Effectively utilizing engine horsepower by
changing pump flow in response to increase
or decrease of engine speed
Operation:
1. When accelerator pedal is stepped, MC makes
arithmetic operation of the target engine speed.
2. MC makes arithmetic operation of the pump
maximum tilting angle by receiving the target
engine speed signal, and transmits signal to the
pump torque control solenoid valve.
Q
Flow
P-Q Line
3. Pump torque control solenoid valve transmits pilot
pressure corresponding to the amplitude of signal
to the main pump regulator, and controls the
pump flow rate.
NOTE: In case the pump torque control solenoid
valve becomes abnormal, standard-torque
control is not made.
Pressure
T2-1-16
P
SYSTEM / Control System
Accelerator Pedal
Accelerator Pedal Sensor
MC
ECM
Engine
Transmission
Main Pump
Regulator
Pump Torque Control
Solenoid Valve
Monitor
Unit
T4GC-02-01-007
T2-1-17
SYSTEM / Control System
Torque Reduction Control
Purpose: Effectively utilizing engine horsepower by
changing pump flow in response to increase
or decrease of the engine speed due to
traveling load
Operation:
1. When accelerator pedal is stepped, MC makes
arithmetic operation of the target engine speed.
Q
Flow
2. MC makes arithmetic operation, using the target
engine speed and signals from the main pump
delivery pressure switch, torque converter input
speed sensor, and torque converter output speed
sensor, and figures out the pump maximum tilting
angle most suitable to each time to transmit it to
the pump torque control solenoid valve.
P-Q Line
3. Pump torque control solenoid valve transmits pilot
pressure corresponding to the amplitude of signal
to the main pump regulator, and controls the
pump flow rate.
4. If load applied to the engine becomes large and
decreases the actual engine speed than the
target speed, the pump tilting angle is decreased
to reduce delivery flow. Thus, maneuverability of
the vehicle body is improved.
5. MC makes arithmetic operation of the actual
engine speed, receiving signal from the torque
converter input speed sensor.
Pressure
P
NOTE: In case the accelerator pedal becomes
abnormal, the back-up control of the
accelerator controls and fixes the engine
speed at 1000 min-1.
NOTE: In case signal from either the main pump
delivery pressure switch, torque converter
input speed sensor, or torque converter
output speed sensor is not transmitted to
the MC, it does not make torque reduction
control, but makes pump control by the
standard-torque control.
NOTE: In case the pump torque control solenoid
valve
becomes
abnormal,
neither
standard-torque
control
nor
torque
reduction control is made.
T2-1-18
SYSTEM / Control System
Accelerator Pedal
Accelerator Pedal Switch
Main Pump Delivery
Pressure Switch
MC
ECM
Engine
Transmission
Main Pump
Regulator
Pump Torque Control
Solenoid Valve
Torque Converter
Output Speed Sensor
Monitor
Unit
Torque Converter
Input Speed Sensor
T4GC-02-01-008
T2-1-19
SYSTEM / Control System
TRANSMISSION CONTROL
Following transmission controls are made.
• Neutral Control
• Forward/Reverse Lever Priority Control
• Forward/Reverse Selector Control While
Traveling
• Manual Speed Shift Control
• Automatic Speed Shift Control
• Down Shift Control
• Up Shift Contrl
• Clutch Cut Control
• Shift Holding Control
T2-1-20
SYSTEM / Control System
Transmission Control System Layout
Key Switch
Driving Mode Switch
Brake Pressure
Sensor
Accelerator
Pedal Sensor
M
Brake Pedal
Accelerator Pedal
L
N
H
Clutch Cut
Position Switch
Forward
Clutch Solenoid
Valve
Transmission
Middle Shaft
Sensor
OFF
S
Reverse Clutch
Solenoid Valve
Transmission
N
D
MC
ECM
Engine
Shift Switch
1 2 3 4
Speed Shift
Solenoid Valve
Parking Brake
Parking Brake
Pressure Sensor
Monitor
Unit
Parking Brake
Solenoid Valve
Vehicle Speed
Sensor
Torque
Converter
Input
Speed
Sensor
Forward/Reverse
Lever
F
Torque
Converter
Output
Speed
Sensor
N
R
Forward/Reverse
Switch
F
N
OFF
DOWN
R
ON
UP
HOLD
Forward/Reverse
Selector Switch
Up-shift/Down-shift
Switch
Hold Switch
T2-1-21
ON
OFF
Parking Brake
Switch
T4GC-02-01-009
SYSTEM / Control System
Neutral Control
Purpose: Protection of transmission during working of
parking brake by restricting clutch connection despite operation of forward/reverse
lever or forward/reverse switch
Operation:
1. In case either of the signal from forward/reverse
lever, forward signal or reverse signal of the forward/reverse switch is transmitted to the MC, the
MC confirms the detected value of the parking
brake pressure sensor.
IMPORTANT: Be careful that in case the parking
brake pressure sensor is abnormal,
traveling is possible even if the
parking brake switch is ON and the
parking brake is at work because the
parking brake alarm lamp is turned
OFF and fixed (release).
2. When the parking brake pressure is higher than
the set pressure, the MC transmits signal to the
clutch solenoid valve, but does not when lower
than that.
NOTE: When the pilot pressure is transmitted, the
parking brake of the vehicle body is released.
NOTE: In case short-circuiting takes place inside
the forward/reverse lever, transmission is
made neutral forcedly.
NOTE: In case electric abnormality takes place
involving the forward/reverse switch, traveling by the forward/reverse lever is possible as an emergency measure.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
T2-1-22
SYSTEM / Control System
Forward Clutch
Solenoid Valve
MC
Reverse Clutch
Solenoid Valve
ECM
Engine
Transmission
Parking Brake
Pressure Sensor
Monitor
Unit
Parking Brake
Solenoid Valve
Parking Brake
Forward/Reverse
Lever
F
N
R
Forward/Reverse
Switch
F
N
OFF
ON
R
ON
OFF
Forward/Reverse
Selector Switch
Parking Brake
Switch
NOTE: Illustration shows flow of the signal in case.
Forward of the forward/reverse lever have
been selected with the parking brake switch
turned OFF – transmitting brake release
signal.
T2-1-23
T4GC-02-01-010
SYSTEM / Control System
Forward/Reverse Lever Priority Control
Purpose: Smoothening danger-preventive function in
forward/reverse operation by giving priority to
signal from forward/reverse lever over signal
from forward/reverse switch
Operation:
1. In case the forward/reverse lever is operated
while traveling using the forward/reverse switch,
the MC disables operation of the forward/reverse
switch, and makes forward/reverse control by input signal from the forward/reverse lever.
2. For restarting operation using the forward/reverse
switch, have the forward/reverse switch effective
again by turning the forward/reverse selector
switch ON while making both the forward/reverse
lever and the forward/reverse switch at the neutral
position.
3. From then on until the forward/reverse lever is
operated next, the MC makes forward/reverse
control by the forward/reverse switch input signal.
NOTE: In case short-circuiting takes place inside
the forward/reverse lever, transmission is
made neutral forcedly, and traveling becomes impossible, which requires towing.
However, in case the forward/reverse
switch is out of order, traveling by the forward/reverse lever is possible as an
emergency measure.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
T2-1-24
SYSTEM / Control System
Forward Clutch
Solenoid Valve
MC
Reverse Clutch
Solenoid Valve
ECM
Engine
Transmission
Monitor
Unit
Forward/Reverse
Lever
F
N
R
Forward/Reverse
Switch
F
N
OFF
R
ON
Forward/Reverse
Selector Switch
T4GC-02-01-011
NOTE: Illustration shows flow of the signal in case
forward of the forward/reverse selector
lever has been selected while traveling reverse of the forward/reverse lever.
T2-1-25
SYSTEM / Control System
Forward/Reverse Selector Control While Traveling
Purpose: Protection of transmission in traveling at set
speed and above by preventing forward/reverse selector unless the vehicle
speed is lowered than that
Operation:
1. In case the forward/reverse lever is changed to
reverse while traveling forward at speed higher
than the speed allowed for operation of the forward/reverse lever, the MC lowers the speed shift
by transmitting speed shift signal of Speed
4→3→2 to the transmission if the speed shift is
Speed 4.
2. If the vehicle speed is lowered to the set speed by
operation of the brake pedal or otherwise, the MC
transmits signal to the reverse clutch solenoid
valve to have the clutch shifted reverse.
3. As the speed increases when the accelerator
pedal is stepped, the MC transmits speed shift
signal of Speed 2 to Speed 3 to each speed shift
solenoid valve, and increases the speed shift.
NOTE: In case the forward/reverse lever is operated when the vehicle speed is below the
value allowed for changeover of the forward/reverse clutch, the forward/reverse
clutch is operated regardless of the speed
shift.
NOTE: Shift switch has two switches, and the combination of their ON varies depending on
each speed shift. Controller judges which
speed shift has been selected by the combination of the two input signals.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
T2-1-26
SYSTEM / Control System
Accelerator Pedal
Sensor
Brake
Sensor
Accelerator Pedal
Brake Pedal
Shift Switch
Forward Clutch
Solenoid Valve
MC
Reverse Clutch
Solenoid Valve
ECM
Engine
1 2 3 4
Speed Shift Solenoid Valve
Vehicle Speed
Sensor
Transmission
Monitor
Unit
Forward/Reverse
Lever
F
N
R
Forward/Reverse
Switch
F
N
OFF
R
ON
Forward/Reverse
Selector Switch
T4GC-02-01-012
NOTE: Illustration shows flow of the signal in case
reverse of the forward/reverse lever has
been selected and the brake pedal has
been stepped while traveling forward at
Speed 4 above the value allowable for selection of the forward/reverse clutch.
T2-1-27
SYSTEM / Control System
Manual Speed Shift Control
Purpose: Making speed shift manually
Operation:
1. When manual (M) of the Driving mode switch is
selected, the MC is provided with voltage of 1V.
2. Manual speed shift program is started in the MC.
3. Shift switch is the rorary type, and has two
switches inside. When the speed shift is selected
from among Speed 1 through Speed 4, signal of
the selected speed shift is transmitted to the MC
depending on the combination of ON inside the
speed shift switch.
Speed Shift
Speed
1
Internal Switch
1
ON
Internal Switch
2
Speed
2
Speed
3
Speed
4
ON
ON
ON
4. MC transmits signal to the solenoid valve of the
selected speed shift.
5. If forward or reverse of the forward/reverse lever
or the forward/reverse switch is selected, traveling
is started when the accelerator pedal is stepped.
6. When the vehicle speed reaches the set speed
change to the selected speed shift, the MC
transmits signal to the solenoid valve of the selected speed shift.
NOTE: MC is so programmed as to dtermine necessary vehicle speed ranges for changing
to the respective speed shifts.
NOTE: In case speed shift from Speed 3 to Speed
1 is attempted while traveling by operating
the speed shift switch, Speed 2 is automatically selected first, and Speed 1 is
reached after the vehicle speed is lowered
to the speed range for Speed 1.
NOTE: In case the solenoid valve of either of the
Speed 1, Speed 3, or Speed 4 becomes
abnormal, the travel speed will be fixed to
Speed 2. In case either of the forward
clutch solenoid valve, reverse clutch solenoid valve, or Speed 2 solenoid valve becomes abnormal, only the abnormal one
cannot be used.
NOTE: In case speed shift is raised, the selected
speed shift is immediately obtained regardless of the vehicle speed.
NOTE: Shift switch has two switches, and the
combination of their ON varies depending
on each speed shift. Controller judges
which speed shift has been selected by the
combination of the two input signals.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
NOTE: Each mode switch of the driving mode
switch is supplied with respectively different
voltages from the monitor unit, and if a
switch is selected, the MC judges which
mode has been selected.
NOTE: Speed shift selected by the speed shift
switch is the highest speed shift.
T2-1-28
SYSTEM / Control System
Driving Mode
Switch
Accelerator Pedal
Sensor
M
Brake Pressure
Sensor
Brake Pedal
Accelerator
Pedal
L
N
H
Shift Switch
Forward Clutch
Solenoid Valve
MC
ECM
Engine
1 2 3 4
Speed Shift Solenoid Valve
Monitor
Unit
Transmission
Vehicle Speed
Sensor
Forward/Reverse
Lever
F
N
R
Forward /Reverse
Switch
F
N
OFF
R
ON
Forward/Reverse
Selector Switch
T4GC-02-01-013
NOTE: Illustration shows flow of the signal in case
forward of the forward/reverse lever has
been selected when manual of the Driving
Mode switch and Speed 1 of the speed shift
switch have been selected.
T2-1-29
SYSTEM / Control System
Automatic Speed Shift Control
Purpose: Automatically changing speed shift with
three kinds of timing selection of automatic
speed shift change
Operation:
1. If either of L, N, and H of the Driving Mode switch
is selected, the MC is supplied with votage corresponding to the selected mode.
Mode
Automatic L
Automatic
N
Automatic
H
Output
Voltage
2V
3V
4V
4. MC transmits signal to the right speed shift solenoid valve in response to the output value each
time of the torque converter input speed sensor,
torque converter output speed sensor, vehicle
speed sensor, and accelerater pedal sensor. MC
eventually makes speed shift control until the selected speed shift.
2. MC started the selected automatic speed shift
program.
• In Automatic L control, the timing of speed shifting up
is slow when started at Speed 2, which is advantageous in making much of low fuel consumption.
• In Automatic N control, the timing of speed shifting
up is fast when started at Speed 2, which is advantageous in making much of production as well as low
fuel consumption.
• In Automatic H control, though started at Speed 2,
besides slow speed shifting up, speed shift to Speed
1 is necessary if traveling load is high, which is advantageous in making much of production.
NOTE: In whichever of Modes L, N, and H, starting
is made at Speed 1, if the speed shift switch
of Speed 1 is selected.
3. Shift switch is the rorary type, and has two
switches inside. When the speed shift is selected
from among Speed 1 through Speed 4, signal of
the selected speed shift is transmitted to the MC
depending on the combination of ON inside the
speed shift switch.
Speed Shift
Speed
1
Internal Switch
1
ON
Internal Switch
2
Speed
2
Speed
3
Speed
4
ON
ON
ON
T2-1-30
NOTE: MC is so programmed as to dtermine necessary vehicle speed ranges for changing
to the respective speed shifts and accelerator pedal output value. Therefore, in
case Automatic L of the Driving mode
switch and Speed 3 of the speed shift
switch are selected at start of traveling,
traveling is started at Speed 2 first, and
shifted up to Speed 3 as the vehicle speed
increases. Conversely, in case speed shift
from Speed 3 to Speed 1 is attempted while
traveling by operating the speed shift switch,
Speed 2 is automatically selected first, and
Speed 1 is reached after the vehicle speed
is lowered to the speed range for Speed 1.
NOTE: In case the Driving mode switch becomes
out of order, the MC makes speed shift
control in the manual traveling mode.
NOTE: In case the solenoid valve of either of the
Speed 1, Speed 3, or Speed 4 becomes
abnormal, the travel speed will be fixed to
Speed 2. In case either of the forward
clutch solenoid valve, reverse clutch solenoid valve, or Speed 2 solenoid valve becomes abnormal, only the abnormal one
cannot be used.
NOTE: In case the travel speed sensor has become abnormal, the travel speed is calculated using the transmission intermediate
shaft sensor, but with a large error. In case
both of the travel speed sensor and the
transmission intermediate shaft sensor
have become abnormal, travel at Speed 2
is fixed.
NOTE: Speed shift selected by the speed shift
switch is the highest speed shift.
SYSTEM / Control System
Driving Mode
Switch
Accelerator Pedal
Sensor
M
Brake Pressure
Sensor
Brake Pedal
Accelerator Pedal
L
N
H
Shift Switch
Forward Clutch
Solenoid Valve
Transmission
MC
ECM
Engine
1 2 3 4
Speed Shift Solenoid Valve
Vehicle Speed
Sensor
Monitor
Unit
Forward/Reverse
Lever
Torque Converter
Input Speed Sensor
Torque Converter
Output Speed Sensor
F
N
R
Forward/Reverse
Switch
F
N
OFF
R
ON
Forward/Reverse
Selector Switch
T4GC-02-01-014
NOTE: Illustration shows flow of the signal in case
Automatic L mode of the Driving mode
switch, Speed 4 of the speed shift switch,
and forward of the forward/reverse selector
lever have been selected, while the brake
pedal has been stepped.
T2-1-31
SYSTEM / Control System
Down Shift Control
Purpose: Decreasing the speed shift by pushing the
switch installed at the right console.
Operation:
1. When traveling at Speed 4 in Automatic L mode of
the Driving mode switch, signal is transmitted to
the MC by pushing the down shift switch once.
2. When traveling faster than the allowable speed
shift, the MC cancels the signal from the down
shift switch, but transmits signal to the speed shift
solenoid valve of Speed 3, when traveling slow.
8. In case of the following, the down shift switch
control is canceled.
• Operation of the forward/reverse lever or the forward/reverse switch
• Operation of the shift switch
• Operation of the Driving mode switch
• Pushing the hold switch
(Only in Automatic mode of the Driving mode
switch)
3. Further, if the down shift switch is pushed and the
vehicle speed is lowered to the range allowing the
speed shift, the speed shift of Speed 2 is selected.
4. In case automatic mode of the Driving mode
switch is selected, automatic speed shift control is
recovered three seconds after the speed shift has
lowered, and then the speed shift is automatically
raised once the vehicle speed increases.
5. By keeping pushing the down shift switch, the
speed shift is lowered to Speed 2, and Speed 2 is
kept during pushing.
6. If the down switch is pushed again within three
seconds after removing the finger once, Speed 1
is obtained in case the vehicle speed is slow
enough to allow the speed shift down.
7. When the down shift switch is pushed in manual
mode of the Driving mode switch, in case the vehicle speed is slow enough to allow the down shift,
the speed shift is lowered and the shifted speed is
kept.
NOTE: In case the vehicle speed sensor becomes
abnormal, the MC receives signal from the
transmission middle shaft sensor, and controls by making arithmetic operation of the
vehicle speed allowable for the speed shift.
In case both the vehicle speed sensor and
the transmission middle shaft sensor are
abnormal, lowering the speed shift is possible as an emergency measure only when
the engine stops for one reason or another
but traveling is not stopped.
NOTE: Shift switch has two switches, and their
combination of ON varies depending on
each speed shift. Controller judges which
speed shift has been selected by the combination of the two input signals.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
NOTE: Each mode switch of the Driving mode
switch is supplied with respectively different
voltages from the monitor unit, and when
the switch selects a mode, the MC judges
which mode has been selected by the input
voltage.
T2-1-32
SYSTEM / Control System
Driving Mode
Switch
Accelerator Pedal Sensor
Brake Pressure Sensor
M
Brake Pedal
Accelerator Pedal
L
N
H
Shift Switch
Transmission
Middle Shaft Sensor
Forward Clutch
Solenoid Valve
Reverse Clutch
Solenoid Valve
MC
ECM
Engine
1 2 3 4
Speed Shift Solenoid Valve
Transmission
Monitor
Unit
Vehicle
Speed Sensor
Forward/Reverse
Lever
F
N
R
Forward/Reverse
Switch
F
N
OFF
DOWN
R
ON
UP
Forward/Reverse
Selector Switch
Up-shift/Down-shift
Switch
NOTE: Illustration shows flow of the signal from the
MC in case Speed 3 has been selected
during forward traveling at Speed 4 and
Automatic L of the Driving mode switch.
T2-1-33
HOLD
Hold Switch
T4GC-02-01-015
SYSTEM / Control System
Up Shift Control
Purpose: Raising the speed shift by putting the left
hand on the steering wheel and pressing the
switch installed at the right console
Operation:
1. Signal is transmitted to the MC by pushing the up
shift switch once when traveling at Automatic L
mode of the Driving mode switch and Speed 4 of
the shift switch.
2. MC transmits signal to the speed shift solenoid
valve of Speed 2, and the speed shift is raised.
3. If the up shift switch is pushed, the speed shift is
further raised to Speed 3 and Speed 4.
4. In case automatic of the Driving mode switch is
selected, the speed shift is raised, and returned to
the automatic speed shift control in three seconds,
eventually raising automatically to the speed shift
selected in advance.
5. In case manual of the Driving mode switch is selected, the raised speed shift is kept.
6. In case the following operations are made, the up
shift switch is released.
• Operation of the forward/reverse lever or forward/reverse switch
• Operation of the shift switch
• Operation of the Driving mode switch
• Pushing the hold switch
(only when the automatic of the Driving mode
switch is selected)
NOTE: Even if the up shift switch is pushed during
traveling at the speed shift slected by the
shift switch, the speed shift is not raised
further.
T2-1-34
NOTE: Shift switch has two switches, and their
combination of ON varies depending on
each speed shift. Controller judges which
speed shift has been selected by the combination of the two input signals.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
NOTE: Each mode switch of the Driving mode
switch is supplied with respectively different
voltages from the monitor unit, and when
the switch selects a mode, the MC judges
which mode has been selected by the input
voltage.
SYSTEM / Control System
Driving Mode Switch
Accelerator Pedal
Sensor
M
Brake Pressure
Sensor
Brake Pedal
Accelerator Pedal
L
N
H
Shift Switch
Forward Clutch
Solenoid Valve
Reverse Clutch
Solenoid Valve
MC
ECM
Engine
1 2 3 4
Speed Shift Solenoid Valve
Transmission
Monitor
Unit
Forward/Reverse
Lever
F
N
R
Forward/Reverse
Switch
F
N
OFF
DOWN
R
ON
UP
HOLD
Forward/Reverse
Selector Switch
Up shift/Down shift/
Switch
Hold
Switch
NOTE: Illustration shows flow of the signal from the
MC in case Speed 2 has been selected
during forward traveling at Speed 1 and
Automatic L of the Driving mode switch.
T2-1-35
T4GC-02-01-016
SYSTEM / Control System
Clutch Cut Control
Purpose: Enabling release of the forward/reverse
clutch of the transmission for making the
most of the engine torque by operating the
brake during operation of the front attachment.
Amount of stepping the brake at the time of
declutching can be selected from among
three kinds depending on the driver’s preference.
5. In case the brake pressure is lowered below the
set pressure by reducing the amount of stepping
of the brake pedal, signal transmitted to the clutch
solenoid valve is raised, and clutching is made
again.
Operation:
1. When either mode of the clutch cut position switch
is selected, voltage corresponding to the selected
mode is transmitted to the MC.
Mode
OFF
S
N
D
Input
Voltage
1V
2V
3V
4V
2. MC starts the corresponding clutch cut control
program.
• Clutch cut does not work in OFF mode.
• In Mode S, clutch cut is made at output voltage
equivalent to the set pressure of Mode S, and
clutching is made again at voltage equivalent to
pressures lower than that of Mode S.
• In Mode N, clutch cut is made at output voltage
equivalent to the set pressure of Mode N, and
clutching is made again at voltage equivalent to
pressures lower than that of Mode N.
• In Mode D, clutch cut is made at output voltage
equivalent to the set pressure of Mode D, and
clutching is made again at voltage equivalent to
pressures lower than that of Mode D.
3. In case the brake pedal is stepped in Mode S,
signal from the brake pressure sensor is transmitted to the MC.
4. For signal higher than the set voltage, the MC declutches by lowering signal transmitted to the excited solenoid valve among the respective solenoid valves.
T2-1-36
NOTE: In case either of the clutch cut position
switch and brake pressure sensor becomes
out of order, clutch cut control is not made
NOTE: Each mode switch of the clutch cut position
switch is supplied with respectively different
voltages from the monitor unit, and when
the switch selects a mode, the MC judges
which mode has been selected by the input
voltage.
SYSTEM / Control System
Brake Pressure
Sensor
Brake Pedal
Clutch Cut
Position Switch
OFF
Forward Clutch
Solenoid Valve
S
N
Reverse Clutch
Solenoid Valve
D
MC
ECM
Engine
Transmission
Monitor
Unit
T4GC-02-01-017
NOTE: Illustration shows flow of the signal in case
the brake pedal has been stepped in Mode
S of the clutch cut position switch.
T2-1-37
SYSTEM / Control System
Shift Holding Control
Purpose: Enabling to hold the speed shift during towing or traveling uphill
Operation:
1. When the hold switch is pressed once, signal is
transmitted to the MC.
2. MC keeps transmitting signal to the speed shift
solenoid valve of each time, and after that the
speed shift is fixed even if the the accelerator or
the brake pedal is stepped.
NOTE: Speed shift holding control is made only
when automatic (L, N, or H) of the Driving
mode switch is selected.
3. MC releases the speed shift holding control in
case the following operations are made or the
following switches are operated.
• Turning OFF the key switch
• Pushing the hold switch again
• Down shift switch
• Up shift switch
• Forward/reverse lever
• Forward/reverse selector switch (only when effective)
• Forward/reverse switch (only when effective)
• Speed shift switch
• Driving mode switch
• Parking brake switch
T2-1-38
NOTE: Shift switch has two switches, and their
combination of ON varies depending on
each speed shift. Controller judges which
speed shift has been selected by the combination of the two input signals.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
NOTE: Each mode switch of the Driving mode
switch is supplied with respectively different
voltages from the monitor unit, and if a
switch is selected, the MC judges which
mode has been selected.
SYSTEM / Control System
Key Switch
Driving Mode Switch
Accelerator Pedal
Sensor
M
Brake Pressure
Sensor
Accelerator Pedal
Brake Pedal
L
N
H
Shift Switch
Forward Clutch
Solenoid Valve
MC
ECM
Engine
1 2 3 4
Speed Shift Solenoid Valve
Transmission
Monitor
Unit
Forward/Reverse
Lever
F
N
R
Forward/Reverse
Switch
F
N
OFF
DOWN
R
ON
UP
Forward/Reverse
Selector Switch
Up-Shift/Down-Shift
Switch
ON
HOLD
OFF
Hold
Switch
Parking Brake
Switch
T4GC-02-01-018
T2-1-39
SYSTEM / Control System
(Blank)
T2-1-40
SYSTEM / Control System
OTHER CONTROLS
Following other controls are made.
• Hydraulic fan cooling control
• Hydraulic fan cleaning control
• Transmission alarm control
• Forward/reverse indicator control
• Reverse Traveling alarm control
• Parking brake alarm control
T2-1-41
SYSTEM / Control System
Hydraulic Fan Cooling Control
Purpose: Improving fuel consumption rate and noise
reduction by restricting the hydraulic fan
speed in response to oil temperature and
coolant temperature.
Operation:
1. When the engine is started, the fan pump rotates,
and discharges oil to the fan motor.
2. Signals from the hydraulic oil temperature sensor,
engine coolant temperature sensor, and torque
converter oil temperature sensor are simultaneously transmitted to the MC, and arithmetic operation of three target hydraulic fan speeds are
carried out.
3. MC selects the highest speed, and transmits signal to the flow control solenoid valve.
4. Flow control solenoid valve operates, and pressure oil coming from it flows into the right end of
the flow control valve, so the flow control valve
spool moves left.
5. When the flow control valve spool moves left, part
of the pressure oil flowing to the fan motor flows to
the tank port, and the fan motor speed is lowered
accordingly.
6. In case oil temperature or coolant temperature of
any part is above the set temperature, the hydraulic fan speed is maximum when the engine
speed is maximum.
7. In case oil temperature or coolant temperature of
any part is below the set temperature, the hydraulic fan speed is lowered in response to the datum
of the highest temperature.
8. Besides, the signal from the outside air temperature sensor also enters the MC, and rotates the
fan always at the maximum speed, disregarding
the controls in 2 through 7 in case the air conditioner switch is ON at the outside air temperature
of 35 °C (95 °F) and above.
NOTE: In case any of the engine speed sensor,
hydraulic oil temperature sensor, engine
coolant temperature sensor, torque converter oil temperature sensor and out side
temperature sensor becomes out of order,
cooling by hydraulic fan control is always
made at the maximum speed.
T2-1-42
SYSTEM / Control System
At oil temperature or coolant temperature above the set temperature (Uncontrolled speed operation)
Fan Motor
Flow Control Valve
Hydraulic Oil Tank
Flow Control
Solenoid Valve
Hydraulic Oil Temperature Sensor
Fan Pump
Engine Coolant Temperature Sensor
Out Side
Temperature
Sensor
MC
ECM
Engine
Air
Conditioner
Control
Panel
Transmission
Monitor
Unit
Torque Converter
Oil Temperature Sensor
T4GC-02-01-019
At oil temperature or coolant temperature below the set temperature (Controlled speed operation)
Fan Motor
Flow Control Valve
Hydraulic Oil Tank
Hydraulic Oil Temperature Sensor
Flow Control
Solenoid Valve
Fan Pump
Engine Coolant
Temperature Sensor
Out Side
Temperature
Sensor
MC
ECM
Engine
Air
Conditioner
Control
Panel
Transmission
Torque Converter
Oil Temperature Sensor
Monitor
Unit
T4GC-02-01-020
T2-1-43
SYSTEM / Control System
Hydraulic Fan Cleaning Control
Purpose: Controlling cleaning by hydraulic fan by reversing the hydraulic fan to blow away dust
in case cleaning of the radiator, and oil
cooler are needed
Operation:
1. When the engine is started after preparing the
following conditions and turning the fan reversing
switch ON, signal is transmitted from the MC to
the reverse control solenoid valve.
2. When the reverse control solenoid valve is operated, the reverse spool strokes, and the fan motor
rotation is reversed.
3. In reverse rotation, as hydraulic fan cooling control is not made, the fan speed fluctuates from
maximum to minimum in response to the amount
of stepping of the accelerator pedal.
4. In case any one of the conditions below is
changed during reverse rotation, the engine
speed is immediately fixed to idling.
5. Hydraulic fan cleaning control is not released by
turning the fan reversing switch OFF only. Control
is released by the procedure of turning the fan
reversing switch OFF – turning the key switch
OFF – turning the key switch ON.
6. In case the engine speed is fixed to idling also, the
control is released by the procedure of turning the
fan reversing switch OFF – turning the key switch
OFF – turning the key switch ON.
Conditions:
•
•
•
•
Fan reversing switch: ON
Parking brake switch: ON (Brake is effective.)
Forward/reverse lever: neutral
Forward/reverse switch: neutral
T2-1-44
NOTE: Reverse control solenoid valve is turned
ON temporarily when the key switch is
turned ON because the spool can stick in
case the reverse control solenoid valve is
not operated for a long time. It is also
turned ON once every one minute after the
key switch is turned ON. This operation is
not made during the hydraulic fan cleaning
operation.
SYSTEM / Control System
In cooling operation (Normal rotation)
Fan Motor
Reverse Spool
Reverse Control
Solenoid Valve
Engine
Transmission
Hydraulic Oil
Tank
T4GB-02-01-007
In cleaning operation (Reverse rotation)
Fan Motor
Reverse Spool
Reverse Control Solenoid Valve
Hydraulic Oil
Tank
Engine
Transmission
Parking Brake
Solenoid Valve
MC
ECM
OFF
Parking Brake
Pressure Sensor
ON
Monitor
Unit
Fan Reversing
Switch
F
F
N
N
ON
R
R
OFF
Forward/Reverse
Lever
Forward/Reverse
Switch
Parking Brake
Switch
T2-1-45
T4GC-02-01-021
SYSTEM / Control System
Transmission Alarm Control
Purpose: Lighting the transmission alarm lamp on the
monitor unit for protection of the transmission in case of disorder of partslikely to
cause damage to the transmission
Operation: In case any of the parts shown right becomes out of order, the MC transmits signal
to the monitor unit, and the transmission
alarm lamp is lit.
Monitor
MC
•
•
•
•
•
•
Torque converter input speed sensor
Torque converter output speed sensor
Vehicle speed sensor
Transmission middle shaft sensor
Forward/reverse lever
Forward/reverse switch during work
ECM
Engine
Transmission
Torque Converter
Input Speed
Sensor
Torque Converter
Output Speed
Sensor
Monitor
Unit
Transmission
Alarm Lamp
Transmission
Middle Shaft Sensor
F
F
N
N
R
R
Forward/Reverse
Lever
Forward/Reverse
Switch
T2-1-46
Vehicle Speed
Sensor
T4GC-02-01-022
SYSTEM / Control System
Forward/Reverse Indicator Control
Purpose: Lighting the forward/reverse indicator on the
monitor when the forward/reverse switch is
effective
NOTE: In case the forward/reverse lever is operated while traveling using the forward/reverse switch, input to the forward/reverse switch becomes ineffective,
and the vehicle body moves by operating
the forward/reverse lever. (Refer to the
Forward/Reverse Lever Priority Control)
Operation:
1. Forward/reverse selector switch is turned ON after
the forward/reverse lever and the forward/reverse
switch are positioned at neutral.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
2. Then the forward/reverse switch becomes effective, and the monitor unit lights the forward/reverse indicator of the monitor.
NOTE: In case the forward/reverse lever becomes
out of order, input to the forward/reverse
switch becomes ineffective, and the forward/reverse indicator is unlit and fixed.
Monitor
MC
ECM
Forward/Reverse Indicator
Monitor
Unit
F
F
N
N
OFF
R
R
ON
Forward/Reverse
Lever
Forward/Reverse
Switch
T2-1-47
Forward/Reverse
Selector Switch
T4GC-02-01-023
SYSTEM / Control System
Reverse Traveling Alarm Control
(Refer to the SYSTEM/Electric System)
Purpose: Sounding alarm buzzer when the forward/reverse lever or the forward/reverse
switch is selected
Operation:
1. When reverse of the forward/reverse lever or the
forward/reverse switch is selected, the MC earths
the terminal from the reverse light relay.
2. Reverse light relay is excited, and electric current
flows to the reverse light and the reverse buzzer.
Right
Reverse Light
Reverse Buzzer
MC
ECM
F
N
Monitor
Unit
Reverse Light
Relay
R
Forward/Reverse
Lever
or
Forward/Reverse
Switch
From Terminal #108
of Fuse Box A
T2-1-48
Left
Reverse Light
T4GC-02-01-024
SYSTEM / Control System
Parking Brake Alarm Control
Purpose: Lighting the parking brake alarm lamp on the
monitor unit during parking operation of the
brake
NOTE: Parking brake of the vehicle body is released if the pilot pressure flows in.
Operation:
NOTE: For operation circuit of the parking brake,
refer to the SYSTEM/Electric System.
1. When the parking brake switch is turned ON, the
MC confirms signal of the parking brake pressure
sensor.
2. At pressure below the set pressure, the MC
transmits signal to the monitor unit, and the parking brake alarm lamp is lit.
IMPORTANT: Be careful that in case the parking
brake pressure sensor is abnormal,
traveling is possible even if the
parking brake switch is ON and the
parking brake is at work because the
parking brake alarm lamp is fixed to
OFF (release).
Monitor
MC
ECM
Engine
Parking Brake
Alarm Lamp
Transmission
Parking Brake
Pressure Sensor
Monitor
Unit
Parking Brake
ON
Parking Brake
Solenoid Valve
OFF
Parking Brake Switch
T4GC-02-01-025
T2-1-49
SYSTEM / Control System
(Blank)
T2-1-50
SYSTEM / Control System
CONTROL BY ELECTRIC AND HYDRAULIC COMBINED CIRCUIT
Electric and hydraulic combined circuit has the following controls.
•
•
•
•
•
Ride control (optional)
Bucket positioner control
Lift arm float control
Lift arm kick-out control
Lift arm auto-leveler upward control
(Optional)
• Lift arm auto-leveler downward control
(Optional)
T2-1-51
SYSTEM / Control System
Ride Control (Optional)
Purpose: Reducing fatigue of the operator by organizing a damper circuit in the lift arm cylinder
and reducing shock in traveling on rough
roads
Operation:
1. When the ride control switch is turned ON, the MC
makes the ride control effective, and the ride control indicator of the monitor is lit.
2. At vehicle speed of 7 km/h (4 mph) and above, the
MC receives signal from the vehicle speed sensor,
and transmits electric current to the ride control
solenoid valve.
3. When the ride control solenoid valve is operated
and the spool moves, a damper circuit is organized between the rod end and the bottom end of
the lift arm cylinder. When the vehicle body travels
on bumpy roads, the fluctuation of the bottom
pressure of the lift arm cylinder is absorbed by the
ride control accumulator, and the shock of the
whole vehicle body is reduced.
NOTE: Ride control is not made at the vehicle
speed of 7 km/h (4 mph) and below.
NOTE: In case the ride control switch or the ride
control solenoid valve becomes out of order,
the ride control is not made.
T2-1-52
SYSTEM / Control System
Lift Arm Cylinder
MC
ECM
Engine
Monitor
Unit
Ride Control
Switch
To Control
Valve
Vehicle Speed Sensor
Ride Control
Accumulator
OFF
ON
Transmission
Ride Control
Indicator
Relief Valve
Ride Control Valve
Ride Control
Solenoid Valve
Spool
Pilot
Pump
Hydraulic Oil
Tank
T4GC-02-01-026
T2-1-53
SYSTEM / Control System
Bucket Auto-leveler Control (ZW220)
Purpose: Automatically tilting the bucket at an appropriate angle (horizontal) to start digging in
returning the bucket to the tilting position
Operation:
1. In dumping operation of the bucket, the bar is located in front of the bucket proximity switch.
While the bar passes by the bucket proximity
switch, the bucket proximity switch becomes ON,
and excites the electromagnet on the bucket tilting
end of the pilot valve.
2. When the bucket operation lever is moved farther
than the bucket tilting detent position (position to
move farther than the tilting position), the bucket
operation lever is retained by the electromagnet
on the bucket tilting end, and pressure oil from the
pilot valve moves the bucket spool of the control
valve.
3. Pressure oil from the main pump flows into the
bottom end of the bucket cylinder through the
bucket spool of the control valve, and extends the
bucket cylinder. When the bucket cylinder is extended, the bar also passes by the bucket proximity switch.
4. When the bar becomes distant from the bucket
proximity switch, the bucket proximity switch is
turned OFF, and the electromagnet on the bucket
tilting end is also turned OFF, which makes the
bucket operation lever in the neutral position. As
the bucket spool of the control valve also returns
to neutral, the bucket cylinder stops. As a result,
the bucket is tilted at the right digging angle
(horizontal).
T2-1-54
SYSTEM / Control System
Bucket Cylinder
Bar
Bucket Proximity Switch
From #194 Terminal
of Fuse Box B
Control Box
Pilot Valve
for Bucket
Bucket
Electromagnet
on Bucket Tilting End
Pilot
Pump
Lift Arm
Main
Pump
T2-1-55
Hydraulic Oil
Tank
T4GB-02-01-013
SYSTEM / Control System
Bucket Auto-leveler Control (ZW250)
Purpose: Automatically tilting the bucket at an appropriate angle (horizontal) to start digging in
returning the bucket to the tilting position
Operation:
1. In dumping operation of the bucket, the bar is located in front of the bucket proximity switch.
While the bar passes by the bucket proximity
switch, the bucket proximity switch becomes ON,
and excites the electromagnet on the bucket tilting end of the pilot valve.
2. When the bucket operation lever is moved farther
than the bucket tilting detent position (position to
move farther than the tilting position), the bucket
operation lever is held by the electromagnet on
the bucket tilting end, and pressure oil from the
pilot valve moves the bucket spool of the control
valve.
3. Pressure oil from the main pump flows into the
bottom end of the bucket cylinder through the
bucket spool of the control valve, and extends the
buket cylinder. When the bucket cylinder is extended, the bar also passes by the bucket proximity switch.
4. When the bar becomes distant from the bucket
proximity switch, the bucket proximity switch is
turned OFF, and the electromagnet on the bucket
tilt end is also turned OFF, which makes the
bucket operation lever in the neutral position. As
the bucket spool of the control valve also returns
to neutral, the bucket cylinder stops. As a result,
the bucket is tilted at the right digging angle
(horizontal).
T2-1-56
SYSTEM / Control System
Bucket Cylinder
Bucket Proximity Switch
From #194 Terminal
of Fuse Box B
Bar
Control Valve
Pilot Valve
for Bucket
Electromagnet
on Bucket Tilting End
Bucket
Pilot
Pump
Lift Arm
Main
Pump
T2-1-57
Hydraulic Oil
Tank
T4GB-02-01-033
SYSTEM / Control System
Lift Arm Float Control (ZW220)
Purpose: Free raising and lowering of the lift arm in
response to the external load for snow removing and road cleaning
Operation:
1. When the lift arm operation lever is moved to the
floating position (farther position than the lift arm
lowering position), the lift arm operation lever is
retained by the electromagnet on the lift arm lowering end, and pressure oil from the pilot valve
moves the lift arm spool of the control valve up to
the floating position (farthest right position).
NOTE: When the engine is rotating, the electromagnet on the lift arm lowering end is always excited by the electric current from
#194 terminal of Fuse Box B.
2. Pressure oil from the main pump is blocked by the
lift arm spool, and ports on the rod end and the
bottom end of the lift arm cylinder are connected
through the lift arm spool, leading to the tank port.
As the both ports of the lift arm cylinder have the
same pressure as the hydraulic oil tank, the lift
arm cylinder is not restricted, allowing free
movement of the lift arm depending on the external force.
3. Lift arm operation lever returns to neutral, if pulled
more strongly than the magnetic force of the
electromagnet. As the lift arm spool of the control
valve also returns to neutral, the lift arm floating
control is released.
T2-1-58
SYSTEM / Control System
Lift Arm Cylinder
Bottom End
Port
Rod End
Port
Control Valve
From #194 Terminal
of Fuse Box B
Electromagnet
on Lift Arm Lowering End
Bucket
Pilot Valve
for Lift Arm
Lift Arm
Pilot
Pump
Main
Pump
T2-1-59
Hydraulic Oil
Tank
T4GB-02-01-014
SYSTEM / Control System
Lift Arm Float Control (ZW250)
Purpose: Free raising and lowering of the lift arm in
response to the external load for snow removing and road cleaning
Operation:
1. When the lift arm operation lever is moved to the
floating position (farther position than the lift arm
lowering position), the lift arm operation lever is
retained by the electromagnet on the lift arm lowering end, and pressure oil from the pilot valve
moves the lift arm spool of the control valve up to
the floating position (farthest left position).
NOTE: When the engine is rotating, the electromagnet on the lift arm lowering end is always excited by the electric current from
#194 terminal of Fuse Box B.
2. Pressure oil from the main pump is blocked by the
lift arm spool, and ports on the rod end and the
bottom end of the lift arm cylinder are connected
through the lift arm spool, leading to the tank port.
As the both ports of the lift arm cylinder have the
same pressure as the hydraulic oil tank, the lift
arm cylinder is not restricted, allowing free
movement of the lift arm depending on the external force.
3. Lift arm operation lever returns to neutral, if pulled
more strongly than the magnetic force of the
electromagnet. As the lift arm spool of the control
valve also returns to neutral, the lift arm floating
control is released.
T2-1-60
SYSTEM / Control System
Lift Arm Cylinder
Bottom End
Port
Rod End
Port
Control Valve
From #194 Terminal
of Fuse Box B
Electromagnet
on Lift Arm Lowering End
Bucket
Pilot Valve
for Lift Arm
Lift Arm
Pilot
Pump
Main
Pump
T2-1-61
Hydraulic Oil
Tank
T4GB-02-01-034
SYSTEM / Control System
Lift Arm Kick-out Control (ZW220)
Purpose: Automatically locating the lift arm at proper
height in returning the lift arm to the highest
position
Operation:
1. When lowering the lift arm, the plate is located in
front of the lift arm proximity switch.
While the plate passes by the lift arm proximity
switch, the lift arm proximity switch becomes ON,
and the electromagnet on the lift arm end is also
excited.
2. When the lift arm operation lever is moved farther
than the lift arm raising detent position (position to
pull farther than the raising position), the bucket
operation lever is retained by the electromagnet
on the lift arm raising end, and pressure oil from
the pilot valve moves the lift arm spool of the
control valve toward raising.
3. Pressure oil from the main pump flows into the
bottom end of the lift cylinder through the lift arm
spool of the control valve, and extends the lift arm
cylinder. When the lift arm cylinder is extended,
the plate also passes by the lift arm proximity
switch.
4. When the plate becomes distant from the lift arm
proximity switch, the lift arm proximity switch is
turned OFF, and the electromagnet on the lift arm
raising end is also turned OFF, which makes the
lift arm operation lever in the neutral position. As
the lift arm spool of the control valve also returns
to neutral, the lift arm cylinder stops. As a result,
the lift arm stops.
T2-1-62
SYSTEM / Control System
Plate
Lift Arm
Proximity Switch
Lift Arm
Cylinder
Bottom End
Port
Rod End
Port
Control Valve
From #194 Terminal
of Fuse Box B
Bucket
Pilot Valve
for Lift Arm
Lift Arm
Pilot
Pump
Electromagnet
on Lift Arm Lowering End
Main
Pump
T2-1-63
Hydraulic Oil
Tank
T4GB-02-01-015
SYSTEM / Control System
Lift Arm Kick-out Control (ZW250)
Purpose: Automatically locating the lift arm at proper
height in returning the lift arm to the highest
position
Operation:
1. When lowering the lift arm, the plate is located in
front of the lift arm proximity switch.
While the plate passes by the lift arm proximity
switch, the lift arm proximity switch becomes ON,
and the electromagnet on the lift arm end is also
excited.
2. When the lift arm operation lever is moved farther
than the lift arm raising detent position (position to
pull farther than the raising position), the bucket
operation lever is retained by the electromagnet
on the lift arm raising end, and pressure oil from
the pilot valve moves the lift arm spool of the
control valve toward raising.
3. Pressure oil from the main pump flows into the
bottom end of the lift cylinder through the lift arm
spool of the control valve, and extends the lift arm
cylinder. When the lift arm cylinder is extended,
the plate also passes by the lift arm proximity
switch.
4. When the plate becomes distant from the lift arm
proximity switch, the lift arm proximity switch is
turned OFF, and the electromagnet on the lift arm
raising end is also turned OFF, which makes the
lift arm operation lever in the neutral position. As
the lift arm spool of the control valve also returns
to neutral, the lift arm cylinder stops. As a result,
the lift arm stops.
T2-1-64
SYSTEM / Control System
Plate
Lift Arm
Proximity Switch
Lift Arm
Cylinder
Bottom End
Port
Rod End
port
Control Valve
From #194 Terminal
Fuse Box B
Pilot Valve
for Lift Arm
Bucket
Electromagnet
for Lift Arm
End
Lift Arm
Pilot
Pump
Main
Pump
T2-1-65
Hydraulic Oil
Tank
T4GB-02-01-035
SYSTEM / Control System
Lift Arm Auto-leveler Upward Control (Optional)
(ZW220)
Purpose: Free locating of the lift arm between the
horizon and the highest position
Operation:
1. If the SET position of the lift arm auto-leveler
upward set switch is selected after the lift arm is
located within the allowable location of the lift arm
auto-leveler (a’ in the illustration), signal from the
lift arm angle sensor is memorized by the MC,
and that is the lift arm auto-leveler upward location.
NOTE: When the lift arm is outside a’, even if the
SET position of the lift arm auto-leveler
upward set switch is selected, setting of the
lift arm auto- leveler upward cannot be
made. In case setting was thus unsuccessful, or setting in a different position is
needed, make setting again with the above
in mind.
3. Pressure oil from the main pump flows into the
bottom end port of the lift cylinder through the lift
arm spool of the control valve, and raises the lift
arm.
4. When the lift arm angle sensor moves up to the lift
arm auto-leveler upward locating position,
earthing of #241 terminal of the MC is released,
and the electromagnet on the lift arm upward end
is unexcited. Thus the lift arm operation lever returns to the neutral position, and supply of pressure oil from the pilot valve to the control valve is
stopped.
5. As the lift arm spool of the control valve also returns to neutral, the lift arm stops at the lift arm
auto-leveler upward stop position.
NOTE: Above the lift arm upward set position, the
electromagnet on the lift arm raising end is
always excited.
NOTE: In case the lift arm angle sensor becomes
out of order, the lift arm auto-leveler upward
control is not made.
a (Lift Arm Upward
Work Range)
a’ (Lift Arm
Auto-leveler
Up ward
Allowable Setting
Range)
Position of
Lift Arm Foot Pin
Position of
Lift Arm Tip Pin
IMPORTANT: In case either the lift arm angle
sensor or the MC has been replaced,
be sure to make learning control of
the lift arm angle sensor. (Refer to
the OPERATIONAL PERFORMANCE
TEST/Adjustment)
2. When the lift arm auto-leveler upward switch is
turned ON, #241 terminal of the MC is earthed,
and excites electromagnet on the lift arm upward
end of the pilot valve. When the lift arm operation
lever is moved to the lift arm upward detent position (position to pull farther than the upward position), the lift arm operation lever is retained by the
electromagnet on the lift arm upward end, and
pressure oil is supplied to the control valve from
the pilot valve.
T2-1-66
SYSTEM / Control System
Link
Lift Arm
Angle Sensor
Lift Arm
Cylinder
Bottom End
Port
Rod End
Port
Lift Arm
Auto-leveler
Upward Set Switch
Control Valve
OFF
SET
ON
234
238
MC
237
Bucket
241
Electromagnet
on Lift Arm Raising End
From #194 Terminal
of Fuse Box B
Lift Arm
Pilot Valve
for Lift Arm
Pilot
Pump
Main
Pump
T2-1-67
Hydraulic Oil
Tank
T4GB-02-01-016
SYSTEM / Control System
Lift Arm Auto-leveler Upward Control (Optional)
(ZW250)
Purpose: Free locating of the lift arm between the
horizon and the highest position
Operation:
1. If the SET position of the lift arm auto-leveler
upward set switch is selected after the lift arm is
located within the allowable location of the lift arm
auto-leveler (a’ in the illustration), signal from the
lift arm angle sensor is memorized by the MC,
and that is the lift arm auto-leveler upward location.
NOTE: When the lift arm is outside a’, even if the
SET position of the lift arm auto-leveler
upward set switch is selected, setting of the
lift arm auto- leveler upward cannot be
made. In case setting was thus unsuccessful, or setting in a different position is
needed, make setting again with the above
in mind.
3. Pressure oil from the main pump flows into the
bottom end port of the lift cylinder through the lift
arm spool of the control valve, and raises the lift
arm.
4. When the lift arm angle sensor moves up to the lift
arm auto-leveler upward locating position,
earthing of #241 terminal of the MC is released,
and the electromagnet on the lift arm upward end.
Thus the lift arm operation lever returns to the
neutral position, and supply of pressure oil from
the pilot valve to the control valve is stopped.
5. As the lift arm spool of the control valve also returns to neutral, the lift arm stops at the lift arm
auto-leveler upward stop position.
NOTE: Above the lift arm upward set position, the
electromagnet on the lift arm raising end is
always excited.
a (Lift Arm Upward
Work Range)
a’ (Lift Arm
Auto-leveler Upward
Allowable Setting
Range)
Position of
Lift Arm Foot Pin
Position of
Lift Arm Tip Pin
NOTE: In case the lift arm angle sensor becomes
out of order, the lift arm auto-leveler upward
control is not made.
IMPORTANT: In case either the lift arm angle
sensor or the MC has been replaced,
be sure to make learning control of
the lift arm angle sensor. (Refer to
the OPERATIONAL PERFORMANCE
TEST/Adjustment)
2. When the lift arm auto-leveler upward switch is
turned ON, #241 terminal of the MC is earthed,
and excites electromagnet on the lift arm upward
end of the pilot valve. When the lift arm operation
lever is moved farther than the lift arm upward
detent position (position to pull farther than the
upward position), the lift arm operation lever is
retained by the electromagnet on the lift arm upward end, and pressure oil is supplied to the control valve from the pilot valve.
T2-1-68
SYSTEM / Control System
Link
Lift Arm
Angle Sensor
Lift Arm
Cylinder
Bottom End
Port
Rod End
Port
Lift Arm
Auto-leveler
Upward Set Switch
OFF
SET
ON
Control Valve
234
238
MC
237
Bucket
241
Electromagnet
on Lift Arm Raising End
From #194 Terminal
of Fuse Box B
Lift Arm
Pilot Valve
for Lift Arm
Pilot
Pump
Main
Pump
T2-1-69
Hydraulic Oil
Tank
T4GB-02-01-036
SYSTEM / Control System
Lift Arm Auto-leveler Downward Control (Optional)(ZW220)
Purpose: Free locating of the lift arm between the horizon and the lowest position
Operation:
1. If the SET position of the lift arm auto-leveler
downward set switch is selected after the lift arm
is located within the allowable location of the lift
arm auto-leveler (b’ in the illustration), signal from
the lift arm angle sensor is memorized by the MC,
and that is the lift arm auto-leveler downward location.
NOTE: When the lift arm is outside b’, even if the
SET position of the lift arm auto-leveler
downward set switch is selected, setting of
the lift arm auto- leveler downward cannot
be made. In case setting was thus unsuccessful, or setting in a different position is
needed, make setting again with the above
in mind.
3. Pressure oil from the main pump flows into the
rod end port of the lift cylinder through the lift arm
spool of the control valve, and lowers the lift arm.
4. When the lift arm angle sensor moves down to the
lift arm auto-leveler downward locating position,
earthing of #242 terminal of the MC is released,
and the electromagnet on the lift arm downward
end is unexcited for a while until it is excited again
soon after.
5. Thus the lift arm operation lever returns to the
neutral position, and supply of pilot pressure from
the pilot valve to the control valve is stopped.
6. As the lift arm spool of the control valve also returns to neutral, the lift arm stops at the lift arm
auto-leveler downward stop position.
Position of
Lift Arm Tip Pin
Position of
Lift Arm Foot Pin
b’ (Lift Arm
Auto-leveler
Downward
Allowable Setting Range)
b (Lift Arm Downward
Work Range)
NOTE: In case the lift arm angle sensor becomes
out of order, the lift arm auto-leveler
downward control is not made.
IMPORTANT: In case either the lift arm angle
sensor or the MC has been replaced,
be sure to make learning control of
the lift arm angle sensor. (Refer to
the OPERATIONAL PERFORMANCE
TEST/Adjustment)
2. When the lift arm auto-leveler downward switch is
turned ON, #242 terminal of the MC is earthed,
and excites electromagnet on the lift arm downward end of the pilot valve. When the lift arm operation lever is moved to the lift arm downward
detent position (position farther than the downward position), the lift arm operation lever is retained by the electromagnet on the lift arm
downward end, and pressure oil is supplied to the
control valve from the pilot valve.
T2-1-70
SYSTEM / Control System
Link
Lift Arm
Angle Sensor
Lift Arm
Cylinder
Bottom End
Port
Rod End
Port
Lift Arm
Auto-leveler Downward
Set Switch
OFF
SET
ON
234
Control Valve
240
MC
239
242
Bucket
Electromagnet on
Lift Arm Lowering End
Pilot Valve
for Lift Arm
From #194 Terminal
of Fuse Box B
Lift Arm
Pilot
Pump
T4GB-02-01-017
T2-1-71
SYSTEM / Control System
Lift Arm Auto-leveler Downward Control (Optional)(ZW250)
Purpose: Free locating of the lift arm between the
horizon and the lowest position
Operation:
1. If the SET position of the lift arm auto-leveler
downward set switch is selected after the lift arm
is located within the allowable location of the lift
arm auto-leveler (b’ in the illustration), signal from
the lift arm angle sensor is memorized by the MC,
and that is the lift arm auto-leveler downward location.
NOTE: When the lift arm is outside b’, even if the
SET position of the lift arm auto-leveler
downward set switch is selected, setting of
the lift arm auto- leveler downward cannot
be made. In case setting was thus unsuccessful, or setting in a different position is
needed, make setting again with the above
in mind.
3. Pressure oil from the main pump flows into the
rod end port of the lift cylinder through the lift arm
spool of the control valve, and lowers the lift arm.
4. When the lift arm angle sensor moves down to the
lift arm auto-leveler downwards locating position,
earthing of #242 terminal of the MC is released,
and the electromagnet on the lift arm downward
end is unexcited for a while until it is excited again
soon after.
5. Thus the lift arm operation lever returns to the
neutral position, and supply of pilot pressure from
the pilot valve to the control valve is stopped.
6. As the lift arm spool of the control valve also returns to neutral, the lift arm stops at the lift arm
auto-leveler downward stop position.
Position of
Lift Arm Tip Pin
Position of
Lift Arm Foot Pin
b’ (Lift Arm
Auto-leveler
Downward
Allowable Setting Range)
b (Lift Arm Downward
Work Range)
NOTE: In case the lift arm angle sensor becomes
out of order, the lift arm auto-leveler
downward control is not made.
IMPORTANT: In case either the lift arm angle
sensor or the MC has been replaced,
be sure to make learning control of
the lift arm angle sensor. (Refer to
the OPERATIONAL PERFORMANCE
TEST/Adjustment)
2. When the lift arm auto-leveler downward switch is
turned ON, #242 terminal of the MC is earthed,
and excites electromagnet on the lift arm downward end of the pilot valve. When the lift arm operation lever is moved to the lift arm downward
detent position (position farther than the downward position), the lift arm operation lever is retained by the electromagnet on the lift arm
downward end, and pressure oil is supplied to the
control valve from the pilot valve.
T2-1-72
SYSTEM / Control System
Link
Lift Arm
Angle Sensor
Lift Arm
Cylinder
Bottom End
Port
Rod End
Port
Lift arm
Auto-leveler Downward
Set Switch
OFF
SET
ON
234
Control Valve
240
MC
239
242
Bucket
Electromagnet on
Lift Arm Lowering End
Pilot Valve
for Lift Arm
From #194 Terminal
of Fuse Box B
Pilot
Pump
Lift Arm
T4GB-02-01-037
T2-1-73
SYSTEM / Control System
(Blank)
T2-1-74
SYSTEM / ECM System
OUTLINE
• Supply pump is driven by engine and generates
Signals from sensors and MC (Main Controller) are
input to ECM (Engine Control Module).
ECM calculates and drives two way valve, suction
control valve and EGR motor in order to control supply
pump, injector and EGR (Exhaust Gas Recirculation).
•
•
•
•
•
high pressure fuel.
• Common rail distributes high pressure fuel generated by supply pump to injector of each engine
cylinder.
• Injector injects high pressure fuel from common
rail.
Fuel Injection Control
Engine Start Control
EGR Control
Correction of Fuel Injection Volume
Engine Stop Control (Refer to System/Electric
System)
Crank Revolution Sensor
Cam Angle Sensor
Atmosphere Sensor
Fuel Temperature Sensor
Coolant Temperature Sensor
Inlet Air Temperature Sensor
Boost Pressure Sensor
Boost Temperature Sensor
Engine Oil Pressure Sensor
EGR Motor Position Sensor
EGR
EGR Motor
ECM
MC
Common Rail
Pressure Sensor
Two Way Valve
Suction Control
Valve
Common Rail
Supply Pump
Injector
Fuel Tank
T4GB-02-02-022
T2-2-1
SYSTEM / ECM System
FUEL INJECTION CONTROL
ECM monitors running state of engine according to
signals from each sensor and MC. ECM controls the
volume, pressure, timing and rate of fuel injection
Crank Revolution Sensor
Control by Two Way Valve
• Fuel injection volume control
• Fuel injection (volume) timing
control
• Fuel injection rate control
Control by Suction Control Valve
• Fuel injection pressure control
Cam Angle Sensor
Atmosphere Sensor
Fuel Temperature Sensor
Coolant Temperature Sensor
Inlet Air Temperature Sensor
Boost Pressure Sensor
Boost Temperature Sensor
Engine Oil Pressure Sensor
EGR Motor Position Sensor
EGR
EGR Motor
ECM
MC
Common Rail
Pressure Sensor
Two Way Valve
Suction Control
Valve
Common Rail
Supply Pump
Injector
Fuel Tank
T4GB-02-02-022
T2-2-2
SYSTEM / ECM System
(Blank)
T2-2-3
SYSTEM / ECM System
Fuel Injection Volume Control
Function: Controls fuel injection volume in order to be
optimum.
Operation:
1. ECM detects engine speed according to input
signals from crank revolution sensor and cam
angle sensor.
2. MC calculates target engine speed according to
input signals from sensors and switches. MC
sends signal to ECM. (Refer to System/Control
System.)
3. ECM turns two way valve in the injector into ON
or OFF mainly according to the engine speed and
signal from MC in order to control fuel injection
volume.
NOTE: Mode switches of the work mode switch
are supplied with respectively different
voltages from the monitor unit. MC judges
the selected mode by the supplied voltage.
NOTE: Two switches are installed inside the shift
switch, and the turning ON condition varies
depending on the combination of speed
shifts. MC judges the selected speed shift
by the combination of two input currents.
T2-2-4
SYSTEM / ECM System
Accelerator
Pedal Sensor
Work Mode
Switch
Crank Revolution Sensor
Cam Angle Sensor
Accelerator
Pedal
Atmosphere Sensor
L
Fuel Temperature Sensor
N
Coolant Temperature Sensor
P
Inlet Air Temperature Sensor
Boost Pressure Sensor
Boost Temperature Sensor
Engine Oil Pressure Sensor
EGR Motor Position Sensor
EGR Motor
Shift Switch
MC
ECM
Common Rail
Pressure Sensor
Two Way
Valve
Monitor
Unit
Common
Rail
Supply Pump
Wheel Speed
Engine Coolant
Sensor
Temperature Sensor
Injector
Fuel Tank
T4GC-02-02-004
T2-2-5
SYSTEM / ECM System
Fuel Injection Pressure Control
Fuel Injection Timing Control
Function: Controls fuel injection pressure according
to fuel pressure in common rail.
Operation:
1. ECM calculates fuel injection volume according to
engine speed and target engine speed signal of
MC. (Refer to Page T2-2-4).
2. Common rail pressure sensor sends signal corresponding to pressure in common rail to ECM.
3. ECM calculates appropriate pressure in common
rail according to engine speed, fuel injection
volume and common rail pressure sensor signal.
ECM drives suction control valve in supply pump
and appropriate volume of fuel to common rail.
4. Fuel in common rail is supplied to each engine
cylinder through injector from common rail.
NOTE: Mode switches of the work mode switch
are supplied with respectively different
voltages from the monitor unit. MC judges
the selected mode by the supplied voltage.
Function: Calculates appropriate fuel injection timing.
Operation:
1. ECM calculates fuel injection timing according to
engine speed and fuel injection volume.
2. ECM drives ON/OFF of two way valve in injector
in order to control fuel injection timing.
Fuel Injection Rate Control
Function: Improves combustion inside the engine
cylinders.
Operation:
1. Injector initially injects small amount of fuel (pilot
injection) for ignition.
2. Injector executes the second injection (main injection) after ignition. ECM drives ON/OFF of two
way valve in injector in order to control fuel injection timing and volume.
NOTE: Two switches are installed inside the shift
switch, and the turning ON condition varies
depending on the combination of speed
shifts. MC judges the selected speed shift
by the combination of two input currents.
T2-2-6
SYSTEM / ECM System
Accelerator
Pedal Sensor
Work Mode
Switch
Crank Revolution Sensor
Cam Angle Sensor
Accelerator
Pedal
Atmosphere Sensor
L
Fuel Temperature Sensor
N
Coolant Temperature Sensor
P
Inlet Air Temperature Sensor
Boost Pressure Sensor
Boost Temperature Sensor
Engine Oil Pressure Sensor
EGR Motor Position Sensor
EGR Motor
Shift Switch
MC
ECM
Suction
Control
Valve
Monitor
Unit
Common Rail
Pressure Sensor
Two Way
Valve
Common
Rail
Supply Pump
Wheel Speed
Sensor
Engine Coolant
Temperature Sensor
Injector
Fuel Tank
T4GC-02-02-005
T2-2-7
SYSTEM / ECM System
Fuel Injection
1. Fuel pressure is constantly applied to the injector
nozzle.
2. When the magnetic coil of the two-way valve is
turned ON, the valve is opened, and the
high-pressure fuel in the control chamber returns
to the fuel tank through Orifice 1.
3. Spring force raises the hydraulic piston, and the
nozzle is opened to start injection.
4. When the magnetic coil of the two-way valve is
turned OFF, the valve is closed, and the circuit
leading to the fuel tank is closed.
5. In this way, the control chamber is filled with
high-pressure fuel.
6. Difference of top and bottom pressure of the piston lowers the piston, and the nozzle is closed to
finish injection.
T2-2-8
SYSTEM / ECM System
1. Two Way Valve: ON
2. Fuel Injection Start
From ECM
From ECM
Magnetic Coil
Valve
From Common Rail
Two Way Valve
Two Way Valve
Return to Fuel
Tank
Return to Fuel
Tank
From Common
Rail
Orifice 1
Control Chamber
Hydraulic Piston
Spring
Spring
Nozzle
Nozzle
3. Two Way Valve: OFF
4. Fuel Injection Stop
From ECM
From ECM
Magnetic Coil
Two Way Valve
Two Way Valve
Valve
From Common Rail
From Common Rail
Control Chamber
Hydraulic Piston
Orifice 2
Nozzle
Nozzle
T1GR-02-02-012
T2-2-9
SYSTEM / ECM System
COMPENSATION OF FUEL INJECTION
VOLUME
1. Atmosphere pressure sensor sends signal corresponding to atmospheric pressure to ECM.
2. ECM calculates atmospheric pressure according
to input signal. ECM controls two way valve in
injector and corrects of fuel injection volume.
Atmosphere
Pressure Sensor
ECM
Two Way
Valve
T1GR-02-02-002
T2-2-10
SYSTEM / ECM System
ENGINE START CONTROL
Function: Controls energizing time of glow plug by
coolant temperature and improves startability of engine.
Operation:
1. Coolant temperature sensor sends signal corresponding to coolant temperature to ECM.
2. ECM connects the ground circuit of glow relay
according to signals and controls energizing time
of glow plug.
Coolant Temperature
Sensor
From Key Switch
Terminal M
ECM
Glow Relay
From Battery
Relay
Glow Plug
T2-2-11
T4GB-02-02-016
SYSTEM / ECM System
EGR (EXHAUST GAS RECIRCULATION)
CONTROL
Function: EGR controls lets part of exhaust gas recirculate inside intake manifold and mix it
with intake air. Consequently, the combustion temperature is lowered and generation
of nitrogen oxide (Nox) is reduced.
Operation:
• EGR Gas Amount Control
1. ECM determines amount of EGR gas according
to engine speed, fuel flow rate, coolant temperature, atmospheric pressure and intake air temperature.
2. ECM drives the EGR motor, and opens the EGR
valve. And transfer the EGR gas corresponding to
the engine condition to the intake manifold to be
mixed with the intake air.
3. At the same time, EGR motor position sensor
detects amount of opening of EGR valve.
•
EGR Gas Coolant
EGR gas is cooled by coolant system located
along EGR gas passage.
By mixing the cooled EGR gas with the intake air,
the combustion temperature is lowered, and the
NOx is reduced in comparison with ordinary EGR
gas.
• Lead Valve
Lead valve prevents new air from entering into
EGR gas passage and reverse flow of EGR gas.
As EGR gas flows in one direction.
T2-2-12
SYSTEM / ECM System
To Inter Cooler
Exhaust Gas
EGR Gas
From Air Cleaner
Coolant Out
Coolant System
Engine
Coolant In
EGR Valve
Intake
Manifold
EGR Motor
Position Sensor
From Inter Cooler
EGR Motor
Lead Valve
Intake Air
ECM
T1GR-02-02-011
T2-2-13
SYSTEM / ECM System
(Blank)
T2-2-14
SYSTEM/Hydraulic System
OUTLINE
Hydraulic system is broadly be divided into the main
circuit, pilot circuit, steering circuit, and hydraulic
drive fan circuit.
• Main Circuit
Main circuit consists of the priority valve circuit,
neutral circuit, single operation circuit, and
combined operation circuit – composed of the
main pump, priority valve, control valve, cylinders,
etc.
• Pilot Circuit
Pilot circuit consists of the charging block circuit,
front attachment operation control circuit, pump
control circuit, brake circuit, and ride control circuit
(optional) – composed of the pilot pump, charging
block and valves for controlling each circuit.
• Steering Circuit
Steering circuit consists of the normal steering
circuit,
steering
shock
damping
circuit,
emergency steering circuit (optional), steering
stop circuit– composed of the pump, priority valve,
steering valve, cylinders, and other valves.
• Hydraulic Drive Fan Circuit
Hydraulic drive fan circuit consists of the flow
control circuit and reverse rotation control circuit –
composed of the motor for radiator cooling fan
and the pump for radiator cooling fan.
NOTE: Steering circuit can be divided into the main
circuit and the pilot circuit, but is described
here as an single circuit for making
explanation clear.
T2-3-1
SYSTEM/Hydraulic System
MAIN CIRCUIT
Outline
• Main pump draws hydraulic oil, from the hydraulic
oil tank through the suction filter and delivers.
• Delivered pressure oil flows to the steering valve
and the control valve through the priority valve.
• Pressure oil led to the steering valve flows to the
steering cylinders in response to operation of the
spool in the steering valve and the return oil flows
back to the hydraulic oil tank through the steering
valve.
• Pressure oil led to the control valve flows to the
cylinders in response to operation of the spool in
the control valve, and the return oil flows back to
the hydraulic oil tank through the control valve.
T2-3-2
SYSTEM/Hydraulic System
Bucket Cylinder
Steering Cylinders
Lift Arm Cylinders
Control Valve
Bucket
Spool
Steering
Valve
Lift Arm
Spool
Priority
Valve
Main Pump
Suction
Filter
Hydraulic oil
Tank
T4GB-02-02-010
T2-3-3
SYSTEM/Hydraulic System
Priority Valve Circuit
• At stop of the engine, the priority valve spool is
• When pressure at Port LS2 and the spring force
pushed leftward, by the spring force.
When the engine is started, pressure oil from the
main pump flows toward the steering valve
through the priority valve spool, while also
entering Ports LS1 and LS2 through Orifices 1
and 2 respectively.
At neutral of the steering valve, pressure oil led to
Port LS2 flows to the hydraulic oil tank through
Orifice 3 and the steering valve spool, so Port LS2
is not pressurized.
As pressure at LS1 causes larger force than the
spring force, the priority valve spool moves right,
and pressure oil from the main pump is all
supplied to the control valve.
Priority valve spool is provided with a notch for
leading pressure oil from the main pump toward
the steering valve and a notch for leading
pressure oil from the main pump toward the
control valve, which are both connected to the
main pump delivery port constantly.
When the priority valve spool moves right, the
notch for leading pressure oil from the main pump
toward the steering valve moves until the delivery
port on the steering valve side in the priority valve
is closed. When pressure balance is obtained and
the spool stops moving.
When the steering valve spool moves, the tank
port connected with Port LS2 is closed.
At this time, Port LS2 is connected with the main
circuit through the steering valve spool, and
pressure corresponding to movement of the
steering valve spool arises at Port LS2.
overcome pressure at Port LS1, the priority valve
spool moves left.
• Larger the movement of the steering valve spool
is, the higher the pressure at Port LS2 rises, the
larger the priority valve spool moves left, and the
more pressure oil from the main pump is supplied
to the steering valve.
•
•
•
•
•
•
•
T2-3-4
NOTE: Orifice 2 of the priority valve is installed for
warming up the circuit by flowing pressure
oil to the hydraulic oil tank from Port LS2 at
neutral of the steering valve. Diameter of
Port 2 is small, and temperature of the oil
passing through it rises rapidly, but
pressure is not raised enough to influence
movement of the priority valve spool.
SYSTEM/Hydraulic System
Bucket Cylinder
Steering Cylinders
Lift Arm
Cylinders
Steering Valve
Control Valve
Hydraulic
Oil Tank
Bucket
Spool
Hydraulic
Oil Tank
Lift Arm
Hydraulic
Oil Tank
Priority
Valve
Spring
Orifice1
Orifice 1
Orifice 3
LS1
Spool
LS2
At Stop of Engine
Main Pump
NOTE: Illustration shows oil flow in idling operation
while the engine is rotating. Control valve
illustrated is for ZW220.
T2-3-5
T4GB-02-02-011
SYSTEM/Hydraulic System
Neutral Circuit
• At neutral position of the control lever, pressure oil
from the main pump returns to the hydraulic oil
tank through the neutral circuit of the control
valve.
• Only when the steering valve spool moves
actuated by the priority valve, pressure oil is
supplied to the steering valve, the steering valve
is not provided with a neutral circuit. (Refer to
Priority Valve Circuit in this section.)
Single Operation Circuit
• Pressure oil from the main pump enters the
control valve, and flows to the lift arm and bucket
spools.
• When the steering valve spool moves, the priority
valve spool moves left, and pressure oil from the
main pump flows to the steering valve. (Refer to
Priority Valve Circuit in this section.)
T2-3-6
SYSTEM/Hydraulic System
Bucket Cylinder
Steering Cylinders
Lift Arm
Cylinders
Steering Valve
Control Valve
Hydraulic
Oil Tank
Bucket
Spool
Hydraulic
Oil Tank
Lift Arm
Hydraulic
Oil Tank
Priority
Valve
Spool
Main Pump
T4GB-02-02-017
NOTE: Illustration shows oil flow in idling operation
while the engine is rotating. Control valve
illustrated is for ZW220.
T2-3-7
SYSTEM/Hydraulic System
Combined Operation Circuit (ZW220)
• Lift Arm Raising/Bucket Dumping
• When the bucket is dumped with the lift arm
•
•
•
•
•
raised, pilot pressure shifts the lift arm and bucket
spools.
Pressure from the own pump is applied to Port
LS1 of the priority valve, but Port LS2 is not
pressurized because it is connected to the
hydraulic oil tank port.
Pressure at Port LS1 causes larger force than the
spring force of the priority valve, and moves the
spool right.
Therefore, pressure oil from the main pump flows
to the lift arm cylinders through the check valve in
the control valve and the lift arm spool, and raises
the lift arm.
Pressure oil from the main pump also flows to the
buket cylinder through the check valve, orifice,
and bucket spool in the control valve, and dumps
the bucket.
Lift arm raising operation is more heavy loaded
than the bucket dumping operation, but pressure
oil passing the bucket operation circuit enters the
bucket cylinder after passing the check valve and
orifice, allowing smooth movement of both the lift
arm cylinders and the buket cylinder.
T2-3-8
SYSTEM/Hydraulic System
Steering Cylinders
Bucket Cylinder
Lift Arm
Cylinders
Steering Valve
Control Valve
From
Pilot
Valve
(Bucket
Dump)
Bucket
Orifice
Hydraulic
Oil Tank
Lift Arm
From Pilot Valve
(Lift Arm Raise)
Check Valve
Hydraulic
Oil Tank
Priority
Valve
Spring
LS2
LS1
Spool
Main Pump
T4GB-02-02-012
T2-3-9
SYSTEM/Hydraulic System
• Lift Arm Raising/Steering Right
• When the steering wheel is turned right with the
lift arm raised, pilot pressure shifts the lift arm
spool in the control valve and the steering valve
spool.
• Pressure from the own pump is applied to Port
LS1 of the priority valve through Orifice 1, and
main pressure returning from the steering valve
spool through Orifice 3 and the spring force are
applied to Port LS2.
• Pressure at Port LS2 changes in proportion to the
steering valve spool stroke, and when pressure at
Port LS2 is low, the priority valve spool moves left
slightly, and when it is high, the spool moves left
drastically.
• Flow rate and direction of the main pump are
controlled by the leftward stroke of the priority
valve spool, and the flow rate corresponding to
the stroke flows to the steering valve, and the
remainder flow rate flows to the control valve.
NOTE: If the steering wheel is turned quickly and
largely for reasons of avoiding danger or
something, the priority valve spool largely
moves left, and much of the pressure oil
from the main pump is supplied to the
steering valve, delaying movement of the
front attachment.
• Pressure oil led to the steering valve flows to the
steering cylinders, and the vehicle body turns
right.
• Pressure oil led to the control valve also flows to
the lift arm cylinder though the check valve and
the lift arm spool, and raises the lift arm.
• In this way, steering and lift arm operations are
simultaneously made.
T2-3-10
SYSTEM/Hydraulic System
Bucket Cylinder
Steering Cylinders
Lift Arm
Cylinders
Steering Valve
Control Valve
Hydraulic
Oil Tank
From Steering
Pilot Valve
(Right Steering)
Bucket
Spool
Hydraulic
Oil Tank
From Pilot
Valve
(Lift Arm Raise)
Lift Arm
Check Valve
Hydraulic
Oil Tank
Priority Valve
Spring
Orifice 2
Orifice 1
Orifice 3
LS1
Spool
LS2
Main Pump
T4GB-02-02-013
T2-3-11
SYSTEM/Hydraulic System
Combined Operation Circuit (ZW250)
• Lift Arm Raising/Bucket Dumping
• When the bucket is dumped with the lift arm
•
•
•
•
•
•
•
•
raised, pilot pressure shift the lift arm and bucket
spools in the control valve.
Also, the same pilot pressure that changed the lift
arm spool in the control valve shifts the selector
valve spool downward as well.
Pressure from the own pump is applied to Port
LS1 of the priority valve, but Port LS2 is not
pressurized because it is connected to the
hydraulic oil tank.
Pressure at Port LS1 causes larger force than the
spring force of the priority valve, and moves the
spool right.
By movement of the spool, pressure oil from the
main pump flows to the lift arm cylinders through
the check valve in the control valve and the lift
arm spool, and raises the lift arm.
Pressure oil from the main pump also flows to the
bucket cylinder though the flow rate control valve
in the control valve and the bucket spool, and
dumps the bucket.
Lift arm raising operation is more heavy loaded
than the bucket dumping operation, but pressure
inside the spring chamber rises in the bucket
dumping operation because shift of the selector
valve is over.
Raised pressure in the spring chamber prevents
the flow rate control valve from moving much, and
flow of pressure oil to the bucket spool is
restricted.
As a result, flow rate to the lift arm cylinders is
secured, causing smooth operation of the lift arm
cylinders and bucket cylinder.
T2-3-12
SYSTEM/Hydraulic System
Steering Cylinders
Bucket Cylinder
Lift Arm
Cylinders
From Pilot Valve
(Bucket Damp)
Flow Rate
Spring
Control Valve Chamber
Steering Valve
Control Valve
Bucket
Hydraulic
Oil Tank
From Pilot Valve
(Lift Arm Raise)
Lift Arm
Selector Valve
From Pilot Valve
(Lift Arm Raise)
Check Valve
Priority
Valve
Hydraulic
Oil Tank
Spring
LS2
LS1
Spool
Main Pump
T4GB-02-02-018
T2-3-13
SYSTEM/Hydraulic System
• Lift Arm Raising/Steering right
• When the steering wheel is turned right with the
lift arm raised, pilot pressure shifts the lift arm
spool in the control valve and the steering valve
spool.
• Pressure from the own pump is applied to Port
LS1 of the priority valve through Orifice 1, and
main pressure returning from the steering valve
spool through Orifice 3 and the spring force are
applied to Port LS2.
• Pressure at Port LS2 changes in proportion to the
steering valve spool stroke, and when pressure at
Port LS2 is low, the priority valve spool moves left
slightly, and when it is high, the spool moves left
drastically.
• Flow rate and direction of the main pump are
controlled by the leftward stroke of the priority
valve spool, and the flow rate corresponding to
the stroke flows to the steering valve, and the
remainder flow rate flows to the control valve.
NOTE: When the steering wheel is turned quickly
and largely for reasons of avoiding danger
or something, the priority valve spool
largely moves left, and much of the
pressure oil from the main pump is
supplied to the steering valve, delaying
movement of the front attachment.
• Pressure oil led to the steering valve flows to the
steering cylinders, and the vehicle body turns
right.
• Pressure oil led to the control valve also flows to
the lift arm cylinders though the check valve and
the lift arm spool, and raises the lift arm.
• In this way, steering and lift arm operations are
simultaneously made.
T2-3-14
SYSTEM/Hydraulic System
Bucket Cylinder
Steering Cylinders
Lift Arm
Cylinders
Steering Valve
Control Valve
Hydraulic
Oil Tank
From Steering
Pilot Valve
(Right Steering)
Bucket
Spool
Hydraulic
Oil Tank
Lift Arm
From Pilot
Valve
(Left Arm
Raise)
Check Valve
Hydraulic
Oil Tank
Priority Valve
Spring
Orifice 2
Orifice 1
Orifice 3
LS1
Spool
LS2
Main Pump
T4GB-02-02-019
T2-3-15
SYSTEM/Hydraulic System
(Blank)
T2-3-16
SYSTEM/Hydraulic System
PILOT CIRCUIT
Outline:
Pressure oil from the pilot pump is used to operate the
circuit below.
• Charging Block Circuit
• Front Attachment Operation Control Circuit
• Pump Control Circuit
• Brake Circuit
• Ride Control Circuit (Optional)
Front Attachment
Control Circuit
Pilot Shutoff
Valve
Lift Arm Pilot
Valve
Bucket Pilot
Valve
Optional Pilot
Valve
Control Valve
Brake
Valve
Service
Brake
Brake Circuit
Parking
Brake
Main Pump
Regulator
Charging Block
Ride
Control
Solenoid
Valve
Spool
Pump Control Circuit
Ride Control Circuit
(Optional)
Ride Control Valve
Charging Block Circuit
Pilot
Filter
Pilot
Pump
Suction
Filter
Hydraulic
Oil
Tank
T4GC-02-02-001
T2-3-17
SYSTEM/Hydraulic System
Charging Block Circuit
• Charging block is installed for supplying pressure
oil from the pilot pump preferentially to the service
brake circuit, while distributing it to other pilot
circuits as well.
• When the engine is started, oil is delivered from
the pilot pump, and enters the charging block.
• At this time, when the amount of accumulated
pressure of the service brake accumulators is low,
the relief valve is closed.
• In this case, only pilot pressure is applied to Port
B of the priority valve, but both the pilot pressure
and the spring force are applied to Port A. So, the
priority valve moves right, restricting pressure oil
to flow further.
• Pressure oil from the pilot pump flows toward the
service brake circuit through the check valve, and
accumulates the service brake accumulators.
(to be continued to T2-3-20)
NOTE: Spring of the priority valve is so adjusted
that the valve is not completely closed.
Even in the minimum opening condition, a
certain amount of pressure oil is being
supplied to the circuits downstream.
T2-3-18
SYSTEM/Hydraulic System
Service Brake
Brake
Valve
Front Brake
Service Brake
Accumulators
Brake
Valve
Rear Brake
Check
Valves
Relief Valve
B
Priority
Valve
A
Spring
Charging Block
Pilot Pump
NOTE: Illustration shows oil flow when the priority
valve is closed in response to pressure
decrease in the service brake circuit.
T2-3-19
T4GC-02-02-002
SYSTEM/Hydraulic System
• When the service accumulators are pressurized
•
•
•
•
•
•
•
•
to a certain amount, the relief valve opens, and
pressure is lost because Port A of the priority
valve is connected to the hydraulic oil tank.
Pressure at Port B of the priority valve causes
larger force than the spring force, and moves the
priority valve spool left. So, pressure oil from the
pilot pump is all supplied to the priority valve and
the circuits downstream.
Pressure oil from the priority valve is supplied
through each port to the respective pilot circuits.
When pressure in the pilot circuit rises higher than
a certain amount, the pilot relief valve opens, and
prevents components of the pilot circuit from
being damaged.
Pressure oil from Port PS1 passes the steering
pilot valve to be supplied for actuation of the
steering valve spool. (Refer to Steering Circuit.)
Pressure oil from Port X changes its flow in
response to the stroke of the pump torque
control solenoid valve which is controlled by the
signal from MC, and is used for controlling the
main pump regulator.
(Refer to Pump Control Circuit.)
Pressure oil from Port BR3 is supplied for parking
brake release pressure by operation of the
parking brake solenoid valve. (Refer to Parking
Brake Circuit)
Pressure oil from Port PS2 is supplied for
controlling the servo piston of the main pump
(Refer to Pump Control Circuit.) and the spool of
the ride control valve (Refer to Ride Control
Circuit.).
Pressure oil from Port PP enters each pilot valve
through the pilot shutoff valve, and is supplied to
the control valve for actuation of the spool. (Refer
to Front Attachment Operation Control Circuit.)
T2-3-20
SYSTEM/Hydraulic System
Bucket
Pilot Valve
Lift Arm
Pilot Valve
Spare Pilot
Valve (Optional)
Pilot Shutoff Valve
To Service Brake
Circuit
Service Brake
Accumulators
Priority Valve
Relief Valve
B
Pilot Pump
Pilot
Relief Valve
Hydraulic Oil Tank
PS1
A
Spring
X
Pump Torque Control
Solenoid Valve
BR3
PS2
Parking Brake
Pressure Sensor
Parking Brake
Solenoid Valve
PP
Charging Block
NOTE: Illustration shows the oil flow in neutral
condition of the pilot valve when the service
brake accumulators are pressurized, the
priority valve is open, and the pilot shutoff
valve is open.
T2-3-21
T4GB-02-02-020
SYSTEM/Hydraulic System
Front Attachment Operation Control Circuit
(ZW220)
• Pressure oil from the pilot pump flows the
•
•
•
•
charging block, and comes out of Port PP of the
charging block to be supplied to each pilot valve
through the pilot shutoff valve.
Priority valve of the charging block supplies
pressure oil preferentially to the service brake
circuit when pressure in the service brake
accumulators are lowered. (Refer to Charging
Block Circuit.)
Pilot shutoff valve is a manually operated type,
and is installed for prevention of accidents due to
mistaken operation by stopping suppy of pressure
oil to the pilot valve when it is closed.
By controlling each pilot valve, pressure oil from
the pilot pump shifts the control valve spools.
At both ends of the spool for the lift arm cylinders
of the control valve, slow-return valves are
installed for moderating sudden movement of the
spool.
T2-3-22
SYSTEM/Hydraulic System
Bucket
Pilot Valve
1
2
Lift Arm
Pilot Valve
3
4
Spare Pilot
Valve (Optional)
5
6
7
8
Control Valve
Pilot Shutoff Valve
8
Spare 2
7
To Service Brake
Circuit
Service Brake
Accumulators
6
Priority Valve
2
Spare 1
5
Bucket
1
Pilot Pump
4
Slow-Return
Valves
Lift Arm
3
Main Pump
PP
T4GB-02-02-002
Charging Block
NOTE: Numeral of each port of the pilot valves and
the control valve shows the port to be
connected.
Illustration shows the oil flow in neutral
condition of the pilot valve when the service
brake accumulators are pressurized, the
priority valve is open, and the pilot shutoff
valve is open.
T2-3-23
SYSTEM/Hydraulic System
Front Attachment Operation Control Circuit
(ZW250)
• Pressure oil from the pilot pump flows the
•
•
•
•
charging block, and comes out of Port PP of the
charging block to be supplied to each pilot valve
through the pilot shutoff valve.
Priority valve of the charging block supplies
pressure oil preferentially to the service brake
circuit when pressure in the service brake
accumulators are lowered. (Refer to Charging
Block Circuit.)
Pilot shutoff valve is a manually operated type,
and is installed for prevention of accidents due to
mistaken operation by stopping suppy of pressure
oil to the pilot valve when it is closed.
By controlling each pilot valve, pressure oil from
the pilot pump shifts the control valve spool.
At both ends of the spool for the lift arm cylinders
of the control valve, slow-return valves are
installed for moderating sudden movement of the
spool.
T2-3-24
SYSTEM/Hydraulic System
Bucket
Pilot Valve
1
Lift Arm
Pilot Valve
2
3
4
Spare Pilot
Valve (Optional)
5
6
7
8
Control Valve
Pilot Shutoff Valve
8
Spare 2
7
To Service Brake
Circuit
Service Brake
Accumulators
6
Priority Valve
2
Spare 1
5
Bucket
1
Pilot Pump
4
Slow-Return
Valves
Lift Arm
3
Main Pump
PP
Charging Block
T4GB-02-02-021
NOTE: Numeral of each port of the pilot valves and
the control valve shows the port to be
connected.
Illustration shows the oil flow in neutral
condition of the pilot valve when the service
brake accumulators are pressurized, the
priority valve is open, and the pilot shutoff
valve is open.
T2-3-25
SYSTEM/Hydraulic System
Pump Control Circuit
(Refer to COMPONENT OPERATION / Pump
Device group)
• Pump Control by Servo Piston Control Pressure
• Servo piston control pressure (PS2) is supplied
from the charging block for actuation of the servo
piston of the main pump.
• Pump Flow Rate Control by Flow Rate Control
Pressure (Pi1/Pi2)
• Pressures upward and downward the orifice – Pi1
and Pi2 – of the pump flow rate control valve
installed at the farthest downstream of the control
valve neutral circuit are supplied to the main
pump regulator for adjusting the pump flow rate.
• Pump Flow Rate Control by Pump Torque Control
Solenoid Valve
• Signal from MC actuates the pump torque control
solenoid valve, and controls the pressure (X)
supplied to the main pump regulator for
controlling the pump flow rate.
T2-3-26
SYSTEM/Hydraulic System
Charging Block
Pilot Pump
Pump Torque Control
Solenoid Valve
Hydraulic Oil Tank
Command Signal from MC
Pilot Presser (X)
PS2
Pump From Control Valve
Orifice
Control Valve
Pi2
Pi1
Main Pump
Servo
Piston
Main Pump
Regulator
T4GB-02-02-003
NOTE: Control valve illustrated is for ZW220.
T2-3-27
SYSTEM/Hydraulic System
Brake Circuit
Service Brake Circuit
(Refer to COMPONENT OPERATION / Charging
Block)
(Refer to COMPONENT OPERATION / Brake
Valve)
• Pressure oil from the pilot pump flows through the
charging block, and is accumulated in the service
brake accumulators.
• By stepping the brake pedal, pressure in the
service brake accumulators is applied to the front
brake and the rear brake through the brake valve,
and actuates the service brake.
• When the brake pedal is stepped several times,
pressure inside the service brake accumulators is
lowered, and the relief valve is closed.
• Priority valve spool moves right, and pressure in
the service brake accumulators is kept constant
by preferentially supplying pressure oil from the
pilot pump to the service brake circuit, and firmly
brakes the vihicle.
Parking Brake Circuit
• Pressure oil from the pilot pump is applied to the
parking brake solenoid valve through the charging
block.
• When the parking brake is switched OFF, the
parking brake solenoid valve is excited, and
pressure oil entering the parking brake cylinder
releases the parking brake.
• If the parking barke is switched ON, the parking
brake solenoid valve is unexcited, and resultant
stop of pressure oil supply to the parking brake
causes working of the parking brake.
• Even if pressure is lowered caused by damage of
hose or something in the upstream of the solenoid
valve, the parking brake accumulators so function
as to retain the parking brake circuit pressure for
a certain period of time.
NOTE: Spring of the priority valve is so adjusted
that the valve is not completely closed.
Even in the minimum opening condition, a
certain amount of pressure oil flow is being
supplied to the circuits downstream.
NOTE: Even when the engine is stopped, the
service brake circuit pressure is retained
for a while with the functions of the service
brake accumulators and the check valve.
T2-3-28
NOTE: Parking brake is released when the
solenoid valve is excited.
SYSTEM/Hydraulic System
Service Brake
Brake
Pedal
Front Brake
Service Brake
Accumulators
Brake
Valve
Rear Brake
Check
Valves
Relief Valve
Priority
Valve
Spring
Parking Brake
Pressure Sensor
Parking
Brake
Solenoid
Valve
Parking Brake
Release
Pilot
Accumulator
No Signal for
Parking Brake
Release
Brake
Charging Block
Pilot Pump
NOTE: Illustration shows oil flow when the relief
valve and the priority valve are open in
response to pressure increase in the
service brake circuit, and also oil flow when
the parking brake is working with the
unexcitement of the parking brake solenoid
valve.
T2-3-29
T4GC-02-02-003
SYSTEM/Hydraulic System
Ride Control Circuit (Optional)
(Refer to SYSTEM / Electric-Hydraulic Combined
Circuit Control in Control System)
• In front attachment operation, operating pressure
from the lift arm cylinders is accumulated in the
ride control accumulator through the charge cut
spool.
• When the ride control switch is turned ON, the
ride control solenoid valve is excited, and the
spool moves downward.
• Bottom end of the lift arm cylinders is connected
with the ride control accumulator, while the rods
side end of the lift arm cylinders is connected to
the hydraulic oil tank.
• In this way, force to raise the front attachment is
relieved to the hydraulic oil tank, and force to
lower the front attachment is absorbed by the ride
control accumulator, thus enabling stable
traveling on rough roads.
T2-3-30
SYSTEM/Hydraulic System
Ride Control
Accumulator
Lift Arm Cylinders
To Control
Valve
Ride Control Valve
Ride Control
Command Signal
Ride Control
Solenoid Valve
Spool
Charge Cut
Spool
Hydraulic Oil Tank
Pilot
Pump
NOTE: Illustration shows oil flow when the ride
control solenoid valve is excited.
T2-3-31
T4GB-02-02-009
SYSTEM/Hydraulic System
STEERING CIRCUIT
Normal Steering Circuit
• Normally, pressure oil from the main pump flows
to the steering valve through the priority valve, but
is not pressurized because the pilot line (LS2) is
led to the hydraulic oil tank.
• Therefore, pressure oil is all supplied to the
control valve because the priority valve spool is
shifted to the right pushed by pressure (LS1) from
the own main pump large enough to overcome
the spring force of the priority valve.
• When the steering wheel is turned, the spool in
the steering pilot valve is shifted, and pressure oil
from the pilot pump moves the steering valve
spool.
• When the steering wheel is quickly turned, a large
amount of pilot pressure oil is supplied in a short
period of time to the end of the steering valve
spool through the steering pilot valve, and the
steering valve spool moves quickly and largely.
• When the steering wheel is slowly turned, a small
amount of pilot pressure oil is supplied gradually
to the end of the steering valve spool through the
steering pilot valve, and the steering valve spool
moves slowly and slightly.
• In proportion to the stroke of the steering valve
spool, pressure in the pilot line (LS2) rises, and
the priority valve spool is pushed left by the spring
force of the priority valve and pressure of the pilot
line (LS2).
• In this way, pressure oil from the main pump flows
to the steering cylinders through the priority valve
and the steering valve, and the steering cylinders
are
actuated.
(Refer
to
COMPONENT
OPERATION / Pump Device)
T2-3-32
NOTE: When pressure oil passes inside the
steering pilot valve, it flows to the steering
valve after passing the Gerotor part.
Gerotor is connected with the middle shaft
of the pilot steering valve, so powered
steering effect is generated. (Refer to
COMPONENT OPERATION / Steering
Pilot Valve)
SYSTEM/Hydraulic System
Steering Cylinders
Steering
Accumulators
Steering Valve
Hydraulic Oil Tank
Spool
Orifice
Orifice
Pump
Discharge Pressure
Switch
Steering
Pilot
Valve
To Control
Valve
Gerotor
Spool
Priority
Valve
Spring
Emergency
Steering
Pump Equipment
LS2
Steering
Wheel
LS1
Pilot
Pump
Hydraulic
Oil Tank
Main Pump
NOTE: Illustration shows flow of pressure oil when
the steering wheel is turned right.
T2-3-33
T4GB-02-02-023
SYSTEM/Hydraulic System
Steering Shock Damping Circuit
• Pressure of the pressure oil supplied from the
steering pilot valve to the spool end of the
steering valve is reduced by passing through the
orifice inside the steering valve, and is applied to
the spool end of the opposite side. In this way, the
vehicle shock due to sudden shift of the spool is
damped, and stable steering operation is possible.
(Refer to COMPONENT OPERATION / Steering
Valve)
• Steering accumulators are provided for damping
the joggling of the vehicle taking place at stop of
the steering wheel rotation.
Emergency Steering Circuit (Optional)
• When traveling, if the main pump delivery is
stopped or drastically decreased caused by
failure of the engine or the main pump, the signal
of the pump delivery pressure switch is
transmitted into the monitor controller, and the
monitor controller starts the motor of the
emergency steering pump equipment.
• Pressure oil is supplied from the emergency
steering pump for 1 minute, and steering
operation is possible.
• When 1 minute have passed or when the key
switch has been turned OFF after moving the
vehicle to a safe place, the emergency steering
pump stops.
NOTE: When engine is started, the monitor unit
automatically
starts
the
emergency
steering pump unit to confirm its function.
When the pressure sensing signal of the
emergency
steering
pump
delivery
pressure switch enters the monitor unit, the
emergency
steering
pump
unit
automatically stops.
T2-3-34
SYSTEM/Hydraulic System
Steering Cylinders
Steering
Accumulators
Steering Valve
Spool
Orifice
Orifice
Pump
Delivery Pressure
Switch
Steering
Pilot
Valve
To Control
Valve
Gerotor
Spool
Priority
Valve
Spring
Emergency
Steering
Pump Delivery
Pressure Sensor
Emergency
Steering
Pump Equipment
LS2
Steering
Wheel
LS1
Pilot
Pump
Main Pump
NOTE: Illustration shows flow of pressure oil when
the steering wheel is turned right.
T2-3-35
T4GB-02-02-023
SYSTEM/Hydraulic System
Steering Stop Circuit
(Refer to COMPONET OPERATION / Steering
Valve)
• When either of the left or right cylinder is at the
• As a result, the steering valve spool is shifted at
stroke end, the stop valve spool contacts the
frame, and the stop valve closes to block
pressure oil from being supplied to the steering
valve from the steering pilot valve.
neutral, and supply of pressure oil from the main
pump to the steering cylinders is stopped.
Steering Cylinders
Steering Valve
Spool
Stop
Valve
Stop
Valve
External Force
Applied
Steering
Pilot Valve
Main Pump
Pilot Pump
Hydraulic
Oil Tank
T4GB-02-02-00
NOTE: Illustration shows flow of oil when the
steering valve is turned right.
T2-3-36
SYSTEM/Hydraulic System
(Blank)
T2-3-37
SYSTEM/Hydraulic System
HYDRAULIC DRIVE FAN CIRCUIT
(Refer to COMPONET OPERATION / Others)
(Refer to COMPONET OPERATION / Hydraulic Fan
Motor)
• Pressure oil from the fan pump flows to the fan
•
•
•
•
•
•
motor for radiator cooling through the flow control
valve and the reverse rotation spool.
Electric current corresponding to the oil
temperature is sent from MC to the flow control
solenoid valve.
Pressure oil is supplied to the flow control valve
spool end in response to the stroke of the flow
control solenoid valve, when it is excited.
When the flow control valve is operated, pressure
oil from the fan pump to the fan motor is restricted,
and speed of the fan motor is controlled.
When the fan reversing rotation switch is turned
ON, electric current flows from MC to the reverse
rotation control solenoid valve.
When the reverse rotation control solenoid valve
is operated, pressure oil is supplied to the reverse
rotation spool end.
When the reverse rotation spool is shifted, the
inlet port of pressure oil supplied to the fan motor
is shifted, and the fan motor rotates reversely.
T2-3-38
SYSTEM/Hydraulic System
Fan Motor
Reverse Rotation Spool
Reverse Rotation Control
Solenoid Valve
Reverse Rotation
Signal from MC
Flow Control Valve
Flow Control Solenoid Valve
Hydraulic oil
Tank
Hydraulic oil
Tank
Fan Pump
Flow Adjustment
Signal from MC
NOTE: Illustration shows flow of pressure oil
controlling nothing.
T2-3-39
T4GB-02-02-008
SYSTEM/Hydraulic System
(Blank)
T2-3-40
SYSTEM/Electric System
OUTLINE
Electric circuit can largely be divided into the main
circuit part, lamplight circuit and control circuit
• Main Circuit
Circuit for engine start/stop, circuit for battery
charging, and circuit for accessories
• Lamplight Circuit
Circuit for use in traveling (composed of head lights,
turn signals, brake lights, and horn)
• Control Circuit (Refer to the SYSTEM/Control
System.)
Control circuit for engine, pumps, transmission, and
valves [composed of actuators like solenoid valves,
MC (main controller), ECM (engine control module),
ICF (information controller), monitor unit, switches,
sensors, and pressure switches]
In this chapter, functions and compositions of the main
circuit and lamplight circuit are explained.
T2-4-1
SYSTEM/Electric System
MAIN CIRCUIT
• Electric Power Circuit: for supplying electricity to
the electric system as power source
• Indicator Light Check Circuit: for checking monitor
warning lamps and indicators
• Accessory Circuit: for working at ACC of the key
switch
• Preheat Circuit: for assisting engine start in chilly
weather
• Starting Circuit: for starting engine
• Charging Circuit: for supplying electricity to the
battery and replenishing electricity
• Surge Voltage Prevention Circuit: for preventing
occurrence of surge voltage at stop of the engine
• Engine Stop Circuit: for stopping the engine by
the ECM
T2-4-2
SYSTEM/Electric System
ELECTRIC
POWER
SWITCH:OFF)
CIRCUIT
(KEY
Ground terminal of the battery is earthed to the base
machine. Electric current from the plus terminal flows
as follows at OFF of the key switch.
→
Even at OFF of the key switch, very small amount of
electric current is being supplied to the circuit, so the
ground terminal of the battery needs to be
disconnected in case of a long downtime.
#6 Terminal
Key Switch
Head Light Switch
Battery
↓
Fusible
Link
→ Fuse Box B
→
#11 Terminal
→
#9 Terminal
Load Dump Relay
→
#2 Terminal
GPS
Flasher Relay
ICF
MC
Optional Control Unit (Optional)
→
#7 Terminal
ECM Relay
→
#37 Terminal
Interior Light
Radio
MC
→
→
#381 Terminal
#711 Terminal
Optional Control Unit (Optional)
Monitor Unit
Head Light Switch
Key Switch
Fuse Box B
348
149
126
6
11
9
35
158
127
2
7
39
42
37
381
711
Fusible
Link
Battery
Relay
638
34
263
70
710
75
Battery
T4GC-02-04--001
T2-4-3
SYSTEM/Electric System
INDICATOR LIGHT CHECK CIRCUIT (KEY
SWITCH:ON)
• When the key switch is turned ON, Terminal B is
• Monitor unit checks warning lamps and indicators
connected inside the key switch to ACC and
Terminal M.
• Electric current from Terminal M of the key switch
is enters #67 Terminal of the monitor unit.
by lighting them, and also starts the liquid crystal
display.
Key Switch
Fuse Box B
348
149
577
327
222
323
6
11
9
35
158
127
2
838
711
75
148
126
638
34
263
Monitor Unit
67
Fusible
Link
Battery
Relay
Battery
T4GB-02-03-002
T2-4-4
SYSTEM/Electric System
ACCESSORY CIRCUIT
• At ACC of the key switch, Terminal B is connected
inside the key switch to Terminal ACC.
• Electric current from Terminal ACC of the key
switch enters #3 Terminal of the radio through #34
and #35 Terminals of Fuse Box B, enabling the
radio to work.
Key Switch
Fuse Box B
Radio
Fusible
Link
348
149
577
327
222
323
6
11
9
35
158
127
2
838
711
75
Battery
Relay
148
126
638
34
Battery
T4GB-02-03-003
T2-4-5
SYSTEM/Electric System
PREHEAT CIRCUIT (KEY SWITCH:ON)
• When the key switch is turned ON, Terminal B is
connected inside the key switch to Terminal M.
• Part of the electric current from Terminal M flows
•
•
•
•
•
•
to the glow relay, and the remainder excites the
battery relay through #54 and #55 Terminals of
Fuse Box A, and the battery power source
supplies electricity to the glow relay through the
fuse (100A).
Electric current from #55 Terminal of Fuse Box A
also enters #56 Terminal of ECM, and the
preheating circuit of the ECM is started.
Signal corresponding to the coolant temperature
is being transmitted from the coolant temperature
sensor to #283 Terminal of the ECM.
ECM earths #60 Terminal, and controls the
excitement time of the glow relay if the coolant
temperature is below a set temperature.
While the glow relay is being excited, electricity
from the power source is supplied to the glow plug
from the glow relay, and so preheating is made.
While preheating is being made, as #233 Terminal
of the ECM is earthed, electricity flows from #233
Terminal of the monitor unit to #233 terminal of
the ECM, and the monitor unit lights the glow
signal.
In case preheating is not made, the glow signal is
lit for two seconds for checking of indicator lights.
NOTE: In case preheating has been made,
preheating continues for a certain period of
time even after the engine start
(after-heating), but the glow signal is not lit.
T2-4-6
SYSTEM/Electric System
Key Switch
Fuse Box A
264
362
692
157
From #6 Terminal
of Fuse Box B
55
163
693
108
54
12
99
698
699
700
697
79
Glow Relay
Monitor
Unit
Glow
Signal
Glow Plug
233
Coolant Temperature
Sensor
Fuse
(100A)
60
56
283
284
233
Battery
Relay
Fusible
Link
To #638 Terminal of
Fuse Box B
ECM
Battery
T4GB-02-03-004
NOTE: Illustration shows flow of electricity in case
preheating is being made with the glow
relay excited and glow plug supplied with
electricity from the power source.
T2-4-7
SYSTEM/Electric System
STARTING
START)
CIRCUIT
(KEY
SWITCH:
Operation of Starter Relay
Forward/Reverse Lever at Neutral Position
• At START of the key switch, Terminal B is
• At START of the key switch, continuity is made
connected inside the key switch to Terminals M
and ST.
Electric current from Terminal M excites the
battery relay through #54 and #55 Terminals of
Fuse Box A, so electricity from the battery power
source is led from the battery relay to Terminals B
of the starter motor and the starter relay.
Electric current from Terminal ST of the key switch
flows through the neutral relay to Terminal S of
the starter relay and the coil inside.
Starter relay is turned ON, and electric current
also flows to Terminal S of the starter from
Terminal C of the starter relay.
As a result, the relay inside the starter is turned
ON, and the starter motor rotates.
Also, the electric current from Terminal M of the
key switch flows to all the controllers as a signal
for notifying the key position at ON or START.
between Terminals B and ST of the key switch,
and electric current flows to the base of Transistor
Q2 through Resistance R4 inside the starter relay.
Transistor Q2 is turned ON, and electric current
flows to Coil L of the relay.
As a result, Terminals B and S of the starter are
connected, and the starter operates.
• When the engine is started, the alternator begins
charging, and the voltage of Terminal R of the
starter relay raises.
• If this voltage reaches 21 – 22 V, Zener Diode Z is
turned ON. As a result, Transistor Q1 is turned ON,
and Transistor Q2 is turning OFF because no
electric current flows to its base.
At this moment, continuity between Terminals B
and S of the starter is lost, and the starter is
turned OFF.
• C1 shown in the illustration below indicates a
condenser for stabilizing working voltage.
D4 is a diode for protection from reverse
connection of the battery.
•
•
•
•
•
Starter Relay
B
S
D3
(1)
R3
R2
From Terminal L
of Alternator
Z
R
L
R4
D2
Q1
C1
C
C
(2)
(1)
S
Q2
M
B
(2)
Starter
E
D4
B
ST
Key Switch
Neutral Relay
12V
Battery
12V
T4GB-02-03-019
T2-4-8
SYSTEM/Electric System
Key Switch
264
Fuse Box A
362
692
From #6 Terminal
of Fuse Box B
Signal of Key ON
to (Monitor Unit)
Signal of Key ON to
(MC, ECM, and ICX)
157
464
55
163
693
108
12
54
79
99
699
700
697
No Forward/Reverse Signal
Neutral Relay
To #638 Terminal
of Fuse Box B
Fuse
(100A)
Starter
Relay
Fusible
Link
Battery
Relay
Battery
Starter
Motor
Alternator
T4GC-02-04--002
T2-4-9
SYSTEM/Electric System
Forward/Reverse Lever at Operate Position
• Starting Safety Circuit (Neutral Relay)
• At START of the key switch, Terminal B can be
•
•
•
•
•
connected inside the key switch to Terminals M
and ST.
Electric current from Terminal ST of the key switch
flows to the neutral relay, and the electric current
from Terminal M of the key switch flows to the
Terminals #54 and #55 of Fuse Box A then excites
the battery relay.
By exciting the battery relay, electricity from the
battery power source flows to Terminals B of the
starter motor and the starter relay.
At this moment, either of the forward-reverse
lever and the forward-reverse switch is at forward
or reverse, the neutral relay is excited.
Circuit between the neutral relay and Terminal S
of the starter relay is blocked by excites the
neutral relay.
Therefore, in case either of the forward-reverse
lever and the forward-reverse switch is at forward
or reverse, the starter motor is not operated even
if the key switch is at START.
T2-4-10
SYSTEM/Electric System
Key Switch
Fuse Box A
264
362
692
210
From #6 Terminal
of Fuse Box B
157
464
55
163
693
108
12
54
79
99
698
699
700
Forward/Reverse
Operation Signal
697
Neutral Relay
To #638 Terminal
of Fuse Box B
Fuse
(100A)
Starter
Relay
Fusible
Link
Battery
Relay
Battery
Starter
Motor
T4GB-02-03-006
T2-4-11
SYSTEM/Electric System
CHARGING CIRCUIT (KEY SWITCH:ON)
• Engine starts, and the key switch returns to ON
automatically.
• At ON, Terminal B is connected inside the key
switch to ACC and Terminal M.
• Electric current from Terminal M of the key switch
excites the battery relay through #54 and #55
Terminals of Fuse Box A.
• When the engine rotates, the alternator begins to
generate electricity, and the electric current from
Terminal B of the alternator flows to the battery
through the battery relay, charging the battery.
• In the mean time, the electric current from
Terminal L of the alternator flows to #119 Terminal
of the monitor unit to have the monitor unit turn off
the alternator indicator, and also flows to #594
Terminal of the ICF and #592 Terminal of the GPS
to record history data of the engine operation
time.
T2-4-12
SYSTEM/Electric System
Key Switch
Fuse Box A
264
362
692
From #6 Terminal
of Fuse Box B
Alternator
Indicator
Monitor
Unit
592
GPS
119
594
ICX
157
464
55
163
693
108
12
144
133
121
696
695
698
699
700
54
79
99
120
674
697
To #638 Terminal
of Fuse Box B
Fuse
(100A)
Starter
Relay
Fusible
Link
Battery
Relay
Battery
Starter
Motor
T4GB-02-03-007
Alternator
T2-4-13
SYSTEM/Electric System
Operation of Alternator
• Alternator consists of Field Coil FC, Stator Coil SC,
• At first, electric current is not flowing to Field Coil
Diode D, and others.
Regulator consists of Transistors T1 and T2, Zener
Diode ZD, Resistances R1 and R2, and others.
Terminal B of the alternator is connected to Base
B of Transistor T1 as follows.
B - R - RF - (R) - R1 - Base B of Transistor T1
At On of the battery relay, the battery voltage
works on Base B of Transistor T1 of the regulator,
and continuity is made between Collector C and
Emitter E. In other words, the earth end of Field
Coil FC is grounded through Transistor T1.
FC. When the rotor rotates, alternating voltage is
generated in Stator Coil SC by the remanent
magnetism of the rotor itself.
• Electric current flows to Field Coil FC, and further
magnetizes the rotor, resulting in rise of electric
generation voltage. This further raises electric
generation voltage, and charging the battery
begins.
•
•
•
•
Alternator
B
Battery Relay
R
L
RF
(R)
Regulator
R3
R4
R5
R6
D
ZD
R2
Battery
B
SC
E
R1
FC
C
T2
B
D1
(F)
G
C
E
T1
(G)
T157-04-02-008
T2-4-14
SYSTEM/Electric System
Operation of Regulator
• As electric generation voltage rises higher than
• If voltage working on Zener Diode ZD lowers
the set voltage of Zener Diode ZD, electric current
flows to Base B of Transistor T2, and continuity is
made between Connector C and Emitter E.
• Operation of Transistor T2 stops flow of the
electric current to Base B of Transistor T1, and
turns T1 OFF.
• Electric current stops flowing to Field Coil FC, and
electric generation voltage of Stator Coil SC
lowers.
below the set voltage, Transistor T2 is turned OFF,
and Transistor T1 is turned ON again.
• Electric current flows to Field Coil FC, and electric
generation voltage of Stator Coil SC is raised.
• Electric generation voltage of the alternator is
kept constant by repeating the above operations.
RF
Battery Relay
R3
R4
R5
R6
Battery
ZD
R2
B
SC
A
E
C
FC
R1
(F)
G
D1
B
C
T2
E
T1
(G)
T157-04-02-009
T2-4-15
SYSTEM/Electric System
SURGE VOLTAGE PREVENTION CIRCUIT
• When the engine is stopped (key switch: OFF),
•
•
•
•
•
the electric current from Terminal M of the key
switch is stopped, and the battery relay is turned
OFF.
Even if the key switch is turned off, the engine
does not stop immediately keeping freewheeling,
and the alternator continues generation of
electricity.
As the generated electric current does not flow to
the battery, surge voltage (voltage rise) is
generated, resulting in causes for failures of
electronic equipment like the controller and other
parts. For this reason, the surge voltage
protection circuit is provided.
During charging, the electric generation current
from Terminal L of the alternator enters #119
Terminal of the monitor unit. Monitor unit earths
#33 Terminal to the ground.
Electric current flows to the excitement circuit of
the load dump relay, and the load dump relay
works.
Therefore, even if the key switch is turned OFF
during rotation of the engine, the electric current
from the battery keeps exciting the battery relay
through the load dump relay. Also, the battery
relay is turned OFF about ten seconds after the
alternator stops generation of electricity.
T2-4-16
SYSTEM/Electric System
Key Switch
Load Dump
Relay
33
Monitor
Unit
119
Fuse Box B
348
149
577
327
222
323
6
11
9
35
158
127
2
838
7
39
42
37
381
711
70
148
126
638
34
263
710
75
Fuse
(100A)
Starter
Relay
Fusible
Link
Battery
Relay
Battery
Starter
Motor
T4GB-02-03-008
Alternator
T2-4-17
SYSTEM/Electric System
ENGINE STOP CIRCUIT
• When the key switch is turned OFF from ON, the
• ECM unexcited the fuel injection solenoid valve,
electric current flowing from Terminal M to #56
Terminal of the ECM to show the key switch at ON
is stopped.
and the engine is stopped.
Key Switch
Fuse Box A
264
362
692
210
From #6 Terminal
of Fuse Box B
157
54
55
163
80
108
12
79
99
698
699
700
697
To #638 Terminal
of Fuse Box B
Fuel Injection
Solenoid Valve
56
Fuse
(100A)
Fusible
Link
Battery
Relay
ECM
Battery
T4GB-02-03-009
T2-4-18
SYSTEM/Electric System
LAMPLIGHT CIRCUIT
• Head Light Circuit: for turning on and off head
lights, clearance lights and license light.
• Turn Signal Circuit: for turning on and off turn
signals
• Brake Light Circuit: for turning on and off brake
lights
• Hazard Light Circuit: for turning on and off hazard
light indicators
• Horn Circuit: for sounding horn
• Reverse Light/Buzzer Circuit: for turning on and
off reverse lights and reverse buzzer
• Parking Brake Circuit: for working and releasing
parking brake
• Emergency Steering Check Circuit (Optional): for
confirming operation of emergency steering pump
unit
T2-4-19
SYSTEM/Electric System
HEAD LIGHT CIRCUIT
Clearance and License Light Circuit
• Terminal B of the key switch is directly connected
to the head light switch.
• When the head light switch is positioned at
(Clearance Lights), part of the electricity from the
S terminal of the head light switch enters #47
Terminal of the monitor unit, and the illumination
light of the monitor unit is lit.
• Remainder of the electricity from the S terminal of
the head light switch enters #710 Terminal of
Fuse Box B, and further divided to #39 and #42
Terminals.
• Electricity from the power source coming out of
#39 Terminal of Fuse Box B lights front left and
rear left clearance lights.
• Electricity from the power source coming out of
#42 Terminal of Fuse Box B lights the license light
and the front right and rear right clearance lights.
T2-4-20
SYSTEM/Electric System
Head Light Switch
Key Switch
Fuse Box A
Illumination
Light
264
362
692
210
124
135
47
Monitor
Unit
157
123
55
63
163
54
121
696
695
698
699
700
120
Front Right
Clearance Light
694
697
Fuse Box B
838
348
149
577
Rear Right
Clearance Light
126
6
11
9
35
158
127
2
License
Light
638
34
263
7
39
42
37
381
711
70
710
75
Rear Left
Clearance Light
Fusible
Link
Front Left
Clearance Light
Battery
Battery Relay
T2-4-21
T4GB-02-03-010
SYSTEM/Electric System
Head Light Lighting Circuit
• When the key switch is turned ON, the electricity
•
•
•
•
•
•
from the power source coming out of Terminal M
of the key switch excites the battery relay through
#54 and #55 Terminals of Fuse Box A, and the
electricity from the battery power source flows to
Fuse Box A and Fuse Box B.
Electricity from the battery power source coming
out of #124 Terminal of Fuse Box A enters the
right head light relay.
Electricity from the battery power source coming
out of #121 Terminal of Fuse Box A enters the left
head light relay.
Electricity from the battery power source coming
out of #127 Terminal of Fuse Box B enters the
high beam relay.
When the head light switch is positioned at
(Head Lights), the electricity from the power
source coming out of Terminal S lights each of the
clearance lights (Refer to Clearance Light
Lighting Circuit.), and the electricity from the
power source coming out of Terminal H flows to
the high-low beam switch.
At this moment, if the high-low beam switch is
turned to Lo (Low Beam), the electricity from the
power source enters the right head light relay and
the left head light relay, and the electricity from
the battery power source enters the head lights to
light them by exciting the respective relays.
If the high-low beam switch is turned to Hi (High
Beam), the electricity from the power source
excites the high-beam relay, and the electricity
from the battery power source enters and lights
the high-beam lights. Electricity from the power
source coming out of the high-low beam switch
also enters #130 Terminal of the monitor unit, and
lights the high-beam indicators.
T2-4-22
SYSTEM/Electric System
Head Light Switch
High-Low Beam Switch
Key Switch
Lo
Hi
Fuse Box A
Monitor
Unit
High-Beam
Indicator
High-Beam Right Head Light Left Head Light
Relay
Relay
Relay
130
264
362
692
210
124
135
157
123
55
63
163
54
121
696
695
698
699
700
120
694
697
Fuse Box B
838
348
149
577
Right High-Beam Light
126
6
11
9
35
158
127
2
Right Head Light
638
34
263
7
39
42
37
381
711
Left High-Beam Light
Left Head Light
70
710
75
Fusible
Link
Battery
Battery Relay
T2-4-23
T4GB-02-03-018
SYSTEM/Electric System
TURN SIGNAL CIRCUIT
• Electricity from the battery power source also
• Electricity from the power source coming out of
flows to the flasher relay coming out of #11
Terminal of Fuse Box B.
• In case the turn signal switch is turned to left (L),
Terminal L of the turn signal switch is earthed, and
the left turn signal relay is excited.
the flasher relay enters the front and rear left turn
signal lights and #23 Terminal of the monitor unit
through the left turn signal relay.
• As a result, front and rear left turn signal lights
and the left turn signal indicators flicker.
Turn Signal Switch
Left
Turn Signal
Monitor
Unit
Right
Turn Signal
Key Switch
Left
Right
Turn Signal Relay Turn Signal
23
26
Rear Right
Turn Signal Light
Flasher
Relay
Fuse Box B
348
149
577
327
222
323
6
11
9
35
158
127
2
838
711
75
148
126
638
34
Front Right
Turn Signal
Rear Left
Turn Signal
Fusible
Link
Battery Relay
Front Left
Turn Signal
Battery
T4GB-02-03-011
T2-4-24
SYSTEM/Electric System
BRAKE LIGHT CIRCUIT
• When the key switch is turned ON, the electricity
• When the brake pedal is stepped, the brake light
from the power source coming out of Terminal M
of the key switch excites the battery relay, and the
electricity from the battery power source enters
#99 Terminal of Fuse Box A and the brake light
relay through #12 Terminal.
switch is earthed.
• As a result, the brake light relay is excited, and
the electricity from the battery power source
enters the brake lights, and light them.
Key Switch
From #6 Terminal
of Fuse Box B
Brake Light Relay
Brake Pedal
Fuse Box A
264
362
692
210
124
135
Brake Light Switch
55
163
693
108
12
144
133
121
696
695
698
699
700
Right Brake Light
157
123
54
79
99
120
694
697
Left Brake Light
Fusible
Link
Battery
Relay
Battery
To #638 Terminal
of Fuse Box B
T4GB-02-03-012
T2-4-25
SYSTEM/Electric System
HAZARD LIGHT CIRCUIT
• Electricity from the battery power source also
• Electricity from the power source coming out of
flows to the flasher relay coming out of #11
Terminal of Fuse Box B.
• In case the hazard switch is turned ON, the
hazard switch is earthed, and the left and right
turn signal relays are excited.
the flasher relay enters all of the front and rear left
and right turn signal lights and #23 and #26
Terminals of the monitor unit through the left and
right turn signal relays.
• As a result, all of the front and rear left and right
turn signal lights and the left and right turn signal
indicators flicker.
Turn Signal Switch
Left
Turn signal
Right
Turn signal
Monitor
Unit
Diode
A
Diode
C
Diode
B
Diode
D
Left Turn
Signal Relay
Right Turn
Signal Relay
23
26
Rear Right
Turn Signal Light
Front Right
Turn Signal Light
Hazard
Switch
Flasher
Relay
Key Switch
Fuse Box B
348
149
577
327
222
323
6
11
9
35
158
127
2
838
7
39
42
37
381
711
70
148
126
638
34
263
710
75
Rear Left
Turn Signal Light
Fusible
Link
Battery Relay
Front Left
Turn Signal Light
Battery
T4GB-02-03-013
T2-4-26
SYSTEM/Electric System
HORN CIRCUIT
• When the key switch is turned ON, the electricity
from the power source coming out of Terminal M
excites the battery relay through #54 and #55
Terminals of Fuse Box A, and the electricity from
the battery power source enters #120 Terminal of
Fuse Box A and the horn relay through #133
Terminal.
• Horn switch is earthed when pushed.
• As a result, the horn relay is excited, and the
electricity from the battery power source enters
the horn, and the horn sounds.
Key Switch
From #6 Terminal
of Fuse Box B
Fuse Box A
264
362
692
210
124
135
Horn Relay
Horn
Switch
55
163
693
108
12
144
133
121
696
695
698
699
700
Horn
157
123
54
79
99
120
694
697
Battery
Relay
Fusible
Link
Battery
To #638 Terminal
of Fuse Box B
T4GB-02-03-014
T2-4-27
SYSTEM/Electric System
REVERSE LIGHT/BUZZER CIRCUIT
• When the key switch is turned ON, the electricity
from the power source coming out of Terminal M
excites the battery relay through #54 and #55
Terminals of Fuse Box A.
• Electricity from the battery power source enters
#99 Terminal of Fuse Box A, and enters the
reverse light relay through #108 Terminal.
• When the forward-reverse lever is turned to
reverse, Terminal R is earthed, and the MC earths
#109 Terminal because the electricity from the
power source flows to the forward-reverse lever
through #84 Terminal of the MC.
• As a result, the reverse light relay is excited, and
the electricity from the battery power source flows
to the reverse light and the reverse buzzer.
T2-4-28
SYSTEM/Electric System
Forward/Reverse Lever
Key Switch
From #6 Terminal
of Fuse Box B
Fuse Box A
MC
84
264
362
692
210
124
135
Reverse
Light
Relay
157
123
54
55
163
693
108
12
144
133
121
696
695
698
699
700
109
Right Reverse Light
79
99
120
694
697
Reverse Buzzer
Left Reverse Light
Fusible
Link
Battery
Relay
Battery
To #638 Terminal
of Fuse Box B
T4GC-02-04-003
T2-4-29
SYSTEM/Electric System
PARKING BRAKE CIRCUIT
• When the key switch is turned ON, the electricity
• However, as a self-exciting circuit is formed in
from the power source coming out of Terminal M
excites the battery relay through #54 and #55
Terminals of Fuse Box A.
Electricity from the power source enters #79
Terminal of Fuse Box A and Parking Brake Relay
1 through #163 Terminal of Fuse Box A.
Electricity from the power source coming out of
Terminal D of Parking Brake Relay 1 through
Terminal B of Parking Brake Relay 1 flows to
Terminal B of Parking Brake Relay 2 and Terminal
B of the parking brake switch.
Parking brake switch is composed of three circuits
of ON, NEUTRAL, and OFF, and so constructed
as to remain at ON when turned ON, but to
automatically return to NEUTRAL when turned
OFF.
When the parking brake switch is turned OFF,
electric current flows from Terminal E of the
parking brake switch to Terminal A of Parking
Brake 2 and the parking brake solenoid valve.
At this moment, if the engine is not running,
Parking Brake Relay 1 is excited because #684
Terminal of the monitor unit is earthed.
Therefore, the parking brake cannot be released
because the electricity from the power source
having been supplied through Parking Brake 1 to
Terminal B of the parking brake switch and
Terminal B of the parking brake relay is blocked.
In case the engine is running, Parking Brake
Relay 2 is excited because the electric current
from Terminal L of the alternator enters #119
Terminal of the monitor unit, releasing earthing of
#684 Terminal of the monitor unit.
As a result, a circuit in which electricity flows from
Terminal C of Parking Brake Relay 2 to Terminal A
of Parking Brake Relay 2 (self-exciting circuit) is
formed, and the parking brake solenoid valve
works, releasing the parking brake.
As the parking brake switch automatically returns
to neutral, the circuit from Terminal E of the
parking brake switch to Parking Brake Relay 2 is
blocked.
Parking Brake Relay 2, electric current keeps
flowing to the parking brake solenoid valve,
keeping the released condition of the parking
brake until the key switch is turned OFF or the
parking brake switch is turned ON.
•
•
•
•
•
•
•
•
•
IMPORTANT: Parking brake cannot be released
unless the engine is running.
T2-4-30
• When the parking brake switch is turned ON,
Terminal A of the parking brake switch is earthed,
and Parking Brake Relay 1 is excited.
• Electricity from the power source having been
supplied to Terminal B of Parking Brake Relay 2
and Terminal B of Parking Brake Switch through
Terminal D of Parking Brake Relay 2 is blocked.
• As a result, the parking brake works because
Parking Brake Relay 2 and the parking brake
solenoid valve are unexcited.
SYSTEM/Electric System
Key Switch
From #163Terminal
of Fuse Box A
From #6 terminal
of Fuse Box B
684
Monitor Unit
119
From Terminal L
of Alternator
NEUTRAL
Parking Brake
Switch
イ
Parking Brake Parking Brake
Relay 2
Relay 1
OFF
AB
E F GH
A B CD E
A B CD E
684
Monitor Unit
119
To #638 Terminal
of Fuse Box B
Fuse
(100A)
157
123
54
55
163
693
108
12
144
133
121
696
695
698
699
700
(When forming a self-exciting circuit)
ON
Fuse Box A
264
362
692
210
124
135
Battery
Relay
79
99
120
694
697
Battery
Parking Brake
Solenoid Valve
From Terminal L
of Alternator
T4GB-02-03-016
NOTE: Illustration shows flow of electric current
when the parking brake switch remains
pushed after the parking brake switch has
been turned OFF during rotation of the
engine.
T2-4-31
SYSTEM/Electric System
EMERGENCY STEERING CHECK CIRCUIT
(OPTIONAL)
(Manual Check Circuit)
• When the key switch is turned ON, the electric
current from Terminal M the battery relay, and the
electricity from the power source enters the
emergency steering relay through #323 terminal
of Fuse Box B, and also enters Terminal B of the
emergency steering pump unit.
• When the emergency steering check switch is
turned ON, electric current flows to #179 Terminal
of the monitor unit.
• At the same time, as the monitor unit excites #180
Terminal, the emergency steering relay is excited.
• Electricity from the power unit enters Terminal C
of the emergency steering pump unit through the
emergency steering relay, exciting Terminal B,
and the emergency steering pump unit is started.
IMPORTANT: Emergency steering pump unit is
not so designed as to be operated
for a long time. When its operation
has been confirmed, turn the
emergency steering check switch
OFF by stopping pushing the switch.
(Auto Check Circuit)
• When the engine is started by turning the key
switch to the ST position, the alternator starts
generating electricity.
• When part of the electricity generation signal from
Terminal L of the alternator enters the monitor unit,
and rises to the predetermined voltage, Terminal
#180 is earthed, and the emergency steering
relay is excited.
• Electricity from the power unit enters Terminal C
of the emergency steering pump unit through the
emergency steering relay, exciting Terminal B,
and the emergency steering pump unit is started.
• The emergency steering pump unit works for
several seconds, and then the earthed circuit of
Terminal #180 is automatically cancelled and the
emergency steering pump unit stops.
• In case hydraulic oil higher than the
predetermined value has been being delivered
during operation of the emergency steering pump
unit, the emergency steering pump delivery
pressure switch is turned OFF, and the automatic
inspection operation is stopped normally.
• In case hydraulic oil higher than the
predetermined value has not been being
delivered, the emergency steering pump delivery
pressure switch remains ON, and the emergency
steering operation warning lamp on the monitor
unit flickers to notify abnormality of the
emergency steering pump unit.
T2-4-32
SYSTEM/Electric System
Key Switch
Fuse Box A
264
362
692
210
124
135
464
55
163
80
108
12
157
123
54
79
120
Emergency
Steering
Check Switch
Emergency
Steering
Relay
694
695
698
699
700
697
Fuse Box B
Emergency
Steering
Pump Delivery
Pressure Sensor
119
179
180
Emergency
Steering
Pump Unit
348
149
577
327
222
323
6
11
9
35
158
148
126
638
710
381
711
Monitor
Unit
838
75
Battery Relay
Fuse
(100A)
Battery
Alternator
T4GB-02-03-020
T2-4-33
SYSTEM/Electric System
(Blank)
T2-4-34
MEMO
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SECTION 3
COMPONENT OPERATION
Group 1 Pump Device
CONTENTS
Group 5 Steering Valve
Outline ...................................................... T3-1-1
Outline ...................................................... T3-5-1
Main Pump ............................................... T3-1-2
Operation .................................................. T3-5-4
Regulator.................................................. T3-1-4
Steering Overload Relief Valve ................. T3-5-8
Priority Valve .......................................... T3-1-18
Pilot Pump,Pump Delivery
Pressure Switch .................................. T3-1-19
Steering Main Relief Valve...................... T3-1-20
Group 2 Control Valve
Group 6 Pilot Valve
Outline (Two Lever Type Pilot Valve for
Front Attachment) ................................... T3-6-1
Operation .................................................. T3-6-2
Electromagnetic Detent............................. T3-6-6
Outline ...................................................... T3-2-1
Outline (Joystick Type Pilot Valve for
Hydraulic Circuit ..................................... T3-2-14
Front Attachment) ................................... T3-6-7
Main Relief Valve.................................... T3-2-22
Operation .................................................. T3-6-8
Overload Relief Valve ............................. T3-2-26
Electromagnetic Detent........................... T3-6-12
Restriction Valve..................................... T3-2-31
Outline (Lever Type Pilot Valve for
Negative Control Valve ........................... T3-2-32
Additional Circuit) (Optional) ................. T3-6-13
Flow Rate Control Valve ......................... T3-2-34
Operation ................................................ T3-6-14
Outline (Joystick Type Pilot Valve for
Group 3 Hydraulic Fan Motor
Outline ...................................................... T3-3-1
Operation ................................................. T3-3-4
Additional Circuit) (Optional) ................... T3-6-17
Operation ................................................ T3-6-18
Flow Control Valve.................................... T3-3-6
Reverse Control Valve .............................. T3-3-8
Fun Pump ............................................... T3-3-10
Group 4 Pilot Valve
Outline ...................................................... T3-4-1
Construction ............................................. T3-4-2
Operation ................................................. T3-4-3
4GCT-3-1
Group 7 Charging Block
Group 11 Brake Valve
Outline ...................................................... T3-7-1
Outline .................................................... T3-11-1
Priority Valve ............................................ T3-7-6
Operation ................................................ T3-11-4
Pilot Relief Valve ...................................... T3-7-7
Pump Torque Control Proportional
Solenoid Valve ....................................... T3-7-8
Group 12 Others
Pilot Shutoff Valve................................... T3-12-1
Propeller Shaft ........................................ T3-12-2
Service Brake Accumulator,
Pilot Accumulator ................................... T3-7-9
Emergency Steering Check Block ........... T3-12-3
Parking Brake Solenoid Valve................ T3-7-10
Emergency Steering Pump (Optional) ..... T3-12-4
Service Brake Pressure Sensor.............. T3-7-12
Parking Brake Pressure Sensor ............. T3-7-12
Group 8 Ride Control Valve
Outline ...................................................... T3-8-1
Operation ................................................. T3-8-4
Charge Cut Spool ..................................... T3-8-6
Over Load Relief Valve ............................. T3-8-8
Ride Control Accumlator ......................... T3-8-10
Drain Plug ...............................................T3-8-11
Group 9 Drive Unit
Outline ...................................................... T3-9-1
Torque Converter...................................... T3-9-2
Transmission ............................................ T3-9-4
Transmisson Regulator Valve ................. T3-9-26
Transmission Control Valve .................... T3-9-28
Manual Spool (Emergency Travel
Spool .................................................... T3-9-36
Proportional Solenoid Valve.................... T3-9-38
Group 10 Axle
Outline .................................................... T3-10-1
Differential .............................................. T3-10-2
Torque Proportioning Differential (TPD).. T3-10-6
Limited Slip Differential (LSD)................. T3-10-8
Service Brake ........................................T3-10-10
Final Drivel Axle Shaft ...........................T3-10-12
4GCT-3-2
COMPONENT OPERATION / Pump Device
OUTLINE
Pump device has a main pump (1) and a pilot pump (2),
and main pump (1) has a built-in priority valve (6).
Driving force of the engine is transmitted to the shaft
(3) through the transmission input shaft, and actuates
main pump (1) and pilot pump (2).
Main pump (1) is a swash-plate type variable
displacement axial plunger pump.
Pilot pump (2) is a gear pump.
Pump delivery pressure switch (4) is provided for
controlling the main pump.
1
2
5
6
3
4
T4GB-03-01-001
1 - Main Pump
3 - Shaft
5-
2 - Pilot Pump
4 - Pump Delivery Pressure
Switch
6-
T3-1-1
Steering Main Relief
Valve
Priority Valve
COMPONENT OPERATION / Pump Device
MAIN PUMP
Main pump supplies pressure oil for operating the
cylinders and other hydraulic components. Also, the
pump is provided with a regulator for controlling the
delivery flow.
Shaft (5) is connected with the cylinder block (1), and
shaft (5) and cylinder block (1) corotate.
1
2
When cylinder block (1) rotates, plungers (2)
reciprocate inside the cylinder block because of the
tilting of swash plate (4), and delivers the hydraulic oil.
Control of the main pump delivery is made by changing
the tilting angle of swash plate (4) with servo piston 1
(3) and servo piston 2 (6) which increase or decrease
the stroke of plungers (2).
3
4
5
6
8
7
T4GB-03-01-002
1 - Cylinder Block
2 - Plunger
34-
Servo Piston 1 (2 pieces)
Swash Plate
56-
T3-1-2
Shaft
Servo Piston 2
78-
Feed Back Lever
Link
COMPONENT OPERATION / Pump Device
Increase and Decrease Operations of Delivery
Flow
Tilting angle variation of swash plate (4) is made by
the movement of servo piston 1 (3) and servo piston
2 (6).
Movement of the servo pistons is controlled by the
regulator. Also, the feed back of the swash plate
movement is given to the regulator by feed back lever
(7) and link (8).
7
8
6
3
4
NOTE: Refer to the following pages for operation of
the regulator.
• Tilting Change Operation
Tilting center of the swash plate is located at A in the
drawings right.
Pilot pressure is always applied to servo piston 2 (6).
Therefore, when the circuit of servo piston 1’s (3) is
connected to the hydraulic oil tank, swash plate (4)
tilts clockwisw around A.
Conversely, as there are two servo piston 1’s (3),
when pilot pressure is applied to both of servo piston
1’s (3) and servo piston 2, the swash plate (4) tilts
counterclockwise around A.
T4GB-03-01-022
A
Minimum Tilting
6
3
4
• Feed Back Operation
End of feed back lever (7) is inserted into the boss
on the side face of the swash plate (4). When swash
plate (4) tilts, the boss also moves, and feed back
lever (7) moves together.
For example, if swash plate (4) tilts to the maximum
tilting position from the minimum tilting position, the
center of feed back lever (7) moves from B to C.
This movement of feed back lever (7) moves link (8),
and feed back is given to the regulator.
Housing
Maximum Tilting
8
7
T4GB-03-01-023
A
4
Boss
Housing
C
T3-1-3
B
T4GB-03-01-024
COMPONENT OPERATION / Pump Device
REGULATOR
Regulator controls flow of the main pump, receiving
various kinds of signal pressure.
The regulator includes the spring (1), sleeve 1 (2),
sleeve 2 (7), spool 1 (3), spool 2 (6), piston (4), load
piston (5), inner spring (8), and outer spring (9).
Regulator opens and closes the circuit leading to servo
piston 1 (10) by receiving various kinds of signal
pressure, and controls delivery flow of the pump by
varying the tilting angle of swash plate (11).
NOTE: Pilot primary pressure (Pg) is always
applied to Servo Piston 2 (12).
3
2
Pi1
T
Air
Vent
1
4
Pi2
Pg
ST
T
Pd1
T
5
7
6
10
8、9
Large
Small
Tilting Angle
12
T4GB-03-01-006
Pd1 - Pump Delivery Pressure
(Self Delivery Pressure)
ST - Pump Torque Control
Pressure
TReturn Line to Hydraulic
Oil Tank
T3-1-4
Pi1 - Pump Control
Pressure 1
Pi2 - Pump Control
Pressure 2
Pg - Pilot Primary
Pressure
(From Pilot Pump)
COMPONENT OPERATION / Pump Device
2
5
4
3
6
7
10
4 - Piston
5 - Load Piston
6 - Spool 2
8
9
11
T4GB-03-01-007
12
1 - Spring
2 - Sleeve 1
3 - Spool 1
1
7 - Sleeve 2
8 - Inner Spring
9 - Outer Spring
T3-1-5
10 - Servo Piston 1(2 pieces)
11 - Swash Plate
12 - Servo Piston 2
COMPONENT OPERATION / Pump Device
Control Function of Regulator
Regulator has the following three control functions.
• Control by Pump Control Pressure
Pump flow control valve inside the control valve
controls the pump control pressure (Pi1 - Pi2) in
response to the operating stroke of the control lever.
By receiving this pump control pressure (Pi1 - Pi2),
the regulator increases or decreases the pump
delivery flow in response to the pressure.
When the control lever is operated, pump control
pressure (Pi1 - Pi2) lowers, and the regulator
increases the pump delivery flow. If the control lever
is returned to neutral, pump control pressure (Pi1 Pi2) rises, and the regulator decreases the pump
delivery flow.
Flow (Q)
0
Pump Control Pressure (Pi1-Pi2)
• Control by Pump Delivery Pressure (Self Delivery
Pressure)
Pump Delivery Pressure (Self Delivery Pressure)
Pd1 enters the regulator. In case this pump pressure
exceeds the set P - Q line, the pump delivery flow is
decreased to return the pressure to the P - Q line.
Flow (Q)
Pressure Increase
Flow Decrease
• Control by Pilot Pressure from Torque Control
Solenoid Valve
MC (Main Controller) makes arithmetic operations of
the operating conditions of the vehicle body, and
transmits signals to the pump torque control
solenoid valve to obtain needed pump torque.
Pump torque control solenoid valve transmits Pump
Torque Control Pressure ST corresponding to this
signal to the regulator. Regulator, receiving the pilot
pressure, decreases the pump delivery flow.
0
Flow (Q)
0
T3-1-6
Pressure (P)
Pressure (P)
COMPONENT OPERATION / Pump Device
(Blank)
T3-1-7
COMPONENT OPERATION / Pump Device
Control by Pump Control Pressure
Flow Decrease
1. When the control lever stroke is reduced,
pressure difference arising before and after the
flow control valve (difference between pressure
Pi1 and Pi2) in the control valve is enlarged.
2. Pump Control Pressure Pi1 pushes Spool 1 (3),
and Spool 1 (3) moves toward the arrow.
3. This movement causes Pilot Primary Pressure Pg
to be led to servo piston 1 (10) also.
4. As there are two servo piston 1’s (10), the swash
plate (11) tilts toward the flow decreasing
direction.
5. Movement of swash plate (11) is conveyed to
sleeve 1 (2) through feed back lever link (13).
Sleeve 1 (2) moves toward the movement of
spool 1 (3).
6. Pilot pressure having been led to servo piston 1
(10) is blocked when sleeve 1 (2) has moved the
same distance as spool 1 (3). This causes servo
piston 1’s (10) to stop and the flow decrease is
completed.
Flow (Q)
0
Pump Control Pressure (Pi1-Pi2)
3
2
Pi1
1
Air
Vent
T
4
Pi2
Pg
ST
T
Pd1
T
13
10
Small
Large
12
Tilting Angle
T4GB-03-01-006
1234-
Spring
Sleeve 1
Spool 1
Piston
Pd1 ST T-
T3-1-8
10 11 12 13 -
Pump Delivery Pressure
(Self Delivery Pressure)
Torque Control
Pressure
Return Line to Hydraulic
Oil Tank
Servo Piston 1
Swash Plate
Servo Piston 2
Feed Back Lever Link
Pi1 Pi2 Pg -
Pump Control
Pressure 1
Pump Control
Pressure 2
Pilot Primary Pressure
(From Pilot Pump)
COMPONENT OPERATION / Pump Device
Pump
Control
Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
3
2
4
1
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
13
Self Delivery
Pressure Pd1
12
11
10
T4GB-03-01-008
Pump
Control
Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
3
2
4
1
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
13
Self Delivery
Pressure Pd1
12
10
11
T4GB-03-01-009
T3-1-9
COMPONENT OPERATION / Pump Device
Flow Increase
1. When the control lever stroke is enlarged,
pressure difference arising before and after the
flow control valve (difference between pressure
Pi1 and Pi2) in the control valve is reduced.
2. Force due to spring (1) and Pump Control
Pressure Pi2 pushes spool 1 (3), and spool 1 (3)
moves toward the arrow.
3. This movement causes the circuit of servo piston
1’s (10) to be led to the hydraulic oil tank.
4. As Pilot Primary Presuure Pg is always applied to
servo piston 2 (12), the swash plate (11) tilts
toward the flow increasing direction.
5. Movement of the swash plate (11) is transmitted
to sleeve 1 (2) through the feed back lever link
(13). Sleeve 1 (2) moves toward the movement of
spool 1 (3).
6. When sleeve 1 (2) has moved the same distance
as spool 1 (3) did, communication of servo piston
1’s (10) with the hydraulic tank is stopped, and
this causes servo piston 1’s (10) to stop and the
flow increase is completed.
Flow (Q)
0
Pump Control Pressure (Pi1-Pi2)
3
2
Pi1
1
Air
Vent
T
4
Pi2
Pg
ST
T
Pd1
T
13
10
Large
Small
12
Tilting Angle
T4GB-03-01-006
1234-
Spring
Sleeve 1
Spool 1
Piston
10 11 12 13 -
Pd1 - Pump Delivery Pressure
(Self Delivery Pressure)
ST - Pump Torque Control
Pressure
TReturn Line to Hydraulic
Oil Tank
T3-1-10
Servo Piston 1
Swash Plate
Servo Piston 2
Feed Back Lever Link
Pi1 Pi2 Pg -
Pump Control
Pressure 1
Pump Control
Pressure 2
Pilot Primary Pressure
(From Pilot Pump)
COMPONENT OPERATION / Pump Device
Pump
Control Pressure
Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
3
2
4
1
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
13
Self Delivery
Pressure Pd1
12
10
11
T4GB-03-01-010
Pump
Control
Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
3
2
4
1
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
13
Self Delivery
Pressure Pd1
12
10
11
T4GB-03-01-011
T3-1-11
COMPONENT OPERATION / Pump Device
Control by Pump Delivery Pressure
(Self Delivery Pressure)
Flow Decrease
1. When load is applied to the pump by making one
operation or another, Pump Delivery Pressure
Pd1 rises. (As done during an operation, the
pump control pressure (Pi1 - Pi2) remains
lowered.)
2. Load piston (5) pushes spool 2 (6), the inner
spring (8), and the outer spring (9), and Spool 2
(6) moves toward the arrow.
3. This movement causes Pilot Primary Pressure Pg
to be led to servo piston 1’s (10) also.
4. As there are two servo piston 1 (10), the swash
plate (11) tilts toward the flow decreasing
direction.
5. This movement of the swash plate (11) is
conveyed to sleeve 2 (7) through the feed back
lever link (13). Sleeve 2 (7) moves toward the
movement of spool 2 (6).
6. Pilot pressure having been led to servo piston 1
(10) is blocked when sleeve 2 (7) has moved the
same distance as spool 2 (6). This causes servo
piston 1’s (10) to stop and the flow decrease is
completed.
Flow (Q)
0
Pressure (P)
Pi1
Air
Vent
T
Pi2
Pg
ST
T
Pd1
T
5
7
6
10
8、9
Large
Small
Tilting Angle
12
13
T4GB-03-01-006
56789-
Load Piston
Spool 2
Sleeve 2
Inner Spring
Outer Spring
Pd1 - Pump Delivery Pressure
(Self Delivery Pressure)
ST - Pump Torque Control
Pressure
TReturn Line to Hydraulic
Oil Tank
T3-1-12
10 11 12 13 -
Servo Piston 1
Swash Plate
Servo Piston 2
Feed Back Lever Link
Pi1 Pi2 Pg -
Pump Control
Pressure 1
Pump Control
Pressure 2
Pilot Primary Pressure
(From Pilot Pump)
COMPONENT OPERATION / Pump Device
Pump
Control Pressure
Pi1
5
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
6
7
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
8
9
13
Self Delivery
Pressure Pd1
12
10
11
T4GB-03-01-012
5
Pump
Control
Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
6
7
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
8
13
Self Delivery
Pressure Pd1
9
12
10
11
T4GB-03-01-013
T3-1-13
COMPONENT OPERATION / Pump Device
Flow Increase
1. When the pump load is reduced, Self Delivery
Pressure Pd1 lowers. (As done during an
operation, the pump control pressure (Pi1 - Pi2)
remains lowered.)
2. Load piston (5) and spool 2 (6) are pushed by
inner spring (8) and outer spring (9), and spool 2
(6) moves toward the arrow.
3. This movement causes the circuit of servo piston
1’s (10) to be led to the hydraulic oil tank.
4. As Pilot Primary Presuure Pg is always applied to
servo piston 2 (12), swash plate (11) tilts toward
the flow increasing direction.
5. Movement of swash plate (11) is conveyed to
sleeve 2 (7) through feed back lever link (13).
sleeve 2 (7) moves toward the movement of spool
2 (6).
6. When sleeve 2 (7) has moved the same distance
as spool 2 (6), the openings of spool 2 (6) and
sleeve 2 (7) close, stopping communication of
servo piston 1’s (10) with the hydraulic tank, and
this causes servo piston 1’s (10) to stop and the
flow increase is completed.
Flow (Q)
0
Pressure (P)
Pi1
Air
Vent
T
Pi2
Pg
ST
T
Pd1
T
5
7
8、9
6
10
12
Large
Small
Tilting Angle
13
T4GB-03-01-006
56789-
Load Piston
Spool 2
Sleeve 2
Inner Spring
Outer Spring
Pd1 - Pump Delivery Pressure
(Self Delivery Pressure)
ST - Pump Torque Control
Pressure
TReturn Line to Hydraulic
Oil Tank
T3-1-14
10 11 12 13 -
Servo Piston 1
Swash Plate
Servo Piston 2
Feed Back Lever Link
Pi1 Pi2 Pg -
Pump Control
Pressure 1
Pump Control
Pressure 2
Pilot Primary Pressure
(From Pilot Pump)
COMPONENT OPERATION / Pump Device
5
Pump
Control
Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
6
7
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
8
13
Self Delivery
Pressure Pd1
9
12
10
11
T4GB-03-01-014
5
Pump
Control
Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
6
7
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
Self Delivery
Pressure Pd1
13
12
10
11
T4GB-03-01-015
T3-1-15
COMPONENT OPERATION / Pump Device
Control of Torque Control Solenoid Valve by Pilot
Pressure
Flow Decrease
1. Command from the MC (main controller) drives
the pump torque control solenoid valve, and
Pump Torque Control Pressure ST enters the
regulator.
2. Adding to Self Delivery Pressure Pd1, Pump
Torque Control Pressure ST works on load piston
(5).
3. Load piston (5) pushes spool 2 (6), inner spring
(8), and outer spring (9), and spool 2 (6) moves
toward the arrow.
4. This movement causes Pilot Primary Pressure Pg
to be led to servo piston 1’s (10) also.
5. As there are two servo piston 1 (10), swash plate
(11) tilts toward the flow decreasing direction.
6. This movement of swash plate (11) is conveyed to
sleeve 2 (7) through feed back lever link (13).
sleeve 2 (7) moves toward the movement of spool
2 (6).
7. Pilot pressure having been led to servo piston 1
(10) is blocked when sleeve 2 (7) has moved the
same distance as spool 2 (6). This causes servo
piston 1’s (10) to stop and the flow decrease is
completed.
Flow (Q)
0
Pressure (P)
Pi1
Air
Vent
T
Pi2
Pg
ST
T
Pd1
T
5
7
8、9
6
10
Large
Small
Tilting Angle
12
13
T4GB-03-01-006
56789-
Load Piston
Spool 2
Sleeve 2
Inner Spring
Outer Spring
Pd1 - Pump Delivery Pressure
(Self Delivery Pressure)
ST - Pump Torque Control
Pressure
TReturn Line to Hydraulic
Oil Tank
T3-1-16
10 11 12 13 -
Servo Piston 1
Swash Plate
Servo Piston 2
Feed Back Lever Link
Pi1 Pi2 Pg -
Pump Control
Pressure 1
Pump Control
Pressure 2
Pilot Primary Pressure
(From Pilot Pump)
COMPONENT OPERATION / Pump Device
5
Pump
Control
Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
6
7
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
8
9
13
Self Delivery
Pressure Pd1
12
10
11
T4GB-03-01-016
5
Pump
Control Pressure
Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
6
7
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
8
13
Self Delivery
Pressure Pd1
9
12
10
11
T4GB-03-01-017
T3-1-17
COMPONENT OPERATION / Pump Device
PRIORITY VALVE
(Refer to the Main Curcuit in the SYSTEM /
Hydraulic System)
Main pump has a built-in priority valve.
Priority valve is installed for effectively distributing the
main pump delivery oil to the steering valve and the
control valve.
Before Steering Operation
Operation
1. Before Steering Operation
Pressure oil from the main pump tends to flow to
the steering valve through Port CF, but flows to
the both ends of the priority valve spool because
Port CF is blocked.
Pressure oil on one end of the spool flows from
Port LS to the hydraulic oil tank through the
steering valve, and its pressure is lowered. The
spool to both ends of which different pressures
are applied moves toward Port LS, overcoming
the the spring force. Therefore, the majority of the
main pump pressure oil flows to the control valve
through Port EF.
2. In Steering Operation
If steering is operated, and the steering valve
spool moves, pressure at Port LS rise in response
to the amount of the steering valve spool
movement. The spool is pushed up by the
pressure at Port LS and the spring force.
Therefore, the main pump pressure oil flows to
both Port EF and Port CF. When the steering
valve spool moves to the maximum stroke, the
majority of the main pump pressure oil flows to
the steering valve through Port CF.
Port
CF
To Steering Valve
From Main Pump
To Control Valve
Port
EF
Spool
Spring
Port LS
To Hydraulic
Oil Tank
T4GB-03-01-018
In Steering Operation
Port
CF
To Steering Valve
From Main Pump
To Control Valve
Spool
Port
EF
Spring
Port LS
T4GB-03-01-019
T3-1-18
COMPONENT OPERATION / Pump Device
PILOT PUMP
Drive gear (1) is driven throught the shaft of the main
pump, and the diven gear (2) geared to this also
rotates.
1 - Drive Gear
Suction Port
1
2
2 - Driven Gear
Delivery Port
T137-02-03-005
PUMP DELIVERY PRESSURE SWITCH
Pump delivery pressure necessary for various kinds of
control is sensed. Hydraulic pressure is received by
the diaphragm (9), and deformation of the diaphragm
is sensed as an electric signal.
6 - Earth
7 - Output
8 - Electric Source (5V)
9 - Pressure-applied Part
(Diaphragm)
6
T3-1-19
7
8
9
T157-02-03-010
COMPONENT OPERATION / Pump Device
STEERING MAIN RELIEF VALVE
Main pump has a built-in steering main relief valve.
When the steering circuit pressure exceed the set
pressure, pressure oil is returned to the hydarulic oil
tank through inside of the main pump housing.
Before Operation
Steering Circuit Pressure for
up to Set Pressure
Operation
In case steering circuit pressure exceed the set
pressure, the puppet is pushed toward the spring,
and pressure is returned to the hydraulic oil tank
through inside of the main pump housing.
NOTE: When the steering relief valve is operated,
the spool of the priority valve moves to the
Port LS end, and the majority of the
pressure oil from the main pump flows to
the control valve through Port EF. (Refer to
T3-1-18.)
T4GB-03-01-020
In Operation
Steering Circuit Pressure for
less than Set Pressure
To Main Pump
Housing
T4GB-03-01-021
T3-1-20
COMPONENT OPERATION / Control Valve
OUTLINE
Control valve controls pressure, flow, and direction of
oil in the hydraulic circuit.
The control valve includes the main relief valve,
overload relief valve, negative control valve, restriction
valve, flow control valve, and spool, and its operation is
of the hydraulic pilot type.
ZW250
ZW220
Lift Arm
Lift Arm
Bucket
Bucket
T4GB-03-02-001
T4GB-03-02-002
T3-2-1
COMPONENT OPERATION / Control Valve
Component Layout
ZW220
1
2
3
4
11
5
6
7
7
10
9
T3-2-2
8
T4GB-03-02-003
COMPONENT OPERATION / Control Valve
ZW220
A
7
6
8
9
7
5
B
C
D
E
4
2
3
T4GB-03-02-004
1 - Bucket Flow Control Valve
2 - Negative Control Valve
3 - Overload Relief Valve
(Bucket: Bottom End)
4 - Overload Relief Valve
(Bucket: Rod End)
5 - Overload Relief Valve
(Lift Arm: Bottom End)
6 - Make-up Valve
(Lift Arm: Rod End)
7 - Restriction Valve
8 - Low-pressure Relief Valve
9 - Main Relief Valve
T3-2-3
10 - Load Check Valve
(Arm Lift Circuit)
11 - Load Check Valve
(Bucket Circuit)
COMPONENT OPERATION / Control Valve
ZW220
1
2
3
4
11
5
6
7
7
10
9
T3-2-4
8
T4GB-03-02-003
COMPONENT OPERATION / Control Valve
ZW220
8
9
Section A
*
7
7
2
T4GB-03-02-005
Section B*
8
9
T4GB-03-02-006
1 - Bucket Flow Control Valve
2 - Negative Control Valve
3 - Overload Relief Valve
(Bucket: Bottom End)
4 - Overload Relief Valve
(Bucket: Rod End)
5 - Overload Relief Valve
(Lift Arm: Bottom End)
6 - Make-up Valve
(Lift Arm: Rod End)
7-
Restriction Valve
8-
Low-pressure Relief Valve
9-
Main Relief Valve
* Refer to T3-2-3.
T3-2-5
10 - Load Check Valve
(Arm Lift Circuit)
11 - Load Check Valve
(Bucket Circuit)
COMPONENT OPERATION / Control Valve
ZW220
1
2
3
4
11
5
6
7
7
10
9
T3-2-6
8
T4GB-03-02-003
COMPONENT OPERATION / Control Valve
ZW220
Section C*
6
10
7
7
5
*
Section D
1
11
4
3
Section E
*
2
T4GB-03-02-007
1 - Bucket Flow Control Valve
2 - Negative Control Valve
3 - Overload Relief Valve
(Bucket: Bottom End)
4 - Overload Relief Valve
(Bucket: Rod End)
5 - Overload Relief Valve
(Lift Arm: Bottom End)
6 - Make-up Valve
(Lift Arm: Rod End)
7-
Restriction Valve
8-
Low-pressure Relief Valve
9-
Main Relief Valve
* Refer to T3-2-3.
T3-2-7
10 - Load Check Valve
(Arm Lift Circuit)
11 - Load Check Valve
(Bucket Circuit)
COMPONENT OPERATION / Control Valve
ZW250
1
2
3
4
5
6
8
7
8
9
11
10
T4GB-03-02-008
T3-2-8
COMPONENT OPERATION / Control Valve
ZW250
D
10
C
6
7
8
8
A
E
5
4
3
T4GB-03-02-009
1 - Flow Control Valve
(Poppet)
2 - Flow Control Valve
(Changeover Valve)
3 - Negative Control Valve
4 - Overload Relief Valve
(Bucket: Bottom End)
5 - Overload Relief Valve
(Bucket: Rod End)
6 - Overload Relief Valve
(Lift Arm: Bottom End)
7 - Make-up Valve
(Lift Arm: for Rod)
8 - Restriction Valve
9 - Low-pressure Relief Valve
T3-2-9
10 - Main Relief Valve
11 - Load Check Valve
(Lift Arm Circuit)
COMPONENT OPERATION / Control Valve
ZW250
1
2
3
4
5
6
8
7
8
9
11
10
T4GB-03-02-008
T3-2-10
COMPONENT OPERATION / Control Valve
ZW250
Section A*
11
7
6
8
8
Section B*
1
2
5
4
T4GB-03-02-010
1 - Flow Control Valve
(Poppet)
2 - Flow Control Valve
(Changeover Valve)
3 - Negative Control Valve
4-
Overload Relief Valve
(Bucket: Bottom End)
5 - Overload Relief Valve
(Bucket: Rod End)
6 - Overload Relief Valve
(Lift Arm: Bottom End)
7-
Make-up Valve
(Lift Arm: for Rod)
8 - Restriction Valve
9-
* Refer to T3-2-9.
T3-2-11
Low-pressure Relief Valve
10 - Main Relief Valve
11 - Load Check Valve
(Lift Arm Circuit)
COMPONENT OPERATION / Control Valve
ZW250
1
2
3
4
5
6
8
7
8
9
10
11
T4GB-03-02-008
T3-2-12
COMPONENT OPERATION / Control Valve
ZW250
Section C:*
10
9
Section D*
C
3
E
Section E*
3
T4GB-03-02-011
1 - Flow Control Valve
(Poppet)
2 - Flow Control Valve
(Changeover Valve)
3 - Negative Control Valve
4-
Overload Relief Valve
(Bucket: Bottom End)
5 - Overload Relief Valve
(Bucket: Rod End)
6 - Overload Relief Valve
(Lift Arm: Bottom End)
7-
Make-up Valve
(Lift Arm: for Rod)
8 - Restriction Valve
9-
* Refer to T3-2-9.
T3-2-13
Low-pressure Relief Valve
10 - Main Relief Valve
11 - Load Check Valve
(Lift Arm Circuit)
COMPONENT OPERATION / Control Valve
HYDRAULIC CIRCUIT
ZW220
Main Circuit
Main circuit contains a parallel circuit, which enables
compound operations.
Main circuit (between the pump and the cylinder) is
provided with the main relief valve. The main relief
valve prevents pressure inside the main circuit from
increasing over the set pressure during operation
(when any control lever is operated).
Front circuit (between the control valve and the
cylinder) of the lift arm bucket is provided with the
overload relief valve. Overload relief valve prevents
surge pressure from being developed be external
loads in the front circuit and from increasing over the
set pressure at neutral position of the spool (neutral
position of the control lever).
T3-2-14
COMPONENT OPERATION / Control Valve
Bucket Cylinder
Lift Arm
Cylinder
Control Valve
Bucket
Overload
Relief Valve
Lift Arm
Parallel Circuit
Main
Relief Valve
Main Pump
T4GB-03-02-012
T3-2-15
COMPONENT OPERATION / Control Valve
ZW250
Main Circuit
Main circuit contains a parallel circuit, which enables
compound operations.
Main circuit (between the pump and the cylinder) is
provided with the main relief valve. The main relief
valve prevents pressure inside the main circuit from
increasing over the set pressure during operation
(when any control lever is operated).
Front circuit (between the control valve and the
cylinder) of the lift arm bucket is provided with the
overload relief valve. Overload relief valve prevents
surge pressure from being developed be external
loads in the front circuit and from increasing over the
set pressure at neutral position of the spool (neutral
position of the control lever).
T3-2-16
COMPONENT OPERATION / Control Valve
Bucket Cylinder
Lift Arm
Cylinder
Control Valve
Overload
Valve
Bucket
Lift Arm
Parallel Circuit
Main Relief Valve
Main Pump
T4GB-03-02-023
T3-2-17
COMPONENT OPERATION / Control Valve
Pilot Operation Circuit
ZW220
Pressure oil from the pilot valve (shown in numerals)
works on the spool of the control valve, and moves
the spool.
• Pressure oil is being sent to the bucket spool for
dumping and crowding operations.
• Pressure oil is being sent to the lift arm spool for
raising and lowering operations.
Spool for lowering is two-staged, and the first
stage is for lowering the lift arm, while the second
stage is for floating the lift arm.
T3-2-18
COMPONENT OPERATION / Control Valve
Bucket
Pilot Valve
Lift Arm
Pilot Valve
1
3
2
4
Pilot Pump
Control Valve
Bucket
1
2
Lift Arm
4
3
Main Pump
T4GB-03-02-013
1 - Bucket Crowding
2 - Bucket Dumping
34-
Lift Arm Lowering
Lift Arm Raising
T3-2-19
COMPONENT OPERATION / Control Valve
ZW250
Pressure oil from the pilot valve (shown in numerals)
works on the spool of the control valve, and moves
the spool.
• Pressure oil is being sent to the bucket spool for
dumping and crowding operations.
• Pressure oil is being sent to the lift arm spool for
raising and lowering operations.
Spool for lowering is two-staged, and the first
stage is for lowering the lift arm, while the second
stage is for floating the lift arm.
T3-2-20
COMPONENT OPERATION / Control Valve
Bucket
Pilot Valve
Lift Arm
Pilot Valve
1
3
2
4
Pilot Pump
Control Valve
Bucket
2
1
4
Lift Arm
3
4
Main Pump
T4GB-03-02-024
1 - Bucket Crowding
2 - Bucket Dumping
3 - Lift Arm Lowering
4 - Lift Arm Raising
T3-2-21
COMPONENT OPERATION / Control Valve
MAIN RELIEF VALVE
Main relief valve prevents pressure inside the main
circuit from increasing over the set pressure during
operation of the cylinder.
This prevents oil leakage from the hoses and piping
fittings as well as cylinder breakage.
ZW220
Operation of Relief Valve
1. Pressure at port HP (in the main circuit) works on
the pilot poppet through orifice A of the main
poppet and orifice B of the seat.
2. When the pressure at Port HP rises to the setting
force of spring B, the pilot poppet opens, and
pressure oil flows to port LP (in the hydraulic oil
tank) passing through passage A and the
periphery of the sleeve.
3. At this time, pressure difference arises between
port HP and the spring chamber, caused by orifice
A.
4. When this pressure difference reaches the value
corresponding to the set force of spring A, the
main poppet opens, and the pressure oil at port
HP flows to port LP.
5. As a result, pressure in the main circuit lowers.
6. If the main circuit pressure lowers to the set
pressure, the main poppet is closed by the force
of spring A.
T3-2-22
COMPONENT OPERATION / Control Valve
In Normal Condition:
Main Poppet
Orifice A
Orifice B
Seat
Passage A
Spring B
HP
Sleeve
LP
Spring
Chamber
Spring A
T4GB-03-02-034
Pilot Poppet
When Relieving:
Main Poppet
Orifice A Orifice B
Seat
Passage A
Spring B
HP
Sleeve
LP
Spring
Chamber
Spring A
T3-2-23
Pilot Poppet
T4GB-03-02-035
COMPONENT OPERATION / Control Valve
ZW250
Operation of Relief Valve
1. Pressure at port HP (in the main circuit) works on
the pilot poppet through orifice A of the main
poppet and orifice B of the seat.
2. When the pressure at port HP rises to the setting
force of spring B, the pilot poppet opens, and
pressure oil flows to port LP (in the hydraulic oil
tank) passing through passage A and the
periphery of the sleeve.
3. At this time, pressure difference arises between
port HP and the spring chamber, caused by orifice
A.
4. When this pressure difference reaches the value
corresponding to the set force of spring A, the
main poppet opens, and the pressure oil at port
HP flows to port LP.
5. As a result, pressure in the the main circuit lowers.
6. If the main circuit pressure lowers to the set
pressure, the main poppet is closed by the force
of spring A.
T3-2-24
COMPONENT OPERATION / Control Valve
In Normal Condition:
Orifice A Main Poppet Orifice B Seat Passage A Spring B
HP
Sleeve
LP
Spring
Chamber
Spring A
Pilot Poppet
T4GB-03-02-025
When Relieving:
Orifice A
Main Poppet
Orifice B Seat
Passage A Spring B
HP
LP
Sleeve
Spring
Chamber
Spring A
Pilot Poppet
T4GB-03-02-026
T3-2-25
COMPONENT OPERATION / Control Valve
OVERLOAD RELIEF VALVE
(With Make-up Function)
Overload relief valve is installed on the bottom end of
the lift arm and the bottom and rod ends of the bucket.
Overload relief valve so controls pressure in each front
circuit not to rise abnormally. It also makes make-up
operation by refilling oil from the hydraulic oil tank for
preventing cavitation.
Operation of Relief Valve in ZW220 (Port on
Bucket Rod) & ZW250 (All Ports)
Make-up Operation
1. When the pressure at port HP (in the front circuit)
lowers than the pressure at port LP (in the
hydraulic oil tank), the sleeve moves right.
2. Hydraulic oil at port LP flows into port HP, and
cavitation is prevented.
3. When the pressure at port HP rises to the set
pressure, the sleeve is closed by the force of
spring C.
1. Pressure at port HP (in the front circuit) works on
the pilot poppet through the orifice of the piston.
2. When the pressure at port HP rises to the setting
force of spring B, the pilot poppet opens, and
pressure oil flows to port LP (in the hydraulic oil
tank) passing through passage A and the
periphery of the sleeve.
3. At this time, pressure difference arises between
port HP and the spring chamber, caused by the
orifice.
4. When this pressure difference reaches the value
corresponding to the set force of spring A, the
piston and the main poppet open, and the
pressure oil at port HP flows to port LP.
5. As a result, pressure in the the main circuit lowers.
6. If the front circuit pressure lowers to the set
pressure, the piston and the main poppet are
closed by the force of spring A.
T3-2-26
COMPONENT OPERATION / Control Valve
In Normal Condition:
Main Poppet
Spring A
Sleeve
Passage A
Spring B
HP
T4GB-03-02-030
LP
Orifice
Piston
Spring Chamber
Pilot Poppet
Spring C
When Relieving:
Main Poppet
Sleeve
Spring A
Passage A Spring B
HP
LP
Orifice
T4GB-03-02-031
Spring Chamber Pilot Poppet
Piston
In Make-up Operation:
Sleeve
HP
LP
R4GB-03-02-032
Spring C
T3-2-27
COMPONENT OPERATION / Control Valve
Operation of Relief Valve in ZW220 (Ports on
Bottom End of Lift Arm and Bucket)
1. Pressure at port HP (front circuit) passes the seat,
and works on the shaft.
2. When the pressure at port HP rises to the value
corresponding to the set force of spring A, the
shaft moves, and pressure oil flows to port LP.
3. As a result, the pressure in the front circuit lowers.
4. If the pressure in the front circuit lowers to the set
pressure, the shaft is moved by the force of spring
A, and the oil passage closes.
Make-up Operation
1. When the pressure at port HP (in the front circuit)
lowers than the pressure at port LP (in the
hydraulic oil tank), the sleeve moves right.
2. Hydraulic oil at port LP flows into port HP, and
cavitation is prevented.
3. When the pressure at port HP rises to the set
pressure, the sleeve is closed by the force of
spring C.
T3-2-28
COMPONENT OPERATION / Control Valve
In Normal Condition:
Seat
HP
Shaft
LP
Spring B
Spring A
T4GB-03-02-027
When Relieving:
Seat
Shaft
HP
LP
Spring B
Spring A
T4GB-03-02-028
In Make-up Operation:
Seat
HP
Shaft
LP
Spring B
Spring A
T4GB-03-02-029
T3-2-29
COMPONENT OPERATION / Control Valve
(Blank)
T3-2-30
COMPONENT OPERATION / Control Valve
RESTRICTION VALVE
Restriction valve is installed at the inlet part to the pilot
circuit on the both ends of the spool for the lift arm.
If the pilot valve is made at the neutral position during
operation of the lift arm, the pilot pressure oil having
been supplied to the spool for the lift arm is drained
through the orifice of the check valve of the restriction
valve, and pilot pressure gradually lowers.
As a result, shock to the body occurring in operation of
the front attachment can be reduced by gradually
returning the lift arm spool to the neutral position.
Check Valve
Spool End
Orifice
Pilot
Valve End
T4GB-03-02-014
T3-2-31
COMPONENT OPERATION / Control Valve
NEGATIVE CONTROL VALVE
Control valve has a built-in negative control valve.
Negative control valve controls the main pump delivery
flow of the main pump by the flow control pressure
(Pc1 and Pc2).
Negative
Control Valve
Orifice
Pc2
Operation
Pc1
• At Neutral
Pressure oil coming through the control valve
neutral circuit at neutral position of the control
valve is supplied as pilot pressure for controlling
the pump delivery flow from before and after the
orifice of the negative control valve installed at the
outlet of the control valve.
At this time, spool B moves left because
differential pressure is occurring between the Pc1
and Pc2. Therefore, pilot pressure (PS2) enters
the large-diameter chamber for the servo piston
through spool B and spool A. Pilot pressure (PS2)
also enters the small-diameter chamber for the
servo piston, but as the the large-diameter
chamber has a larger area than the
small-diameter chamber, the servo piston moves
right, and the pump delivery flow is reduced.
• In Operation
In operations handling the lift arm and the bucket,
pressure oil is not supplied to Pc1 and Pc2.
At this time, differential pressure is lowered
between the Pc1 and Pc2, so the regulator for the
main pump is at neutral, and restriction of delivery
flow is not made (increase pump delivery flow).
Main Pump
Neutral
Circuit
NOTE: Illustration shows the control valve for the
ZW220.
T3-2-32
Large-Diameter
Chamber
Servo Piston
Small-Diameter
Chamber
Spool A
Pilot Pressure
(PS2)
Spool B
T4GB-03-02-015
COMPONENT OPERATION / Control Valve
ZW220
Section A
ZW250
*1,*2
Section D
*3,*4
From Main Pump
From Main Pump
Pc2
Section E
Pc1
E
Orifice Part
*1
Section E
*3
Pc1
Pc1
Orifice Part
Pc2
Pc2
Negative Control
Valve
T4GB-03-02-017
Negative Control
Valve
T4GB-03-02-016
*1: Refer to T3-2-3.
*2: Refer to T3-2-5.
*3: Refer to T3-2-9.
*4: Refer to T3-2-13.
T3-2-33
COMPONENT OPERATION / Control Valve
FLOW CONTROL VALVE
In Compound Operation of Bucket Crowding and
Lift Arm Raising
Flow control valve is installed in the bucket circuit, and
narrows the circuit in compound operations, giving
priority to operations of the other actuators.
ZW220
In Single Operation of Bucket Crowding
1. Pressure oil from the main pump passes the lift
arm spool.
2. Pressure oil from the lift arm spool flows to the
bucket spool through check valve 1, and is
supplied to the bucket cylinder.
1. Part of the pressure oil from the main pump is
supplied to the lift arm cylinder through the lift arm
spool.
2. Remainder of the pressure oil from the main
pump is supplied to the bucket spool through the
parallel circuit.
3. At that time, flow is restricted because pressure
oil passes the orifice through check valve 2.
4. Pressure oil having passed the orifice flows to the
bucket spool, and is supplied to the bucket
cylinder.
5. As a result, flow to the bucket spool is restricted,
and more pressure oil is supplied to the lift arm
end having higher pressure, and both the bucket
and the arm move.
Inlet of Pressure Oil from
Main Pump in Lift Arm
Spool Operation
Check Valve 2
Orifice
Check
Valve 1
To Bucket Spool
T4GB-03-02-020
Inlet of Pressure Oil from
Main Pump at Neutral of Lift
Arm Spool
T3-2-34
COMPONENT OPERATION / Control Valve
ZW220
In Single Operation of Bucket Crowding
Bucket
Cylinder
Bucket Spool
Pilot Pressure
Check
Valve 1
Lift Arm Spool
T4GB-03-02-019
In Compound Operation of Bucket Crowding and Lift Arm Raising
Bucket
Cylinder
Pilot Pressure
Bucket Spool
Check
Valve 2
Lift Arm
Cylinder
Orifice
Pilot Pressure
Lift Arm Spool
Parallel Circuit
T4GB-03-02-019
T3-2-35
COMPONENT OPERATION / Control Valve
ZW250
In Single Operation of Bucket Crowding
In Compound Operation of Bucket Crowding and
Lift Arm Raising
1. Pressure oil from the main pump flows toward the
poppet.
2. Pressure oil entering the poppet pushes the
poppet left, and flows to the bucket spool, with its
small portion also flowing to the bucket spool
through the check valve inside the poppet to be
supplied to the bucket cylinder.
1. Part of the pressure oil from the main pump is
supplied to the lift arm cylinder through the lift arm
spool.
2. Remainder of the pressure oil from the main
pump is supplied toward the bucket spool.
3. Pressure oil from the main pump passes the
parallel circuit, and flows to the changeover valve
through the check valve of the poppet.
4. At this time, the changeover valve is positioned
on the orifice end because pilot pressure for
raising the lift arm is working on the changeover
valve.
5. By the effect of the orifice of the changeover valve,
pressure on the spring end of the poppet rises,
and force to push the poppet right (for closing)
arises.
6. As a result, flow to the bucket spool is restricted,
and more pressure oil is supplied to the lift arm
end having higher pressure, and both the bucket
cylinder and the arm cylinder move.
Spring A
Check Valve
Poppet
Spring B
To Bucket Spool
Pilot Presser
for Lift Arm Raising
Pressure Oil
from Main Pump
Changeover Valve
To Hydraulic Oil Tank
To Bucket Spool
T1V1-03-03-064
T3-2-36
COMPONENT OPERATION / Control Valve
ZW250
In Single Operation of Bucket Crowding
Bucket
Cylinder
Spring A
Bucket Spool
Poppet
Pilot Pressure
Spring B
Lift Arm Spool
Check
Valve
Main Pump
T4GB-03-02-021
In Compound Operation of Bucket Crowding and Lift Arm Raising
Bucket
Cylinder
Spring A
Poppet
Bucket Spool
Pilot Pressure
Pilot Pressure
Changeover
Valve
Check
Valve
Parallel Circuit
Lift Arm Cylinder
Spring B
Lift Arm
Spool
Pilot Pressure
Main Pump
T4GB-03-02-022
T3-2-37
COMPONENT OPERATION / Control Valve
(Blank)
T3-2-38
COMPONENT OPERATION / Hydraulic Fan Motor
OUTLINE
Shaft of the fan motor is provided with the cooling fan,
and the pressure oil from the fan pump rotates the
cooling fan by driving the shaft.
Fan motor has a built-in reverse control solenoid valve,
a flow adjustment solenoid valve, and others, and
controls the motor rotational direction and rotation
speed.
Reverse Control
Solenoid Valve
Flow Adjustment
Solenoid Valve
C
A
B
B
C
A
T4GB-03-03-001
T3-3-1
COMPONENT OPERATION / Hydraulic Fan Motor
Component Layout
Cooling Fan
Shaft
Fan Motor
Reverse Spool
Reverse Control
Solenoid Valve
Flow Control Valve
Reverse Signal
from MC
Flow Control Valve
Spring
Flow Adjustment
Solenoid Valve
Relief Valve
Hydraulic Oil
Tank
Hydraulic Oil
Tank
Fan Pump
Flow Adjustment
Command Signal
from MC
T3-3-2
T4GB-02-02-008
COMPONENT OPERATION / Hydraulic Fan Motor
Section B-B*
Section C-C*
5
6
7
8
9
10
Section A-A*
1
2
3
4
12
11
T4GB-03-03-002
1 - Shaft
4 - Cylinder Block
2 - Thrust Plate
3 - Piston
5 - Center Spring
6 - Valve Plate
7 - Flow Adjustment Solenoid
Valve
8 - Flow Control Valve
9 - Relief Valve
*Refer to T3-3-1
T3-3-3
10 - Reverse Control Solenoid
Valve
11 - Reverse Spool
12 - Flow Control Valve Spring
COMPONENT OPERATION / Hydraulic Fan Motor
OPERATION
Fan motor is a swash-plate type axial piston motor,
and converts the pressure oil sent from the fan motor
into rotational motion.
Operation Principle of Hydraulic Motor
1. Pressure oil from the fan motor is led to cylinder
block (4) through valve plate (6).
2. Pressure oil entering cylinder block (4) pushes
respective pistons (3).
3. This force F1 works on thrust plate (2), and is
divided into the component forces of F2 and F3
because thrust plate (2) is fixed to shaft (1) at an
angle of ⍺°.
4. Resultant force of F3 is a rotational force, and
rotates cylinder block (4) through pistons (3).
5. Cylinder block (4) is conncted to shaft (1) by the
splines, and the output shaft rotates.
T3-3-4
COMPONENT OPERATION / Hydraulic Fan Motor
α°
F1
F3
F2
2
1
4
2
3
4
6
3
T4GB-03-03-003
From Fan Pump
To Tank
T4GB-03-03-004
T3-3-5
COMPONENT OPERATION / Hydraulic Fan Motor
FLOW CONTROL VALVE
In case the cooling water and oil are below the set
temperature, the flow control valve supplies necessary
amount of the pressure oil from the fan pump, and
returns redundant amount to the tank to make control
for lowering the engine load and wind noise of the
cooling fan.
Operation
1. Pressure oil flowing from port P works on the A
end as upstream pressure of flow control valve
orifice (8), and on the B end as its downstream
pressure, and the differential pressure works on
flow control valve spring (12).
2. When the pressure difference becomes larger
than the set force, flow control valve spool (8)
moves, and redundant flow flows to port T.
T3-3-6
COMPONENT OPERATION / Hydraulic Fan Motor
7
8
From Fan Pump
P
B
A
12
T
T4GB-03-03-005
To Tank
T3-3-7
COMPONENT OPERATION / Hydraulic Fan Motor
REVERSE CONTROL VALVE
Fan motor is reversed by operations of the reverse
control solenoid valve and the reverse spool.
Operation
• At Neutral of Reverse Control Solenoid Valve
1. When reverse control solenoid valve (1) is at
neutral, the pressure oil (P) from the fan pump is
blocked by changeover valve (2).
2. As reverse spool (11) is being pushed by spring
(4), the pressure oil (P) from the fan pump flows
to port MB, and the fan motor rotates normally.
• In Operation of Reverse Control Solenoid Valve
1. When reverse control solenoid valve (1) is
operated, the pressure oil from the fan pump
flows to the right end of reverse spool (11)
through changeover valve (2).
2. When the pressure oil entering the right end of
reverse spool (11) overcomes the spring (4),
reverse spool (11) moves leftwards.
3. Pressure oil (P) from the fan pump flows to port
MA, and the fan motor makes reverse rotation.
T3-3-8
COMPONENT OPERATION / Hydraulic Fan Motor
At Neutral
1
P
OFF
2
MB
MA
4
T
3
T4GB-03-03-006
In Operation
1
P
ON
2
MA
MB
4
T
T3-3-9
3
T4GB-03-03-007
COMPONENT OPERATION / Hydraulic Fan Motor
FAN PUMP
Fan pump is a gear pump always supplying pressure
oil to the fan motor during the engine operation.
Fan pump is installed to the engine.
1
2
3
4
5
T4GB-03-03-008
6
1 - Drive Gear
2 - Oil Seal
3 - Bushing
4 - Body
5 - Cover
6 - Front Cover
7
8
9
7 - Gasket
8 - Driven Gear
9 - Side Plate
T3-3-10
10
10 - Gasket
COMPONENT OPERATION / Steering Pilot Valve
OUTLINE
Steering pilot valve is located between the brake/pilot
pump and the steering valve.
Steering pilot valve supplies the pressure oil from the
pilot pump to the steering valve in response to the
movement of the steering handle. (Refer to the
Steering Curcuit in the SYSTEM / Hydraulic System)
Port L (for Steering Left)
Port R (for Steering Right)
Steering
Handle
T487-03-02-001
Port T
(to Hydraulic Oil Tank)
Port P
(from Brake/Pilot Pump)
T3-4-1
COMPONENT OPERATION / Steering Pilot Valve
CONSTRUCTION
8
7
11
Steering pilot valve consists of gerotor (8), drive (7),
sleeve (3), spool (4), pin (5), housing (1), centering
springs (2), and others.
10
When the steering handle is rotated, spool (4) rotates,
and an oil passage is generated between spool (4) and
sleeve (3). Flow of the pressure oil from the pilot pump
is controlled by spool (4) and sleeve (3), and flows to
the steering valve.
Centering springs (2) are arranged both in spool (4)
and sleeve (3), and so function as to return sleeve (3)
to the neutral position when holding the handle is
stopped.
9
1
2
5
4
3
4
2
1
6
T1F3-03-07-002
3
Port R
Port L
Hole
5
Port P
10
9
8
7
6
T4GB-03-04-008
1 - Housing
2 - Centering Spring
3 - Sleeve
456-
Spool
Pin
Plate
789-
T3-4-2
Drive
Gerotor
Spacer
10 - Cap
11 - Check Valve
COMPONENT OPERATION / Steering Pilot Valve
OPERATION
4
Sleeve (3), spool (4), and drive (7) are mutually
connected by pin (5). When the handle (or the spool
(4)) is turned, a relative angular difference arises
between sleeve (3) and spool (4) because the hole of
spool (4) is a lengthened one.
Movement of the steering handle is conveyed only to
spool (4), and port P (from the steering pump) is
connected to port R (to the steering valve) or port L
through sleeve (3) and spool (4).
1
3
Port L
2
Port R
Handle
Port T
Port P
7
8
7
T4GB-03-04-007
11
1
6
10
9
2
T1F3-03-07-002
1
5
4
3
T3-4-3
7
8
COMPONENT OPERATION / Steering Pilot Valve
Steering Left:
4. Return oil from the steering valve enters port R,
and flows in the order of housing (1) - sleeve (3) spool (4) - sleeve (3) - port T to return to the
hydraulic oil tank.
5. When the pressure oil from the brake/pilot pump
enters gerotor (8), gerotor (8) rotates leftwards.
Rotation of gerotor (8) is transmitted to the sleeve
(3) through drive (7), and sleeve (3) rotates
leftwards similarly.
6. When sleeve (3) rotates the same amount of turns
as spool (4), passages of sleeve (3) and spool (4)
are closed, and operation of the steering valve is
stopped.
7. Therefore, gerotor (8) rotates in response to
rotation of the handle, and the steering valve is
operated in response to the amount of turns of the
handle.
1. When the steering handle is turned left, spool (4)
rotates, and the pressure oil from the brake/pilot
pump flows in the order of port P - sleeve (3) spool (4) - sleeve (3) - housing (1) - gerotor (8).
2. Pressure oil from gerotor (8) flows in the order of
housing (1) - sleeve (3) - spool (4) - sleeve (3) port L - steering valve, and controls the steering
valve.
3. Steering valve drives the steering cylinder with the
pressure oil from the main pump, and directs the
vehicle body toward left.
Steering Cylinder
Steering Valve
Main Pump
Port L
Port R
Port P
Port T
Brake/Pilot
Pump
1
8
7
4
2
3
Steering Pilot Valve
T4GB-03-04-009
T3-4-4
L
R
P
COMPONENT OPERATION / Steering TPilot
Valve
Steering Right
When the steering handle is turned right, the
pressure oil from the pilot pump flows in the order of
port P - port R - steering cylinder, and operates the
steering valve to direct the front wheel right.
Return oil from the steering valve flows in the order of
port L - port T to return to the hydraulic oil tank.
T4GB-03-04--010
Neutral
When the steering handle is not being turned, the oil
from the pilot pump works on port P of the steering
pilot valve, but does not flow to the steering valve
because it is blocked by spool (4). Therefore, the
steering cylinder is not operated.
T
P
4
T4GB-03-04--011
T3-4-5
COMPONENT OPERATION / Steering Pilot Valve
(Blank)
T3-4-6
COMPONENT OPERATION / Steering Valve
OUTLINE
Steering valve is located between the main pump and
the steering cylinder.
Steering valve supplies the pressure oil from the main
pump to the steering cylinder in response to the pilot oil
pressure of the steering pilot valve.
Steering cylinder is provided with the overload relief
valve.
A
C
B
T4GB-03-04-001
T3-5-1
COMPONENT OPERATION / Steering Valve
Component Layout
4
1
2
3
Port A
Port T
Port B
Port Pa
Port Pb
5
Port A: Pressure for Steering
Right
Port P: From Main Pump
6
Port DR
Port P
Port LS
Port B: Pressure for Steering
Left
Port T: Return to Hydraulic Oil
Tank
4
5
Port Pa: Pilot Pressure for
Steering Right
Port LS: To Port LS of Priority
Valve
T3-5-2
T4GB-03-04-002
Port Pb: Pilot Pressure for
Steering Left
Port DR: Return to Hydraulic Oil
Tank
COMPONENT OPERATION / Steering Valve
Section A
*
7
Port P
Port DR
1
Port T
Section B
*
3
Port LS
Port B
Port A
2
Port Pb
Port Pa
4
5
7
Section C
*
T4GB-03-04-003
4
6
T4GB-03-04-006
1 - Spool
2 - Overload Relief Valve
3 - Overload Relief Valve
4 - Lord Check Valve
5 - Variable Orifice
6 - Fixed Orifice
*: Refer to T3-5-1
T3-5-3
7-
Passage A
COMPONENT OPERATION / Steering Valve
OPERATION
In Neutral
1. When steering spool (1) is in the neutral position,
port A and port B of the steering cylinder are
closed.
2. Pressure oil from the main pump does not flow to
the steering cylinder because port P is closed.
T3-5-4
COMPONENT OPERATION / Steering Valve
Section A
*
Port P
Port DR
Port T
Section B
:*
Port B
Port A
T4GB-03-04-004
1
*: Refer to T3-5-1.
T3-5-5
COMPONENT OPERATION / Steering Valve
When Steering Left
1. When the steering handle is turned left, the pilot
pressure oil is sent to port Pb from the steering
pilot valve, and spool (1) moves right.
2. Pressure oil from the main pump is sent to the
steering valve through port P, and further sent to
passage A (7) through variable orifice (5).
3. Pressure oil in passage A (7) pushes and opens
load check valve (4), and flows to the steering
cylinder through port B.
4. And the return oil from the steering cylinder enters
spool (1) through port A, and returns to the
hydraulic oil tank through port T.
5. Also, the pilot pressure oil flowing into port Pb
pushes spool (1) on port Pb end, while flowing to
port Pa after being decompressed by fixed orifice
(6). This reduces the shock caused by fast
operation of the handle. (Refer to T3-5-2 and also
Steering Curcuit in the SYSTEM / Hydraulic
System)
NOTE: Opening area of the variable orifice (5) is
proportional to the amount of stroke of the
spool (1) due to the pilot pressure from the
steering pilot valve. (Refer to the Steering
Curcuit in the SYSTEM / Hydraulic System)
T3-5-6
COMPONENT OPERATION / Steering Valve
Port P
1
7
5
Port T
Port LS
Port B
Port A
Port Pb
Port Pa
4
6
5
7
T3-5-7
T4GB-03-04-005
COMPONENT OPERATION / Steering Valve
STEERING OVERLOAD RELIEF VALVE
Steering overload relief valve is installed in the left and
right steering circuits. Overload relief valve controls
pressure in the respective steering circuits from rising
abnormally high when the steering cylinder is moved
by an external force.
Make-up Operation
Operation of Relief Valve
1. Pressure at port HP (in the steering circuit) works
on the pilot poppet, passing the orifice in the
piston.
2. When the pressure at port HP rises to the setting
force of spring B, the pilot poppet opens, and
pressure oil flows to port LP (in the hydraulic oil
tank), passing passage A and the periphery of the
sleeve.
3. At this moment, pressure difference arises
between port HP and the spring chamber caused
by the orifice.
4. When this pressure difference reaches the value
corresponding to the set force of spring A, the
piston and the main poppet open, and the
pressure oil at port HP flows to port LP.
5. As a result, the pressure in the steering cylinder
circuit lowers.
6. If the steering cylinder circuit pressure lowers to
the set pressure value, the piston and the main
poppet are closed by the force of spring A.
T3-5-8
1. When the pressure at port HP (in the steering
cylinder circuit) lowers than the pressure at port
LP (in the hydraulic oil tank), the sleeve moves
right.
2. Hydraulic oil flows into port HP, and cavitation is
prevented.
3. If the pressure at port HP rises to the set pressure
value, the sleeve is closed by the force of spring
C.
COMPONENT OPERATION / Steering Valve
Normally (When not Relieving):
Main
Poppet
Sleeve
Spring A
Passage A
Spring B
HP
T4GB-03-02-030
LP
Orifice
Piston
When Relieving:
Spring Chamber
Main
Poppet
Pilot
Poppet
Sleeve
Spring A
Spring C
Passage A
Spring B
HP
LP
Orifice
Piston
T4GB-03-02-031
Spring
Chamber
In Make-up Operation:
Pilot
Poppet
Sleeve
HP
LP
T4GB-03-02-032
Spring C
T3-5-9
COMPONENT OPERATION / Steering Valve
(Blank)
T3-5-10
COMPONENT OPERATION / Pilot Valve
OUTLINE (TWO LEVER TYPE PILOT
VALVE FOR FRONT ATTACHMENT)
Pilot valve is a valve for controlling the pilot pressure
oil for moving the spool of the control valve. Provided
with the PPC (Pressure Proportional Control Valve)
function,
the
pilot
valve
outputs
pressure
corresponding to the control lever stroke of the control
lever, and moves the spool of the control valve.
The bi-directional, four-port type is adopted for the
front-end attachment.
Port No.
1
2
3
4
Bucket Crowd
Bucket Tilting Out
Lift Arm Lower
Lift Arm Raise
Hydraulic Symbol
P
1
2
3
4 T
T4GB-03-05-001
P
T3-6-1
1
2
3
4
T
T4GB-03-05-002
COMPONENT OPERATION / Pilot Valve
OPERATION
At Neutral (between A and B of Pusher Stroke)
1. At the neutral position of the control lever, spool
(7) is completely blocking the pressure oil of port
P. Also, the outlet port is connected to port T
through the notch part of spool (7), and the
pressure oil at the output port is equal to the
pressure in the hydraulic tank.
2. When the control lever is moved slightly, lever (1)
is tilted, and push rod (2) and pusher (3) are
pushed in. Pusher (3) and spring guide (4) remain
mutually connected, and move downward,
compressing return spring (6).
3. At this time, spool (7) is pushed by balance spring
(5), and moves downward until the clearance in
Part A becomes zero.
4. During this movement, the output port remains
connected with port T, and pressure oil is not
supplied to the output port.
NOTE: Lever stroke during the period when the
clearance (A) becomes zero is the play of
the control lever.
T3-6-2
E
Pilot
Pressure
F
D
C
A
B
Pusher Stroke
Output Diagram
T505-02-07-006
COMPONENT OPERATION / Pilot Valve
Pusher Stroke: between A and B
1
2
3
4
5
6
Port T
(Clearance of
Part A: 0)
(A)
Port P
Notch Part
7
Output Port
1 - Lever
2 - Push Rod
3 - Pusher
4 - Spring Guide
T4GB-03-05-004
T4GB-03-05-003
5 - Balance Spring
6 - Return Spring
T3-6-3
7-
Spool
COMPONENT OPERATION / Pilot Valve
During Metering or Pressure Decrease (In Pusher
Stroke between C and D)
Full Stroke (Pusher Stroke between E and F)
1. When the control lever is further tilted, the ouput
port is connected with port P through spool (7).
2. Pressure oil from Port P flows into the output port
through spool (7), and the pressure at the output
port is raised.
3. Pressure at the output port works on face B of
spool (7), and tends to push up spool (7).
4. In case the force tending to push up the spool (7)
is smaller than the spring force of balance spring
(5), balance spring (5) is not compressed.
Therefore, port P and the output port remain
connected, and the pressure at the output port
keeps rising.
5. When the pressure at the output port rises further,
the force tending to push spool (7) up increases. If
this force becomes larger than the force of
balance spring (5), spool (7) moves upwards,
compressing the balance spring (5).
6. When spool (7) moves upward, the output port is
not connected any longer, and pressure oil stops
flowing from port P to the output port.
And pressure increase at the output port is
stopped.
7. In this way, balance spring (5) is compressed by
the amount spool (7) is pushed down, and the
pressure at the output port is the balanced
pressure working on the spring force and spool
(7).
T3-6-4
1. When the control lever is fully stroked, pusher (3)
moves downward until spring guide (4) contacts
the shoulder part of the casing.
2. At this time, spool (7) is directly pushed by the
bottom of pusher (3). Therefore, the output port
remains connected with port P through the notch
part of spool (7) because even if the pressure at
the output port is raised, spool (7) does not move
upward.
3. As a result, the pressure on the output port end is
equal to the pressure at port P.
Stroke amount C of the pusher determines the
total stroke of the lever.
E
Pilot
Pressure
F
D
C
A
B
Pusher Stroke
Output Diagram
T505-02-07-006
COMPONENT OPERATION / Pilot Valve
Pusher Stroke: between C and D
Pusher Stroke: between E and F
3
5
(C)
Port T
4
Notch Part
Face B
Port P
Port P
7
7
Output Port
3-
Pusher
4-
Spring Guide
Output Port
T4GB-03-05-005
5-
T3-6-5
Balance Spring
7-
Spool
T4GB-03-05-006
COMPONENT OPERATION / Pilot Valve
Electromagnetic Detent
Coil for detent is installed at the push rod part of the
pilot valve.
3. Adsorbed condition is retained until the coil
assembly is unexcited or until adsorption is
forcefully cancelled by moving the control lever
the other way around.
1. When one of the control levers is tilted, push rod
(2) and plate (8) of the other are pushed upwards
by the spring force.
2. If the control lever is operated until its stroke end,
plate (8) of the other is adsorbed by coil assembly
(10).
2
10
8
T4GB-03-05-007
2-
Push Rod
8-
Plate
10 - Coil Assembly
T3-6-6
COMPONENT OPERATION / Pilot Valve
OUTLINE (JOYSTICK TYPE PILOT VALVE
FOR FRONT ATTACHMENT)
Port No.
1
2
3
4
Bucket Crowd
Bucket Tilting Out
Lift Arm Lower
Lift Arm Raise
Hydraulic Symbol
1
2
3
4
P
T
T4GB-03-05-001
2
3
T
1
4
P
T3-6-7
T4GB-03-05-008
COMPONENT OPERATION / Pilot Valve
OPERATION
At Neutral
1. At neutral, spool (7) completely blocks the
pressure oil at port P. Also, the output port is
connected with port T through the fine control
hole of spool (7).
For this reason, the pressure at the output port is
equal to the pressure at port T.
2. If the control lever is tilted slightly, disc (1) is tilted,
and push rod (2) and piston (3) are pushed in.
Piston (3) pushes down spring guide (4) and
balance spring (5), and moves downward.
3. At this time, spool (7) is pushed by spring (5), and
moves downward until the clearance at part A
becomes zero.
4. During this movement, the output port remains
connected with port T, and pressure oil is not
supplied to the output port.
NOTE: Lever stroke during the period when the
clearance (A) becomes zero is the play of
the control lever.
T3-6-8
COMPONENT OPERATION / Pilot Valve
At Neutral
1
2
3
4
5
6
Port T
(A)
Port P
(Clearance of Part A: 0)
Fine Control Hole
7
Output Port
T4GB-03-05-009
12-
Disc
Push Rod
3 - Piston
4 - Spring Guide
T4GB-03-05-010
56-
T3-6-9
Balance Spring
Return Spring
7 - Spool
COMPONENT OPERATION / Pilot Valve
During Metering or Pressure Decrease
Full Stroke
1. When the control lever is further tilted, the ouput
port is connected with port P through the fine
control hole of spool (7).
2. Pressure oil from port P flows into the output port
through spool (7), and the pressure at the output
port is raised.
3. Pressure at the output port works on spool (7),
and tends to push up spool (7).
4. In case the force tending to push up spool (7) is
smaller than the spring force of balance spring (5),
balance spring (5) is not compressed. Therefore,
port P and the output port remain connected, and
the pressure at the output port keeps rising.
5. When the pressure at the output port rises further,
the force tending to push spool (7) up increases. If
this force becomes larger than the force of
balance spring (5), spool (7) moves upwards,
compressing the balance spring (5).
6. When spool (7) moves upward, the output port is
not connected any longer, and pressure oil stops
flowing from port P to the output port.
And pressure increase at the output port is
stopped.
7. In this way, balance spring (5) is compressed by
the amount spool (7) is pushed down, and the
pressure at the output port is the balanced
pressure working on the spring force and spool
(7).
1. When the control lever is fully stroked, disc (7)
pushes down push rod (2) and piston (3), and
spring guide (4) pushes down spool (7).
2. Output port is connected with port P through the
fine control hole of spool (7).
3. Spool (7) is being pushed down by spring guide
(4), and the output port remains connected
through the fine control hole of spool (7) because
even if the pressure at the output port is raised,
spool (7) does not move upward.
4. As a result, the pressure on the output port end is
equal to the pressure at Port P.
T3-6-10
COMPONENT OPERATION / Pilot Valve
During Metering or Pressure Decrease
Full Stroke
2
3
4
5
Fine Control Hole
Port P
Fine Control Hole
Port P
7
7
Output Port
Output Port
T4GB-03-05-011
23-
Push Rod
Piston
45-
Spring Guide
Balance Spring
T4GB-03-05-012
7-
T3-6-11
Spool
COMPONENT OPERATION / Pilot Valve
ELECTROMAGNETIC DETENT
Coil for detent is installed at the push rod part of the
pilot valve.
3. Adsorption condition is retained until coil
assembly (8) is unexcited or until adsorption is
forcefully cancelled by operating the control lever
toward the other direction.
1. When one of the control levers is tilted, push rod
(2) and plate (9) of the other are pushed upwards
by the spring force.
2. If the control lever is operated until its stroke end,
plate (9) of the other is adsorbed by coil assembly
(8).
2
8
9
T4GB-03-05-013
2-
Push Rod
8-
Coil Assembly
9-
T3-6-12
Plate
COMPONENT OPERATION / Pilot Valve
OUTLINE (LEVER TYPE PILOT VALVE
FOR ADDITIONAL CIRCUIT) (OPTIONAL)
Port No.
1
2
Optional
Optional
T
T
Hydraulic Symbol
P
P
T
P
1
1
2
2
T554-02-07-009
1
T3-6-13
2
T1LA-03-04-001
COMPONENT OPERATION / Pilot Valve
OPERATION
At Neutral (between A and B of Pusher Stroke)
1. At the neutral position of the control lever, spool
(7) is completely blocking the pressure oil of port
P. Also, the outlet port is connected to port T
through the notch part of spool (7), and the
pressure oil at the output port is equal to the
pressure in the hydraulic tank.
2. When the control lever is moved slightly, cam (1)
is tilted, and pusher (2) and spring guide (4) are
pushed in. Pusher (3) and spring guide (4) move
downward, remaining mutually connected, and
compressing return spring (6).
3. At this time, spool (7) is pushed by balance spring
(5), and moves downward until the clearance in
Part A becomes zero.
4. During this movement, the output port remains
connected with port T, and pressure oil is not
supplied to the output port.
5. When the pressure at the output port rises further,
the force tending to push spool (7) up increases. If
this force becomes larger than the force of
balance spring (5), spool (7) moves upwards,
compressing balance spring (5).
6. When spool (7) moves upward, the notch part
closes, and pressure oil stops flowing from port P
to the output port. And pressure increase at the
output port is stopped.
7. In this way, balance spring (5) is compressed by
the amount the spool (7) is pushed down, and the
pressure at the output port is the balanced
pressure working on the spring force and spool
(7).
NOTE: Lever stroke during the period when Part A
becomes zero is the play of the control
lever.
Pilot
Pressure
D
During Metering or Pressure Decrease (In Pusher
Stroke between C and D)
1. When the control lever is further tilted, the hole
part of spool (7) is connected with notch part (B).
2. Pressure oil from port P flows into the output port
through notch part (B) and the hole part of spool
(7), and the pressure at the output port is raised.
3. Pressure at the output port works on the bottom of
spool (7), and tends to push up spool (7).
4. In case the force tending to push up spool (7) is
smaller than the spring force of balance spring (5),
balance spring (5) is not compressed. Therefore,
port P and the output port remain connected, and
the pressure at the output port keeps rising.
T3-6-14
C
A
B
Pusher Stroke
T1F3-03-09-004
Output Diagram
COMPONENT OPERATION / Pilot Valve
Between A and B of Pusher Stroke
1
2
3
4
5
Port T
6
(A)
Clearance at
Part A: 0
Port P
Hole Part
7
Passage
T1LA-03-04-002
Output Port
T1LA-03-04-003
Between C and D of Pusher Stroke
5
Port T
Notch Part (B)
Port P
Hole Part
7
Output Port
1 - Cam
2 - Pusher
3 - Plate
4 - Spring Guide
T1LA-03-04-004
56-
T3-6-15
Balance Spring
Return Spring
7 - Spool
COMPONENT OPERATION / Pilot Valve
(Blank)
T3-6-16
COMPONENT OPERATION / Pilot Valve
OUTLINE (JOYSTICK TYPE PILOT VALVE
FOR ADDITIONAL CIRCUIT) (OPTIONAL)
Port No.
1
2
3
4
Optional
Optional
Optional
Optional
P
Hydraulic
Symbol
T
P
1
3
2
4
4
T105-02-07-020
3
1
2
T1V1-03-04-001
T
T3-6-17
COMPONENT OPERATION / Pilot Valve
OPERATION
Head of spool (6) is hung by the top face of spring
guide (3). Spring guide (3) is lifted up by return spring
(5).
At Neutral (Output Diagram: between A and B):
1. At neutral, spool (6) completely blocks the
pressure oil at port P (from the pilot pump). Also,
the output port is connected with port T (to the
hydraulic oil tank) through the internal passage of
spool (6).
2. For this reason, the pressure at the output port (to
the control valve) is equal to the pressure at Port
T.
3. If the control lever is tilted slightly, cam (1) is tilted,
and pusher (2) is pushed in. Pusher (2) and
spring guide (3), mutually connected, push down
return spring (5), and moves downward.
4. At this time, the pressures at the output port and
port T are equal, so spool (6) moves downward
with the bottom face of its head keeping contact
with spring guide (3) by the force of balance
spring (4).
5. This condition continues until hole part (7) of
spool (6) is connected with port P.
T3-6-18
E
Pilot
Pressure
F
D
C
A B
Lever Stroke
T523-02-05-001
Output Diagram
COMPONENT OPERATION / Pilot Valve
1
1
2
2
3
3
4
4
5
5
6
7
Port P
6
6
Output Port
Port T
7
1 - Cam
2 - Pusher
Port T
7
Port P
Output Port
3 - Spring Guide
4 - Balance Spring
Port T
Port P
Output Port
T1V1-03-04-007
5 - Return Spring
6 - Spool
T3-6-19
T1V1-03-04-008
7 - Hole Part
COMPONENT OPERATION/Pilot Valve
During Metering or Pressure Decrease (Output
Diagram: between C and D)
1. When the control lever is further tilted and pusher
(2) is pushed down, hole part (7) of spool (6)
reaches port P, and the prsessure oil from port P
flows into the output port.
2. Pressure at the output port works on the bottom of
spool (6), and tends to push up spool (6).
3. In case the force working on spool (6) is smaller
than the spring force of balance spring (4),
balance spring (5) is not compressed. Therefore,
spool (6) is not pushed up, and the pressure at
the output port keeps rising.
4. When the pressure at the output port rises further,
the force tending to push spool (6) up increases. If
this force becomes larger than the force of the
balance spring (4), spool (6) moves upwards,
compressing the balance spring (4).
5. When spool (6) moves upward, hole part (7)
closes, pressure oil stops flowing from Port P to
the output port, and pressure increase at the
output port is stopped.
6. In this way, the balance spring (4) is compressed
by the amount spool (6) is pushed down, and the
pressure at the output port is the balanced
pressure working on the spring force and spool
(6).
T3-6-20
E
Pilot
Pressure
F
D
C
A B
Lever Stroke
T523-02-05-001
Output Diagram
COMPONENT OPERATION/Pilot Valve
1
1
2
2
3
3
4
4
5
5
6
6
Port T
7
Port P
7
Output Port
1 - Cam
2 - Pusher
Port T
3 - Spring Guide
4 - Balance Spring
Port P
Output Port
T1V1-03-04-009
5 - Return Spring
6 - Spool
T3-6-21
7 - Hole Part
T1V1-03-04-010
COMPONENT OPERATION/Pilot Valve
Full Stroke (Output Diagram: between E and F)
1. When the control lever is fully stroked, pusher (2)
moves downward until it contacts the shoulder
part of the casing.
2. At this time, spool (6) is directly pushed by the
bottom of the pusher (2). Therefore, even if the
pressure at the output port is raised, hole part (7)
of spool (6) is not closed.
3. As a result, the pressure on the output port end is
equal to the pressure at port P.
E
Pilot
Pressure
D
C
A
NOTE: Stroke amount E of the pusher (2)
determines the total stroke of the lever.
B
Lever Stroke
T523-02-05-001
Output Diagram
T3-6-22
F
COMPONENT OPERATION/Pilot Valve
1
2
2
3
4
5
E
6
Port T
7
Port P
Output Port
1 - Cam
2 - Pusher
3 - Spring Guide
4 - Balance Spring
T1V1-03-04-011
T1V1-03-04-007
5 - Return Spring
6 - Spool
T3-6-23
7 - Hole Part
COMPONENT OPERATION/Pilot Valve
(Blank)
T3-6-24
COMPONENT OPERATION / Charging Block
OUTLINE
Charging block is installed for supplying the pressure
oil from the pilot pump not only to the service brake
accumulator and the brake valve by giving them priority,
but also to the parking brake, the steering pilot valve,
and others.
Charging block consists of the priority valve, relief
valve, pump torque control proportional solenoid valve,
pilot relief valve, check valve, and others.
2
Port for Attaching
Service Brake
Accumulator (Rear)
Port for Attaching
Service Brake
Accumulator (Front)
3
5
Pump Torque
Control
Proportional
Solenoid Valve
13
Parking Brake
Solenoid Valve
17
Port for Attaching
Pilot Accumulator
T4GB-03-06-001
T3-7-1
COMPONENT OPERATION / Charging Block
Component Layout
1
2
3
4
5
6
7
8
22
9
10
11
21
12
13
14
20
15
16
17
18
T4GB-03-06-013
4
19
1 - Service Brake Accumulator
(Rear)
2 - Adaptor
9 - Priority Valve
16 - Port BR3 (To Parking Brake)
10 - Pilot Relief Valve
3 - Port M2
(To Rear End of Brake Valve)
4 - Check Valve
5 - Port M1
(To Front End of Brake Valve)
6 - Service Brake Accumulator
(Front)
7 - Service Brake Pressure Sensor
8 - Port P (from Pilot Pump)
11 - Port DR (To Hydraulic Oil Tank)
17 - Port PS2
(To Main Pump Regulator
and Ride Control Valve (Optional))
18 - Pilot Accumulator
12 - Port DR2(To Hydraulic Oil Tank)
13 - Port PS1
(To Steering Pilot Valve)
14 - Port X
(To Main Pump Regulator)
15 - Parking Brake Pressure Sensor
T3-7-2
19 - Port PP (To Pilot Shutoff Valve)
20 - Parking Brake Solenoid Valve
21 - Pump Torque Control Proportional
Solenoid Valve
22 - Relief Valve
COMPONENT OPERATION / Charging Block
11
Section V-V*
10
14
Section U-U*
12
21
15
16
Section T-T*
20
Section S-S
19
*
18
4
T4GB-03-06-003
*Refer to T3-7-1.
4
T3-7-3
COMPONENT OPERATION / Charging Block
Layout Drawing
1
2
3
4
5
6
7
8
22
9
10
11
21
12
13
14
20
15
16
17
18
T4GB-03-06-013
4
19
1 - Service Brake Accumulator
(Rear)
2 - Adaptor
9-
Priority Valve
3 - Port M2
(To Rear End of Brake Valve)
4 - Check Valve
5 - Port M1
(To Front End of Brake Valve)
6 - Service Brake Accumulator
(Front)
7 - Service Brake Pressure Sensor
8 - Port P (From Pilot Pump)
11 - Port DR (To Hydraulic Oil Tank)
10 - Pilot Relief Valve
12 - Port DR2 (To Hydraulic Oil Tank)
13 - Port PS1
(To Steering Pilot Valve)
14 - Port X
(To Main Pump Regulator)
15 - Parking Brake Pressure Sensor
T3-7-4
16 - Port BR3 (To Parking Brake)
17 - Port PS2
(To Main Pump Regulator
and Ride Control Valve (Optional))
18 - Pilot Accumulator
19 - Port PP (To Pilot Shutoff Valve)
20 - Parking Brake Solenoid Valve
21 - Pump Torque Control Proportional
Solenoid Valve
22 - Relief Valve
COMPONENT OPERATION / Charging Block
Section Z-Z*
6
1
4
Section Y-Y*
*
Section X-X
7
8
4
Section W-W*
22
9
*Refer to T3-7-1.
T3-7-5
T4GB-03-06-004
COMPONENT OPERATION / Charging Block
PRIORITY VALVE (REFER TO THE PILOT
CURCUIT IN THE SYSTEM / HYDRAULIC
SYSTEM)
1. Pressure oil from the pilot pump flows in through
port P, and works on the both ends of the plunger
of the priority valve.
2. Same pressure is applied to the both ends of the
plunger, so the plunger does not move, and a
restricted amount of pressure oil is supplied to the
other pilot circuits.
3. When the service brake accumulator is
accumulated exceeding the set pressure, the
piston of the relief valve pushes the needle valve.
4. Pressure oil in the spring chamber of the plunger
flows to the hydraulic oil tank through port DR.
5. Plunger is pushed toward the spring chamber to
stroke because the spring chamber is
decompressed.
6. A larger amount of the pressure oil from the pilot
pump is supplied to the other pilot circuits through
the priority valve.
Below Set Pressure of Service Brake Accumulator
Relief Valve
From Port P
Plunger
(Section W-W)
T4GB-03-06-005
To Service Brake Circuit
To Other
Pilot Circuits
Above Set Pressure of Service Brake Accumulator
Needle Valve
Piston
Service Brake
Accumulator
Pressure
To Port Dr
From Port P
Plunger
Spring Chamber
(Section W-W)
T4GB-03-06-006
To Other Pilot Circuits
T3-7-6
COMPONENT OPERATION / Charging Block
PILOT RELIEF VALVE
1. Pilot relief valve prevents the pressure in the pilot
circuit from increasing over the set pressure
during operations of the actuators like the pilot
valve.
2. When the pilot circuit pressure is above the set
pressure, pressure oil works on the poppet of the
pilot relief valve.
3. Poppet works toward the spring to be connected
with port DR.
4. Pressure oil in the pilot circuit returns to the
hydraulic oil tank through port DR.
5. When the pilot circuit pressure is below the set
pressure to the spring force, the poppet moves
left, closing connection of port DR.
Normally
Poppet
(Section V-V)
From Port P
T4GB-03-06-007
When Relieving
Poppet
(Section V-V)
T3-7-7
Port DR
Spring
T4GB-03-06-008
COMPONENT OPERATION / Charging Block
PUMP TORQUE CONTROL PROPORTIONAL SOLENOID VALVE (REFER TO THE
PILOT CURCUIT IN THE SYSTEM /
HYDRAULIC SYSTEM)
Pilot pressure supplied to the main pump regulator for
controlling the pump delivery flow is controlled by the
operation of the pump torque control proportional
solenoid valve.
Not in Operation of Solenoid Valve
To Main Pump
Regulator
Port X
1. When there is no signal from the MC (Main
Controller), the spool of the solenoid valve is
being pushed by the spring.
2. Pilot pressure oil is supplied to port ST of the main
pump regulator through port X.
3. When signal is transmitted from the MC, the spool
moves toward the spring in response to the signal
of the spool, and the amount of the pilot pressure
oil flowing out of port X is lowered.
4. When the signal from the MC becomes the
maximum value, the spool fully strokes toward the
spring, and the pilot pressure oil is blocked by the
spool.
5. Port X and port DR2 are connected, and the pilot
pressure oil at port X is lost.
Spring
(Section U-U)
Pilot Pressure Oil
T4GB-03-06-009
In Operation of Solenoid Valve
Port X
Port
DR2
Spool
(Section U-U)
Spring
Pilot Pressure Oil
T4GB-03-06-010
T3-7-8
COMPONENT OPERATION / Charging Block
SERVICE BRAKE ACCUMULATOR /
PILOT ACCUMULATOR
Accumulator is installed in the pilot circuit leading to
the service brake and the pilot valve.
High-pressure nitrogen gas is contained in the
accumulator, and the pilot pressure oil compresses
the nitrogen gas through the diaphragm.
Circuit pressure oil is retained by compression of the
nitrogen gas.
IMPORTANT: Construction of the accumulator
does not allow disassembly.
Replace the whole assembly, when
necessary.
Seal Ring
Retainer
Shell
Diaphragm
Valve Poppet
T4GB-03-06-011
T3-7-9
COMPONENT OPERATION / Charging Block
PARKING BRAKE SOLENOID VALVE
Pressure oil from the pilot pump is accumulated in the
pilot accumulator, and its pressure always works on
the outlet of the parking brake solenoid valve.
When the parking brake solenoid valve is operated,
the pilot accumulator enters the parking brake through
the spool, and releases the parking brake.
Parking Brake
Solenoid Valve
Port for Attaching
Pilot Accumulator
T3-7-10
T4GB-03-07-004
COMPONENT OPERATION / Charging Block
Not in Operation
Parking Brake
Pressure Sensor
Parking Brake
Drain Port
Spool
Spring
Parking Brake
Solenoid Valve
(Section T-T)
Pilot Accumulator
Pressure
T4GB-03-07-005
In Operation
Parking Brake
Pressure Sensor
Parking Brake
Spool
Spring
Parking Brake
Solenoid Valve
(Section T-T)
Pilot Pressure
Accumulator
Pressure
T3-7-11
T4GB-03-07-006
COMPONENT OPERATION / Charging Block
SERVICE BRAKE PRESSURE SENSOR
Brake pressure necessary for the service brake is
sensed. Sensor is installed in the service brake circuit
of the charging block, and senses the oil pressure of
the service brake accumulator.
1 - Earth
2 - Output
3 - Electric Power Source
(5V)
4 - Pressure Applied Part
(Diaphragm)
1
2
4
3
T4GB-03-06-012
PARKING BRAKE PRESSURE SENSOR
Brake pressure oil necessary for the parking brake is
sensed. Sensor is installed in the parking brake circuit
of the charging block, and senses the oil pressure of
the pilot accumulator.
3 - Pressure-applied Part
5 - (Diaphragm)
6 - Earth
7-
Output
8-
Electric Source (5V)
5
6
7
8
T176-03-01-023
T3-7-12
COMPONENT OPERATION / Ride Control Valve
OUTLINE
(Refer to the SYSTEM / Control System)
Ride control valve enables stable traveling by
absorbing the force generated in the lift arm cylinder in
traveling on rough roads.
Ride control valve consists of the ride control solenoid
valve, spool, charge-cut spool, overload relief valve,
and others.
Overload
Relief Valve
A
B
Ride Control
Solenoid Valve
T4GB-03-08-001
T3-8-1
COMPONENT OPERATION / Ride Control Valve
Component Layout
Lift Arm
Cylinder
Ride Control
Accumulator
5
Ride Control Valve
SP
3
Pi
1
4
B
A
2
To Hydraulic Oil Tank
T
From Charging
Block
T4GB-03-08-002
1 - Ride Control Solenoid Valve
2 - Charge-cut Spool
34-
Overload Relief Valve
Spool
5-
T3-8-2
Draing Plug
COMPONENT OPERATION / Ride Control Valve
Section A*
Port Pi
To Ride Control
Accumulator
1
Port SP
3
Port B
Port A
Port T
2
*Refer to T3-8-1.
T3-8-3
4
T4GB-03-08-003
COMPONENT OPERATION / Ride Control Valve
OPERATION
1. At neutral, port Pi and the ouput port are not
connected, blocked by the spool.
2. When the signal from the MC (Main Controller)
enters the solenoid, the solenoid is excited.
3. Solenoid pushes the spool with the force
corresponding to the signal from the MC, so port
Pi and the output port are connected, and pilot
pressure oil pushes the main spool.
4. When the main spool is pushed toward spring 2,
port A (on the bottom end of the lift arm cylinder)
and the ride control accumulator are connected,
and port B (on the rod end of the lift arm cylinder)
and port T are connected.
5. As a result, the pushing force of the lift arm
cylinder is absorbed by the accumulator, and the
load generated by the pushing up force is
absorbed by sucking up the hydraulic oil from the
tank port.
Section A*
Pilot Pressure
Spool
To Ride Control
Accumulator
Port Pi
Port A
Port B
Spring 1
Output Port
Spring 2
T4GB-03-08-006
Tank Port
Main Spool
*Refer to T3-8-1.
T3-8-4
COMPONENT OPERATION / Ride Control Valve
(Blank)
T3-8-5
COMPONENT OPERATION / Ride Control Valve
CHARGE-CUT SPOOL
Charge-cut spool accumulates the pressure oil in the
lift arm cylinder in the ride control accumulator, and
shuts down the pressure oil from the lift arm cylinder
when the ride control accumulator is accumulated to
the set pressure.
1. When the ride control is not in operation, the
pressure oil on the lift arm cylinder bottom end
flows to port X, passing the orifice through port A.
2. Pressure oil flowing into port X passes in the
spool of the charge-cut spool, and opening the
check valve, flows into port Y to be accumulated
in the ride control accumulator.
3. As Spool Sectional Area M is larger than Spool
Sectional Area N, when the ride control
accumulator is accumulated to the set pressure,
the pressure oil from port X pushes the spool
toward the spring.
4. When the spool moves toward the spring, the
passage of the pressure oil from the spool to port
Y is closed, and accumulating the ride control
accumulator is stopped.
T3-8-6
COMPONENT OPERATION / Ride Control Valve
During Accumulation of Accumulator
Orifice
Spring
Port A
Spool
Port X
To Ride Control
Accumulator
Port Y
Check Valve
T4GB-03-08-007
After Accumulation of Accumulator
Sectional Area M
Sectional Area N
T3-8-7
T4GB-03-08-008
COMPONENT OPERATION / Ride Control Valve
OVERLOAD RELIEF VALVE
Overload relief valve is installed for preventing hoses
and the ride control accumulator from being damaged
in case the pressure in the bottom end circuit of the lift
arm cylinder is suddenly raised by an external force or
something during operation of the lift arm cylinder.
Operation
1. Pressure at port HP (in the main circuit) works on
the pilot poppet, passing orifice A of the main
poppet and orifice B of the seat.
2. When the pressure at port HP rises to the setting
force of spring B, the pilot poppet opens, and
pressure oil flows to port LP, passing passage A
and the periphery of the sleeve.
3. At this moment, pressure difference arises
between port HP and the spring chamber caused
by orifice A.
4. When this pressure difference reaches the value
corresponding to the set force of spring A, the
main poppet opens, and the pressure oil at port
HP flows to port LP.
5. As a result, the pressure in the actuator circuit
lowers.
6. If the actuator circuit pressure lowers to the set
pressure, the main poppet is closed by the force
of spring A.
IMPORTANT: Never disassemble or adjust the
overload relief valve. Replace the
whole assembly, when necessary.
T3-8-8
COMPONENT OPERATION / Ride Control Valve
Normally:
Sleeve
Make-up Valve
Main Poppet
Orifice A
Orifice B
Seat
Passage A Spring B
HP
LP
Spring C
T176-03-03-012
Spring Chamber
Spring A
Pilot
Poppet
When Relieving:
Sleeve
Main Poppet
Orifice A
Orifice B
Seat
Passage A
Spring B
HP
LP
T176-03-03-013
Spring
Chamber
Spring A
T3-8-9
Pilot
Poppet
COMPONENT OPERATION / Ride Control Valve
RIDE CONTROL ACCUMULATOR
Ride control accumulator is installed in the
accumulation circuit of the ride control.
High-pressure nitrogen gas is contained in the
accumulator, and the pressure oil compresses the
nitrogen gas through the piston.
Compression of the nitrogen gas dampens shock of
the pressure oil due to pitching and the like of the lift
arm cylinder raising circuit.
IMPORTANT: Construction of the ride control
accumulator
does
not
allow
disassembly. Replace the whole
assembly, when necessary.
T4GB-03-08-009
T3-8-10
COMPONENT OPERATION / Ride Control Valve
DRAIN PLUG
Ride control valve is provided with the drain plug for
returning the pressure oil of the ride control
accumulator to the oil tank at the time of maintenance
or something.
When necessary, connect the accumulator port (port
SP) and the tank port (port T) by loosening the lock nut
first and the drain plug later.
CAUTION: Excessive loosening (More than 2
turns) of the drain plug can result in oil burst
due to removal of the drain plug itself.
Section B
*
Port SP
Lock Nut
Drain Plug
Relief Plug
Port T
*Refer to T3-8-1.
T3-8-11
T4GB-03-08-010
COMPONENT OPERATION / Ride Control Valve
(Blank)
T3-8-12
COMPONENT OPERATION / Drive Unit
OUTLINE
Drive unit consists of the transmission and the torque
converter.
Drive unit is connected with the engine. Power from the
engine is transmitted to the transmission through the
engine flywheel and the torque converter.
Torque Converter
T4GC-03-09-005
Transmission
T3-9-1
COMPONENT OPERATION / Drive Unit
TORQUE CONVERTER
Torque converter consists of the converter wheel
assembly, pump drive device, turbine shaft, and others.
In the converter wheel assembly, impeller (7) and
turbine (3) are mutually opposed with stator (4)
installed in between, and they are all contained in the
casing filled with oil.
Engine rotation is transmitted from the engine wheel to
the transmission through input plate (2), cover wheel
(1), impeller (7), turbine (3), and turbine shaft (11).
Hydraulic oil for the torque converter supplied from the
transmission control valve enters the converter wheel
through the oil passage of the stator support.
When impeller (7) is rotated by the engine rotation, oil
flows along the blade of impeller (7) toward the
periphery, and flows into the turbine (3). This oil flow
collides with the blade of turbine (3), and rotates
turbine (3) and turbine shaft (11). Also, the output
torque of turbine shaft (11) is generated by the reaction
force caused by the oil flow direction change due to
collision of oil with the blade of turbine (3).
Stator (4) always rectifies the oil flow coming out of
turbine (3) in the determined direction, and flows the oil
into impeller (7) for enlarging torque.
T3-9-2
COMPONENT OPERATION / Drive Unit
7
8
9
10
11
1
2
3
4
5
6
T4GC-03-09-001
1 - Cover Wheel
2 - Input Plate
3 - Turbine
4 - Stator
5 - Input Guide
6 - Stator Hub
7 - Impeller
8 - Impeller Hub
9 - Pump Drive Gear
T3-9-3
10 - Guide Carrier
11 - Turbine Shaft
COMPONENT OPERATION / Drive Unit
TRANSMISSION
Transmission so fuctions as to transform the rotation
speed and rotation direction of the power transmitted
from the torque converter.
Transmission is composed of the four clutch shaft
assemblies, the reverse gear, output shaft, parking
brake, control valve, and others.
Safety valve is installed at the inlet part of the hydraulic
oil for the torque converter, and relieves redundant oil
into the converter housing.
Input
Forward
Clutch
Reverse
Gear
Reverse
Clutch
Idler Gear
3rd & 4th
Speeds Clutch
1st & 2nd
Speeds Clutch
Output
T4GC-03-09-002
Transmission Gear Layout Drawing
(Viewed from Vehicle Front End)
T3-9-4
COMPONENT OPERATION / Drive Unit
Front View of Transmission
1
A
2
5
B
6
B
C
3
C
7
8
4
A
T4GC-03-09-003
1 - Breather
2 - from Oil Cooler
3 - Control Valve
4 - Oil Feed Port
5 - Charging Pump
6 - Rotation Sensor (A)
T3-9-5
7 - Rotation Sensor (B)
8 - Vehicle Speed Sensor
COMPONENT OPERATION / Drive Unit
Rear View of Transmission
1
D
D
2
3
9
8
7
E
6
4
Detail E
5
T4GC-03-09-004
Section DD
1 - Engine Speed Sensor
2 - Suction Tube
3 - Hose
4 - Strainer
5 - To Oil Cooler
6 - Converter Outlet Boss
7 - Oil Pressure Gauge Port
8 - Safety Valve
9 - Spring
T3-9-6
COMPONENT OPERATION / Drive Unit
Side View of Transmission
2
1
3
4
3
5
6
9
10
7
8
T4GC-03-09-005
1 - Converter Inlet Pressure
Port
2 - Regulator Valve
3 - Forward Clutch Pressure
Port
4 - Reverse Clutch Pressure
Port
5 - 1st Speed Clutch Pressure
Port
6 - 2nd Speed Clutch Pressure
Port
7 - 3rd Speed Clutch Pressure
Port
8 - 4th Speed Clutch Pressure
Port
9 - Parking Brake Release
Pressure Inlet
T3-9-7
10 - Parking Brake Pressure
Switch Port
COMPONENT OPERATION / Drive Unit
Cross-Sectional Drawing of Transmission
1
2
14
3
4
Section BB※
13
5
12
11
10
9
Section
15
1234-
Charging Pump
Pump Drive Shaft
Forward Clutch
Distributor Cap
CC※
5678-
7
8
Section AA※
T4GC-03-09-006
16
Parking Brake
Front Output Flange
Output Shaft
Drain Plug
6
910 11 12 -
※Refer to T3-9-5
T3-9-8
Rear Output Flange
1st & 2nd Speeds Clutch
Distributor Cap
Idler Shaft
13 14 15 16 -
Torque Converter
Reverse Clutch
Distributor Cap
3rd & 4th Speeds Clutch
COMPONENT OPERATION / Drive Unit
Clutch Shaft
Clutch shaft assemblies contain clutch discs of the
respective speed shifts, and transmit or stop power.
1
2
3
4
5
A
6
7
8
9
10
11
B
12
13
Detail B
Detail A
1234-
Hub Gear
End Plate
Return Spring
Seal Ring (Inner)
567-
Bleed Valve
Seal Ring (Outer)
Piston
T4GC-03-09-007
8 - Disk
9 - Plate
10 - Hub Gear
T3-9-9
11 - Shaft
12 - Plug
13 - Seal Ring
COMPONENT OPERATION / Drive Unit
(Forward Clutch Shaft)
T4GC-03-09-008
(Reverse Clutch Shaft)
T4GC-03-09-009
T3-9-10
COMPONENT OPERATION / Drive Unit
(1st & 2nd Speeds Clutch Shaft)
T4GC-03-09-010
(3rd & 4th Speeds Clutch Shaft)
T4GC-03-09-011
T3-9-11
COMPONENT OPERATION / Drive Unit
Operation
In Operation
Clutch is operated by the pressure oil from the
transmission control valve.
Pressure oil transmitted from the transmission control
valve reaches the back of piston (7) through the oil
passage inside shaft (11). Oil passage is blocked
because the pressure oil pushes the bleed valve (5)
in piston (7) toward disc (8), and piston (7) is pushed
toward disc (8). Piston (7) transmits power to the
whole of shaft (11) and hub gear (1) connected by
pressing and adhering disc (8) and plate (9).
Not in Operation
When pressure oil is not transmitted from the
transmission control valve, bleed valve (5) is opened
by the centrifugal force of shaft (11), so the risidual
pressure oil in the piston and others are discharged
toward disc (8). Piston (7) is pushed back by the
return spring (3) between plates (9).
There arises a clearance between disc (8) and plate
(9), so shaft (11) and clutch hub gear (1) rotate
separately, and power is not transmitted.
T3-9-12
COMPONENT OPERATION / Drive Unit
In Operation
1
8
9
7
11
Detail A
From
Control Valve
A
T4GC-03-09-012
Not in Operation
1
9
3
8
7
5
11
Detail B
B
T4GC-03-09-013
1 - Hub Gear
3 - Return Spring
57-
Bleed Valve
Piston
89-
T3-9-13
Disk
Plate
11 - Shaft
COMPONENT OPERATION / Drive Unit
Transmission of Power
1
2
Input
Reverse
Gear
4
Forward
Clutch
Reverse
Clutch
5
3
7
9
1st & 2nd
Speeds Clutch
6
Idler Gear
8
3rd & 4th
Speeds Clutch
12
10
13
14
11
15
16
Output
1234-
Input Gear
Reverse Gear
F-R Gear
F Hub Gear
5678-
F-R Gear
R Hub Gear
Idler Gear
Idler Gear
910 11 12 -
T3-9-14
T4GC-03-09-002
2nd Hub Gear
1st Hub Gear
Low-range Gear
4th Hub Gear
13 14 15 16 -
3rd Hub Gear
High-range Gear
Output Gear
Output Gear
COMPONENT OPERATION / Drive Unit
5
6
Reverse Clutch
2
1
4
Forward Clutch
8
10
3
11
7
9
1st & 2nd
Speeds Gear
16
15
14
12
13
T4GC-03-09-014
T3-9-15
COMPONENT OPERATION / Drive Unit
Forward 1st Speed
In the case of forward 1st speed, the forward clutch
and the 1st speed part of the 1st & 2nd speeds clutch
are connected. Torque converter transmits torque to
F hub gear (4) geared to the input gear (1).
Torque from F hub gear (4) is transmitted to the 1st
speed hub gear (10) through F - R gear (3), the idler
gear (7), and the idler gear (8).
Furthermore, torque is outputted from the 1st hub
gear (10) to the low-range gear (11), and eventually
outputted to the output gear (16).
1
Input
4
Forward
Clutch
3
7
1st & 2nd
Speeds
Clutch
8
10
11
16
Output
Power Flow: Forward 1st Speed
T3-9-16
T4GC-03-09-015
COMPONENT OPERATION / Drive Unit
1
4
Forward Clutch
3
8
10
7
11
1st & 2nd
Speeds Clutch
16
T4GC-03-09-016
1 - Input Gear
3 - F−R Gear
47-
F Hub Gear
Idler Gear
8 - Idler Gear
10 - 1st Speed Hub Gear
T3-9-17
11 - Low-Range Gear
16 - Output Gear
COMPONENT OPERATION / Drive Unit
Forward 2nd Speed
In the case of forward 2nd speed, the forward clutch
and the 2nd speed part of the 2nd speed clutch are
connected. Torque converter transmits torque to F
hub gear (4) geared to input gear (1).
Torque from F hub gear (4) is transmitted to the 2nd
speed hub gear (9) through F - R gear (3) and idler
gear (7).
Furthermore, torque is outputted from 2nd hub gear
(9) to low-range gear (11), and eventually outputted
to output gear (16).
1
Input
4
Forward
Clutch
3
7
1st & 2nd Speeds
Clutch
9
11
16
Output
Power Flow: Forward 2nd Speed
T3-9-18
T4GC-03-09-017
COMPONENT OPERATION / Drive Unit
1
4
Forward Clutch
3
7
11
1st & 2nd Speeds
Clutch
16
9
T4GC-03-09-018
1 - Input Gear
3 - F−R Gear
47-
F Hub gear
Idler Gear
9 - 2nd Speed Hub Gear
11 - Low-range Gear
T3-9-19
16 - Output Gear
COMPONENT OPERATION / Drive Unit
Forward 3rd Speed
In the case of forward 3rd speed, the forward clutch
and the speed 3 part of the 3rd & 4th Speeds clutch
are connected. Torque converter transmits torque to
F hub gear (4) geared to the input gear (1).
Torque from F hub gear (4) is transmitted to 3rd
Speed hub gear (13) through F - R gear (3) and idler
gear (8).
Furthermore, torque is outputted from 3rd hub gear
(13) to high-range gear (14), and eventually
outputted to output gear (15).
1
Input
4
Forward
Clutch
3
7
8
13
14
15
Output
Power Flow: Forward 3rd Speed
T3-9-20
T4GC-03-09-019
COMPONENT OPERATION / Drive Unit
1
4
3
Forward
Clutch
8
7
15
14
3rd & 4th
Speeds Clutch
13
T4GC-03-09-020
1 - Input Gear
3 - F−R Gear
47-
F Hub Gear
Idler Gear
8 - Idler Gear
13 - 3rd Hub Gear
T3-9-21
14 - High-Range Gear
15 - Output Gear
COMPONENT OPERATION / Drive Unit
Forward 4th Speed
In the case of forward 4th speed, forward clutch and
the 4th speed part of 3rd & 4th speeds clutch are
connected. Torque converter transmits torque to F
hub gear (4) geared to input gear (1).
Torque from F hub gear (4) is transmitted to 4th
speed hub gear (12) through F - R gear (3) and the
idler gear (7).
Furthermore, torque is outputted from the 4th hub
gear (12) to the high-range gear (14), and eventually
outputted to the output gear (15).
1
Input
4
Forward
Clutch
3
3rd & 4th
Speeds Clutch
7
12
14
15
Output
Power Flow: Forward 4th Speed
T3-9-22
T4GC-03-09-021
COMPONENT OPERATION / Drive Unit
1
4
Forward Clutch
3
7
15
12
3rd & 4th
Speeds Clutch
14
T4GC-03-09-022
1 - Input Gear
3 - F−R Gear
47-
F Hub Gear
Idler Gear
12 - 4th Hub Gear
14 - High-Range Gear
T3-9-23
15 - Output Gear
COMPONENT OPERATION / Drive Unit
Reverse 1st Speed
In the case of reverse 1st speed, the reverse clutch
and the 1st Speed part of the 1st & 2nd Speeds
clutch are connected. Torque converter transmits
torque to R hub gear (6) from reverse gear (2) geared
to input gear (1).
Torque from R hub gear (6) is transmitted to 1st
speed gear (10) through F - R gear (5), idler gear (7),
and idler gear (8).
Furthermore, torque is outputted from 1st hub gear
(10) to low-range gear (11), and eventually outputted
to output gear (16).
Processes of the idler gear and after are applied to
the other reverse speed shifts similarly.
1
2
Input
Reverse
Clutch
7
6
5
8
1st & 2nd
Speeds Clutch
10
11
16
Output
Power Flow: Reverse 1st Speed
T3-9-24
T4GC-03-09-023
COMPONENT OPERATION / Drive Unit
5
Reverse Clutch
6
2
1
7
8
10
11
1st & 2nd
Speeds Clutch
16
T4GC-03-09-024
1 - Input Gear
2 - Reverse Gear
5 - FR Gear
678-
R Hub Gear
Idler Gear
Idler Gear
10 - 1st Hub Gear
11 - Low-Range Gear
16 - Output Gear
T3-9-25
COMPONENT OPERATION / Drive Unit
TRANSMISSION REGULATOR VALVE
The transmission regulator valve so controls the
pressure oil from the charging pump as to be constant,
and supplies it to the transmission control valve for
controlling the clutch.
Pressure oil entering the P port of the regulator valve
from the charging pump passes the small hole of the
regulator spool, and enters the back chamber of the
spool. When the oil pressure entering the back
chamber rises higher than the pressure corresponding
to the spring force, the regulator spool moves toward
the spring, and the pressure oil at the P port flows from
the outlet port to the torque converter. This movement
of the spool keeps the pressure at port P constant. port
P is connected to the transmission control valve, and
pressure oil of a constant pressure is supplied to the
transmission control valve. The pressure oil from Port
P passes the oil passage inside the transmission
casing, and is transferred to the transmission control
valve. Oil overflow passes the oil passage in the
mission case, and is transferred to the torque
converter.
T3-9-26
COMPONENT OPERATION / Drive Unit
Normally
Small Hole of
Regulator Spool
Regulator Spool
Spring
From
Charging Pump
T4GC-03-09-025
When overflowing
Regulator Spool
Spring
To Transmission
Control Valve
From
Charging Pump
To Torque
Converter
T3-9-27
T4GC-03-09-026
COMPONENT OPERATION / Drive Unit
TRANSMISSION CONTROL VALVE
Transmission control valve transfers to each clutch the
oil sent from the regulator valve, and makes
changeover of the vehicle travel direction and speed
shift.
Transmission control valve is composed of the valve
body and the solenoid valves for the respective
clutches, and controls the clutch oil pressure by
operating the shift lever to actuate each solenoid valve,
and by moving the modulation spool of the valve body.
Proportional solenoid valves are controlled about their
oil pressure by the electric signal transmitted from the
controller, and can obtain oil pressure waves of
different characteristics depending on the vehicle
condition.
T3-9-28
COMPONENT OPERATION / Drive Unit
Control Valve
4th Speed Clutch
3rd Speed Clutch
2nd Speed Clutch
1st Speed Clutch
Reverse Clutch
Forward Clutch
Regulator
Valve
Clutch
Lubrication
Torque
Converter
Cooler
Torque
Converter
Torque
Converter
Safety
Valve
Filter
Charging
Pump
T4GC-03-09-027
T3-9-29
COMPONENT OPERATION / Drive Unit
9
8
7
6
5
4
T4GC-03-09-028
3
1 - Cover
2 - Valve Body
3 - Solenoid Body
2
4 - 4th Speed Proportional
Solenoid Valve
5 - 3rd Speed Proportional
Solenoid Valve
6 - 2nd Speed Proportional
Solenoid Valve
7 - 1st Speed Proportional
Solenoid Valve
8 - Reverse Proportional
Solenoid Valve
9 - Forward Proportional
Solenoid Valve
T3-9-30
1
COMPONENT OPERATION / Drive Unit
1
2
3
24
4
5
23
6
7
8
22
9
21
10
11
12
20
13
14
19
15
16
17
18
T4GC-03-09-029
From
Charging Pump
1 - Solenoid Body
7 - Emergency Reverse Spool
2 - Valve Body
8 - Reverse Modulation Spool
3 - Cover
9 - Reverse Modulation Spring
4 - Emergency Forward Spool
10 - 1st Speed Modulation
Spool
11 - 1st Speed Modulation
Spring
12 - Emergency 2nd Speed
Spool
5 - Forward Modulation Spool
6 - Forward Modulation Spring
13 - 2nd Speed Modulation
Spool
14 - 2nd Speed Modulation
Spring
15 - 3rd Speed Modulation
Spool
16 - 3rd Speed Modulation
Spring
17 - 4th Speed Modulation
Spool
18 - 4th Speed Modulation
Spring
T3-9-31
19 - 4th Speed Proportional
Solenoid Valve
20 - 3rd Speed Proportional
Solenoid Valve
21 - 2nd Speed Proportional
Solenoid Valve
22 - 1st Speed Proportional
Solenoid Valve
23 - Reverse Proportional
Solenoid Valve
24 - Forward Proportional
Solenoid Valve
COMPONENT OPERATION / Drive Unit
Operation
Modulation mechanism enables smoother speed
change by varying the pressure increase wave or
pressure decrease wave of each clutch depending on
the the vehicle condition (engine speed, vehicle
speed, and others).
Vehicle condition is judged by analyzing the
information (electric signal) sensed by the engine
speed sensor, vehicle speed sensor, and shift lever
utilizing the mission controller, and the electric signal
is transmitted from the controller to the proportional
solenoid valve depending on the shift change.
Proportional solenoid valve regulates the oil pressure
depending on the electric signal transmitted from the
controller, and transfers oil to the modulation spool.
Modulation spool regulates the clutch oil pressure
also, depending on the oil pressure transmitted from
the proportional solenoid valve, and transfers oil to
the clutch piston.
In Pressure
Decrease
Oil
Pressure
In Pressure
Increase
Time
Transition Point
T4GC-03-09-030
Clutch Oil Pressure Wave
T3-9-32
COMPONENT OPERATION / Drive Unit
At Neutral
Pressure oil regulated by the regulator valve flows to
the oil passage (a) of the transmission control valve,
and is divided flowing into the oil passage (b) leading
to the proportional solenoid valve (1) and the oil
passage (c) of the modulation spool (2).
Oil does not flow from the oil passage (b) to the oil
passage (d) because the electric signal to be
transmitted from the controller to the proportional
solenoid valve (1) is stopped in the neutral condition.
Also, oil is confined between the oil passage (c) and
the oil passage (e) of the piston, so the clutch
pressure is not raised, becoming the neutral
condition.
1
d
2
To Piston
T4GC-03-09-031
c
a
From
Regulator Valve
b
1 - Proportional Solenoid
Valve
2 - Modulation Spool
T3-9-33
e
COMPONENT OPERATION / Drive Unit
Shift to 2nd Speed from Neutral (In Pressure
Increase)
• In Process of Clutch Connection
(Refer to Oil Pressure Wave A of T3−9−32.)
2. Also, the oil transferred to the oil passage (e)
passes back chamber (g) of modulation spool (2),
and is sent to back chamber (h) of the modulation
spool (2).
As modulation spring (3) is assembled in back
chamber (h) of modulation spool (2), overcomes
the oil pressure in oila passage (e), and moves
modulation spool (2) right, closing oil passage (e)
temporarily.
When the transmission is shifted by the lever,
electric signal is transmitted from the controller to
proportional solenoid valve (1).
During oil pressure wave A, the oil transferred to
oil passage (b) of proportional solenoid valve (1)
is regulated to the pressure corresponding to the
electric signal of the controller, and is transferred
to the oil passage (d).
1. Oil transferred to oil passage (d) is transferred to
pressure chamber (f) of the modulation spool (2),
overcomes the force of modulation spring (3), and
moves modulation spool (2) to the left column.
As a result, oil is transferred from the oil passage
(c) to oil passage (e) of the clutch piston, and the
clutch pressure is raised.
1
3
h
Electric current from the controller is enlarged
gradually, and repeats the processes in 1. and 2. As a
result, the clutch oil pressure is gradually raised.
g
d
f
To 2nd Speed
Clutch
T4GC-03-09-032
c
a
b
1 - Proportional Solenoid
Valve
2 - Modulation Spool
3 - Modulation Spring
T3-9-34
e
2
COMPONENT OPERATION / Drive Unit
• At End of Clutch Connection
• In Shift Down Condition from Forward 2nd Speed
(Refer to Pressure Oil Wave B of T3-9-32.)
to 1st Speed [at DSS]
Finally, pressures in pressure chamber (f) and
pressure chamber (h) become equal.
Spring (3) is assembled in pressure chamber (h),
but as the spool diameter in the pressure
chamber (f) is larger than the diameter
corresponding to the pressure chamber (h) plus
spring (3) force, the modulation spool (2) is
pushed to fully stroke. Therefore, completely
opening oil passage (c) and the oil passage (e).
(Refer to the drawing below.)
As a result, the clutch pressure and the regulator
pressure become equal and constant.
Pressure increase of the 1st Speed clutch
pressure is similar to “Speed Shift Change from
Neutral to 2nd Speed.”
Pressure decrease of the 2nd Speed clutch
pressure is operated reversely, and the clutch
pressure is gradually lowered by gradually
lowering the electric signal (electric current value)
from the high condition.
Overlapping the clutch pressure of the partner
clutch pressure by gradually raising the 1st Speed
clutch pressure and gradually lowering the 2 nd
clutch pressure eliminates lack of torque at the
time of shift down in digging, and achieves
smooth workability.
Proportional solenoid valve and the modulation
spool organize a set in terms of construction, and
enables obtaining constantly best modulation
pressure wave by combining the pressure
increase characteristics and the pressure
decrease characteristics. (Refer to Clutch Oil
Pressure Wave on T3-9-32.)
3
To 2nd
Speed Clutch
2
f
T4GC-03-09-033
c
h
1 - Modulation Spool
2 - Modulation Spring
T3-9-35
e
COMPONENT OPERATION / Drive Unit
MANUAL SPOOL (EMERGENCY TRAVEL
SPOOL)
In case the solenoid valve cannot be operated caused
by electric disorders (e.g.: disconnection), changeover
of the control valve to Forward 2nd Speed or Reverse
2nd Speed is possible by manually operating this spool.
This spool is used for self-traveling of the vehicle to the
place of maintenance in an emergency or something.
IMPORTANT: Prior to use of the manual spool,
stop the engine. Operating the
manual spool while the engine is
running is dangerous because the
vehicle can begin moving.
Operation
• Forward 2nd Speed
When changeover to Forward 2nd Speed is made,
push in the forward emergency travel spool (3)
and 2nd emergency travel spool (5) each by 5
mm, and turn them 90 degrees, keeping pushing
them.
Oil regulated to the regulator pressure flows into
the passage (b) through the passage (a) opened
by the forward modulation spool, and flows to the
forward clutch to connect the clutch.
Similarly, the 2nd clutch also flows into the oil
passage (f) through the oil passage (e) opened by
the 2nd modulation spool (7), and flows to the 2nd
clutch to connect the clutch.
• Reverse 2nd Speed
When the forward emergency travel spool (3) is
turned by 90 degrees, the spool returns to the
original position by the force of the spring (1).
Similarly to forward 2nd speed, in reverse 2nd
speed, push in the reverse emergency travel
spool (5) by 5 mm, and turns it 90 degrees.
Oil regulated to the regulator pressure flows into
the oil passage (d), through the oil passage (c)
opened by the reverse modulation spool (4), and
flows to the reverse clutch to connect the clutch.
IMPORTANT: Avoid simultaneous use of the
forward emergency travel spool (3)
and the reverse emergency travel
spool (5).
Breakage of the clutch can be
caused.
T3-9-36
COMPONENT OPERATION / Drive Unit
From Regulator
Valve
c
1
a
Forward
Clutch
b
2
3
4
5
d
Reverse
Clutch
f
2nd
Clutch
6
7
e
• In Operation of Manual Spool
From
To Each
Regulator Valve Clutches
T4GC-03-09-034
1 - Modulation Spring
3-
Emergency Forward Spool
5-
Emergency Reverse Spool
2 - Forward Modulation Spool
4-
Reverse Modulation Spool
6-
Emergency 2nd Speed
Spool
T3-9-37
7-
2nd Speed Modulation
Spool
COMPONENT OPERATION / Drive Unit
PROPORTIONAL SOLENOID VALVE
Operation
• At Neutral: Spool (1) is pushed right by the spring
Proportional splenoid valve is used as a pilot valve for
the clutch oil pressure, and transfers oil to the
modulation spool by receiving the electric signal from
the controller, and by raising or lowering the oil
pressure.
S
T
P
1
(2), and outlet port S is connected with tank port
T.
• At Excitement: Solenoid valve (3) pushes the
spool (1) left with a force in proportion to the
electric current flowing at the solenoid (3). Pilot
pressure oil flows to output port S from port P, and
the pressure at output port S rises.
This pressure at output port S works on the
shoulder part ‘a’ of the spool (1). Shoulder part ‘a’
has different sectional areas, and generates a
force to push the spool (1). When the pressure at
output port S rises, and the force pushing the
spool (1) right becomes larger than the force due
to the solenoid (3) to push the spool (1) left, the
spool (1) is returned to the right, the passage
between output port S and port P is closed, and
the pressure at output port S stops rising.
2
3
a
a
T107-02-07-005
1 - Spool
2-
Spring
3-
T3-9-38
Solenoid
COMPONENT OPERATION / Axle
OUTLINE
Axle consists of the differential, final drive, axle shaft,
brake, and others.
Axle Shaft
Final
Drive
Power from the transmission is transmitted to the front
axle and the rear axle through the propeller shaft. Inside the axle, power is transmitted to the differential,
and divided into left and right, and drives the axle
shaft and the wheels through the final drive.
Differential
Brake
Brake
T4GB-03-10-001
T3-10-1
COMPONENT OPERATION / Axle
DIFFERENTIAL
Differential enables the left and the right drive wheels
to rotate at different rotating speeds in steering of the
vehicle body or traveling on bumpy roads.
4
5
6
7
8
9
10
11
3
2
12
1
13
14
15
16
17
18
19
20
21
123456-
Brake Ring
Brake Disc
Piston
Side Gear
Case A
Ring Gear
78910 11 12 -
Pinion Gear
Spider
Case B
Roller Bearing
Differential Body
Gear & Shaft
13 14 15 16 17 18 -
T3-10-2
Adjusting Nut
Bearing Retainer
Pinion Shaft
Roller Bearing
Bearing Cage
Spacer
19 - Roller Bearing
20 - Oil Seal
21 - Flange
T4GB-03-10-002
COMPONENT OPERATION / Axle
Function
• Purpose of Differential
When the vehicle body is steered, the inner wheel
turns with a smaller radius, so the outer wheel
needs to rotate faster for smooth steering.
Suppose driving the rear wheel by directly installing
the gear to the propeller shaft with a shaft having no
differential.
In this case, the outer wheel and the rear wheel rotate the same amount. In other words, when the
vehicle body is steered, the outer wheel cannot rotate more than the inner wheel, and as a result,
skidding sideways or tire wear takes place. Also,
the axle shaft is subjected to torsional stress, resulting in unstable transmission of drive force.
On the other hand, in case a differential is installed,
the inner and the outer wheels can rotate at different speeds, and the problem mentioned above can
be eliminated.
Extension Line of
Rear Wheel Centers
In Turning of Vehicle Body
In Traveling of Vehicle Body on Rough Roads
T202-03-05-005
T3-10-3
COMPONENT OPERATION / Axle
• Principle of Differential
Operation principle of the differential is explained
here comparing it to the racks and the pinion gear
in the drawing.
When the load W is equally applied to the racks A
and B, if C is moved upward by the distance of H,
the racks A and B both move by the same distance
of H in unison with the pinion.
If moved by removing the load to the rack B, the
pinion rotates on the rack A (with load applied), and
moves the rack B upward. At this time, the distance
the rack B moves is longer than the distance the
pinion moves rotating.
Distance the rack B moves can be calculated using
the equation of H+H=2H. This principle is applied to
the differential.
W
W
W
C
C
H
H
H
2H
Rack (A)
Rack (B)
Rack (A)
Pinion
• Operation of Differential
Rack (B)
Pinion
T202-03-05-006
In Traveling Straight
In case resistances applied to the axle shafts (7)
and (8) connected by spline to the differential side
gears (2) and (3) are the same, or in case the vehicle body is traveling straight on plane roads, the differential pinion gears (1) and (4) remain unrotated.
Differential pinion gears (1) and (4) and the side
gears (2) and (3) remain fixed by being mutually
geared, and rotate in unison with the housing (6)
connected with the ring gear (9).
In case the constituent portion of the whole is rotating solidly like this, the differential function of the
differential does not work, but gears (1), (2), (3),
and (4) play only the role of joints for connecting the
axle shafts (7) and (8).
10
9
1
8
2
3
4
7
6
T487-03-06-014
T3-10-4
COMPONENT OPERATION / Axle
In Steering
When the vehicle body swings, uneven resistances
are applied to the drive wheels. Therefore, caused by
the difference of the resistances applied to the inner
and outer wheels, the differential pinion gears (1) and
(4) begin revolving on the side gears (2) and (3), each
rotating round the pinion shaft. As a result, in case the
resistance force applied to the shaft (7) is large, the
pinion gears (1) and (4) rotate in the same direction
as the rotational direction on the side gear (2) of the
shaft (7). And the speed of the shaft (7) is lowered,
and the amount of the speed reduction is applied to
the shaft (8), working the differential function.
Suppose the ring gear (9) is driven by the drive pinion
(10) at the speed of 100. In the condition of the vehicle body traveling straight, the drive wheels on the
both sides rotate at the same speed.
However, in case the vehicle body swings, and the
speed of the right drive wheel is lowered to 90, the left
wheel turns at the speed of 100+(100−90)=110 because the speed of 10(100−90=10) is added to the
speed of the left wheel.
If the ring gear (9) rotates at 100, the summation of
the speeds of the left and right wheels becomes always 200 regardless of movement of the respective
wheels.
T3-10-5
10
9
1
8
2
3
4
7
6
T487-03-06-014
COMPONENT OPERATION / Axle
TORQUE PROPORTIONING DIFFERENTIAL (TPD)
Wheel loader is operated mostly on roads of bad conditions. In case of skidding, working efficiency and tire
lives are lowered. In order to avoid lowering of working efficiency and tire lives, the axle is provided with
the torque proportioning differential.
Differential pinion gear of the torque proportioning differential has an odd number of teeth, and the differential pinion gear and the side gear have special tooth
profiles. Therefore, the difference of the road resistances to the left and right tires causes deviation of
the gearing locations between the differential pinion
gear and the left and right side gears, and the drive
force transferred to the left and right tires changes.
Differential Pinion Gear
Right Side Gear
Left Side Gear
Forward Rotation
T3-10-6
T487-03-06-015
COMPONENT OPERATION / Axle
Traveling Straight with the Same Resistances to
Left and Right Tires
In case resistances to the left and right tires are the
same, the distances ‘a’ and ‘b’ from the differential
pinion gear center to the respective contact points of
the left and right side gears are the same. Therefore,
the differential pinion gear and the left and right side
gears solidly rotate toward forward, and the drive
forces of the left and right tires become the same.
Differential
Pinion Gear
Left Side Gear
Right Side Gear
T487-03-06-016
Traveling on Soft Roads (Different Resistances to
Left and Right Tires)
In traveling on soft roads, if the left tire skids, the
side gear on the left tire receiving little resistance
tends to rotate more forward than the right side gear.
This rotation causes deviation of the contact points
of the differential pinion gear and the left and right
side gears in the torque proportioning differential.
In case the left side gear rotates slightly more forward than the right side gear, the distance ‘a’ of the
contact point of the differential pinion gear and the
left side gear is lengthened. Correlation of the forces
at this time is as follows. a×TA (force applied to the
left side gear) = b×TB (force applied to the right side
gear).
Until the difference of the road resistances exceeds
certain value, the differential pinion gear does not
roate, but the left and right side gears rotate at the
same speed solidly. Besides, the left tire does not
rotate reduntantly, and does not skid. (Right tire can
have drive force larger than the left tire.) Therefore,
tire lives are prolonged, and working efficiency is improved.
Differential
Pinion Gear
Left Side Gear
T3-10-7
Right Side Gear
T487-03-06-017
COMPONENT OPERATION / Axle
LIMITED SLIP DIFFERENTIAL (LSD)
(Optional)
Operation Principle
Wheel loader, as required by the kind of work, must
be operated in places where skidding takes place
easily like sand and muddy soil. In places like these,
Tires can slip even if the torque proportioning differential (TPD) is installed. Rotation is transmitted to the
slipping tire, but not to the tires contacting the earth,
so not only the funtion of the wheel loader is worsened, but the tire lives are shortened.
In order to avoid this, the limited slip differential (LSD)
provided with the differential movement restriction device for avoiding different movement of the left and
right wheels is adopted. Drive force transmitted to the
left and right tires further changes.
LSD is so constructed that the clutch disc is inserted
between the pressure ring supporting the spider with
the cam and the case, which makes restriction of different movement by keeping the tire speeds the
same by the resistances of the friction surfaces. Also,
the variation of the dive force transmitted to the left
and right tires is made larger than the TPD.
Ring Gear
Pressure Ring
Side Gear
Pressure Plate
Clutch Disc
Case
Spider
Pinion Gear
T4GB-03-10-003
T3-10-8
COMPONENT OPERATION / Axle
Traveling Straight with the Same Road Resistances to Left and Right Tires
As the differential pinion gear and the left and right
pinion gears rotate solidly, the drive forces of the left
and right tires are the same similarly to the TPD.
Traveling on Soft Roads (Different Road Resistances to Left and Right Tires)
Drive force is transmitted to the case, pressure ring,
and spider through the ring gear. At this time, the
spider having the cam construction pushes the
pressure ring with the thrust P. Clutch disc is geared
with the case through the pressure ring. Side gears
fitted to the clutch disc by spline rotate solidly with
the case, and the left and right gears rotate at the
same speed.
Like this, the left and right axle shafts fitted to the
side gears by spline tend to rotate solidly with the
case, and the differential movement restriction works.
In case the drive force provided for the skidding tire
is larger than the road resistance, part of the torque
of the skidding tire is added to the tire contacting the
road by the differential movement restriction (because of the same speed of the left and right tires),
and the tire contacting the road is provided with
more torque.
Until the difference of the resistances between the
left and right tires exceeds certain value (until the
clutch disc begins to slip), the left and right gears
solidly rotate at a constant speed. On such soft
roads, the drive force increases by 1.5 times the
value for the TPD if the LSD is provided.
T3-10-9
Clutch Disc
Pressure Plate
Spider
Pressure Ring
T4GB-03-10-004
COMPONENT OPERATION / Axle
SERVICE BRAKE
Brake adopted is the wet type multi-disc brake, and is
assembled in the differential body of the axle. Four
wheels of this vehicle has all this disc brake.
• In Operation of Brake
Oil pressure from the brake valve works on the
back of brake piston (5) to move brake piston(5),
and brake disc (3) and brake ring (2) is compressed.
Inner surface of brake disc (3) is fitted by spline to
shaft (8) through disk hub (7). Also, the outer surface of brake ring (2) is fixed to differential body (4).
Therefore, the rotation of the pushed and compressed brake disc (3) stops, restricting the vehicle.
• In Release of Brake
When the oil pressure from the brake valve is decreased, brake piston(5) is returned by return
spring (6), and brake disc (3) is freed. Restriction of
the vehicle is released.
T3-10-10
COMPONENT OPERATION / Axle
1
2
2
3
3
2
Brake Oil
Pressure
4
5
6
7
8
T4GB-03-10-005
1 - End Plate
2 - Brake Ring
34-
Brake Disc
Differential Body
56-
• Operation
1
2
Brake Piston
Return Spring
78-
Disc Hub
Shaft
3
2 To
• Release
3
2
3
2
1
From
Brake Valve
5
2
3
2
Brake Valve
5
6
6
T4GB-03-10-007
T3-10-11
T4GB-03-10-008
COMPONENT OPERATION / Axle
FINAL DRIVE / AXLE SHAFT
Final drive is the device for finally decreasing the
speed in the power transmission system, and of the
planetary gear type. As for power transmission, the
power from the differential, transmitted from the shaft,
rotates the three planetary gears in the ring gear, and
transmits rotation of the planetary carrier to the axle
shaft through the planetary carrier.
Final
Drive
Axle Shaft
Ring Gear
Shaft
Housing
Planetary Carrier
Planetary Gear
T4GB-03-10-006
T3-10-12
COMPONENT OPERATION / Brake Valve
OUTLINE
Brake valve is operated by the brake pedal. (Refer to
the Brake Circuit of SYSTEM/Hydraulic System)
Brake valve sends pilot pressure depending on the
extent of stepping the brake pedal, and operates the
fore wheel or rear wheel service brake.
Brake Pedal
Brake Valve
T4GB-03-11-001
T3-11-1
COMPONENT OPERATION / Brake Valve
Component Layout
1
2
3
4
Port T
5
6
Port BR1
Port M1
11
7
Port BR2
Port M2
10
8
9
T4GB-03-11-002
1 - Pedal
2 - Roller
3 - Spool Input
4 - Spring
5 - Spring
6 - Spring
7 - Spool
8 - Spool
9 - Spring
T3-11-2
10 - Plunger
11 - Plunger
COMPONENT OPERATION / Brake Valve
1
5
7
From Port M2
of Charging Block
M1
From Port M2
of Charging Block
M2
BR1
BR2
T
To Front
Service Brake
To Rear
Service Brake
8
9
T4GB-03-11-003
T3-11-3
COMPONENT OPERATION / Brake Valve
OPERATION
Not in Operation of Brake
1. When the brake valve is not in operation, the ports
(BR1 and BR2) are connected with the tank port
(T) because the spring (9) returns the spools (7
and 8) to the non-operating position.
2. Ports (M1 and M2) and the brake ports (BR1 and
BR2) are blocked by the spools (7 and 8), and the
pressure oil in the service brake accumulator is
retained.
T
M1
BR1
M2
BR2
7
8
9
T4GB-03-11-004
T3-11-4
COMPONENT OPERATION / Brake Valve
In Operation of Brake
1. When the brake valve is stepped, spool input (3)
is pushed through roller (2).
Spool input moves the spools (7 and 8) forward
through the spring (5).
2. When the spools (7 and 8) moves forward, ports
(BR1 and BR2) and port (T) are disconnected.
When spools (7 and 8) are further moved forward,
the ports (BR1 and BR2) and the ports (M1 and
M2) are connected, and the pressure oil of the
accumulator flows out from the ports (BR1 and
BR2), beginning braking operation.
3. Pressure oil on the ports (BR1 and BR2) end
passes the orifices installed in spools (7 and 8),
and works on the built-in plungers (10 and 11) of
spools (7 and 8) as the return force (oil pressure
rection force) of the spools (7 and 8). Summation
of this oil pressure reaction force and the load of
spring (9) balances with the load of spring (5), and
controls the brake oil pressure on the brake ports
(BR1 and BR2) end.
4. Deflection and load of spring (5) are fed back as
the stroke and operating force of the brake pedal,
and provides the operator with virtual operation
feeling.
2
3
5
T
BR1
M1
7
11
BR2
M2
8
10
9
T4GB-03-11-005
T3-11-5
COMPONENT OPERATION / Brake Valve
In Brake Release
1. When the operating force is released, spool input
(3) is pushed back by spring (4).
2. Compression of spring (5) is released, and spools
(7 and 8) are returned to the non-operation
position by the summation of the oil pressure
reaction force working on the plunger and load of
the spring (9).
3. At this time, the ports (BR1 and BR2) and the port
(M1 and M2) are blocked by the spools (7 and 8),
and the ports (BR1 and BR2) are relieved to the
port (T).
Pressure oil on the ports (BR1 and BR2) end is
discharged to the port (T), and the brake operation
is released.
3
4
T
5
BR1
M1
7
BR2
M2
8
9
T4GB-03-11-006
T3-11-6
COMPONENT OPERATION / Others
PILOT SHUTOFF VALVE
Pilot shutoff valve is a munually operated changeover
valve, and by operating the pilot control shutoff lever,
rotates the spool to turn ON and OFF the pilot pressure
to the pilot valve.
Section Z-Z
Shutoff Position of Pilot Shutoff Valve
At OFF of the pilot shutoff valve, the pressure oil from
the pilot pump does not flow to the pilot valve. Oil on
the pilot valve end flows to the hydraulic oil tank.
At ON of Pilot Control Shutoff Lever
At ON of the pilot shutoff valve, the drain circuit is
blocked, and the pressure oil from the pilot pump
flows to the pilot valve.
From Brake/
Pilot Pump
To Pilot
Valve
T4GB-03-12-001
A2
A1
Z
T1
T2
T3
P
Z
A3
A4
T4
A5
T4GB-03-12-002
A1 - Extra
A2 - Extra
A3 - To Pilot Valve (Optional)
A4 - To Pilot Valve
A5 - Extra
P - From Brake/Pilot Pump
T1 - From Pilot Valve
T2 - Extra
T3-12-1
T3 - From Pilot Valve (Optional)
T4 - To Hydraulic Oil Tank
COMPONENT OPERATION / Others
PROPELLER SHAFT
Propeller shafts are installed between the transmission
and the front axle, and between the transmission and
the rear axle, respectively.
Propeller shaft transmits the power from the
transmission to the front axle and the rear axle. Joint
adopted is the universal joint most commonly used.
Between Front Axle and Transmission
Universal Joint
T4GB-03-12-003
Between Transmission and Rear Axle
Universal Joint
T4GB-03-12-004
T3-12-2
COMPONENT OPERATION / Others
EMERGENCY STEERING CHECK BLOCK
Emergency steering check block is installed between
the main pump and steering valve.
Built-in check valve is provided for preventing the
delivery oil of the emergency steering pump from
flowing to the main pump.
A
A: from main pump
B: from emergency steering pump
C: pressure sensor port
D: to steering valve
E: to hydraulic oil tank
B
Section X-X
B
A
C
Y
D
Section Y-Y
A
Y
E
C
D
E
X
X
T4GB-03-12-007
T3-12-3
COMPONENT OPERATION / Others
EMERGENCY STEERING PUMP
(OPTIONAL)
Emergency steering pump is installed to be started in
case supply of the pressure oil from the main pump is
suddenly stopped for one reason or another, and for
supplying pressure oil to the steering valve in place of
the main pump until the time when the vehicle body is
moved to a safe place.
Emergency steering pump consists of the gear pump,
electric motor, relief valve, and check valve.
Electric Motor Part
Gear Pump Part
Relief Valve
Check Valve
T4GB-03-12-008
T3-12-4
MEMO
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Hitachi Construction Machinery Co. Ltd
Attn: Publications, Marketing & Product Support
Fax: 81-29-831-1162
Hitachi Ref. No.
SERVICE MANUAL REVISION REQUEST FORM
NAME OF COMPANY:
MODEL:
PUBLICATION NO.:
YOUR NAME:
DATE:
FAX:
(Located at the right top corner in the cover page)
PAGE NO.:
(Located at the bottom center in the page. If two or more revisions are requested, use the comment column)
YOUR COMMENTS / SUGGESTIONS:
Attach photo or sketch if required.
If your need more space, please use another sheet.
REPLY:
(Copy this form for usage)
SECTION 1
GENERAL
―CONTENTS―
Group 1 Specifications
Group 3 Component Specifications
Specifications ........................................... T1-1-1
Engine ...................................................... T1-3-1
Engine Accessories .................................. T1-3-6
Group 2 Component Layout
Main Component Layout........................... T1-2-1
Electrical Component Layout.................... T1-2-4
Hydraulic Component ............................... T1-3-8
Electrical Component.............................. T1-3-13
(Overview)
Electrical System (Cab) ............................ T1-2-5
Electrical System .................................... T1-2-6
(Controller and Relays)
Electrical System (Right Console) ............ T1-2-7
Electrical System (Monitor and Switchs)... T1-2-8
Monitor Panel ........................................... T1-2-9
Engine and Fan Pump ............................ T1-2-10
Pump Device and Drive Unit....................T1-2-11
Control Valve .......................................... T1-2-12
Ride Control Valve,Charging Block
and Fan Motor ................................... T1-2-13
Steering Valve and Emergency Steering
Pump (Optional) .................................. T1-2-14
4GCT-1-1
(Blank)
4GCT-1-2
GENERAL / Specification
SPECIFICATIONS
M4GB-12-002
−
ZW220 (Standard)
ZW250 (Standard)
Operating Weight
kg(lb)
3.4 (BOC)
3.7 (BOC)
Static Tipping Load (Full Turn)
kg(lb)
17290
19610
Rated Loading Weight
kg(lb)
5120
5600
−
ISUZU
6HK1
139.3 kW/2170 rpm
(189 PS/2170 rpm)
ISUZU
6HK1
163.0 kW/2240 rpm
(221.5 PS/2240 rpm)
A: Overall Length
mm(ft.in)
8245
8385
B: Overall Width (Bucket)
mm(ft.in)
2910
3050
C: Overall Height
mm(ft.in)
3375
3405
D: Wheel Base
mm(ft.in)
3300
3350
E: Tread
mm(ft.in)
2160
2200
F: Ground Clearance
mm(ft.in)
450
425
G: Height to Bucket Hinge Pin, Fully Raised
mm(ft.in)
4090
4195
H: Dumping Clearance 45 Degree, Full Height
mm(ft.in)
2880
2950
I:
mm(ft.in)
1150
1120
R1: Turning Radius (Centerline of Outside Tire)
mm(ft.in)
5620
5715
R2: Loader Clearance Circle, Bucket in Carry Position
mm(ft.in)
6620
6780
Maximum Travel Speed (Forward/Reverse)
km/h(mph)
34.5/34.5
34.5/34.5
Number of Travel Shift (Forward/Reverse)
−
4/4
4/4
Degree(%)
40
40
−
23.5-25-16PR
23.5-25-16PR
Type
Engine
Dumping Reach, 45 Degree Dump, Full Height
Articulation Angle (Left/Right)
Tire Size
T1-1-1
GENERAL / Specification
(Blank)
T1-1-2
GENERAL / Component Layout
MAIN COMPONENT LAYOUT (OVERVIEW)
1
2
3
PHOTO
4
5
Overview
001
6
12
7
11
10
9
T4GB-01-02-005
8
1 - Bucket
2 - Bell Crank
4 - Head Light
5 - Front Working Light
3 - Bucket Cylinder
6 - Rear Working Light
(Optional)
7 - Rear Working Light
8 - Rear Combination Light (Turn
Signal, Hazard Light Clearance
Light and Brake Light)
9 - Turn Signal, Hazard Light and
Clearance Light
T1-2-1
10 - Lift Arm Cylinder
11 - Lift Arm
12 - Bucket Link
GENERAL / Component Layout
MAIN COMPONENT LAYOUT (UPPERSTRUCTURE)
PHOTO
Overview
002
1
20
2
3
4
5
21
19
18
17
16
15
6
7
8
9
10
14
13
12
11
T4GB-01-02-002
123456-
Charging Block
Pilot Valve
Brake Valve
Steering Pilot Valve
Steering Valve
Control Valve
78910 11 12 -
Stop Valve
Pilot Shutoff Valve
Engine Oil Filter
Pilot Filter
Engine
Fuel Tank
13 14 15 16 17 18 -
T1-2-2
Torque Converter Cooler
Hydraulic Oil Cooler
Hydraulic Fan Motor
Radiator
Inter Cooler
Reserve Tank
19 - Muffler
20 - Air Cleaner
21 - Hydraulic Oil Tank
GENERAL / Component Layout
MAIN COMPONENT LAYOUT (TRAVEL SYSTEM)
PHOTO
Overview
1
003
2
3
4
5
6
9
8
7
T4GB-01-02-004
1 - Front Axle
2 - Propeller Shaft (Front)
3 - Steering Cylinder
45-
Pump Device
Transmission
6 - Rear Axle
7 - Propeller Shaft (Rear)
T1-2-3
8 - Steering Accumulator
9 - Brake Pressure Sensor
GENERAL / Component Layout
ELECTRICAL COMPONENT LAYOUT (OVERVIEW)
Cab
(Refer to T1-2-5)
1
2
11
12
Engine and Fan Pump
(Refer to T1-2-10)
10
3
4
5
6
7
8
Pump Device
(Refer to T1-2-11)
Drive Unit
(Refer to T1-2-11)
9
T4GB-01-02-019
1 - Hydraulic Oil Level Switch
2 - Air Filter Restriction Switch
4 - Reverse Buzzer
5 - Battery
3 - ECM
6 - Boost Pressure Sensor
7 - Fuel Level Sensor
8 - Hydraulic Oil Temperature
Sensor
9 - Lift Arm Angle Sensor
(Optional)
T1-2-4
10 - Bucket Proximity Switch
11 - Lift Arm Proximity Switch
GENERAL / Component Layout
ELECTRICAL SYSTEM (CAB)
1
2
3
Monitor and Switches
(Refer to T1-2-8)
4
Right Consol
(Refer to T1-2-7)
6
5
Controller and Relays
(Refer to T1-2-6)
T4GB-01-02-006
1 - Radio
3 - Speaker
2 - Auxiliary Switch Panel
(Optional)
4 - Rear Wiper Motor
5 - Brake Lamp
Switch
T1-2-5
6 - Front Wiper Motor
GENERAL / Component Layout
Controller and Relays
5
6
T4GB-01-02-006
10
4
1
14
15
16
17
18
2
19
20
21
22
23
11
7
12
8
13
9
3
24
25
26
27
28
29
30
31
32
33
T4GC-01-02-002
1-
Flasher Relay
2-
Option Controller
(Optional)
3 - MCF
9-
Front Window Heater
Relay
10 - Neutral Relay
11 - Rear Window Heater Relay
4-
ICF
12 - Wiper Relay (Left)
5-
Dr.ZX Connector
13 - Wiper Relay (Right)
6-
Fuse Box
7-
Fog Light Relay (Optional)
14 - Reverse Light Relay
(A-R5)
15 - Brake Light Relay (A-R4)
8-
Auxiliary
16 - High Beam Relay (A-R3)
17 - Head Light Relay (Right)
(A-R2)
T4GB-01-02-022
18 - Head Light Relay (Left)
(A-R1)
19 - Emergency Steering Relay
(A-R10)
20 - Horn Relay (A-R9)
21 - Turn Signal Relay (Right)
(A-R8)
22 - Working Light Relay (Rear)
(A-R7)
23 - Working Light Relay
(Front) (A-R8)
24 - Front Wiper Relay (B-R5)
25 - Neutral Relay (B-R4)
T1-2-6
26 - Load Dump Relay (B-R3)
27 - Parking Brake Relay
(B-R2)
28 - Parking Brake Relay
(B-R1)
29 - Fuel Pump Relay (B-R10)
30 - Main Relay (B-R9)
31 - Rear Washer Relay (B-R8)
32 - Turn Signal Relay (Left)
(B-R7)
33 - Rear Wiper Relay (B-R6)
GENERAL / Component Layout
Right Console
PHOTO
Control Lever
011
012
PHOTO
Right Console
013
T4GB-01-02-006
2
3
4
6
5
7
1
8
9
10
18
17
16
15
14
13
12
T4GB-01-02-023
11
1 - Down Shift Switch
2 - Bucket Control Lever
3 - Lift Arm Control Lever
4 - Forward/Reverse Switch
5 - Horn Switch
6 - Auxiliary Control Lever
(Optional)
7 - Quick Coupler Switch (Optional)
8 - Lift Arm Auto Leveler Downward
Set Switch (Optional)
9 - Lift Arm Auto Leveler Upward
Set Switch (Optional)
10 - Front Control Lock Lever
11 - Emergency Steering Check
Switch
12 - Fan Reversing Switch
13 - Fog Light Switch (Optional)
15 - Forward/Reverse Selector
Switch
16 - Lighter
17 - Up-shift/Down-shift Switch
14 - Ride Control Switch
(Optional)
18 - Hold Switch
T1-2-7
GENERAL / Component Layout
Monitor and Switches
PHOTO
Cab
004
1
005
2
T4GB-01-02-006
14
3
13
12
4
5
11
6
7
10
9
8
1 - Monitor Panel
(Refer to T1-2-9)
2 - Driving Mode Switch
3 - Turn Signal Lever /Head Light
Switch/Dimmer Switch
4 - Parking Brake Switch
T4GB-01-02-024
5 - Work Mode Selector Switch
9 - Front Wiper Switch
12 - Rear Wiper Switch
6 - Clutch Cut Position Switch
10 - Forward/Reverse Lever
and Shift Switch
11 - Air Conditioner Switch
Panel
13 - Working Light Switch
7 - Key Switch
8 - Steering Column Tilt
/Telescopic Lever
T1-2-8
14 - Hazard Light Switch
GENERAL / Component Layout
Monitor Panel
1
2
3
4
5
6
7
8
9
10
11
34
12
33
13
14
32
15
31
T4GB-01-02-001
30
29
28
1 - Coolant Temperature
Gauge
2 - Transmission Oil
Temperature Gauge
3 - Turn Signal Indicator
(Left)
4 - High Beam Indicator
5 - Working Light Indicator
6 - Turn Signal Indicator
(Right)
7 - Monitor Display
8 - Stop Indicator
9 - Service Indicator
27
26
25
24
23
22
10 - Parking Brake Indicator
21
20
19
18
11 - Clearance Light Indicator
19 - Lever Steering Indicator
(Optional)
20 - Monitor Mode Selector
12 - Fuel Gauge
21 - Glow Signal
13 - Brake Low Oil Pressure
Indicator
14 - Brake Low Oil Level
Indicator
15 - Emergency Steering
Indicator (Optional)
16 - Low Steering Oil Pressure
Indicator
17 - Seat Belt Indicator
22 - Monitor Display Selector (Up)
23 - Maintenance Indicator
24 - Monitor Display selector
(Down)
25 - Forward/Reverse Switch
Indicator
26 - Water Separator Indicator
18 - Discharge Warning
Indicator
T1-2-9
17
16
27 - Engine Warning Indicator
28 - Overheat Indicator
29 - Engine Low Oil Pressure
Indicator
30 - Air Filter Restriction Indicator
31 - Transmission Warning
Indicator
32 - Transmission Oil Filter
Restriction Indicator
33 - Hydraulic Oil Temperature
Indicator
34 - Transmission Oil
Temperature Indicator
GENERAL / Component Layout
ENGINE AND FAN PUMP
1
2
PHOTO
Engine
030
3
6
7
8
042
9
5
10
11
4
14
13
12
T4GB-01-02-025
1 - Glow Plug
9 - EGR Valve
12 - Crank Revolution Sensor
2 - Injector
5 - Coolant Temperature
Sensor
6 - Overheat Switch
10 - Supply Pump
3 - Cam Angle Sensor
7 - Boost Pressure Sensor
11 - Fuel Temperature Sensor
13 - Engine Oil Pressure
Sensor
14 - Common Rail Pressure
Sensor
4 - Fan Pump
8 - Boost Temperature Sensor
T1-2-10
GENERAL / Component Layout
PUMP DEVICE
1
2
PHOTO
Hydraulic System
114
3
6
5
T4GB-01-02-009
4
DRIVE UNIT
PHOTO
7
21
8
9
Transmission
108
109
13
14
15
16
17
18
20
12
19
11
10
T4GC-01-02-001
1 - Main Pump
7-
2 - Regulator
Torque Converter Input
Speed Sensor
8 - Air Breather
3 - Priority Valve
9-
4 - Pump Delivery Pressure
Switch
5 - Pilot Pump
10 - Vehicle Speed
Sensor
11 - Transmission Output
Speed Sensor
Charge Pump
12 - Transmission Middle Shaft
Sensor
13 - Forward Clutch Solenoid
Valve
14 - Reverse Clutch Solenoid
Valve
15 - 1st Clutch Solenoid Valve
16 - 2nd Clutch Solenoid Valve
6 - Steering Relief Valve
T1-2-11
17 - 3rd Clutch Solenoid Valve
18 - 4th Clutch Solenoid Valve
19 - Transmission Control Valve
20 - Parking Brake Pressure
Switch
21 - Regulator Valve
GENERAL / Component Layout
CONTROL VALVE
ZW220
5
4
1
2
3
T4GB-01-02-027
ZW250
5
1
4
PHOTO
Control Valve
089
3
090
2
T4GB-03-02-002C
1 - Over Load Relief Valve
(Lift Arm: Bottom)
2 - Over Load Relief Valve
(Bucket: Bottom)
3 - Over Load Relief Valve
(Bucket: Rod)
4 - Make-up Valve
(Lift Arm: Rod)
T1-2-12
5 - Main Relief Valve
GENERAL / Component Layout
RIDE CONTROL VALVE (OPTIONAL)
CHARGING BLOCK
PHOTO
1
2
Charging Block
3
4
073
5
6
PHOTO
Ride Control
099
10
T4GB-01-02-014
9
8
7
T4GB-01-02-013
FAN MOTOR
10
11
12
PHOTO
Cooling Fan
039
T4GB-01-02-012
1 - Overload Relief Valve
2 - Ride Control Solenoid
Valve
3 - Ride Control Accumulator
5 - Service Brake Accumulator
(Front)
6 - Service Brake Accumulator
(Rear)
7 - Relief Valve
89-
Pilot Relief Valve
Pump Torque Control
Solenoid Valve
10 - Parking Brake Solenoid
Valve
4 - Pilot Accumulator
T1-2-13
11 - Reverse Control Solenoid
Valve
12 - Relief Valve
13 - Flow Control Solenoid
Valve
GENERAL / Component Layout
STEERING VALVE
PHOTO
1
Steering System
2
078
T4GB-01-02-020
EMERGENCY STEERING PUMP
(OPTIONAL)
3
PHOTO
Emergency Steering
081
4
5
6
T4GB-01-02-010
1 - Overload Relief Valve
2 - Overload Relief Valve
3 - Electric Motor
4 - Gear Pump
5 - Check Valve
T1-2-14
6-
Relief Valve
GENERAL / Component Specifications
ENGINE
ZW220
Manufacturer ............................................ ISUZU
Model........................................................ AH-6HK1XYWT-03 (Wet Type)
Type.......................................................... Diesel, 4 Cycle, Water Cooled, Over Head Valve, Inline,
Direct Injection, Turbo Charged
Cyl. NO. - Bore×Stroke............................. 6-115 mm×125 mm (4.53 in×4.92 in)
3
3
Piston Displacement................................. 7790 cm (475 in )
-1
Rated Output ............................................ 139.3±3 kW/2170 min (189±4 PS/2170 rpm)
-1
Max. Output .............................................. 164.3±3 kW/2000 min (223.4±4 PS/2000 rpm)
Compression Ratio................................... 17.5
Dry Weight................................................ 630 kg (1389 lb)
Firing Order .............................................. 1-5-3-6-2-4
Rotation Direction ..................................... Clock Wise (Viewed from fan side)
ZW250
Manufacturer ............................................ ISUZU
Model........................................................ AH-6HK1XYWT-04 (Wet Type)
Type.......................................................... Diesel, 4 Cycle, Water Cooled, Over Head Valve, Inline,
Direct Injection, Turbo Charged
Cyl. NO. - Bore×Stroke............................. 6-115 mm×125 mm (4.53in×4.92 in)
3
3
Piston Displacement................................. 7790 cm (475 in )
-1
Rated Output ............................................ 163.0±3 kW/2240 min (222±4 PS/2240 rpm)
-1
Max. Output .............................................. 179.1±3 kW/2000 min (243.5±4 PS/2000 rpm)
Compression Ratio................................... 17.5
Dry Weight................................................ 630 kg (1389 lb)
Firing Order .............................................. 1-5-3-6-2-4
Rotation Direction ..................................... Clock Wise (Viewed from fan side)
COOLING SYSTEM
Cooling Fan .............................................. Diameter 850 mm (33.47 in),
6 Blades (N6G-Type Blade, Steel Center), Draw-in Type
Thermostat ............................................... Cracking Temperature at Atmospheric Pressure:
82 °C (180 °F)
Full Open (Stroke: 10 mm (0.39 in) or more) Temperature:
95 °C (203 °F)
Fan Pump................................................. Gear Pump
T1-3-1
GENERAL / Component Specifications
LUBRICATION SYSTEM
Lubrication Pump Type............................. Gear Pump
Oil Filter .................................................... Full-Flow Paper Element Type with Bypass
Oil Cooler ................................................. Water Cooled Integral Type
STARTING SYSTEM
Motor ........................................................ Magnetic Pinion Shift Reduction Type
Voltage/Output.......................................... 24 V⋅5 kW
PREHEAT SYSTEM
Preheating Method ................................... Glow Plug (QOS II Type with After Glow)
ENGINE STOP SYSTEM
Stop Method ............................................. Fuel Shut Off (Electrically Controlled)
ALTERNATOR
Type.......................................................... Regulator Integrated AC Type
Voltage/Output.......................................... 24 V⋅50 A (Brush less)
SUPERCHARGING SYSTEM
Model........................................................ RHG6
Type.......................................................... Exhaust Turbocharger Type
FUEL SYSTEM
Type.......................................................... Common Rail Type (HP4 Model)
Governor .................................................. Electrically Controlled
Injection Nozzle ........................................ Electric Multi Hole Injector (G2 Type)
T1-3-2
GENERAL / Component Specifications
PERFORMANCE
IMPORTANT: This list shows design specifications, which are not servicing standards.
ZW220
Fuel Consumption Ratio........................... 212.0±13.6 g/kW⋅h (156±10 g/PS⋅h) @ 2000 min-1 (rpm)
Maximum Output Torque .......................... 981±60 N⋅m (100±6 kgf⋅m) @ at approx. 1400 min-1 (rpm)
Compression Pressure............................. 3.04 Mpa (31 kgf/cm2) @ 200 min-1 (rpm)
Valve Clearance (Inlet/Exhaust)............... 0.4/0.4 mm (when cool)
No Load Speed......................................... Slow: (at Full Load: 850±20 min-1 (rpm))
Fast: (at Full Load: 2260±20 min-1 (rpm))
ZW250
Fuel Consumption Ratio........................... 212.0±13.6 g/kW⋅h (156±10 g/PS⋅h) @ 2000 min-1(rpm)
Maximum Output Torque .......................... 1022±60 N⋅m (104±6 kgf⋅m) @ at approx 1400 min-1 (rpm)
Compression Pressure............................. 3.04 MPa (31 kgf/cm2) @ 200 min-1 (rpm)
Valve Clearance (Inlet/Exhaust)............... 0.4/0.4 mm (0.016/0.016 in) (when cool)
No load Speed.......................................... Slow: (at Full Load: 850±20 min-1 (rpm))
Fast: (at Full Load: 2330±20 min-1 (rpm))
T1-3-3
GENERAL / Component Specifications
ZW220
Engine Performance Curve (AH-6HK1XYWT-03)
Test Condition:
1. In conformity with JIS D1005 (Performance Test Method for Diesel Engine Used for Construction Machinery)
under standard atmospheric pressure.
2. Equipped with the fan and alternator.
Torque
(N⋅m)
Output
(kW)
Fuel
Consumption
(g/kW⋅h)
-1
Engine Speed min (rpm)
T1-3-4
T4GC-01-03-001
GENERAL / Component Specifications
ZW250
Engine Performance Curve (AH-6HK1XYWT-04)
Test Condition:
1. In conformity with JIS D1005 (Performance Test Method for Diesel Engine Used for Construction Machinery)
under standard atmospheric pressure.
2. Equipped with the fan and alternator.
Torque
(N⋅m)
Output
(kW)
Fuel
Consumption
(g/kW⋅h)
Engine Speed min-1 (rpm)
T1-3-5
T4GC-01-03-002
GENERAL / Component Specifications
ENGINE ACCESSORIES
RADIATOR ASSEMBLY
Type.......................................................... Radiator and Oil Cooler Tandem Type Assembly
Intercooler and Torque Converter Cooler Tandem Type Assembly
Weight ...................................................... 67 kg (148 Ib) (ZW220)
74.5 kg (164 Ib) (ZW250)
ZW220
Radiator
Capacity.................................................... 15 L (4 US gal)
Air-Tight Test Pressure ............................. 100 kPa (1.0 kgf/cm2, 14.5 psi)
Cap Opening Pressure............................. 49 kPa (0.5 kgf/cm2, 7 psi)
Oil Cooler
5.1 L (3.3 US gal)
1500 kPa (15 kgf/cm2, 217 psi))
−
Intercooler
Capacity.................................................... 11.5 L (3 US gal)
Air-Tight Test Pressure ............................. 245 kPa (2.5 kgf/cm2, 36 psi)
Cap Opening Pressure.............................
−
Torque Converter Cooler
10.2 L (2.7 US gal)
1500 kPa (15 kgf/cm2, 217 psi)
−
ZW250
Radiator
Capacity.................................................... 18 L (4.8 US gal)
Air-Tight Test Pressure ............................. 100 kPa (1.0 kgf/cm2,14.5 psi)
Cap Opening Pressure............................. 49 kPa (0.5 kgf/cm2, 7 psi)
Oil Cooler
5.1 L (1.3 US gal)
1500 kPa (15 kgf/cm2,217 psi))
−
Intercooler
Capacity.................................................... 12.5 L (3.3 US gal)
Air-Tight Test Pressure ............................. 245 kPa (2.5 kgf/cm2, 36 psi)
Cap Opening Pressure.............................
−
Torque Converter Cooler
10.7 L (2.8 US gal)
1500 kPa (15 kgf/cm2, 217 psi)
−
BATTERY
Voltage...................................................... 12 V
Capacity.................................................... 108 Ah
T1-3-6
GENERAL / Component Specifications
HYDRAULIC FAN PUMP
Model........................................................ SGP1A27D2H1
Type.......................................................... Fixed Displacement Type Gear Pump
Maximum Flow (Theoretical Value).......... 60 L/min (15.85 US gpm)
HYDRAULIC FAN MOTOR
Relief Set Pressure .................................. 20.6 MPa (210 kgf/cm2) @ 5 L/min (1.32 US gpm)
SOLENOID VALVE
Function.................................................... Fan Motor Reverse Control
Fan Motor Speed Control
T1-3-7
GENERAL / Component Specifications
HYDRAULIC CONPONENT
MAIN PUMP
Type.......................................................... Bent Axis Type Variable Displacement Axial Plunger Pump
Maximum Flow (Theoretical Value).......... 270 L/min (71 US gum) (ZW220)
290 L/min (77 US gum) (ZW250)
REGULATOR
Type.......................................................... Hydraulic Pressure Operated Type
PRIORITY VALVE
Relief Set Pressure .................................. 27.4 MPa (280 kgf/cm2) @ 70 L/min (18.5 US gpm) (ZW220)
29.4 MPa (300 kgf/cm2) @ 90 L/min (23.8 US gpm) (ZW250)
PILOT PUMP
Model........................................................ HY/ZFS11/16.8
Type.......................................................... Fixed Displacement Type Gear Pump
Maximum Flow (Theoretical Value).......... 35 L/min (9.3 US gpm)
CONTROL VALVE
ZW220
Type.......................................................... Pilot Pressure Operated Type (2 Spools)
Main Relief Set Pressure.......................... 27.4 MPa (280 kgf/cm2) @ 200 L/min (52.8 US gpm)
Overload Relief Set Pressure................... 34.3 MPa (350 kgf/cm2) @ 35 L/min (9.3 US gpm)
(Lift Arm)
30.4 MPa (310 kgf/cm2) @ 35 L/min (9.3 US gpm)
(Bucket Tilt)
30.4 MPa (310 kgf/cm2) @ 50 L/min (13 US gpm)
(Bucket Dump)
ZW250
Type.......................................................... Pilot Pressure Operated Type (2 Spools)
Main Relief Set Pressure.......................... 29.4 MPa (300 kgf/cm2) @ 220 L/min (58 US gpm)
Overload Relief Set Pressure................... 36.8 MPa (375 kgf/cm2) @ 50 L/min (13 US gpm)
(Lift Arm)
32.5 MPa (330 kgf/cm2) @ 50 L/min (13 US gpm)
(Bucket Tilt, Bucket Dump)
T1-3-8
GENERAL / Component Specifications
RIDE CONTROL VALVE (OPTIONAL)
Type.......................................................... Pilot Pressure Operated Type
Overload Relief Set Pressure................... 39.2 MPa (400 kgf/cm2) @ 50 L/min (13 US gpm)
Charge Cut Pressure................................ 11.3 MPa (115 kgf/cm2)
RIDE CONTROL ACCUMULATOR (OPTIONAL)
Capacity.................................................... 4 L (244 in3)
Charging Pressure ................................... 2.9 MPa (30 kgf/cm2)
CHARGING BLOCK
Charging Pressure ................................... Cut In Pressure: 11.8 MPa (120 kgf/cm2)
Cut Out Pressure: 14.7 MPa (150 kgf/cm2)
Pilot Relief Valve Set Pressure................. 3.7 MPa (38 kgf/cm2) @ 40 L/min (10.6 US gpm)
SOLENOID VALVE (For Charging Block)
Function.................................................... • Main Pump Torque Control
• Parking Brake
SERVICE BRAKE ACCUMULATOR
Capacity.................................................... 1.4 L (85.4 in3)
Charging Pressure ................................... 4.4 MPa (45 kgf/cm2)
PILOT ACCUMULATOR
Capacity.................................................... 0.75 L (45.8 in3)
Charging Pressure ................................... 2.0 MPa (20 kgf/cm2)
PILOT SHUT OFF VALVE
Type.......................................................... Rotary Type
STEERING VALVE
Type.......................................................... Flow Amp Type
Over Load Relief Set Pressure ................ 32.3 MPa (330 kgf/cm2) @50 L/min (13 US gpm) (ZW220)
34.3 MPa (350 kgf/cm2) @50 L/min (13 US gpm) (ZW250)
T1-3-9
GENERAL / Component Specifications
STEERING PILOT VALVE
Type.......................................................... Orbitrol Type
Gerotor Capacity ...................................... 96 cm3/rev (5.9 in3/rev)
STEERING ACCUMULATORv
Capacity.................................................... 0.2 L (12 in3)
Charging Pressure ................................... 8 MPa (82 kgf/cm2)
BRAKE VALVE
Brake Pressure......................................... 3.9 MPa (40 kgf/cm2)
T1-3-10
GENERAL / Component Specifications
• Travel System
TRANSMISSION
Type.......................................................... Counter Shaft Type
Gear Ratio ................................................ Forward 1st : 3.225
Forward 2nd : 1.901
Forward 3rd : 1.026
Forward 4th : 0.605
Reverse 1st : 3.225
Reverse 2nd : 1.901
Reverse 3rd : 1.026
Reverse 4th : 0.605
Parking Brake Release Pressure ............. 2.7 MPa (28 kgf/cm2)
STANDARD AXLE (FRONT/REAR)
ZW220
Model........................................................ Two Stage Transmission
Brake Type ............................................... Wet Multiplate Disk Brake
Brake Pressure......................................... 3.92 MPa (40 kgf/cm2)
Final Reduction Gear Ratio...................... 25.766
ZW250
Model........................................................ Two Stage Transmission
Brake Type ............................................... Wet Multiplate Disk Brake
Brake Pressure......................................... 3.92 MPa (40 kgf/cm2)
Final Reduction Gear Ratio...................... 26.760
STANDARD PROPELLER SHAFT
Type.......................................................... Cruciform Joint Type
Dimension between Pins.......................... Front : 1500 mm (59.06”)
Rear : 367.18 mm (14.46”)
T1-3-11
GENERAL / Component Specifications
• Front Attachment
CYLINDER
ZW220
Lift Arm (Left/Right)
Rod Diameter ........................................... 85 mm (3.35”)
Cylinder Bore............................................ 130 mm (5.12”)
Stroke ....................................................... 880 mm (34.65”)
Fully Retracted Length ............................. 1420 mm (55.91”)
Plating Thickness ..................................... 30 µm (1.2 µin)
Bucket
95 mm (3.74”)
165 mm (6.5”)
510 mm (20.08”)
1060 mm (41.73”)
30 µm (1.2 µin)
Steering
45 mm (1.77”)
70 mm (2.76”)
442 mm (17.40”)
804 mm (31.65”)
30 µm (1.2 µin)
ZW250
Lift Arm (Left/Right)
Rod Diameter ........................................... 85 mm (3.35”)
Cylinder Bore............................................ 130 mm (5.12”)
Stroke ....................................................... 940 mm (37.01”)
Fully Retracted Length ............................. 1481 mm (58.31”)
Plating Thickness ..................................... 30 µm (1.2 µin)
Bucket
100 mm (3.94”)
165 mm (6.5”)
530 mm (20.87”)
1090 mm (42.91”)
30 µm (1.2 µin)
Steering
45 mm (1.77”)
70 mm (2.76”)
542 mm (21.34”)
900 mm (35.43”)
30 µm (1.2 µin)
T1-3-12
GENERAL / Component Specifications
ELECTRICAL COMPONENT
ENGINE OIL PRESSURE SENSOR
Operation Pressure .................................. 29.4 kPa (0.3 kgf/cm2)
OVERHEAT SWITCH
Operation Temperature ............................ 105±2 ° C (221±2 °F)
COOLANT TEMPERATURE SENSOR
(For Coolant Temperature Gauge)
Operation Temperature ............................ 25 to 120 °C (77 to 248 °F)
AIR FILTER RESTRICTION SWITCH
Operation Pressure .................................. 6.3±0.6 kPa (635±58 mmH2O)
FUEL LEVEL SENSOR
Resistance Value...................................... Empty: 90+100Ω, Full: 100-4Ω
ENGINE OIL TEMPERATURE SENSOR
Operation Temperature ............................ -30 to 120 °C (-22 to 248 °F)
BATTERY RELAY
Voltage/Current ........................................ 24 V⋅100 A
GLOW RELAY
Voltage...................................................... 24 V
SAFETY RELAY
Voltage...................................................... 24 V
HORN
Voltage/Current ........................................ 24 V⋅3.0±0.5 A
Sound Pressure........................................ 113±5 dB (A) @ 2 m (6’ 7”)
T1-3-13
GENERAL / Component Specifications
ILLUMINATION
Work Light ................................................ : Halogen 24 V, 55/70 W
Cab Light .................................................. : 24 V, 10 W
Head Light ................................................ : Halogen 24 V、75/70 W
Turn Signal Light ...................................... : Front : 24 V, 25 W
:Rear : 24 V, 21 W
Clearance Light ........................................ : 24 V, 5 W
License Light ............................................ : 24 V, 12 W
Reverse Light ........................................... : 24 V, 21 W
Tail Light ................................................... : 24 V, 5 W
Brake Light ............................................... : 24 V, 21 W
AIR CONDITIONER
Refrigerant................................................ 134a
Cooling Ability........................................... 4.65 kW (16.74 MJ, 3999 kcal) or more
Cool Air Volume........................................ 550 m3/h or more
Heating Ability........................................... 5.81 kW (20.92 MJ, 4997 kcal) or more
Warm Air Volume...................................... 400 m3/h or more
Temperature Adjusting System ................ Electronic Type
Refrigerant Quantity ................................. 1050±50 g
Compressor Oil Quantity .......................... 160 cm3
EMERGENCY STEERING PUMP UNIT
Type.......................................................... Electrical Motor Operated Type
Maximum Flow ......................................... 17 L/min (4.49 gpm) @10.3 MPa (105 kgf/cm2)
ELECTRICAL MOTOR
Voltage...................................................... 24 V, 2.4 kW
T1-3-14
SECTION 2
SYSTEM
—CONTENTS—
Group 1 Control System
Group 4 Electrical System
Outline ...................................................... T2-1-1
Outline ...................................................... T2-4-1
Engine Control.......................................... T2-1-6
Main Circuit............................................... T2-4-2
Pump Control ......................................... T2-1-15
Electric Power Circuit................................ T2-4-3
Transmission Control.............................. T2-1-20
Indicator Light Check Circuit ..................... T2-4-4
Other Controls ........................................ T2-1-41
Accessory Circuit ...................................... T2-4-5
Control by Electric and Hydraulic
Preheat Circuit .......................................... T2-4-6
Combined Circuit .................................. T2-1-51
Starting Circuit .......................................... T2-4-8
Charging Circuit ...................................... T2-4-12
Group 2 ECM System
Serge Voltage Prevention Circuit ............ T2-4-16
Outline ...................................................... T2-2-1
Engine Stop Circuit ................................. T2-4-18
Fuel Injection Control ............................... T2-2-2
Lamplight Circait ..................................... T2-4-19
Compensation of Fuel Injection
Head Light Circuit ................................... T2-4-20
Volume ................................................. T2-2-10
Turn Signal Circuit .................................. T2-4-24
Engine Start Control ................................T2-2-11
Brake Light Circuit .................................. T2-4-25
EGR Control ........................................... T2-2-12
Hazard Light Circuit ................................ T2-4-26
Horn Circuit............................................. T2-4-27
Group 3 Hydraulic System
Outline ...................................................... T2-3-1
Reverse Light/Buzzer Circuit .................. T2-4-28
Main Circuit .............................................. T2-3-2
Parking Brake Circuit .............................. T2-4-30
Pilot Circuit ............................................. T2-3-17
Emergency Steering Check
Steering Circuit ....................................... T2-3-32
Circuit (Optional) ................................... T2-4-32
Hydraulic Drive Fan Circuit ..................... T2-3-38
4GCT-2-1
(Blank)
4GCT-2-2
SYSTEM / Control System
GENERAL
There are four controllers as shown below with MC –
Main Controller – installed at their center.
·
·
·
·
MC: Main Controller
ICF: Information Controller
ECM: Engine Control Module
Monitor Unit
Controllers are mutually connected through CAN, and
each controller uploads analog signals detected by
sensors and switches as well as analog output signals
to solenoid valves on the CAN by converting them into
digital ones.
As the signals are processed into the digital ones, a
large amount of signals detected at each controller can
be transmitted through few wires in a short time.
PHOTO
MC, ECM, and monitor unit display indications on
monitors and make various controls of the vehicle
body by using analog signals received by each
controller as well as digital signals detected on the
CAN.
ICF stores machine history, receives digital signals for
various adjustments from Dr-ZX, transmits them to the
CAN, and transmits the vehicle body signal (digital
signal) received by each controller to Dr-ZX.
A GPS-provision (optional) vehicle makes location
arithmetic operation, utilising signals received by
artificial sattelites, and transmits body information to
the e-service host computer through artificial satellites.
(Refer to the TROUBLESHOOTING/ICF)
PHOTO
Cab
PHOTO
MCF & ICF
004
020
ECM
037
Receipt and Transmission by
Analog Signal
Monitor
Unit
GPS
S
Dr-ZX
ICF
Receipt and
Transmission by
Digital Signal
ECM
MC
CAN
S
S
T2-1-1
Sensors, Switches and
Solenoid Valves
SYSTEM / Control System
MC, ECM, and Monitor Unit are used for various
operation controls of the body.
·
Analog input signals from sensors and switches
attached to devices other than the engine and
monitor unit as well as analog output signals from
solenoid valves are transmitted into the MC, and
converted into digital signals to be uploaded on the
CAN.
· Analog input signals from sensors attached to the
engine are transmitted to the ECM, and converted
into digital signals to be uploaded on the CAN.
· Analog input signals from cabin, and analog input
signals from sensors and switches necessary for
indication of the monitor are transmitted into the
monitor unit, and converted into digital signals to be
uploaded on the CAN.
Each controller detects lacking information necessary
for the control program from among the CAN data.
(digital signals)
Each controller makes various control program
arithmetic operations using the detected data (digital
signals), outputs actuation signals to the solenoid
valves unit and torque control solenoid valve, and
controls the pump, engine, transmission, and valves.
Analog signals from various sensors, switches, and
solenoid valves are periodically transmitted into each
controller, and converted into digital signals to be
uploaded on the CAN.
By repeating the above operations, the vehicle body
movement is watched and controlled.
T2-1-2
SYSTEM / Control System
Injectors
Sensors and
Switches for
Vehicle Body
MC
ECM
Engine
Solenoid Valves
for Vehicle Body
Transmission
Sensors and
Switches
Sensors and
Switches for Cab
and Monitor
Solenoid Valves
Monitor
Unit
Relays for
Cab
Sensors and
Switches
Switches for
Traveling
Light-emitting
Dildes
Dr-ZX
ICF
GPS
T4GC-02-01-001
T2-1-3
SYSTEM / Control System
Sensors and switches to detect signals for various
operation controls and their controllers are as shown
below.
Input Signals
• Accelerator Pedal Sensor
• Driving Mode Switch
•
•
•
•
•
•
•
•
•
•
•
Work Mode Selector Switch
Fan Reversing Switch
Ride Control Switch
Parking Brake Pressure Sensor
Pump Delivery Pressure Switch
Imprement Pressure Sensor
Hydraulic Oil Temperature sensor
Clutch Cut Position Sensor
Lift Arm Kick-out Switch
Lift Arm Angle Sensor (OP)
Lift Arm Auto-leveler Upwards
Set Switch (OP)
• Lift Arm Auto-leveler Downwards
Set Switch (OP)
•
Output Signals
Engine Control
®
®
→Accelerator Pedal Control
®
®
®
®
®
®
®
®
®
®
MC
→Automatic Warming Up Control
→Engine Torque Control
Pump Control
→Standard Torque Control
→Torque Reduction Control
Other Controls
→Hydraulic Fan Cooling Control
→Hydraulic Fan Cleaning Control
→Transmission Alarm Control
→Forward/Reverse Indicator Control
→Reverse Traveling Alarm Control
→Parking Brake Alarm Control
®
®
CAN
(See next chart)
NOTE: OP : Stands for optional.
* : Controls for optional parts provision
machines only
T2-1-4
Control by Electric and Hydraulic
Combined Circuit
→*Ride Control
Bucket Auto-leveler Control
Lift Arm Float Control
→Lift Arm Kick-out Control
→*Lift Arm Auto-leveler Upward Control
→*Lift Arm Auto-leveler Downward Control
SYSTEM / Control System
Input Signal
(See previous chart)
• Forward/Reverse Lever
• Shift Switch
•
•
•
•
•
•
•
•
•
•
(Refer to the SYSTEM/ECM System)
Transmission control
→Neutral Control
→Forward/Reverse Lever Priority Control
→Forward/Reverse Selector Control While
Traveling
→
→
Down Shift Switch
→
Up Shift Switch
→
Hold Switch
→
Forward/Reverse Selector Switch
→
Forward/Reverse Switch
→
Brake Pressure Sensor
→
Torque Converter Input Speed Sensor →
Torque Converter Output Speed Sensor →
Transmission Middle Shaft Sensor
→
Vehicle Speed Sensor
→
Output Signal
CAN
MC
→Manual Speed Shift Control
→Automatic Speed Shift Control
→Down Shift Control
→Up Shift Control
→Clutch Cut Control
→Shift Holding Control
→
ECM
• Engine Coolant Temperature Sensor →
• Torque Converter Oil Temeperature
Sensor
→
Monitor
Unit
NOTE: ECM controls the engine speed and others
based on the target engine speed
transmitted from the MC and the converted
signal of the torque curve, and on the
signals detected by the sensors installed at
the engine. For details, refer to the
SYSTEM/ECM System.
T2-1-5
→(Refer to the SYSTEM/ECM System)
SYSTEM / Control System
ENGINE CONTROL
Following engine controls are made.
• Accelerator pedal Control
• Automatic warming up control
• Engine torque control
T2-1-6
SYSTEM / Control System
Engine Control System Layout
PHOTO
Pedals
009
Work Mode
Selector Switch
L
Accelerator Pedal
Hydraulic Oil
Temperature
Sensor
Accelerator Pedal Sensor
N
P
Main Pump
Delivery
Pressure Switch
Shift Switch
MC
ECM
Transmission
Engine
Torque Converter Output
Speed Sensor
Torque Converter Input
Speed Sensor
Monitor
Unit
Engine Coolant
Temperature Sensor
Work Mode Selector Switch
L: Light Mode (Fast Front Speed)
N: Normal Mode
P: Power Mode (High Traction Force)
Shift Control Switch
st
1: 1 Speed
nd
2: 2 Speed
rd
3: 3 Speed
th
4: 4 Speed
T2-1-7
T4GC-02-01-002
SYSTEM / Control System
Accelerator Pedal Control
Purpose: Control of the engine speed in response to
stepping amount of accelerator pedal.
Engine Actual
Speed
Operation:
1. MC converts the input value into the target engine
speed, and transmits it to the ECM.
Maximum
Speed
2. ECM controls the engine speed in response to the
target engine speed.
NOTE: Output value of the accelerator pedal
sensor is 0.5 V – 4.5 V.
NOTE: In case the accelerator pedal sensor
becomes abnormal, the MC makes
back-up control, and the engine speed is
fixed at about 1000 min-1.
NOTE: In case the MC becomes out of order, or
the CAN fails, the ECM makes back-up
control, and the engine speed is fixed at
about 1000 min-1.
NOTE: In case the MC becomes out of order with
the accelerator remaining normal, control
of the engine speed is possible by
connecting the accelerator pedal sensor
wires directly to the ECM.
T2-1-8
Minimum
Speed
Minimum
Speed
Maximum
Speed
Target
Engine
Speed
SYSTEM / Control System
Accelerator Pedal
Accelerator Pedal Sensor
Transmission
ECM
MC
Engine
Monitor
Unit
T4GC-02-01-003
T2-1-9
SYSTEM / Control System
Automatic Warming Up Control
Purpose: Automatic warming up of the engine in
response to the hydraulic oil temperature
Engine
Actual
Speed
Operation:
1. At start of the engine, if the hydraulic oil
temperature is 0°C (32°F) or below, the MC
transmits signal to the ECM for setting the engine
minimum speed at 1000 min-1.
Maximum
Speed
Automatic
Warming Up
Speed
2. ECM increases the minimum engine speed to
1000 min-1.
3. When the engine coolant temperature or
hydraulic oil temperature is 40°C (104°F) or
above, or when 10 minutes have passed, the MC
stops signals, and the ECM decreases the engine
minimum speed to the idling value.
NOTE: At start of the engine, if the hydraulic oil
temperature is 1°C (34°F) or above,
automatic warming up control is not made.
NOTE: In case the hydraulic oil temperature
sensor becomes abnormal, automatic
warming up control is not made.
NOTE: When the parking brake switch is turned
OFF, automatic warming up control is
released.
NOTE: In case automatic warming up control is
released by Dr. ZX, retrieve the automatic
warming up control effective by Dr. ZX the
moment releasing becomes unnecessary.
(Retrieving is impossible by just turning the
key switch OFF.)
T2-1-10
Speed
Increase
Minimum
Speed
Minimum
Speed
Maximum
Speed
Target Engine
Speed
SYSTEM / Control System
PHOTO
Hydraulic Oil Temp
PHOTO
Overheat and
Coolant Temp
048
098
Hydraulic Oil
Temperature Sensor
Transmission
MC
ECM
Engine
Monitor
Unit
Engine
Coolant
Temperature
Sensor
T4GC-02-01-004
T2-1-11
SYSTEM / Control System
Engine Torque Control
Purpose: Improving fuel consumption rate by
changing the torque curve in response to
input signals from the work mode selector
switch, shift switch and vehicle speed
sensor
Engine
Torque
1
2
Operation:
3
1. When the signal of the selected work mode is
transmitted to the MC, it detects signals from the
main pump delivery pressure switch, shift switch,
torque converter input speed sensor and torque
converter output speed sensor.
2. MC has programmed torque curves to be
selected in response to the combination of work
mode, speed shift, torque converter speed ratio,
pump delivery pressure and outputs to the ECM
the selection command signal most suitable to
each time.
• When the light mode (L) is selected, Torque
Curve 4 or 3 is primarily used, which is
advantageous in making much of low fuel
consumption at light-load work.
• When normal mode (N) is selected, Torque Curve
3 or 2 is primarily used, which is advantageous in
making much of production as well as low fuel
consumption.
• When the power mode (P) is selected, Torque
Curve 1 or 2 is primarily used, which is
advantageous in making much of production
mainly as well as low fuel consumption slightly.
3. ECM controls torque curves in response to the
inputted torque curve selection command signal.
4
Engine
Speed
Conceptual Diagram of
Engine Torque Curve
NOTE: In case the signal from the work mode
selector switch is not transmitted to the MC,
back-up control of fixing the work mode to
the normal mode is made.
NOTE: In case the signal from the torque converter
input speed sensor or the torque converter
output sensor is not transmitted to the MC,
engine torque control is made by setting
the vehicle speed at the back-up speed.
NOTE: In case the signal from the shift switch is
not transmitted to the MC, back-up control
of fixing to Torque Curve 2 is made.
NOTE: Each mode switch of the mode selector
switch is supplied with respectively different
voltages from the monitor unit, and when
the switch selects a mode, the MC judges
which mode has been selected by the input
voltage.
NOTE: Shift switch has two switches, and the
combination of their ON varies depending
on each speed shift. Controller judges
which speed shift has been selected by the
combination of the two input signals.
T2-1-12
SYSTEM / Control System
Work Mode
Selector Switch
L&C
PHOTO
N
Torque Converter
P
109
Main Pump
Delivery
Pressure Switch
Shift Switch
MC
ECM
Transmission
Engine
Torque Converter
Output Speed Sensor
Torque Converter
Input Speed Sensor
Monitor
Unit
T4GC-02-01-005
NOTE: Illustration shows flow of the signal in case
the light mode of the work mode selector
switch and Speed 1 of the speed shift
switch have been selected.
T2-1-13
SYSTEM / Control System
(Blank)
T2-1-14
SYSTEM / Control System
PUMP CONTROL
Following pump controls are made.
• Standard Torque Control
• Torque Reduction Control
Pump Control System Layout
Accelerator Pedal
PHOTO
PHOTO
Hydraulic System
Torque Converter
114
107
Accelerator Pedal Sensor
Main Pump Delivery
Pressure Switch
MC
ECM
Engine
Transmission
Main Pump
regulator
Pump Torque Control
Solenoid Valve
Torque Converter
Output Speed Sensor
Monitor
Unit
Torque Converter
Input Speed Sensor
T4GC-02-01-006
T2-1-15
SYSTEM / Control System
Standard Torque Control
Purpose: Effectively utilizing engine horsepower by
changing pump flow in response to increase
or decrease of engine speed
Operation:
1. When accelerator pedal is stepped, MC makes
arithmetic operation of the target engine speed.
2. MC makes arithmetic operation of the pump
maximum tilting angle by receiving the target
engine speed signal, and transmits signal to the
pump torque control solenoid valve.
Q
Flow
P-Q Line
3. Pump torque control solenoid valve transmits pilot
pressure corresponding to the amplitude of signal
to the main pump regulator, and controls the
pump flow rate.
NOTE: In case the pump torque control solenoid
valve becomes abnormal, standard-torque
control is not made.
Pressure
T2-1-16
P
SYSTEM / Control System
Accelerator Pedal
Accelerator Pedal Sensor
MC
ECM
Engine
Transmission
Main Pump
Regulator
Pump Torque Control
Solenoid Valve
Monitor
Unit
T4GC-02-01-007
T2-1-17
SYSTEM / Control System
Torque Reduction Control
Purpose: Effectively utilizing engine horsepower by
changing pump flow in response to increase
or decrease of the engine speed due to
traveling load
Operation:
1. When accelerator pedal is stepped, MC makes
arithmetic operation of the target engine speed.
Q
Flow
2. MC makes arithmetic operation, using the target
engine speed and signals from the main pump
delivery pressure switch, torque converter input
speed sensor, torque converter output speed
sensor and figures out the pump maximum tilting
angle most suitable to each time to transmit it to
the pump torque control solenoid valve.
P-Q Line
3. Pump torque control solenoid valve transmits pilot
pressure corresponding to the amplitude of signal
to the main pump regulator, and controls the
pump flow rate.
4. If load applied to the engine becomes large and
decreases the actual engine speed than the
target speed, the pump tilting angle is decreased
to reduce delivery flow. Thus, maneuverability of
the vehicle body is improved.
5. MC makes arithmetic operation of the actual
engine speed, receiving signal from the torque
converter input speed sensor.
Pressure
P
NOTE: In case the accelerator pedal becomes
abnormal, the back-up control of the
accelerator controls and fixes the engine
-1
speed at 1000 min .
NOTE: In case signal from either the main pump
delivery pressure switch, torque converter
input speed sensor, or torque converter
output speed sensor is not transmitted to
the MC, it does not make torque reduction
control, but makes pump control by the
standard-torque control.
NOTE: In case the pump torque control solenoid
valve
becomes
abnormal,
neither
standard-torque
control
nor
torque
reduction control is made.
T2-1-18
SYSTEM / Control System
Accelerator Pedal
Accelerator Pedal Switch
Main Pump Delivery
Pressure Switch
MC
ECM
Engine
Transmission
Main Pump
Regulator
Pump Torque Control
Solenoid Valve
Torque Converter
Output Speed Sensor
Monitor
Unit
Torque Converter
Input Speed Sensor
T4GC-02-01-008
T2-1-19
SYSTEM / Control System
TRANSMISSION CONTROL
Following transmission controls are made.
• Neutral Control
• Forward/Reverse Lever Priority Control
• Forward/Reverse Selector Control While
Traveling
• Manual Speed Shift Control
• Automatic Speed Shift Control
• Down Shift Control
• Up Shift Contrl
• Clutch Cut Control
• Shift Holding Control
T2-1-20
SYSTEM / Control System
Transmission Control System Layout
Key Switch
Driving Mode Switch
Brake Pressure
Sensor
Accelerator
Pedal Sensor
M
Brake Pedal
Accelerator Pedal
L
N
H
Clutch Cut
Position Switch
Forward
Clutch Solenoid
Valve
Transmission
Middle Shaft
Sensor
OFF
S
Reverse Clutch
Solenoid Valve
Transmission
N
D
MC
ECM
Engine
Shift Switch
1 2 3 4
Speed Shift
Solenoid Valve
Parking Brake
Parking Brake
Pressure Sensor
Monitor
Unit
Parking Brake
Solenoid Valve
Vehicle Speed
Sensor
Torque
Converter
Input
Speed
Sensor
Forward/Reverse
Lever
F
Torque
Converter
Output
Speed
Sensor
N
R
Forward/Reverse
Switch
F
N
OFF
DOWN
R
ON
UP
HOLD
Forward/Reverse
Selector Switch
Up-shift/Down-shift
Switch
Hold Switch
T2-1-21
ON
OFF
Parking Brake
Switch
T4GC-02-01-009
SYSTEM / Control System
Neutral Control
Purpose: Protection of transmission during working of
parking brake by restricting clutch connection despite operation of forward/reverse
lever or forward/reverse switch
Operation:
1. In case either of the signal from forward/reverse
lever, forward signal or reverse signal of the forward/reverse switch is transmitted to the MC, the
MC confirms the detected value of the parking
brake pressure sensor.
IMPORTANT: Be careful that in case the parking
brake pressure sensor is abnormal,
traveling is possible even if the
parking brake switch is ON and the
parking brake is at work because the
parking brake alarm lamp is turned
OFF and fixed (release).
2. When the parking brake pressure is higher than
the set pressure, the MC transmits signal to the
clutch solenoid valve, but does not when lower
than that.
NOTE: When the pilot pressure is supplied, the
parking brake of the vehicle body is released.
NOTE: In case short-circuiting takes place inside
the forward/reverse lever, transmission is
made neutral forcedly.
NOTE: In case electric abnormality takes place
involving the forward/reverse switch, traveling by the forward/reverse lever is possible as an emergency measure.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
T2-1-22
SYSTEM / Control System
PHOTO
PHOTO
Cab
004
005
PHOTO
PHOTO
Control Lever
Transmission
Parking Brake
011
108
112
012
109
Forward Clutch
Solenoid Valve
MC
Reverse Clutch
Solenoid Valve
ECM
Engine
Transmission
Parking Brake
Pressure Sensor
Monitor
Unit
Parking Brake
Solenoid Valve
Parking Brake
Forward/Reverse
Lever
F
N
R
Forward/Reverse
Switch
F
N
OFF
ON
R
ON
OFF
Forward/Reverse
Selector Switch
Parking Brake
Switch
NOTE: Illustration shows flow of the signals in case.
Forward of the forward/reverse lever have
been selected with the parking brake switch
turned OFF – transmitting brake release
signal.
T2-1-23
T4GC-02-01-010
SYSTEM / Control System
Forward/Reverse Lever Priority Control
Purpose: Smoothening danger-preventive function in
forward/reverse operation by giving priority to
signal from forward/reverse lever over signal
from forward/reverse switch
Operation:
1. In case the forward/reverse lever is operated
while traveling using the forward/reverse switch,
the MC disables operation of the forward/reverse
switch, and makes forward/reverse control by input signal from the forward/reverse lever.
2. For restarting operation using the forward/reverse
switch has the forward/reverse switch effective
again by turning the forward/reverse selector
switch ON while making both the forward/reverse
lever and the forward/reverse switch at the neutral
position.
3. From then on until the forward/reverse lever is
operated next, the MC makes forward/reverse
control by the forward/reverse switch input signal.
NOTE: In case short-circuiting takes place inside
the forward/reverse lever, transmission is
made neutral forcedly, and traveling becomes impossible, which requires towing.
However, in case the forward/reverse
switch is out of order, traveling by the forward/reverse lever is possible as an
emergency measure.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
T2-1-24
SYSTEM / Control System
PHOTO
Right Console
Forward Clutch
Solenoid Valve
013
MC
Reverse Clutch
Solenoid Valve
ECM
Engine
Transmission
Monitor
Unit
Forward/Reverse
Lever
F
N
R
Forward/Reverse
Switch
F
N
OFF
R
ON
Forward/Reverse
Selector Switch
T4GC-02-01-011
NOTE: Illustration shows flow of the signals in case
forward of the forward/reverse selector
lever has been selected while traveling reverse of the forward/reverse lever.
T2-1-25
SYSTEM / Control System
Forward/Reverse Selector Control While Traveling
Purpose: Protection of transmission in traveling at set
speed and above by preventing forward/reverse selector unless the vehicle
speed is lowered than that
Operation:
1. In case the forward/reverse lever is changed to
reverse while traveling forward at speed higher
than the speed allowed for operation of the forward/reverse lever, the MC lowers the speed shift
by transmitting speed shift signal of Speed
4®3®2 to the transmission if the speed shift is
Speed 4.
2. If the vehicle speed is lowered to the set speed by
operation of the brake pedal or otherwise, the MC
transmits signal to the reverse clutch solenoid
valve to have the clutch shifted reverse.
3. As the speed increases when the accelerator
pedal is stepped, the MC transmits speed shift
signal of Speed 2 to Speed 3 to each speed shift
solenoid valve, and increases the speed shift.
NOTE: In case the forward/reverse lever is operated when the vehicle speed is below the
value allowed for changeover of the forward/reverse clutch, the forward/reverse
clutch is operated regardless of the speed
shift.
NOTE: Shift switch has two switches, and the combination of their ON varies depending on
each speed shift. Controller judges which
speed shift has been selected by the combination of the two input signals.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
T2-1-26
SYSTEM / Control System
Accelerator Pedal
Sensor
Brake
Sensor
Accelerator Pedal
Brake Pedal
Shift Switch
Forward Clutch
Solenoid Valve
MC
Reverse Clutch
Solenoid Valve
ECM
Engine
1 2 3 4
Speed Shift Solenoid Valve
Vehicle Speed
Sensor
Transmission
Monitor
Unit
Forward/Reverse
Lever
F
N
R
Forward/Reverse
Switch
F
N
OFF
R
ON
Forward/Reverse
Selector Switch
T4GC-02-01-012
NOTE: Illustration shows flow of the signals in case
reverse of the forward/reverse lever has
been selected and the brake pedal has
been stepped while traveling forward at
Speed 4 above the value allowable for selection of the forward/reverse clutch.
T2-1-27
SYSTEM / Control System
Manual Speed Shift Control
Purpose: Making speed shifts manually
Operation:
1. When manual (M) of the Driving mode switch is
selected, the MC is provided with voltage of 1V.
2. Manual speed shift program is started in the MC.
3. Shift switch is the rorary type, and has two
switches inside. When the speed shift is selected
from among Speed 1 through Speed 4, signal of
the selected speed shift is transmitted to the MC
depending on the combination of ON inside the
speed shift switch.
Speed Shift
Speed
1
Internal Switch
1
ON
Internal Switch
2
Speed
2
Speed
3
Speed
4
ON
ON
ON
4. MC transmits signal to the solenoid valve of the
selected speed shift.
5. If forward or reverse of the forward/reverse lever
or the forward/reverse switch is selected, traveling
is started when the accelerator pedal is stepped.
6. When the vehicle speed reaches the set speed
change to the selected speed shift, the MC
transmits signal to the solenoid valve of the selected speed shift.
NOTE: MC is so programmed as to dtermine necessary vehicle speed ranges for changing
to the respective speed shifts.
NOTE: In case speed shift from Speed 3 to Speed
1 is attempted while traveling by operating
the speed shift switch, Speed 2 is automatically selected first, and Speed 1 is
reached after the vehicle speed is lowered
to the speed range for Speed 1.
NOTE: In case the solenoid valve of either of the
Speed 1, Speed 3, or Speed 4 becomes
abnormal, the travel speed will be fixed to
Speed 2. In case either of the forward
clutch solenoid valve, reverse clutch solenoid valve, or Speed 2 solenoid valve becomes abnormal, only the abnormal one
cannot be used.
NOTE: In case speed shift is raised, the selected
speed shift is immediately obtained regardless of the vehicle speed.
NOTE: Shift switch has two switches, and the
combination of their ON varies depending
on each speed shift. Controller judges
which speed shift has been selected by the
combination of the two input signals.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
NOTE: Each mode switch of the driving mode
switch is supplied with respectively different
voltages from the monitor unit, and if a
switch is selected, the MC judges which
mode has been selected.
NOTE: Speed shift selected by the speed shift
switch is the highest speed shift.
T2-1-28
SYSTEM / Control System
Driving Mode
Switch
Accelerator Pedal
Sensor
M
Brake Pressure
Sensor
Accelerator
Pedal
L
PHOTO
Cab
Brake Pedal
005
N
H
Shift Switch
Forward Clutch
Solenoid Valve
MC
ECM
Engine
1 2 3 4
Speed Shift Solenoid Valve
Monitor
Unit
Transmission
Vehicle Speed
Sensor
Forward/Reverse
Lever
F
N
R
Forward /Reverse
Switch
F
N
OFF
R
ON
Forward/Reverse
Selector Switch
T4GC-02-01-013
NOTE: Illustration shows flow of the signals in case
forward of the forward/reverse lever has
been selected when manual of the Driving
Mode switch and Speed 1 of the speed shift
switch have been selected.
T2-1-29
SYSTEM / Control System
Automatic Speed Shift Control
Purpose: Automatic speed shift with three kinds of
timing selection
Operation:
1. If either of L, N, and H of the Driving Mode switch
is selected, the MC is supplied with votage corresponding to the selected mode.
Mode
Automatic L
Automatic
N
Automatic
H
Output
Voltage
2V
3V
4V
4. MC transmits signal to the selected speed shift
solenoid valve in response to the output value
each time of the torque converter input speed
sensor, torque converter output speed sensor,
vehicle speed sensor and accelerator pedal sensor. MC eventually makes speed shift control until
the selected speed shift.
2. MC started the selected automatic speed shift
program.
· In Automatic L control, the timing of speed shifting up
is slow when started at Speed 2, which is advantageous in making much of low fuel consumption.
· In Automatic N control, the timing of speed shifting
up is fast when started at Speed 2, which is advantageous in making much of production as well as low
fuel consumption.
· In Automatic H control, though started at Speed 2,
besides slow speed shifting up, speed shift to Speed
1 is necessary if traveling load is high, which is advantageous in making much of production.
NOTE: In whichever of Modes L, N, and H, starting
is made at Speed 1, if the speed shift switch
of Speed 1 is selected.
3. Shift switch is the rorary type, and has two
switches inside. When the speed shift is selected
from among Speed 1 through Speed 4, signal of
the selected speed shift is transmitted to the MC
depending on the combination of ON inside the
speed shift switch.
Speed Shift
Speed
1
Internal Switch
1
ON
Internal Switch
2
Speed
2
Speed
3
Speed
4
ON
ON
ON
T2-1-30
NOTE: MC is so programmed as to dtermine necessary vehicle speed ranges for changing
to the respective speed shifts and accelerator pedal output value. Therefore, in
case Automatic L of the Driving mode
switch and Speed 3 of the speed shift
switch are selected at start of traveling,
traveling is started at Speed 2 first, and
shifted up to Speed 3 as the vehicle speed
increases. Conversely, in case speed shift
from Speed 3 to Speed 1 is attempted while
traveling by operating the speed shift switch,
Speed 2 is automatically selected first, and
Speed 1 is reached after the vehicle speed
is lowered to the speed range for Speed 1.
NOTE: In case the Driving mode switch becomes
out of order, the MC makes speed shift
control in the manual traveling mode.
NOTE: In case the solenoid valve of either of the
Speed 1, Speed 3, or Speed 4 becomes
abnormal, the travel speed will be fixed to
Speed 2. In case either of the forward
clutch solenoid valve, reverse clutch solenoid valve, or Speed 2 solenoid valve becomes abnormal, only the abnormal one
cannot be used.
NOTE: In case the travel speed sensor has become abnormal, the travel speed is calculated using the transmission intermediate
shaft sensor, but with a large error. In case
both of the travel speed sensor and the
transmission intermediate shaft sensor
have become abnormal, travel at Speed 2
is fixed.
NOTE: Speed shift selected by the speed shift
switch is the highest speed shift.
SYSTEM / Control System
Driving Mode
Switch
Accelerator Pedal
Sensor
M
Brake Pressure
Sensor
Brake Pedal
Accelerator Pedal
L
N
H
Shift Switch
Forward Clutch
Solenoid Valve
Transmission
MC
ECM
Engine
1 2 3 4
Speed Shift Solenoid Valve
Vehicle Speed
Sensor
Monitor
Unit
Forward/Reverse
Lever
Torque Converter
Input Speed Sensor
Torque Converter
Output Speed Sensor
F
N
R
Forward/Reverse
Switch
F
N
OFF
R
ON
Forward/Reverse
Selector Switch
T4GC-02-01-014
NOTE: Illustration shows flow of the signal in case
Automatic L mode of the Driving mode
switch, Speed 4 of the speed shift switch,
and forward of the forward/reverse selector
lever have been selected, while the accelerator pedal has been stepped.
T2-1-31
SYSTEM / Control System
Down Shift Control
Purpose: Decreasing the speed shift by pushing the
switch installed at the right console.
Operation:
1. When traveling at Speed 4 in Automatic L mode of
the Driving mode switch, signal is transmitted to
the MC by pushing the down shift switch once.
2. When traveling faster than the allowable speed
shift, the MC cancels the signal from the down
shift switch, but transmits signal to the speed shift
solenoid valve of Speed 3, when traveling slow.
8. In case of the following, the down shift switch
control is canceled.
• Operation of the forward/reverse lever or the forward/reverse switch
• Operation of the shift switch
• Operation of the Driving mode switch
• Pushing the hold switch
(Only in Automatic mode of the Driving mode
switch)
3. Further, if the down shift switch is pushed and the
vehicle speed is lowered to the range allowing the
speed shift, the speed shift of Speed 2 is selected.
4. In case automatic mode of the Driving mode
switch is selected, automatic speed shift control is
recovered three seconds after the speed shift has
lowered, and then the speed shift is automatically
raised once the vehicle speed increases.
5. By keeping pushing the down shift switch, the
speed shift is lowered to Speed 2, and Speed 2 is
kept during pushing.
6. If the down switch is pushed again within three
seconds after removing the finger once, Speed 1
is obtained in case the vehicle speed is slow
enough to allow the speed shift down.
7. When the down shift switch is pushed in manual
mode of the Driving mode switch, in case the vehicle speed is slow enough to allow the down shift,
the speed shift is lowered and the shifted speed is
kept.
NOTE: In case the vehicle speed sensor becomes
abnormal, the MC receives signal from the
transmission middle shaft sensor, and controls by making arithmetic operation of the
vehicle speed allowable for the speed shift.
In case both the vehicle speed sensor and
the transmission middle shaft sensor are
abnormal, lowering the speed shift is possible as an emergency measure only when
the engine stops for one reason or another
but traveling is not stopped.
NOTE: Shift switch has two switches, and their
combination of ON varies depending on
each speed shift. Controller judges which
speed shift has been selected by the combination of the two input signals.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
NOTE: Each mode switch of the Driving mode
switch is supplied with respectively different
voltages from the monitor unit, and when
the switch selects a mode, the MC judges
which mode has been selected by the input
voltage.
T2-1-32
SYSTEM / Control System
Driving Mode
Switch
Accelerator Pedal Sensor
Brake Pressure Sensor
M
Brake Pedal
Accelerator Pedal
L
N
H
Shift Switch
Transmission
Middle Shaft Sensor
Forward Clutch
Solenoid Valve
Reverse Clutch
Solenoid Valve
MC
ECM
Engine
1 2 3 4
Speed Shift Solenoid Valve
Transmission
Monitor
Unit
Vehicle
Speed Sensor
Forward/Reverse
Lever
F
N
R
Forward/Reverse
Switch
F
N
OFF
DOWN
R
ON
UP
Forward/Reverse
Selector Switch
Up-shift/Down-shift
Switch
NOTE: Illustration shows flow of the signals from
the MC in case Speed 3 has been selected
during forward traveling at Speed 4 and
Automatic L of the Driving mode switch.
T2-1-33
HOLD
Hold Switch
T4GC-02-01-015
SYSTEM / Control System
Up Shift Control
Purpose: Raising the speed shift by putting the left
hand on the steering wheel and pressing the
switch installed at the right console
Operation:
1. Signal is transmitted to the MC by pushing the up
shift switch once when traveling at Automatic L
mode of the Driving mode switch and Speed 4 of
the shift switch.
2. MC transmits signal to the speed shift solenoid
valve of Speed 2, and the speed shift is raised.
3. If the up shift switch is pushed, the speed shift is
further raised to Speed 3 and Speed 4.
4. In case automatic travel mode switch is selected,
the speed shift is raised, and returned to the
automatic speed shift control in three seconds,
eventually rising automatically to the speed shift
selected in advance.
5. In case manual travel mode switch is selected, the
raised speed shift is kept.
6. In case the following operations are made, the up
shift switch is released.
• Operation of the forward/reverse lever or forward/reverse switch
• Operation of the shift switch
• Operation of the Driving mode switch
• Pushing the hold switch
(only when the automatic of the Driving mode
switch is selected)
NOTE: Even if the up shift switch is pushed during
traveling at the speed shift slected by the
shift switch, the speed shift is not raised
further.
T2-1-34
NOTE: Shift switch has two switches, and their
combination of ON varies depending on
each speed shift. Controller judges which
speed shift has been selected by the combination of the two input signals.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
NOTE: Each mode switch of the Driving mode
switch is supplied with respectively different
voltages from the monitor unit, and when
the switch selects a mode, the MC judges
which mode has been selected by the input
voltage.
SYSTEM / Control System
Driving Mode Switch
Accelerator Pedal
Sensor
M
Brake Pressure
Sensor
Brake Pedal
Accelerator Pedal
L
N
H
Shift Switch
Forward Clutch
Solenoid Valve
Reverse Clutch
Solenoid Valve
MC
ECM
Engine
1 2 3 4
Speed Shift Solenoid Valve
Transmission
Monitor
Unit
Forward/Reverse
Lever
F
N
R
Forward/Reverse
Switch
F
N
OFF
DOWN
R
ON
UP
HOLD
Forward/Reverse
Selector Switch
Up shift/Down shift
Switch
Hold
Switch
NOTE: Illustration shows flow of the signals from
the MC in case Speed 2 has been selected
during forward traveling at Speed 1 and
Automatic L of the Driving mode switch.
T2-1-35
T4GC-02-01-016
SYSTEM / Control System
Clutch Cut Control
Purpose: Enabling release of the forward/reverse
clutch of the transmission for making the
most of the engine torque by operating the
brake during operation of the front attachment.
Amount of stepping the brake pedal at the
time of declutching can be selected from
among three kinds depending on the driver’s
preference.
5. In case the brake pressure is lowered below the
set pressure by reducing the amount of stepping
of the brake pedal, signal transmitted to the clutch
solenoid valve is raised, and clutching is made
again.
Operation:
1. When either mode of the clutch cut position switch
is selected, voltage corresponding to the selected
mode is transmitted to the MC.
Mode
OFF
S
N
D
Input
Voltage
1V
2V
3V
4V
2. MC starts the corresponding clutch cut control
program.
• Clutch cut does not work in OFF mode.
• In Mode S, clutch cut is made at output voltage
equivalent to the set pressure of Mode S, and
clutching is made again at voltage equivalent to
pressures lower than that of Mode S.
• In Mode N, clutch cut is made at output voltage
equivalent to the set pressure of Mode N, and
clutching is made again at voltage equivalent to
pressures lower than that of Mode N.
• In Mode D, clutch cut is made at output voltage
equivalent to the set pressure of Mode D, and
clutching is made again at voltage equivalent to
pressures lower than that of Mode D.
3. In case the brake pedal is stepped in Mode S,
signal from the brake pressure sensor is transmitted to the MC.
4. For signal higher than the set voltage, the MC declutches by lowering signal transmitted to the excited solenoid valve among the respective solenoid valves.
T2-1-36
NOTE: In case either of the clutch cut position
switch and brake pressure sensor becomes
out of order, clutch cut control is not made
NOTE: Each mode switch of the clutch cut position
switch is provided with respectively different
voltages from the monitor unit, and when
the switch selects a mode, the MC judges
which mode has been selected by the input
voltage.
SYSTEM / Control System
PHOTO
Cab
005
Brake Pressure
Sensor
Brake Pedal
Clutch Cut
Position Switch
OFF
Forward Clutch
Solenoid Valve
S
N
Reverse Clutch
Solenoid Valve
D
MC
ECM
Engine
Transmission
Monitor
Unit
T4GC-02-01-017
NOTE: Illustration shows flow of the signals in case
the brake pedal has been stepped in Mode
S of the clutch cut position switch.
T2-1-37
SYSTEM / Control System
Shift Holding Control
Purpose: Enabling to hold the speed shift during towing or traveling uphill
Operation:
1. When the hold switch is pressed once, signal is
transmitted to the MC.
2. MC keeps transmitting signal to the speed shift
solenoid valve of each time, and after that the
speed shift is fixed even if the the accelerator or
the brake pedal is stepped.
NOTE: Speed shift holding control is made only
when automatic (L, N, or H) of the Driving
mode switch is selected.
3. MC releases the speed shift holding control in
case the following operations are made or the
following switches are operated.
• Turning OFF the key switch
• Pushing the hold switch again
• Down shift switch
• Up shift switch
• Forward/reverse lever
• Forward/reverse selector switch (only when effective)
• Forward/reverse switch (only when effective)
• Speed shift switch
• Driving mode switch
• Parking brake switch
T2-1-38
NOTE: Shift switch has two switches, and their
combination of ON varies depending on
each speed shift. Controller judges which
speed shift has been selected by the combination of the two input signals.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
NOTE: Each mode switch of the Driving mode
switch is provided with respectively different
voltages from the monitor unit, and if a
switch is selected, the MC judges which
mode has been selected.
SYSTEM / Control System
Key Switch
PHOTO
Driving Mode Switch
Accelerator Pedal
Sensor
M
Brake Pressure
Sensor
Accelerator Pedal
Brake Pedal
Control Lever
011
012
L
N
H
Shift Switch
Forward Clutch
Solenoid Valve
MC
ECM
Engine
1 2 3 4
Speed Shift Solenoid Valve
Transmission
Monitor
Unit
Forward/Reverse
Lever
F
N
R
Forward/Reverse
Switch
F
N
OFF
DOWN
R
ON
UP
Forward/Reverse
Selector Switch
Up-Shift/Down-Shift
Switch
ON
HOLD
OFF
Hold
Switch
Parking Brake
Switch
T4GC-02-01-018
T2-1-39
SYSTEM / Control System
(Blank)
T2-1-40
SYSTEM / Control System
OTHER CONTROLS
Following other controls are made.
• Hydraulic fan cooling control
• Hydraulic fan cleaning control
• Transmission alarm control
• Forward/reverse indicator control
• Reverse Traveling alarm control
• Parking brake alarm control
T2-1-41
SYSTEM / Control System
Hydraulic Fan Cooling Control
Purpose: Improving fuel consumption rate and noise
reduction by restricting the hydraulic fan
speed in response to hydraulic oil temperature and coolant temperature.
Operation:
1. When the engine is started, the fan pump rotates
and discharges oil to the fan motor.
2. Signals from the hydraulic oil temperature sensor,
engine coolant temperature sensor and torque
converter oil temperature sensor are simultaneously transmitted to the MC, and arithmetic operation of three target hydraulic fan speeds are
carried out.
3. MC selects the highest temperature and transmits
signal to the flow control solenoid valve.
4. Flow control solenoid valve operates and pressure
oil coming from it flows into the right end of the
flow control valve, so the flow control valve spool
moves left.
5. When the flow control valve spool moves left, part
of the pressure oil flowing to the fan motor flows to
the tank port, and the fan motor speed is lowered
accordingly.
6. In case oil temperature or coolant temperature of
any part is above the set temperature, the hydraulic fan speed is maximized when the engine
speed is in maximum.
7. In case oil temperature or coolant temperature of
any part is below the set temperature, the hydraulic fan speed is lowered in response to the datum
of the highest temperature.
8. Besides, the signal from the outside air temperature sensor also enters the MC, and rotates the
fan always at the maximum speed, disregarding
the controls in 2 through 7 in case the air conditioner switch is ON at the outside air temperature
of 35 °C (95 °F) and above.
NOTE: In case any of the engine revolution sensor,
hydraulic oil temperature sensor, engine
coolant temperature sensor, torque converter oil temperature sensor and out side
temperature sensor becomes out of order,
cooling by hydraulic fan control is always
made at the maximum speed.
T2-1-42
SYSTEM / Control System
At oil temperature or coolant temperature above the set temperature (Uncontrolled speed operation)
PHOTO
Fan Motor
Cooling Fan
039
Flow Control Valve
Hydraulic Oil Tank
Flow Control
Solenoid Valve
Hydraulic Oil Temperature Sensor
Fan Pump
Engine Coolant Temperature Sensor
Out Side
Temperature
Sensor
MC
ECM
Engine
Air
Conditioner
Control
Panel
Transmission
Monitor
Unit
Torque Converter
Oil Temperature Sensor
T4GC-02-01-019
At oil temperature or coolant temperature below the set temperature (Controlled speed operation)
Fan Motor
Flow Control Valve
Hydraulic Oil Tank
Hydraulic Oil Temperature Sensor
Flow Control
Solenoid Valve
Fan Pump
Engine Coolant
Temperature Sensor
Out Side
Temperature
Sensor
MC
ECM
Engine
Air
Conditioner
Control
Panel
Transmission
Torque Converter
Oil Temperature Sensor
Monitor
Unit
T4GC-02-01-020
T2-1-43
SYSTEM / Control System
Hydraulic Fan Cleaning Control
Purpose: Control of cleaning by hydraulic fan by reversing the hydraulic fan to blow away dust
in case cleaning of the radiator and oil cooler
are needed
Operation:
1. When the engine is started after preparing the
following conditions and turning the fan reversing
switch ON, signal is transmitted from the MC to
the reverse control solenoid valve.
2. When the reverse control solenoid valve is operated, the reverse spool strokes and the fan motor
rotation is reversed.
3. In reverse rotation, as hydraulic fan cooling control is not made, the fan speed fluctuates from
maximum to minimum in response to the amount
of stepping the accelerator pedal.
4. In case any one of the conditions below is
changed during reverse rotation, the engine
speed is immediately fixed to idling.
5. Hydraulic fan cleaning control is not released by
turning the fan reversing switch OFF only. Control
is released by the procedure of turning the fan
reversing switch OFF – turning the key switch
OFF – turning the key switch ON.
6. In case the engine speed is fixed to idling also, the
control is released by the procedure of turning the
fan reversing switch OFF – turning the key switch
OFF – turning the key switch ON.
Conditions:
•
•
•
•
Fan reversing switch: ON
Parking brake switch: ON (Brake is effective.)
Forward/reverse lever: neutral
Forward/reverse switch: neutral
T2-1-44
NOTE: Reverse control solenoid valve is turned
ON temporarily when the key switch is
turned ON because the spool can stick in
case the reverse control solenoid valve is
not operated for a long time. It is also
turned ON once every one minute after the
key switch is turned ON. This operation is
not made during the hydraulic fan cleaning
operation.
SYSTEM / Control System
In cooling operation (Normal rotation)
Fan Motor
Reverse Spool
Reverse Control
Solenoid Valve
Engine
Transmission
Hydraulic Oil
Tank
T4GB-02-01-007
In cleaning operation (Reverse rotation)
Fan Motor
Reverse Spool
Reverse Control Solenoid Valve
Hydraulic Oil
Tank
Engine
Transmission
Parking Brake
Solenoid Valve
MC
ECM
OFF
Parking Brake
Pressure Sensor
ON
Monitor
Unit
Fan Reversing
Switch
F
F
N
N
ON
R
R
OFF
Forward/Reverse
Lever
Forward/Reverse
Switch
Parking Brake
Switch
T2-1-45
T4GC-02-01-021
SYSTEM / Control System
Transmission Alarm Control
Purpose: Lighting the transmission alarm lamp on the
monitor unit for protection of the transmission in case of disorder of parts likely to
cause damage to the transmission
Operation: In case any of the parts shown right becomes out of order, the MC transmits signal
to the monitor unit, and the transmission
alarm lamp is lit.
Monitor
MC
•
•
•
•
•
•
Torque converter input speed sensor
Torque converter output speed sensor
Vehicle speed sensor
Transmission middle shaft sensor
Forward/reverse lever
Forward/reverse switch during work
ECM
Engine
Transmission
Torque Converter
Input Speed
Sensor
Torque Converter
Output Speed
Sensor
Monitor
Unit
Transmission
Alarm Lamp
Transmission
Middle Shaft Sensor
F
F
N
N
R
R
Forward/Reverse
Lever
Forward/Reverse
Switch
T2-1-46
Vehicle Speed
Sensor
T4GC-02-01-022
SYSTEM / Control System
Forward/Reverse Indicator Control
Purpose: Lighting the forward/reverse indicator on the
monitor when the forward/reverse switch is
effective
NOTE: In case the forward/reverse lever is operated while traveling using the forward/reverse switch, input to the forward/reverse switch becomes ineffective,
and the vehicle body moves by operating
the forward/reverse lever. (Refer to the
Forward/Reverse Lever Priority Control)
Operation:
1. Forward/reverse selector switch is turned ON after
the forward/reverse lever and the forward/reverse
switch are positioned at neutral.
NOTE: Forward/reverse switch does not transmit
neutral signal. In case of no electric current
from the forward/reverse switch, the controller judges the switch as neutral (N).
2. Then the forward/reverse switch becomes effective, and the monitor unit lights the forward/reverse indicator of the monitor.
NOTE: In case the forward/reverse lever becomes
out of order, input to the forward/reverse
switch becomes ineffective, and the forward/reverse indicator is unlit and fixed.
Monitor
MC
ECM
Forward/Reverse Indicator
Monitor
Unit
F
F
N
N
OFF
R
R
ON
Forward/Reverse
Lever
Forward/Reverse
Switch
T2-1-47
Forward/Reverse
Selector Switch
T4GC-02-01-023
SYSTEM / Control System
Reverse Traveling Alarm Control
(Refer to the SYSTEM/Electric System)
Purpose: Sounding alarm buzzer when the forward/reverse lever or the forward/reverse
switch is selected
Operation:
1. When reverse of the forward/reverse lever or the
forward/reverse switch is selected, the MC earths
the terminal from the reverse light relay.
2. Reverse light relay is excited, and electric current
flows to the reverse light and the reverse buzzer.
Right
Reverse Light
Reverse Buzzer
MC
ECM
F
N
Monitor
Unit
Reverse Light
Relay
R
Forward/Reverse
Lever
or
Forward/Reverse
Switch
From Terminal #108
of Fuse Box A
T2-1-48
Left
Reverse Light
T4GC-02-01-024
SYSTEM / Control System
Parking Brake Alarm Control
Purpose: Lighting the parking brake alarm lamp on the
monitor unit during parking operation of the
brake
NOTE: Parking brake of the vehicle body is released if the pilot pressure flows in.
Operation:
NOTE: For operation circuit of the parking brake,
refer to the SYSTEM/Electric System.
1. When the parking brake switch is turned ON, the
MC confirms signal of the parking brake pressure
sensor.
2. At pressure below the set pressure, the MC
transmits signal to the monitor unit, and the parking brake alarm lamp is lit.
IMPORTANT: Be careful that in case the parking
brake pressure sensor is abnormal,
traveling is possible even if the
parking brake switch is ON and the
parking brake is at work because the
parking brake alarm lamp is fixed to
OFF (release).
Monitor
MC
ECM
Engine
Parking Brake
Alarm Lamp
Transmission
Parking Brake
Pressure Sensor
Monitor
Unit
Parking Brake
ON
Parking Brake
Solenoid Valve
OFF
Parking Brake Switch
T4GC-02-01-025
T2-1-49
SYSTEM / Control System
(Blank)
T2-1-50
SYSTEM / Control System
CONTROLS BY ELECTRICAL AND HYDRAULIC COMBINED CIRCUIT
Electrical and hydraulic combined circuit has the following controls.
•
•
•
•
•
Ride control (optional)
Bucket positioner control
Lift arm float control
Lift arm kick-out control
Lift arm auto-leveler upward control
(Optional)
• Lift arm auto-leveler downward control
(Optional)
T2-1-51
SYSTEM / Control System
Ride Control (Optional)
Purpose: Reducing fatigue of the operator by organizing a damper circuit in the lift arm cylinders and reducing shock in traveling
Operation:
1. When the ride control switch is turned ON, the MC
makes the ride control effective and the ride control indicator of the monitor is lit.
2. At vehicle speed of 7 km/h (4 mph) and above, the
MC receives signal from the vehicle speed sensor,
and transmits electric current to the ride control
solenoid valve.
3. When the ride control solenoid valve is operated
and the spool moves, a damper circuit is organized between the rod ends and the bottom ends of
the lift arm cylinder. When the vehicle travels on
bumpy roads, the fluctuation of the bottom pressure of the lift arm cylinders is absorbed by the
ride control accumulator, and the shock of the
whole vehicle body is reduced.
NOTE: Ride control is not made at the vehicle
speed of 7 km/h (4 mph) and below.
NOTE: In case the ride control switch or the ride
control solenoid valve becomes out of order,
the ride control is not made.
T2-1-52
SYSTEM / Control System
PHOTO
PHOTO
Right Console
013
Ride Control
099
Lift Arm Cylinder
MC
ECM
Engine
Monitor
Unit
Ride Control
Switch
To Control
Valve
Vehicle Speed Sensor
Ride Control
Accumulator
OFF
ON
Transmission
Ride Control
Indicator
Relief Valve
Ride Control Valve
Ride Control
Solenoid Valve
Spool
Pilot
Pump
Hydraulic Oil
Tank
T4GC-02-01-026
T2-1-53
SYSTEM / Control System
Bucket Auto-leveler Control (ZW220)
Purpose: Automatically tilting the bucket at an appropriate angle (horizontal) to start digging in
returning the bucket to the tilting position
Operation:
1. In dumping operation of the bucket, the bar is located in front of the bucket proximity switch.
While the bar passes by the bucket proximity
switch, the bucket proximity switch becomes ON,
and excites the electromagnet on the bucket tilting
end of the pilot valve.
2. When the bucket operation lever is moved farther
than the bucket tilting detent position (position to
move farther than the tilting position), the bucket
operation lever is retained by the electromagnet
on the bucket tilting end, and pressure oil from the
pilot valve moves the bucket spool of the control
valve.
3. Pressure oil from the main pump flows into the
bottom end of the bucket cylinder through the
bucket spool of the control valve, and extends the
bucket cylinder. When the bucket cylinder is extended, the bar also passes by the bucket proximity switch.
4. When the bar becomes distant from the bucket
proximity switch, the bucket proximity switch is
turned OFF, and the electromagnet on the bucket
tilting end is also turned OFF, which makes the
bucket operation lever in the neutral position. As
the bucket spool of the control valve also returns
to neutral, the bucket cylinder stops. As a result,
the bucket is tilted at the right digging angle
(horizontal).
T2-1-54
SYSTEM / Control System
PHOTO
Proximity Switch
Bucket Cylinder
From #194 Terminal
of Fuse Box B
092
Bar
Bucket Proximity Switch
093
Control Valve
Pilot Valve
for Bucket
Bucket
Electromagnet
on Bucket Tilting End
Pilot
Pump
Lift Arm
Main
Pump
T2-1-55
Hydraulic Oil
Tank
T4GB-02-01-013
SYSTEM / Control System
Bucket Auto-leveler Control (ZW250)
Purpose: Automatically tilting the bucket at an appropriate angle (horizontal) to start digging in
returning the bucket to the tilting position
Operation:
1. In dumping operation of the bucket, the bar is located in front of the bucket proximity switch.
While the bar passes by the bucket proximity
switch, the bucket proximity switch becomes ON,
and excites the electromagnet on the bucket tilting end of the pilot valve.
2. When the bucket operation lever is moved farther
than the bucket tilting detent position (position to
move farther than the tilting position), the bucket
operation lever is held by the electromagnet on
the bucket tilting end, and pressure oil from the
pilot valve moves the bucket spool of the control
valve.
3. Pressure oil from the main pump flows into the
bottom end of the bucket cylinder through the
bucket spool of the control valve, and extends the
buket cylinder. When the bucket cylinder is extended, the bar also passes by the bucket proximity switch.
4. When the bar becomes distant from the bucket
proximity switch, the bucket proximity switch is
turned OFF, and the electromagnet on the bucket
tilt end is also turned OFF, which makes the
bucket operation lever in the neutral position. As
the bucket spool of the control valve also returns
to neutral, the bucket cylinder stops. As a result,
the bucket is tilted at the right digging angle
(horizontal).
T2-1-56
SYSTEM / Control System
Bucket Cylinder
Bucket Proximity Switch
From #194 Terminal
of Fuse Box B
Bar
Control Valve
Pilot Valve
for Bucket
Electromagnet
on Bucket Tilting End
Bucket
Pilot
Pump
Lift Arm
Main
Pump
T2-1-57
Hydraulic Oil
Tank
T4GB-02-01-033
SYSTEM / Control System
Lift Arm Float Control (ZW220)
Purpose: Free raising and lowering of the lift arm in
response to the external load for snow removing and road cleaning
Operation:
1. When the lift arm operation lever is moved to the
floating position (farther position than the lift arm
lowering position), the lift arm operation lever is
retained by the electromagnet on the lift arm lowering end, and pressure oil from the pilot valve
moves the lift arm spool of the control valve up to
the floating position (farthest right position).
NOTE: When the engine is rotating, the electromagnet on the lift arm lowering end is always excited by the electric current from
#194 terminal of Fuse Box B.
2. Pressure oil from the main pump is blocked by the
lift arm spool, and ports on the rod ends and the
bottom ends of the lift arm cylinders are connected through the lift arm spool, leading to the
tank port. As the both ports of the lift arm cylinder
have the same pressure as the hydraulic oil tank,
the lift arm cylinders are not restricted, allowing
free movement of the lift arm depending on the
external force.
3. Lift arm operation lever returns to neutral, if pulled
more strongly than the magnetic force of the
electromagnet. As the lift arm spool of the control
valve also returns to neutral, the lift arm floating
control is released.
T2-1-58
SYSTEM / Control System
Lift Arm Cylinder
Bottom End
Port
Rod End
Port
Control Valve
From #194 Terminal
of Fuse Box B
Electromagnet
on Lift Arm Lowering End
Bucket
Pilot Valve
for Lift Arm
Lift Arm
Pilot
Pump
Main
Pump
T2-1-59
Hydraulic Oil
Tank
T4GB-02-01-014
SYSTEM / Control System
Lift Arm Float Control (ZW250)
Purpose: Free raising and lowering of the lift arm in
response to the external load for snow removing and road cleaning
Operation:
1. When the lift arm operation lever is moved to the
floating position (farther position than the lift arm
lowering position), the lift arm operation lever is
retained by the electromagnet on the lift arm lowering end, and pressure oil from the pilot valve
moves the lift arm spool of the control valve up to
the floating position (farthest left position).
NOTE: When the engine is rotating, the electromagnet on the lift arm lowering end is always excited by the electric current from
#194 terminal of Fuse Box B.
2. Pressure oil from the main pump is blocked by the
lift arm spool, and ports on the rod ends and the
bottom ends of the lift arm cylinders are connected through the lift arm spool, leading to the
tank port. As the both ports of the lift arm cylinders
have the same pressure as the hydraulic oil tank,
the lift arm cylinders are not restricted, allowing
free movement of the lift arm depending on the
external force.
3. Lift arm operation lever returns to neutral, if pulled
more strongly than the magnetic force of the
electromagnet. As the lift arm spool of the control
valve also returns to neutral, the lift arm floating
control is released.
T2-1-60
SYSTEM / Control System
Lift Arm Cylinder
Bottom End
Port
Rod End
Port
Control Valve
From #194 Terminal
of Fuse Box B
Electromagnet
on Lift Arm Lowering End
Bucket
Pilot Valve
for Lift Arm
Lift Arm
Pilot
Pump
Main
Pump
T2-1-61
Hydraulic Oil
Tank
T4GB-02-01-034
SYSTEM / Control System
Lift Arm Kick-out Control (ZW220)
Purpose: Automatically locating the lift arm at proper
height in returning the lift arm to the highest
position
Operation:
1. When lowering the lift arm, the plate is located in
front of the lift arm proximity switch.
While the plate passes by the lift arm proximity
switch, the lift arm proximity switch becomes ON,
and the electromagnet on the lift arm end is also
excited.
2. When the lift arm operation lever is moved farther
than the lift arm raising detent position (position to
pull farther than the raising position), the bucket
operation lever is retained by the electromagnet
on the lift arm raising end, and pressure oil from
the pilot valve moves the lift arm spool of the
control valve toward raising.
3. Pressure oil from the main pump flows into the
bottom ends of the lift arm cylinders through the
lift arm spool of the control valve, and extends the
lift arm cylinders. When the lift arm cylinders are
extended, the plate also passes by the lift arm
proximity switch.
4. When the plate becomes distant from the lift arm
proximity switch, the lift arm proximity switch is
turned OFF, and the electromagnet on the lift arm
raising end is also turned OFF, which makes the
lift arm operation lever in the neutral position. As
the lift arm spool of the control valve also returns
to neutral, the lift arm cylinders stop. As a result,
the lift arm stops.
T2-1-62
SYSTEM / Control System
Plate
Lift Arm
Proximity Switch
Lift Arm
Cylinder
Bottom End
Port
Rod End
Port
Control Valve
From #194 Terminal
of Fuse Box B
Bucket
Pilot Valve
for Lift Arm
Lift Arm
Pilot
Pump
Electromagnet
on Lift Arm Lowering End
Main
Pump
T2-1-63
Hydraulic Oil
Tank
T4GB-02-01-015
SYSTEM / Control System
Lift Arm Kick-out Control (ZW250)
Purpose: Automatically locating the lift arm at proper
height in returning the lift arm to the highest
position
Operation:
1. When lowering the lift arm, the plate is located in
front of the lift arm proximity switch.
While the plate passes by the lift arm proximity
switch, the lift arm proximity switch becomes ON,
and the electromagnet on the lift arm end is also
excited.
2. When the lift arm operation lever is moved farther
than the lift arm raising detent position (position to
pull farther than the raising position), the bucket
operation lever is retained by the electromagnet
on the lift arm raising end, and pressure oil from
the pilot valve moves the lift arm spool of the
control valve toward raising.
3. Pressure oil from the main pump flows into the
bottom ends of the lift cylinders through the lift
arm spool of the control valve, and extends the lift
arm cylinders. When the lift arm cylinder is extended, the plate also passes by the lift arm
proximity switch.
4. When the plate becomes distant from the lift arm
proximity switch, the lift arm proximity switch is
turned OFF, and the electromagnet on the lift arm
raising end is also turned OFF, which makes the
lift arm operation lever in the neutral position. As
the lift arm spool of the control valve also returns
to neutral, the lift arm cylinders stop. As a result,
the lift arm stops.
T2-1-64
SYSTEM / Control System
Plate
Lift Arm
Proximity Switch
Lift Arm
Cylinder
Bottom End
Port
Rod End
port
Control Valve
From #194 Terminal
Fuse Box B
Pilot Valve
for Lift Arm
Bucket
Electromagnet
for Lift Arm
End
Lift Arm
Pilot
Pump
Main
Pump
T2-1-65
Hydraulic Oil
Tank
T4GB-02-01-035
SYSTEM / Control System
Lift Arm Auto-leveler Upward Control (Optional)
(ZW220)
Purpose: Free locating of the lift arm between the
horizon and the highest position
Operation:
1. If the SET position of the lift arm auto-leveler
upward set switch is selected after the lift arm is
located within the allowable location of the lift arm
auto-leveler (a’ in the illustration), signal from the
lift arm angle sensor is memorized by the MC,
and that is the lift arm auto-leveler upward location.
NOTE: When the lift arm is outside a’, even if the
SET position of the lift arm auto-leveler
upward set switch is selected, setting of the
lift arm auto-leveler upward cannot be
made. In case setting was thus unsuccessful, or setting in a different position is
needed, make setting again with the above
in mind.
3. Pressure oil from the main pump flows into the
bottom end ports of the lift cylinder through the lift
arm spool of the control valve, and raises the lift
arm.
4. When the lift arm angle sensor moves up to the lift
arm auto-leveler upward locating position,
earthing of #241 terminal of the MC is released,
and the electromagnet on the lift arm upward end
is unexcited. Thus the lift arm operation lever returns to the neutral position, and supply of pressure oil from the pilot valve to the control valve is
stopped.
5. As the lift arm spool of the control valve also returns to neutral, the lift arm stops at the lift arm
auto-leveler upward stop position.
NOTE: Above the lift arm upward set position, the
electromagnet on the lift arm raising end is
always excited.
NOTE: In case the lift arm angle sensor becomes
out of order, the lift arm auto-leveler upward
control is not made.
a (Lift Arm Upward
Work Range)
a’ (Lift Arm
Auto-leveler
Up ward
Allowable Setting
Range)
Position of
Lift Arm Foot Pin
Position of
Lift Arm Tip Pin
IMPORTANT: In case either the lift arm angle
sensor or the MC has been replaced,
be sure to make learning control of
the lift arm angle sensor. (Refer to
the OPERATIONAL PERFORMANCE
TEST/Adjustment)
2. When the lift arm auto-leveler upward switch is
turned ON, #241 terminal of the MC is earthed,
and excites electromagnet on the lift arm upward
end of the pilot valve. When the lift arm operation
lever is moved to the lift arm upward detent position (position to pull further than the upward position), the lift arm operation lever is retained by the
electromagnet on the lift arm upward end, and
pressure oil is supplied to the control valve from
the pilot valve.
T2-1-66
SYSTEM / Control System
PHOTO
Lift Arm Auto-Leveler
100 101 102 103
Link
Lift Arm
Angle Sensor
Lift Arm
Cylinder
Bottom End
Port
Rod End
Port
Lift Arm
Auto-leveler
Upward Set Switch
Control Valve
OFF
SET
ON
234
238
MC
237
Bucket
241
Electromagnet
on Lift Arm Raising End
From #194 Terminal
of Fuse Box B
Lift Arm
Pilot Valve
for Lift Arm
Pilot
Pump
Main
Pump
T2-1-67
Hydraulic Oil
Tank
T4GB-02-01-016
SYSTEM / Control System
Lift Arm Auto-leveler Upward Control (Optional)
(ZW250)
Purpose: Free locating of the lift arm between the
horizon and the highest position
Operation:
1. If the SET position of the lift arm auto-leveler
upward set switch is selected after the lift arm is
located within the allowable location of the lift arm
auto-leveler (a’ in the illustration), signal from the
lift arm angle sensor is memorized by the MC,
and that is the lift arm auto-leveler upward location.
NOTE: When the lift arm is outside a’, even if the
SET position of the lift arm auto-leveler
upward set switch is selected, setting of the
lift arm auto-leveler upward cannot be
made. In case setting was thus unsuccessful, or setting in a different position is
needed, make setting again with the above
in mind.
3. Pressure oil from the main pump flows into the
bottom end port of the lift cylinder through the lift
arm spool of the control valve, and raises the lift
arm.
4. When the lift arm angle sensor moves up to the lift
arm auto-leveler upward locating position,
earthing of #241 terminal of the MC is released,
and the electromagnet on the lift arm upward end.
Thus the lift arm operation lever returns to the
neutral position, and supply of pressure oil from
the pilot valve to the control valve is stopped.
5. As the lift arm spool of the control valve also returns to neutral, the lift arm stops at the lift arm
auto-leveler upward stop position.
NOTE: Above the lift arm upward set position, the
electromagnet on the lift arm raising end is
always excited.
a (Lift Arm Upward
Work Range)
a’ (Lift Arm
Auto-leveler Upward
Allowable Setting
Range)
Position of
Lift Arm Foot Pin
Position of
Lift Arm Tip Pin
NOTE: In case the lift arm angle sensor becomes
out of order, the lift arm auto-leveler upward
control is not made.
IMPORTANT: In case either the lift arm angle
sensor or the MC has been replaced,
be sure to make learning control of
the lift arm angle sensor. (Refer to
the OPERATIONAL PERFORMANCE
TEST/Adjustment)
2. When the lift arm auto-leveler upward switch is
turned ON, #241 terminal of the MC is earthed,
and excites electromagnet on the lift arm upward
end of the pilot valve. When the lift arm operation
lever is moved farther than the lift arm upward
detent position (position to pull farther than the
upward position), the lift arm operation lever is
retained by the electromagnet on the lift arm upward end, and pressure oil is supplied to the control valve from the pilot valve.
T2-1-68
SYSTEM / Control System
Link
Lift Arm
Angle Sensor
Lift Arm
Cylinder
Bottom End
Port
Rod End
Port
Lift Arm
Auto-leveler
Upward Set Switch
OFF
SET
ON
Control Valve
234
238
MC
237
Bucket
241
Electromagnet
on Lift Arm Raising End
From #194 Terminal
of Fuse Box B
Lift Arm
Pilot Valve
for Lift Arm
Pilot
Pump
Main
Pump
T2-1-69
Hydraulic Oil
Tank
T4GB-02-01-036
SYSTEM / Control System
Lift Arm Auto-leveler Downward Control (Optional)(ZW220)
Purpose: Free locating of the lift arm between the horizon and the lowest position
Operation:
1. If the SET position of the lift arm auto-leveler
downward set switch is selected after the lift arm
is located within the allowable location of the lift
arm auto-leveler (b’ in the illustration), signal from
the lift arm angle sensor is memorized by the MC,
and that is the lift arm auto-leveler downward location.
NOTE: When the lift arm is outside b’, even if the
SET position of the lift arm auto-leveler
downward set switch is selected, setting of
the lift arm auto-leveler downward cannot
be made. In case setting was thus unsuccessful, or setting in a different position is
needed, make setting again with the above
in mind.
3. Pressure oil from the main pump flows into the
rod end ports of the lift arm cylinders through the
lift arm spool of the control valve, and lowers the
lift arm.
4. When the lift arm angle sensor moves down to the
lift arm auto-leveler downward locating position,
earthing of #242 terminal of the MC is released,
and the electromagnet on the lift arm downward
end is unexcited for a while until it is excited again
soon after.
5. Thus the lift arm operation lever returns to the
neutral position, and supply of pilot pressure from
the pilot valve to the control valve is stopped.
6. As the lift arm spool of the control valve also returns to neutral, the lift arm stops at the lift arm
auto-leveler downward stop position.
Position of
Lift Arm Tip Pin
Position of
Lift Arm Foot Pin
b’ (Lift Arm
Auto-leveler
Downward
Allowable Setting Range)
b (Lift Arm Downward
Work Range)
NOTE: In case the lift arm angle sensor becomes
out of order, the lift arm auto-leveler
downward control is not made.
IMPORTANT: In case either the lift arm angle
sensor or the MC has been replaced,
be sure to make learning control of
the lift arm angle sensor. (Refer to
the OPERATIONAL PERFORMANCE
TEST/Adjustment)
2. When the lift arm auto-leveler downward switch is
turned ON, #242 terminal of the MC is earthed,
and excites electromagnet on the lift arm downward end of the pilot valve. When the lift arm operation lever is moved to the lift arm downward
detent position (position farther than the downward position), the lift arm operation lever is retained by the electromagnet on the lift arm
downward end, and pressure oil is supplied to the
control valve from the pilot valve.
T2-1-70
SYSTEM / Control System
Link
Lift Arm
Angle Sensor
Lift Arm
Cylinder
Bottom End
Port
Rod End
Port
Lift Arm
Auto-leveler Downward
Set Switch
OFF
SET
ON
234
Control Valve
240
MC
239
242
Bucket
Electromagnet on
Lift Arm Lowering End
Pilot Valve
for Lift Arm
From #194 Terminal
of Fuse Box B
Lift Arm
Pilot
Pump
T4GB-02-01-017
T2-1-71
SYSTEM / Control System
Lift Arm Auto-leveler Downward Control (Optional)(ZW250)
Purpose: Free locating of the lift arm between the
horizon and the lowest position
Operation:
1. If the SET position of the lift arm auto-leveler
downward set switch is selected after the lift arm
is located within the allowable location of the lift
arm auto-leveler (b’ in the illustration), signal from
the lift arm angle sensor is memorized by the MC,
and that is the lift arm auto-leveler downward location.
NOTE: When the lift arm is outside b’, even if the
SET position of the lift arm auto-leveler
downward set switch is selected, setting of
the lift arm auto-leveler downward cannot
be made. In case setting was thus unsuccessful, or setting in a different position is
needed, make setting again with the above
in mind.
3. Pressure oil from the main pump flows into the
rod end ports of the lift arm cylinders through the
lift arm spool of the control valve, and lowers the
lift arm.
4. When the lift arm angle sensor moves down to the
lift arm auto-leveler downwards locating position,
earthing of #242 terminal of the MC is released,
and the electromagnet on the lift arm downward
end is unexcited for a while until it is excited again
soon after.
5. Thus the lift arm operation lever returns to the
neutral position, and supply of pilot pressure from
the pilot valve to the control valve is stopped.
6. As the lift arm spool of the control valve also returns to neutral, the lift arm stops at the lift arm
auto-leveler downward stop position.
Position of
Lift Arm Tip Pin
Position of
Lift Arm Foot Pin
b’ (Lift Arm
Auto-leveler
Downward
Allowable Setting Range)
b (Lift Arm Downward
Work Range)
NOTE: In case the lift arm angle sensor becomes
out of order, the lift arm auto-leveler
downward control is not made.
IMPORTANT: In case either the lift arm angle
sensor or the MC has been replaced,
be sure to make learning control of
the lift arm angle sensor. (Refer to
the OPERATIONAL PERFORMANCE
TEST/Adjustment)
2. When the lift arm auto-leveler downward switch is
turned ON, #242 terminal of the MC is earthed,
and excites electromagnet on the lift arm downward end of the pilot valve. When the lift arm operation lever is moved to the lift arm downward
detent position (position farther than the downward position), the lift arm operation lever is retained by the electromagnet on the lift arm
downward end, and pressure oil is supplied to the
control valve from the pilot valve.
T2-1-72
SYSTEM / Control System
Link
Lift Arm
Angle Sensor
Lift Arm
Cylinder
Bottom End
Port
Rod End
Port
Lift arm
Auto-leveler Downward
Set Switch
OFF
SET
ON
234
Control Valve
240
MC
239
242
Bucket
Electromagnet on
Lift Arm Lowering End
Pilot Valve
for Lift Arm
From #194 Terminal
of Fuse Box B
Pilot
Pump
Lift Arm
T4GB-02-01-037
T2-1-73
SYSTEM / Control System
(Blank)
T2-1-74
SYSTEM / ECM System
OUTLINE
• Supply pump is driven by engine and generates
Signals from sensors and MC (Main Controller) are
input to ECM (Engine Control Module).
ECM calculates and drives two way valve, suction
control valve and EGR motor in order to control supply
pump, injectors and EGR (Exhaust Gas Recirculation).
•
•
•
•
•
high pressure fuel.
• Common rail distributes high pressure fuel generated by supply pump to injector of each engine
cylinder.
• Injector injects high pressure fuel from common
rail.
Fuel Injection Control
Engine Start Control
EGR Control
Correction of Fuel Injection Volume
Engine Stop Control (Refer to System/Electric
System)
Crank Revolution Sensor
Cam Angle Sensor
Atmospheric Pressure Sensor
Fuel Temperature Sensor
Coolant Temperature Sensor
Inlet Air Temperature Sensor
Boost Pressure Sensor
Boost Temperature Sensor
Engine Oil Pressure Sensor
EGR Motor Position Sensor
EGR
EGR Motor
ECM
MC
Common Rail
Pressure Sensor
Two Way Valve
Suction Control
Valve
Common Rail
Supply Pump
Injector
Fuel Tank
T4GB-02-02-022
T2-2-1
SYSTEM / ECM System
FUEL INJECTION CONTROL
ECM monitors running state of engine according to
signals from each sensor and MC. ECM controls the
volume, pressure, timing and volume of fuel injection
PHOTO
PHOTO
Common Rail
045
046
Fuel Supply Pump
047
049
Crank Revolution Sensor
Control for Two Way Valve
• Fuel injection volume control
• Fuel injection (volume) timing
control
• Fuel injection Volume control
Control for Suction Control Valve
• Fuel injection pressure control
Cam Angle Sensor
Atmospheric Pressure Sensor
Fuel Temperature Sensor
Coolant Temperature Sensor
Inlet Air Temperature Sensor
Boost Pressure Sensor
Boost Temperature Sensor
Engine Oil Pressure Sensor
EGR Motor Position Sensor
EGR
EGR Motor
ECM
MC
Common Rail
Pressure Sensor
Two Way Valve
Suction Control
Valve
Common Rail
Supply Pump
Injector
Fuel Tank
T4GB-02-02-022
T2-2-2
SYSTEM / ECM System
(Blank)
T2-2-3
SYSTEM / ECM System
Fuel Injection Volume Control
Function: Controls fuel injection volume in order to be
optimum.
Operation:
1. ECM detects engine speed according to input
signals from crank revolution sensor and cam
angle sensor.
2. MC calculates target engine speed according to
input signals from sensors and switches. MC
sends signal to ECM. (Refer to System/Control
System.)
3. ECM turns two way valves in the injectors into ON
or OFF mainly according to the engine speed and
signal from MC in order to control fuel injection
volume.
NOTE: Mode switches of the work mode switch
are supplied with respectively different
voltages from the monitor unit. MC judges
the selected mode by the supplied voltage.
NOTE: Two switches are installed inside the shift
switch, and the turning ON condition varies
depending on the combination of speed
shifts. MC judges the selected speed shift
by the combination of two input currents.
T2-2-4
SYSTEM / ECM System
Accelerator
Pedal Sensor
Work Mode
Switch
Crank Revolution Sensor
Cam Angle Sensor
Accelerator
Pedal
Atmospheric Pressure Sensor
L
Fuel Temperature Sensor
N
Coolant Temperature Sensor
P
Inlet Air Temperature Sensor
Boost Pressure Sensor
Boost Temperature Sensor
Engine Oil Pressure Sensor
EGR Motor Position Sensor
EGR Motor
Shift Switch
MC
ECM
Common Rail
Pressure Sensor
Two Way
Valve
Monitor
Unit
Common
Rail
Supply Pump
Wheel Speed
Engine Coolant
Sensor
Temperature Sensor
Injector
Fuel Tank
T4GC-02-02-004
T2-2-5
SYSTEM / ECM System
Fuel Injection Pressure Control
Fuel Injection Timing Control
Function: Controls fuel injection pressure according
to fuel pressure in common rail.
Operation:
1. ECM calculates fuel injection volume according to
engine speed and target engine speed signal of
MC. (Refer to Page T2-2-4).
2. Common rail pressure sensor sends signal corresponding to pressure in common rail to ECM.
3. ECM calculates appropriate pressure in common
rail according to engine speed, fuel injection
volume and common rail pressure sensor signal.
ECM drives suction control valve in supply pump
and appropriate volume of fuel to common rail.
4. Fuel in common rail is supplied to each engine
cylinder through injector from common rail.
NOTE: Mode switches of the work mode switch
are supplied with respectively different
voltages from the monitor unit. MC judges
the selected mode by the supplied voltage.
Function: Calculates appropriate fuel injection timing.
Operation:
1. ECM calculates fuel injection timing according to
engine speed and fuel injection volume.
2. ECM drives ON/OFF of two way valves in injectors in order to control fuel injection timing.
Fuel Injection Volume Control
Function: Improves combustion inside the engine
cylinders.
Operation:
1. Injectors initially inject small amount of fuel (pilot
injection) for ignition.
2. Injectors execute the second injection (main injection) after ignition. ECM drives ON/OFF of two
way valves in injectors in order to control fuel injection timing and volume.
NOTE: Two switches are installed inside the shift
switch, and the turning ON condition varies
depending on the combination of speed
shifts. MC judges the selected speed shift
by the combination of two input currents.
T2-2-6
SYSTEM / ECM System
Accelerator
Pedal Sensor
Work Mode
Switch
Crank Revolution Sensor
Cam Angle Sensor
Accelerator
Pedal
Atmospheric Pressure Sensor
L
Fuel Temperature Sensor
N
Coolant Temperature Sensor
P
Inlet Air Temperature Sensor
Boost Pressure Sensor
Boost Temperature Sensor
Engine Oil Pressure Sensor
EGR Motor Position Sensor
EGR Motor
Shift Switch
MC
ECM
Common Rail
Pressure Sensor
Two Way
Valve
Suction
Control
Valve
Monitor
Unit
Common
Rail
Supply Pump
Wheel Speed
Sensor
Engine Coolant
Temperature Sensor
Injector
Fuel Tank
T4GC-02-02-005
T2-2-7
SYSTEM / ECM System
Fuel Injection
1. Fuel pressure is constantly applied to the injector
nozzles.
2. When the magnetic coil of the two-way valve is
turned ON, the valve is opened, and the
high-pressure fuel in the control chamber returns
to the fuel tank through Orifice 1.
3. Spring force raises the hydraulic piston, and the
nozzle is opened to start injection.
4. When the magnetic coil of the two-way valve is
turned OFF, the valve is closed, and the circuit
leading to the fuel tank is closed.
5. In this way, the control chamber is filled with
high-pressure fuel.
6. Difference of top and bottom pressure of the piston lowers the piston, and the nozzle is closed to
finish injection.
T2-2-8
SYSTEM / ECM System
1. Two Way Valve: ON
2. Fuel Injection Start
From ECM
From ECM
Magnetic Coil
Valve
From Common Rail
Two Way Valve
Two Way Valve
Return to Fuel
Tank
Return to Fuel
Tank
From Common
Rail
Orifice 1
Control Chamber
Hydraulic Piston
Spring
Spring
Nozzle
Nozzle
3. Two Way Valve: OFF
4. Fuel Injection Stop
From ECM
From ECM
Magnetic Coil
Two Way Valve
Two Way Valve
Valve
From Common Rail
From Common Rail
Control Chamber
Hydraulic Piston
Orifice 2
Nozzle
Nozzle
T1GR-02-02-012C
T2-2-9
SYSTEM / ECM System
COMPENSATION OF FUEL INJECTION
VOLUME
1. Atmosphere pressure sensor sends signal corresponding to atmospheric pressure to ECM.
2. ECM calculates atmospheric pressure according
to input signal. ECM controls two way valves in
injectors and corrects of fuel injection volume.
Atmospheric Pressure Sensor
ECM
Two Way
Valve
T1GR-02-02-002C
T2-2-10
SYSTEM / ECM System
ENGINE START CONTROL
Function: Controls energizing time of glow plugs by
coolant temperature and improves startability of engine.
Operation:
1. Coolant temperature sensor sends signal corresponding to coolant temperature to ECM.
2. ECM connects the ground circuit of glow relay
according to signals and controls energizing time
of glow plugs.
Coolant Temperature
Sensor
From Key Switch
Terminal M
ECM
Glow Relay
From Battery
Relay
Glow Plug
T2-2-11
T4GB-02-02-016
SYSTEM / ECM System
EGR (EXHAUST GAS RECIRCULATION)
CONTROL
Function: EGR controls lets part of exhaust gas recirculate inside intake manifold and mix it
with intake air. Consequently, the combustion temperature is lowered and generation
of nitrogen oxide (Nox) is reduced.
Operation:
• EGR Gas Amount Control
1. ECM determines amount of EGR gas according
to engine speed, fuel flow rate, coolant temperature, atmospheric pressure and intake air temperature.
2. ECM drives the EGR motor, and opens the EGR
valve. And transfer the EGR gas corresponding to
the engine condition to the intake manifold to be
mixed with the intake air.
3. At the same time, EGR motor position sensor
detects amount of opening of EGR valve.
• EGR Gas Coolant
EGR gas is cooled by coolant system located
along EGR gas passage.
By mixing the cooled EGR gas with the intake air,
the combustion temperature is lowered, and the
NOx is reduced in comparison with ordinary EGR
gas.
• Lead Valve
Lead valve prevents new air from entering into
EGR gas passage and reverse flow of EGR gas.
As EGR gas flows in one direction.
T2-2-12
SYSTEM / ECM System
To Intercooler
Exhaust Gas
EGR Gas
From Air Cleaner
Coolant Out
Coolant System
Engine
Coolant In
EGR Valve
Intake
Manifold
EGR Motor
Position Sensor
From Intercooler
EGR Motor
Lead Valve
Intake Air
ECM
T1GR-02-02-011
T2-2-13
SYSTEM / ECM System
(Blank)
T2-2-14
SYSTEM/Hydraulic System
OUTLINE
Hydraulic system is broadly divided into the main
circuit, pilot circuit, steering circuit, and hydraulic
drive fan circuit.
• Main Circuit
Main circuit consists of the priority valve circuit,
neutral circuit, single operation circuit, and
combined operation circuit – composed of the
main pump, priority valve, control valve, cylinders,
etc.
• Pilot Circuit
Pilot circuit consists of the charging block circuit,
front attachment operation control circuit, pump
control circuit, brake circuit, and ride control circuit
(optional) – composed of the pilot pump, charging
block and valves for controlling each circuit.
• Steering Circuit
Steering circuit consists of the normal steering
circuit,
steering
shock
damping
circuit,
emergency steering circuit (optional), steering
stop circuit– composed of the pump, priority valve,
steering valve, cylinders, and other valves.
• Hydraulic Drive Fan Circuit
Hydraulic drive fan circuit consists of the flow
control circuit and reverse rotation control circuit –
composed of the motor for radiator cooling fan
and the pump for radiator cooling fan.
NOTE: Steering circuit can be divided into the main
circuit and the pilot circuit, but is described
here as an single circuit for making
explanation clear.
T2-3-1
SYSTEM/Hydraulic System
MAIN CIRCUIT
Outline
• Main pump draws hydraulic oil from the hydraulic
oil tank through the suction filter and delivers.
• Delivered pressure oil flows to the steering valve
and the control valve through the priority valve.
• Pressure oil led to the steering valve flows to the
steering cylinders in response to operation of the
spool in the steering valve and the return oil flows
back to the hydraulic oil tank through the steering
valve.
• Pressure oil led to the control valve flows to the
cylinders in response to operation of the spool in
the control valve, and the return oil flows back to
the hydraulic oil tank through the control valve.
T2-3-2
SYSTEM/Hydraulic System
PHOTO
PHOTO
Hydraulic System
Main Control Valve
114
089
Bucket Cylinder
Steering Cylinders
Lift Arm Cylinders
Control Valve
Bucket
Spool
Steering
Valve
Lift Arm
Spool
Priority
Valve
Main Pump
Suction
Filter
Hydraulic oil
Tank
T4GB-02-02-010
T2-3-3
SYSTEM/Hydraulic System
Priority Valve Circuit
• With the engine stopped, the priority valve spool
• When pressure at Port LS2 and the spring force
is pushed leftward by the spring force.
When the engine is started, pressure oil from the
main pump flows toward the steering valve
through the priority valve spool, while also
entering Ports LS1 and LS2 through Orifices 1
and 2 respectively.
With the steering valve in neutral, pressure oil led
to Port LS2 flows to the hydraulic oil tank through
Orifice 3 and the steering valve spool, so Port LS2
is not pressurized.
As pressure at LS1 causes larger force than the
spring force, the priority valve spool moves right,
and pressure oil from the main pump is all
supplied to the control valve.
Priority valve spool is provided with a notch for
leading pressure oil from the main pump toward
the steering valve and a notch for leading
pressure oil from the main pump toward the
control valve, which are both connected to the
main pump delivery port constantly.
When the priority valve spool moves right, the
notch for leading pressure oil from the main pump
toward the steering valve moves until the delivery
port on the steering valve side in the priority valve
is closed. When pressure balance is obtained and
the spool stops moving.
When the steering valve spool moves, the tank
port connected with Port LS2 is closed.
At this time, Port LS2 is connected with the main
circuit through the steering valve spool, and
pressure corresponding to movement of the
steering valve spool arises at Port LS2.
overcome pressure at Port LS1, the priority valve
spool moves left.
• Larger the movement of the steering valve spool
is, the higher the pressure at Port LS2 rises, the
larger the priority valve spool moves left, and the
more pressure oil from the main pump is supplied
to the steering valve.
•
•
•
•
•
•
•
T2-3-4
NOTE: Orifice 2 of the priority valve is installed for
warming up the circuit by flowing pressure
oil to the hydraulic oil tank from Port LS2 at
neutral of the steering valve. Diameter of
Port 2 is small, and temperature of the oil
passing through it rises rapidly, but
pressure is not raised enough to influence
movement of the priority valve spool.
SYSTEM/Hydraulic System
Bucket Cylinder
Steering Cylinders
Lift Arm
Cylinders
Steering Valve
Control Valve
Hydraulic
Oil Tank
Bucket
Spool
Hydraulic
Oil Tank
Lift Arm
Hydraulic
Oil Tank
Priority
Valve
Spring
Orifice 2
Orifice 1
Orifice 3
LS1
Spool
LS2
At Stop of Engine
Main Pump
NOTE: Illustration shows oil flow in idling operation
while the engine is rotating. Control valve
illustrated is for ZW220.
T2-3-5
T4GB-02-02-011
SYSTEM/Hydraulic System
Neutral Circuit
• At neutral position of the control lever, pressure oil
from the main pump returns to the hydraulic oil
tank through the neutral circuit of the control
valve.
• Only when the steering valve spool moves
actuated by the priority valve, pressure oil is
supplied to the steering valve, the steering valve
is not provided with a neutral circuit. (Refer to
Priority Valve Circuit in this section.)
Single Operation Circuit
• Pressure oil from the main pump enters the
control valve, and flows to the lift arm and bucket
spools.
• When the steering valve spool moves, the priority
valve spool moves left, and pressure oil from the
main pump flows to the steering valve. (Refer to
Priority Valve Circuit in this section.)
T2-3-6
SYSTEM/Hydraulic System
Bucket Cylinder
Steering Cylinders
Lift Arm
Cylinders
Steering Valve
Control Valve
Bucket
Lift Arm
Priority
Valve
Main Pump
T4GB-02-02-017
NOTE: Illustration shows oil flow while the engine
is rotating in idling operation. Control valve
illustrated is for ZW220.
T2-3-7
SYSTEM/Hydraulic System
Combined Operation Circuit (ZW220)
· Lift Arm Raising/Bucket Dumping
• When the bucket is dumped with the lift arm
•
•
•
•
•
raised, pilot pressure shifts the lift arm and bucket
spools.
Pressure from the main pump is applied to Port
LS1 of the priority valve, but Port LS2 is not
pressurized because it is connected to the
hydraulic oil tank port.
Pressure at Port LS1 causes larger force than the
spring force of the priority valve, and moves the
spool right.
Therefore, pressure oil from the main pump flows
to the lift arm cylinders through the check valve in
the control valve and the lift arm spool, and raises
the lift arm.
Pressure oil from the main pump also flows to the
bucket cylinder through the check valve, orifice,
and bucket spool in the control valve, and dumps
the bucket.
Lift arm raising operation is more heavy loaded
than the bucket dumping operation, but pressure
oil passing the bucket operation circuit enters the
bucket cylinder after passing the check valve and
orifice, allowing smooth movement of both the lift
arm cylinders and the bucket cylinder.
T2-3-8
SYSTEM/Hydraulic System
Steering Cylinders
Bucket Cylinder
Lift Arm
Cylinders
Steering Valve
Control Valve
From
Pilot
Valve
(Bucket
Dump)
Bucket
Orifice
Hydraulic
Oil Tank
Lift Arm
From Pilot Valve
(Lift Arm Raise)
Check Valve
Hydraulic
Oil Tank
Priority
Valve
Spring
LS2
LS1
Spool
Main Pump
T4GB-02-02-012
T2-3-9
SYSTEM/Hydraulic System
· Lift Arm Raising/Steering Right
• When the steering wheel is turned right with the
lift arm raised, pilot pressure shifts the lift arm
spool in the control valve and the steering valve
spool.
• Pressure from the main pump is applied to Port
LS1 of the priority valve through Orifice 1, and
main pressure returning from the steering valve
spool through Orifice 3 and the spring force are
applied to Port LS2.
• Pressure at Port LS2 changes in proportion to the
steering valve spool stroke, and when pressure at
Port LS2 is low, the priority valve spool moves left
slightly, and when it is high, the spool moves left
drastically.
• Flow rate and direction of the main pump are
controlled by the leftward stroke of the priority
valve spool, and the flow rate corresponding to
the stroke flows to the steering valve, and the
remainder flow rate flows to the control valve.
NOTE: If the steering wheel is turned quickly and
largely for reasons of avoiding danger or
something, the priority valve spool largely
moves left, and much of the pressure oil
from the main pump is supplied to the
steering valve, delaying movement of the
front attachment.
• Pressure oil led to the steering valve flows to the
steering cylinders, and the vehicle body turns
right.
• Pressure oil led to the control valve also flows to
the lift arm cylinder though the check valve and
the lift arm spool, and raises the lift arm.
• In this way, steering and lift arm operations are
simultaneously made.
T2-3-10
SYSTEM/Hydraulic System
Bucket Cylinder
Steering Cylinders
Lift Arm
Cylinders
Steering Valve
Control Valve
Hydraulic
Oil Tank
From Steering
Pilot Valve
(Right Steering)
Bucket
Spool
Hydraulic
Oil Tank
From Pilot
Valve
(Lift Arm Raise)
Lift Arm
Check Valve
Hydraulic
Oil Tank
Priority Valve
Spring
Orifice 2
Orifice 1
Orifice 3
LS1
Spool
LS2
Main Pump
T4GB-02-02-013
T2-3-11
SYSTEM/Hydraulic System
Combined Operation Circuit (ZW250)
· Lift Arm Raising/Bucket Dumping
• When the bucket is dumped with the lift arm
•
•
•
•
•
•
•
•
raised, pilot pressure shifts the lift arm and bucket
spools in the control valve.
Also, the same pilot pressure that changed the lift
arm spool in the control valve shifts the selector
valve spool downward as well.
Pressure from the main pump is applied to Port
LS1 of the priority valve, but Port LS2 is not
pressurized because it is connected to the
hydraulic oil tank.
Pressure at Port LS1 causes larger force than the
spring force of the priority valve, and moves the
spool right.
By movement of the spool, pressure oil from the
main pump flows to the lift arm cylinders through
the check valve in the control valve and the lift
arm spool, and raises the lift arm.
Pressure oil from the main pump also flows to the
bucket cylinder though the flow rate control valve
in the control valve and the bucket spool, and
dumps the bucket.
Lift arm raising operation is heavier loaded than
the bucket dumping operation, but pressure
inside the spring chamber rises in the bucket
dumping operation because shift of the selector
valve is over.
Raised pressure in the spring chamber prevents
the flow rate control valve from moving much, and
flow of pressure oil to the bucket spool is
restricted.
As a result, flow rate to the lift arm cylinders is
secured, causing smooth operation of the lift arm
cylinders and bucket cylinder.
T2-3-12
SYSTEM/Hydraulic System
Steering Cylinders
Bucket Cylinder
Lift Arm
Cylinders
From Pilot Valve
(Bucket Damp)
Flow Rate
Spring
Control Valve Chamber
Steering Valve
Control Valve
Bucket
From Pilot Valve
(Lift Arm Raise)
Lift Arm
Selector Valve
From Pilot Valve
(Lift Arm Raise)
Priority
Valve
LS2
LS1
Main Pump
T4GB-02-02-018
T2-3-13
SYSTEM/Hydraulic System
· Lift Arm Raising/Steering right
• When the steering wheel is turned right with the
lift arm raised, pilot pressure shifts the lift arm
spool in the control valve and the steering valve
spool.
• Pressure from the main pump is applied to Port
LS1 of the priority valve through Orifice 1, and
main pressure returning from the steering valve
spool through Orifice 3 and the spring force are
applied to Port LS2.
• Pressure at Port LS2 changes in proportion to the
steering valve spool stroke, and when pressure at
Port LS2 is low, the priority valve spool moves left
slightly, and when it is high, the spool moves left
drastically.
• Flow rate and direction of the main pump are
controlled by the leftward stroke of the priority
valve spool, and the flow rate corresponding to
the stroke flows to the steering valve, and the
remainder flow rate flows to the control valve.
NOTE: When the steering wheel is turned quickly
and largely for reasons of avoiding danger
or something, the priority valve spool
largely moves left, and much of the
pressure oil from the main pump is
supplied to the steering valve, delaying
movement of the front attachment.
• Pressure oil led to the steering valve flows to the
steering cylinders, and the vehicle body turns
right.
• Pressure oil led to the control valve also flows to
the lift arm cylinders though the check valve and
the lift arm spool, and raises the lift arm.
• In this way, steering and lift arm operations are
simultaneously made.
T2-3-14
SYSTEM/Hydraulic System
Bucket Cylinder
Steering Cylinders
Lift Arm
Cylinders
Steering Valve
Control Valve
Hydraulic
Oil Tank
From Steering
Pilot Valve
(Right Steering)
Bucket
Spool
Hydraulic
Oil Tank
Lift Arm
From Pilot
Valve
(Left Arm
Raise)
Check Valve
Hydraulic
Oil Tank
Priority Valve
Spring
Orifice 2
Orifice 1
Orifice 3
LS1
Spool
LS2
Main Pump
T4GB-02-02-019
T2-3-15
SYSTEM/Hydraulic System
(Blank)
T2-3-16
SYSTEM/Hydraulic System
PILOT CIRCUIT
Outline:
Pressure oil from the pilot pump is used to operate the
circuit below.
• Charging Block Circuit
• Front Attachment Operation Control Circuit
• Pump Control Circuit
• Brake Circuit
• Ride Control Circuit (Optional)
Front Attachment
Control Circuit
Pilot Shutoff
Valve
Lift Arm Pilot
Valve
Bucket Pilot
Valve
Optional Pilot
Valve
Control Valve
Brake
Valve
Service
Brake
Brake Circuit
Parking
Brake
Main Pump
Regulator
Charging Block
Ride
Control
Solenoid
Valve
Spool
Pump Control Circuit
Ride Control Circuit
(Optional)
Ride Control Valve
Charging Block Circuit
Pilot
Filter
Pilot
Pump
Suction
Filter
Hydraulic
Oil
Tank
T4GC-02-02-001
T2-3-17
SYSTEM/Hydraulic System
Charging Block Circuit
• Charging block is installed for supplying pressure
oil from the pilot pump preferentially to the service
brake circuit, while distributing it to other pilot
circuits as well.
• When the engine is started, oil is delivered from
the pilot pump, and enters the charging block.
• At this time, when the amount of accumulated
pressure of the service brake accumulators is low,
the relief valve keeps closed.
• In this case, only pilot pressure is applied to Port
B of the priority valve, but both the pilot pressure
and the spring force are applied to Port A. So, the
priority valve moves right, restricting pressure oil
to flow further.
• Pressure oil from the pilot pump flows toward the
service brake circuit through the check valve, and
accumulates the service brake accumulators.
(to be continued to T2-3-20)
NOTE: Spring of the priority valve is so adjusted
that the valve is not completely closed.
Even in the minimum opening condition, a
certain amount of pressure oil is being
supplied to the circuits downstream.
T2-3-18
SYSTEM/Hydraulic System
PHOTO
PHOTO
Pedals
006
PHOTO
PHOTO
Charging Block
Service Brake
Parking Brake
073
105
113
Service Brake
Brake
Pedal
Front Brake
Service Brake
Accumulators
Brake
Valve
Rear Brake
Check
Valves
Relief Valve
B
Priority
Valve
A
Charging Block
Pilot Pump
NOTE: Illustration shows oil flow when the priority
valve is closed in response to pressure
decrease in the service brake circuit.
T2-3-19
T4GC-02-02-002
SYSTEM/Hydraulic System
• When the service accumulators are pressurized
•
•
•
•
•
•
•
•
to a certain amount, the relief valve opens, and
pressure is lost because Port A of the priority
valve is connected to the hydraulic oil tank.
Pressure at Port B of the priority valve causes
larger force than the spring force, and moves the
priority valve spool left. So, pressure oil from the
pilot pump is all supplied to the priority valve and
the circuits downstream.
Pressure oil from the priority valve is supplied
through each port to the respective pilot circuits.
When pressure in the pilot circuit rises higher than
a certain amount, the pilot relief valve opens, and
prevents components of the pilot circuit from
being damaged.
Pressure oil from Port PS1 passes the steering
pilot valve to be supplied for actuation of the
steering valve spool. (Refer to Steering Circuit.)
Pressure oil from Port X changes its flow in
response to the stroke of the pump torque
control solenoid valve which is controlled by the
signal from MC, and is used for controlling the
main pump regulator.
(Refer to Pump Control Circuit.)
Pressure oil from Port BR3 is supplied for parking
brake release pressure by operation of the
parking brake solenoid valve. (Refer to Parking
Brake Circuit)
Pressure oil from Port PS2 is supplied for
controlling the servo piston of the main pump
(Refer to Pump Control Circuit.) and the spool of
the ride control valve (Refer to Ride Control
Circuit.).
Pressure oil from Port PP enters each pilot valve
through the pilot shutoff valve, and is supplied to
the control valve for actuation of the spool. (Refer
to Front Attachment Operation Control Circuit.)
T2-3-20
SYSTEM/Hydraulic System
PHOTO
Bucket
Pilot Valve
Lift Arm
Pilot Valve
Spare Pilot
Valve (Optional)
Pilot Valve
018
Pilot Shutoff Valve
To Service Brake
Circuit
Service Brake
Accumulators
Priority Valve
Relief Valve
B
Pilot Pump
Pilot
Relief Valve
Hydraulic Oil Tank
PS1
A
Spring
X
Pump Torque Control
Solenoid Valve
BR3
PS2
Parking Brake
Pressure Sensor
Parking Brake
Solenoid Valve
PP
Charging Block
NOTE: Illustration shows the oil flow in neutral
condition of the pilot valve when the service
brake accumulators are pressurized, the
priority valve is open, and the pilot shutoff
valve is open.
T2-3-21
T4GB-02-02-020
SYSTEM/Hydraulic System
Front Attachment Operation Control Circuit
(ZW220)
• Pressure oil from the pilot pump flows the
•
•
•
•
charging block, and comes out of Port PP of the
charging block to be supplied to each pilot valve
through the pilot shutoff valve.
Priority valve of the charging block supplies
pressure oil preferentially to the service brake
circuit when pressure in the service brake
accumulators are lowered. (Refer to Charging
Block Circuit.)
Pilot shutoff valve is a manually operated type,
and is installed for prevention of accidents due to
mistaken operation by stopping suppy of pressure
oil to the pilot valve when it is closed.
By controlling each pilot valve, pressure oil from
the pilot pump shifts the control valve spools.
At both ends of the spool for the lift arm cylinders
of the control valve, slow-return valves are
installed for moderating sudden movement of the
spool.
T2-3-22
SYSTEM/Hydraulic System
Bucket
Pilot Valve
1
2
Lift Arm
Pilot Valve
3
4
Spare Pilot
Valve (Optional)
5
6
7
8
Control Valve
Pilot Shutoff
Valve
8
Spare 2
7
To Service Brake
Circuit
Service Brake
Accumulators
6
Priority Valve
2
Spare 1
5
Bucket
1
Pilot Pump
4
Slow-Return
Valves
Lift Arm
3
Main Pump
PP
T4GB-02-02-002
Charging Block
NOTE: Numeral of each port of the pilot valves and
the control valve shows the port to be
connected.
Illustration shows the oil flow in neutral
condition of the pilot valve when the service
brake accumulators are pressurized, the
priority valve is open, and the pilot shutoff
valve is open.
T2-3-23
SYSTEM/Hydraulic System
Front Attachment Operation Control Circuit
(ZW250)
• Pressure oil from the pilot pump flows the
•
•
•
•
charging block, and comes out of Port PP of the
charging block to be supplied to each pilot valve
through the pilot shutoff valve.
Priority valve of the charging block supplies
pressure oil preferentially to the service brake
circuit when pressure in the service brake
accumulators are lowered. (Refer to Charging
Block Circuit.)
Pilot shutoff valve is a manually operated type,
and is installed for prevention of accidents due to
mistaken operation by stopping suppy of pressure
oil to the pilot valve when it is closed.
By controlling each pilot valve, pressure oil from
the pilot pump shifts the control valve spool.
At both ends of the spool for the lift arm cylinders
of the control valve, slow-return valves are
installed for moderating sudden movement of the
spool.
T2-3-24
SYSTEM/Hydraulic System
Bucket
Pilot Valve
1
Lift Arm
Pilot Valve
2
3
4
Spare Pilot
Valve (Optional)
5
6
7
8
Control Valve
Pilot Shutoff Valve
8
Spare 2
7
To Service Brake
Circuit
Service Brake
Accumulators
6
Priority Valve
2
Spare 1
5
Bucket
1
Pilot Pump
4
Slow-Return
Valves
Lift Arm
3
Main Pump
PP
Charging Block
T4GB-02-02-021
NOTE: Numeral of each port of the pilot valves and
the control valve shows the port to be
connected.
Illustration shows the oil flow in neutral
condition of the pilot valve when the service
brake accumulators are pressurized, the
priority valve is open, and the pilot shutoff
valve is open.
T2-3-25
SYSTEM/Hydraulic System
Pump Control Circuit
(Refer to COMPONENT OPERATION / Pump
Device group)
· Pump Control by Servo Piston Control Pressure
• Servo piston control pressure (PS2) is supplied
from the charging block for actuation of the servo
piston of the main pump.
· Pump Flow Rate Control by Flow Rate Control
Pressure (Pi1/Pi2)
• Pressures upward and downward the orifice – Pi1
and Pi2 – of the pump flow rate control valve
installed at the farthest downstream of the control
valve neutral circuit are supplied to the main
pump regulator for adjusting the pump flow rate.
· Pump Flow Rate Control by Pump Torque Control
Solenoid Valve
• Signal from MC actuates the pump torque control
solenoid valve, and controls the pressure (X)
supplied to the main pump regulator for
controlling the pump flow rate.
T2-3-26
SYSTEM/Hydraulic System
PHOTO
Charging Block
Main Control Valve
090
Pilot Pump
Pump Torque Control
Solenoid Valve
Hydraulic Oil Tank
Command Signal from MC
Pilot Presser (X)
PS2
Pump From Control Valve
Orifice
Control Valve
Pi2
Pi1
Main Pump
Servo
Piston
Main Pump
Regulator
T4GB-02-02-003
NOTE: Control valve illustrated is for ZW220.
T2-3-27
SYSTEM/Hydraulic System
Brake Circuit
Service Brake Circuit
(Refer to COMPONENT OPERATION / Charging
Block)
(Refer to COMPONENT OPERATION / Brake
Valve)
• Pressure oil from the pilot pump flows through the
charging block, and is accumulated in the service
brake accumulators.
• By stepping the brake pedal, pressure in the
service brake accumulators is applied to the front
brake and the rear brake through the brake valve,
and actuates the service brake.
• When the brake pedal is stepped several times,
pressure inside the service brake accumulators is
lowered, and the relief valve is closed.
• Priority valve spool moves right, and pressure in
the service brake accumulators is kept constant
by preferentially supplying pressure oil from the
pilot pump to the service brake circuit, and firmly
brakes the vihicle.
Parking Brake Circuit
• Pressure oil from the pilot pump is applied to the
parking brake solenoid valve through the charging
block.
• When the parking brake is switched OFF, the
parking brake solenoid valve is excited, and
pressure oil entering the parking brake cylinder
releases the parking brake.
• If the parking barke is switched ON, the parking
brake solenoid valve is unexcited, and resultant
stop of pressure oil supply to the parking brake
causes working of the parking brake.
• Even if pressure is lowered caused by damage of
hose or something in the upstream of the solenoid
valve, the parking brake accumulators so function
as to retain the parking brake circuit pressure for
a certain period of time.
NOTE: Spring of the priority valve is so adjusted
that the valve is not completely closed.
Even in the minimum opening condition, a
certain amount of pressure oil flow is being
supplied to the circuits downstream.
NOTE: Even when the engine is stopped, the
service brake circuit pressure is retained
for a while with the functions of the service
brake accumulators and the check valve.
T2-3-28
NOTE: Parking brake is released when the
solenoid valve is excited.
SYSTEM/Hydraulic System
PHOTO
PHOTO
Parking Brake
Service Brake
112
067
Service Brake
Brake
Pedal
Front Brake
Service Brake
Accumulators
Brake
Valve
Rear Brake
Check
Valves
Relief Valve
Priority
Valve
Spring
Parking Brake
Pressure Sensor
Parking
Brake
Solenoid
Valve
Parking Brake
Release
Pilot
Accumulator
Brake
Charging Block
Pilot Pump
NOTE: Illustration shows oil flow when the relief
valve and the priority valve are open in
response to pressure increase in the
service brake circuit, and also oil flow when
the parking brake is working with the
unexcitement of the parking brake solenoid
valve.
T2-3-29
T4GC-02-02-003
SYSTEM/Hydraulic System
Ride Control Circuit (Optional)
(Refer to SYSTEM / Electric-Hydraulic Combined
Circuit Control in Control System)
• In front attachment operation, operating pressure
for the lift arm cylinders is accumulated in the ride
control accumulator through the charge cut spool.
• When the ride control switch is turned ON, the
ride control solenoid valve is excited, and the
spool moves downward.
• Bottom ends of the lift arm cylinders are
connected with the ride control accumulator, while
the rods side ends of the lift arm cylinders are
connected to the hydraulic oil tank.
• In this way, force to lower the front attachment is
relieved to the hydraulic oil tank, and force to
lower the front attachment is absorbed by the ride
control accumulator, thus enabling stable
traveling.
T2-3-30
SYSTEM/Hydraulic System
PHOTO
Ride Control
099
Ride Control
Accumulator
Lift Arm Cylinders
To Control
Valve
Ride Control Valve
Ride Control
Command Signal
Ride Control
Solenoid Valve
Spool
Charge Cut
Spool
Hydraulic Oil Tank
Pilot
Pump
NOTE: Illustration shows oil flow when the ride
control solenoid valve is excited.
T2-3-31
T4GB-02-02-009
SYSTEM/Hydraulic System
STEERING CIRCUIT
Normal Steering Circuit
• Normally pressure oil from the main pump flows
to the steering valve through the priority valve, but
is not pressurized because the pilot line (LS2) is
led to the hydraulic oil tank.
• Therefore, pressure oil is all supplied to the
control valve because the priority valve spool is
shifted to the right pushed by pressure (LS1) from
the main pump large enough to overcome the
spring force of the priority valve.
• When the steering wheel is turned, the spool in
the steering pilot valve is shifted, and pressure oil
from the pilot pump moves the steering valve
spool.
• When the steering wheel is quickly turned, a large
amount of pilot pressure oil is supplied in a short
period of time to the end of the steering valve
spool through the steering pilot valve, and the
steering valve spool moves quickly and largely.
• When the steering wheel is slowly turned, a small
amount of pilot pressure oil is supplied gradually
to the end of the steering valve spool through the
steering pilot valve, and the steering valve spool
moves slowly and slightly.
• In proportion to the stroke of the steering valve
spool, pressure in the pilot line (LS2) rises, and
the priority valve spool is pushed left by the spring
force of the priority valve and pressure of the pilot
line (LS2).
• In this way, pressure oil from the main pump flows
to the steering cylinders through the priority valve
and the steering valve, and the steering cylinders
are
actuated.
(Refer
to
COMPONENT
OPERATION / Pump Device)
T2-3-32
NOTE: When pressure oil passes inside the
steering pilot valve, it flows to the steering
valve after passing the Gerotor part.
Gerotor is connected with the middle shaft
of the pilot steering valve, so powered
steering effect is generated. (Refer to
COMPONENT OPERATION / Steering
Pilot Valve)
SYSTEM/Hydraulic System
PHOTO
Steering Cylinders
Steering System
076 077 078 079
Steering
Accumulators
Steering Valve
Spool
Orifice
Orifice
Pump
Discharge Pressure
Switch
Steering
Pilot
Valve
To Control
Valve
Gerotor
Priority
Valve
Emergency
Steering
Pump Equipment
LS2
Steering
Wheel
LS1
Pilot
Pump
Main Pump
NOTE: Illustration shows flow of pressure oil when
the steering wheel is turned right.
T2-3-33
T4GB-02-02-023
SYSTEM/Hydraulic System
Steering Shock Damping Circuit
• Pressure of the pressure oil supplied from the
steering pilot valve to the spool end of the
steering valve is reduced by passing through the
orifice inside the steering valve, and is applied to
the spool end of the opposite side. In this way, the
vehicle shock due to sudden shift of the spool is
damped, and stable steering operation is possible.
(Refer to COMPONENT OPERATION / Steering
Valve)
• Steering accumulators are provided for damping
the joggling of the vehicle taking place at stop of
the steering wheel rotation.
Emergency Steering Circuit (Optional)
• When traveling, if the main pump delivery is
stopped or drastically decreased caused by
failure of the engine or the main pump, the signal
of the pump delivery pressure switch is
transmitted into the monitor controller, and the
monitor controller starts the motor of the
emergency steering pump equipment.
• Pressure oil is supplied from the emergency
steering pump for 1 minute, makes steering
operation possible.
• When 1 minute have passed or when the key
switch has been turned OFF after moving the
vehicle to a safe place, the emergency steering
pump stops supplying oil flow to the steering
valve..
T2-3-34
SYSTEM/Hydraulic System
Steering Cylinders
Steering
Accumulators
Steering Valve
Orifice
Orifice
Pump
Delivery Pressure
Switch
Steering
Pilot
Valve
To Control
Valve
Gerotor
Priority
Valve
Emergency
Steering
Pump Delivery
Pressure Sensor
Emergency
Steering
Pump Equipment
LS2
Steering
Wheel
LS1
Pilot
Pump
Main Pump
NOTE: Illustration shows flow of pressure oil when
the steering wheel is turned right.
T2-3-35
T4GB-02-02-023
SYSTEM/Hydraulic System
Steering Stop Circuit
(Refer to COMPONET OPERATION / Steering
Valve)
• When either of the left or right cylinder is at the
• As a result, the steering valve spool is shifted at
stroke end, the stop valve spool contacts the
frame, and the stop valve closes to block
pressure oil from being supplied to the steering
valve from the steering pilot valve.
neutral, and supply of pressure oil from the main
pump to the steering cylinders is stopped.
Steering Cylinders
PHOTO
Steering System
077
Steering Valve
Spool
Stop
Valve
Stop
Valve
External Force
Applied
Steering
Pilot Valve
Main Pump
Pilot Pump
Hydraulic
Oil Tank
T4GB-02-02-00
NOTE: Illustration shows flow of oil when the
steering valve is turned right.
T2-3-36
SYSTEM/Hydraulic System
(Blank)
T2-3-37
SYSTEM/Hydraulic System
HYDRAULIC DRIVE FAN CIRCUIT
(Refer to COMPONET OPERATION / Others)
(Refer to COMPONET OPERATION / Hydraulic Fan
Motor)
• Pressure oil from the fan pump flows to the fan
•
•
•
•
•
•
motor for radiator cooling through the flow control
valve and the reverse rotation spool.
Electric current corresponding to the oil
temperature is sent from MC to the flow control
solenoid valve.
Pressure oil is supplied to the flow control valve
spool end in response to the stroke of the flow
control solenoid valve, when it is excited.
When the flow control valve is operated, pressure
oil from the fan pump to the fan motor is restricted,
and speed of the fan motor is controlled.
When the fan reversing rotation switch is turned
ON, electric current flows from MC to the reverse
rotation control solenoid valve.
When the reverse rotation control solenoid valve
is operated, pressure oil is supplied to the reverse
rotation spool end.
When the reverse rotation spool is shifted, the
inlet port of pressure oil supplied to the fan motor
is shifted, and the fan motor rotates reversely.
T2-3-38
SYSTEM/Hydraulic System
PHOTO
Fan Motor
Cooling Fan
039
Reverse Rotation Spool
Reverse Rotation Control
Solenoid Valve
Reverse Rotation
Signal from MC
Flow Control Valve
Flow Control Solenoid Valve
Hydraulic oil
Tank
Hydraulic oil
Tank
Fan Pump
Flow Adjustment
Signal from MC
NOTE: Illustration shows flow of pressure oil
controlling nothing.
T2-3-39
T4GB-02-02-008
SYSTEM/Hydraulic System
(Blank)
T2-3-40
SYSTEM/Electric System
OUTLINE
Electrical circuits can largely be divided into the main
circuit parts, lamplight circuits and control circuits.
· Main Circuits
Circuit for engine start/stop, circuit for battery
charging, and circuit for accessories.
· Lamplight Circuits
Circuit for use in traveling (composed of head lights,
turn signals, brake lights, and horn)
· Control Circuits (Refer to the SYSTEM/Control
System.)
Control circuit for engine, pumps, transmission, and
valves [composed of actuators like solenoid valves,
MC (main controller), ECM (engine control module),
ICF (information controller), monitor unit, switches,
sensors, and pressure switches]
In this chapter, functions and compositions of the main
circuits and lamplight circuits are explained.
T2-4-1
SYSTEM/Electric System
MAIN CIRCUIT
• Electrical Power Circuit: for supplying electricity to
the electric system as power source
• Indicator Light Check Circuit: for checking monitor
warning lamps and indicators
• Accessory Circuit: for working at ACC of the key
switch
• Preheat Circuit: for assisting engine start in chilly
weather
• Starting Circuit: for starting engine
• Charging Circuit: for supplying electricity to the
battery and replenishing electricity
• Surge Voltage Prevention Circuit: for preventing
occurrence of surge voltage at stop of the engine
• Engine Stop Circuit: for stopping the engine by
the ECM
T2-4-2
SYSTEM/Electric System
ELECTRICAL POWER
SWITCH:OFF)
CIRCUIT
(KEY
Ground terminal of the battery is earthed to the base
machine. Electrical current from the plus positive flows
as follows at OFF of the key switch.
®
Even at OFF of the key switch, very small amount of
electrical current is being supplied to the circuit, so the
ground terminal of the battery needs to be
disconnected in case of a long downtime.
#6 Terminal
Key Switch
Head Light Switch
Battery
¯
Fusible
Link
® Fuse Box B
®
#11 Terminal
Flasher Relay
®
#9 Terminal
Load Dump Relay
®
#2 Terminal
GPS
ICF
MC
Optional Control Unit (Optional)
®
#7 Terminal
ECM Relay
®
#37 Terminal
Interior Light
Radio
MC
®
®
#381 Terminal
#711 Terminal
Optional Control Unit (Optional)
Monitor Unit
Head Light Switch
Key Switch
Fuse Box B
348
149
126
6
11
9
35
158
127
2
7
39
42
37
381
711
Fusible
Link
Battery
Relay
638
34
263
70
710
75
Battery
T4GC-02-04--001
T2-4-3
SYSTEM/Electric System
INDICATOR LIGHT CHECK CIRCUIT (KEY
SWITCH:ON)
• When the key switch is turned ON, Terminal B is
• Monitor unit checks warning lamps and indicators
connected inside the key switch to ACC and
Terminal M.
• Electrical current from Terminal M of the key
switch is enters #67 Terminal of the monitor unit.
by lighting them, and also starts the liquid crystal
display.
Key Switch
Fuse Box B
348
149
577
327
222
323
6
11
9
35
158
127
2
838
711
75
148
126
638
34
263
Monitor Unit
67
Fusible
Link
Battery
Relay
Battery
T4GB-02-03-002
T2-4-4
SYSTEM/Electric System
ACCESSORY CIRCUIT
• At ACC of the key switch, Terminal B is connected
inside the key switch to Terminal ACC.
• Electrical current from Terminal ACC of the key
switch enters #3 Terminal of the radio through #34
and #35 Terminals of Fuse Box B, enabling the
radio to work.
Key Switch
Fuse Box B
Radio
Fusible
Link
348
149
577
327
222
323
6
11
9
35
158
127
2
838
711
75
Battery
Relay
148
126
638
34
Battery
T4GB-02-03-003
T2-4-5
SYSTEM/Electric System
PREHEAT CIRCUIT (KEY SWITCH:ON)
• When the key switch is turned ON, Terminal B is
connected inside the key switch to Terminal M.
• Part of the electrical current from Terminal M
•
•
•
•
•
•
flows to the glow relay, and the remainder excites
the battery relay through #54 and #55 Terminals
of Fuse Box A, and the battery power source
supplies electricity to the glow relay through the
fuse (100A).
Electrical current from #55 Terminal of Fuse Box A
also enters #56 Terminal of ECM, and the
preheating circuit of the ECM is started.
Signal corresponding to the coolant temperature
is being transmitted from the coolant temperature
sensor to #283 Terminal of the ECM.
ECM earths #60 Terminal, and controls the
excitement time of the glow relay if the coolant
temperature is below a set temperature.
While the glow relay is being excited, electricity
from the power source is supplied to the glow plug
from the glow relay, and so preheating is made.
While preheating is being made, as #233 Terminal
of the ECM is earthed, electricity flows from #233
Terminal of the monitor unit to #233 terminal of
the ECM, and the monitor unit lights the glow
signal.
In case preheating is not made, the glow signal is
lit for two seconds for checking of indicator lights.
NOTE: In case preheating has been made,
preheating continues for a certain period of
time even after the engine start
(after-heating), but the glow signal is not lit.
T2-4-6
SYSTEM/Electric System
PHOTO
Fusiable Links
Key Switch
032
Fuse Box A
264
362
692
157
From #6 Terminal
of Fuse Box B
55
163
693
108
54
12
99
698
699
700
697
79
Glow Relay
Monitor
Unit
。
Glow
Signal
Glow Plug
233
Coolant Temperature
Sensor
Fuse
(100A)
60
56
283
284
233
Battery
Relay
Fusible
Link
To #638 Terminal of
Fuse Box B
ECM
Battery
T4GB-02-03-004
NOTE: Illustration shows flow of electricity in case
preheating is being made with the glow
relay excited and glow plug supplied with
electricity from the power source.
T2-4-7
SYSTEM/Electric System
STARTING
START)
CIRCUIT
(KEY
SWITCH:
Forward/Reverse Lever at Neutral Position
Operation of Starter Relay
• At START of the key switch, Terminal B is
• At START of the key switch, continuity is made
connected inside the key switch to Terminals M
and ST.
Electric current from Terminal M excites the
battery relay through #54 and #55 Terminals of
Fuse Box A, so electricity from the battery power
source is led from the battery relay to Terminals B
of the starter motor and the starter relay.
Electric current from Terminal ST of the key switch
flows through the neutral relay to Terminal S of
the starter relay and the coil inside.
Starter relay is turned ON, and electric current
also flows to Terminal S of the starter from
Terminal C of the starter relay.
As a result, the relay inside the starter is turned
ON, and the starter motor rotates.
Also, the electric current from Terminal M of the
key switch flows to all the controllers as a signal
for notifying the key position at ON or START.
between Terminals B and ST of the key switch,
and electric current flows to the base of Transistor
Q2 through Resistance R4 inside the starter relay.
Transistor Q2 is turned ON, and electric current
flows to Coil L of the relay.
As a result, Terminals B and S of the starter are
connected, and the starter operates.
• When the engine is started, the alternator begins
charging, and the voltage of Terminal R of the
starter relay raises.
• If this voltage reaches 21 – 22 V, Zener Diode Z is
turned ON. As a result, Transistor Q1 is turned ON,
and Transistor Q2 is turning OFF because no
electric current flows to its base.
At this moment, continuity between Terminals B
and S of the starter is lost, and the starter is
turned OFF.
• C1 shown in the illustration below indicates a
condenser for stabilizing working voltage.
D4 is a diode for protection from reverse
connection of the battery.
•
•
•
•
•
Starter Relay
B
S
D3
(1)
R3
R2
From Terminal L
of Alternator
Z
R
L
R4
D2
Q1
C1
C
C
(2)
(1)
S
Q2
M
B
(2)
Starter
E
D4
B
ST
Key Switch
Neutral Relay
12V
Battery
12V
T4GB-02-03-019
T2-4-8
SYSTEM/Electric System
Key Switch
264
Fuse Box A
362
692
From #6 Terminal
of Fuse Box B
Signal of Key ON
to (Monitor Unit)
Signal of Key ON to
(MC, ECM, and ICX)
157
464
55
163
693
108
12
54
79
99
699
700
697
No Forward/Reverse Signal
Neutral Relay
To #638 Terminal
of Fuse Box B
Fuse
(100A)
Starter
Relay
Fusible
Link
Battery
Relay
Battery
Starter
Motor
Alternator
T4GC-02-04--002
T2-4-9
SYSTEM/Electric System
Forward/Reverse Lever at Operational Position
· Starting Safety Circuit (Neutral Relay)
• At START of the key switch, Terminal B can be
•
•
•
•
•
connected inside the key switch to Terminals M
and ST.
Electric current from Terminal ST of the key switch
flows to the neutral relay, and the electric current
from Terminal M of the key switch flows to the
Terminals #54 and #55 of Fuse Box A then excites
the battery relay.
By exciting the battery relay, electricity from the
battery power source flows to Terminals B of the
starter motor and the starter relay.
At this moment, either of the forward-reverse
lever and the forward-reverse switch is at forward
or reverse, the neutral relay is excited.
Circuit between the neutral relay and Terminal S
of the starter relay is blocked by excites the
neutral relay.
Therefore, in case either of the forward-reverse
lever and the forward-reverse switch is at forward
or reverse, the starter motor is not operated even
if the key switch is at START.
T2-4-10
SYSTEM/Electric System
Key Switch
Fuse Box A
264
362
692
157
210
From #6 Terminal
of Fuse Box B
464
55
163
693
108
12
54
79
99
698
699
700
Forward/Reverse
Operation Signal
697
Neutral Relay
To #638 Terminal
of Fuse Box B
Fuse
(100A)
Starter
Relay
Fusible
Link
Battery
Relay
Battery
Starter
Motor
T4GB-02-03-006
T2-4-11
SYSTEM/Electric System
CHARGING CIRCUIT (KEY SWITCH:ON)
• Engine starts, and the key switch returns to ON
•
•
•
•
automatically by releasing fingers away from the
key switch.
At ON, Terminal B is connected inside the key
switch to ACC and Terminal M.
Electric current from Terminal M of the key switch
excites the battery relay through #54 and #55
Terminals of Fuse Box A.
When the engine rotates, the alternator begins to
generate electricity, and the electric current from
Terminal B of the alternator flows to the battery
through the battery relay, charging the battery.
In the mean time, the electric current from
Terminal L of the alternator flows to #119 Terminal
of the monitor unit to have the monitor unit turn off
the alternator indicator, and also flows to #594
Terminal of the ICF and #592 Terminal of the GPS
to record history data of the engine operation
time.
T2-4-12
SYSTEM/Electric System
PHOTO
Alternator
Key Switch
034
Fuse Box A
264
362
692
From #6 Terminal
of Fuse Box B
Alternator
Indicator
Monitor
Unit
592
GPS
119
594
ICX
157
464
55
163
693
108
12
144
133
121
696
695
698
699
700
54
79
99
120
674
697
To #638 Terminal
of Fuse Box B
Fuse
(100A)
Starter
Relay
Fusible
Link
Battery
Relay
Battery
Starter
Motor
T4GB-02-03-007
Alternator
T2-4-13
SYSTEM/Electric System
Operation of Alternator
• Alternator consists of Field Coil FC, Stator Coil SC,
• At first, electric current is not flowing to Field Coil
Diode D, and others.
Regulator consists of Transistors T1 and T2, Zener
Diode ZD, Resistances R1 and R2, and others.
Terminal B of the alternator is connected to Base
B of Transistor T1 as follows.
B - R - RF - (R) - R1 - Base B of Transistor T1
At On of the battery relay, the battery voltage
works on Base B of Transistor T1 of the regulator,
and continuity is made between Collector C and
Emitter E. In other words, the earth end of Field
Coil FC is grounded through Transistor T1.
FC. When the rotor rotates, alternating voltage is
generated in Stator Coil SC by the remanent
magnetism of the rotor itself.
• Electric current flows to Field Coil FC, and further
magnetizes the rotor, resulting in rise of electric
generation voltage. This further raises electric
generation voltage, and charging the battery
begins.
•
•
•
•
Alternator
B
Battery Relay
R
L
RF
(R)
Regulator
R3
R4
R5
R6
D
ZD
R2
Battery
B
SC
E
R1
FC
C
T2
B
D1
(F)
G
C
E
T1
(G)
T157-04-02-008C
T2-4-14
SYSTEM/Electric System
Operation of Regulator
• As electric generation voltage rises higher than
• If voltage working on Zener Diode ZD lowers
the set voltage of Zener Diode ZD, electric current
flows to Base B of Transistor T2, and continuity is
made between Connector C and Emitter E.
• Operation of Transistor T2 stops flow of the
electric current to Base B of Transistor T1, and
turns T1 OFF.
• Electric current stops flowing to Field Coil FC, and
electric generation voltage of Stator Coil SC
lowers.
below the set voltage, Transistor T2 is turned OFF,
and Transistor T1 is turned ON again.
• Electric current flows to Field Coil FC, and electric
generation voltage of Stator Coil SC is raised.
• Electric generation voltage of the alternator is
kept constant by repeating the above operations.
RF
Battery Relay
R3
R4
R5
R6
Battery
ZD
R2
B
SC
A
E
C
FC
R1
(F)
G
D1
B
C
T2
E
T1
(G)
T157-04-02-009
T2-4-15
SYSTEM/Electric System
SURGE VOLTAGE PREVENTION CIRCUIT
• When the engine is stopped (key switch: OFF),
•
•
•
•
•
the electric current from Terminal M of the key
switch is stopped, and the battery relay is turned
OFF.
Even if the key switch is turned off, the engine
does not stop immediately keeping freewheeling,
and the alternator continues generation of
electricity.
As the generated electric current does not flow to
the battery, surge voltage (voltage rise) is
generated, resulting in causes for failures of
electronic equipment like the controller and other
parts. For this reason, the surge voltage
protection circuit is provided.
During charging, the electric generation current
from Terminal L of the alternator enters #119
Terminal of the monitor unit. Monitor unit earths
#33 Terminal to the ground.
Electric current flows to the excitement circuit of
the load dump relay, and the load dump relay
works.
Therefore, even if the key switch is turned OFF
during rotation of the engine, the electric current
from the battery keeps exciting the battery relay
through the load dump relay. Also, the battery
relay is turned OFF about ten seconds after the
alternator stops generation of electricity.
T2-4-16
SYSTEM/Electric System
Key Switch
Load Dump
Relay
33
Monitor
Unit
119
Fuse Box B
348
149
577
327
222
323
6
11
9
35
158
127
2
838
7
39
42
37
381
711
70
148
126
638
34
263
710
75
Fuse
(100A)
Starter
Relay
Fusible
Link
Battery
Relay
Battery
Starter
Motor
T4GB-02-03-008
Alternator
T2-4-17
SYSTEM/Electric System
ENGINE STOP CIRCUIT
• When the key switch is turned OFF from ON, the
• ECM unexcited the fuel injection solenoid valve,
electric current flowing from Terminal M to #56
Terminal of the ECM to show the key switch at ON
is stopped.
and the engine is stopped.
Key Switch
Fuse Box A
264
362
692
210
From #6 Terminal
of Fuse Box B
157
54
55
163
80
108
12
79
99
698
699
700
697
To #638 Terminal
of Fuse Box B
Fuel Injection
Solenoid Valve
56
Fuse
(100A)
Fusible
Link
Battery
Relay
ECM
Battery
T4GB-02-03-009
T2-4-18
SYSTEM/Electric System
LAMPLIGHT CIRCUIT
• Head Light Circuit: for turning on and off head
lights, clearance lights and license light.
• Turn Signal Circuit: for turning on and off turn
signals
• Brake Light Circuit: for turning on and off brake
lights
• Hazard Light Circuit: for turning on and off hazard
light indicators
• Horn Circuit: for sounding horn
• Reverse Light/Buzzer Circuit: for turning on and
off reverse lights and reverse buzzer
• Parking Brake Circuit: for working and releasing
parking brake
• Emergency Steering Check Circuit (Optional): for
confirming operation of emergency steering pump
unit
T2-4-19
SYSTEM/Electric System
HEAD LIGHT CIRCUIT
Clearance and License Light Circuit
• Terminal B of the key switch is directly connected
to the head light switch.
• When the head light switch is positioned at
(Clearance Lights), part of the electricity from the
S terminal of the head light switch enters #47
Terminal of the monitor unit, and the illumination
light of the monitor unit is lit.
• Remainder of the electricity from the S terminal of
the head light switch enters #710 Terminal of
Fuse Box B, and further divided to #39 and #42
Terminals.
• Electricity from the power source coming out of
#39 Terminal of Fuse Box B lights front left and
rear left clearance lights.
• Electricity from the power source coming out of
#42 Terminal of Fuse Box B lights the license light
and the front right and rear right clearance lights.
T2-4-20
SYSTEM/Electric System
Head Light Switch
Key Switch
Fuse Box A
Illumination
Light
264
362
692
210
124
135
47
Monitor
Unit
157
123
55
63
163
54
121
696
695
698
699
700
120
Front Right
Clearance Light
694
697
Fuse Box B
838
348
149
577
Rear Right
Clearance Light
126
6
11
9
35
158
127
2
License
Light
638
34
263
7
39
42
37
381
711
70
710
75
Rear Left
Clearance Light
Fusible
Link
Front Left
Clearance Light
Battery
Battery Relay
T2-4-21
T4GB-02-03-010
SYSTEM/Electric System
Head Light Lighting Circuit
• When the key switch is turned ON, the electricity
•
•
•
•
•
•
from the power source coming out of Terminal M
of the key switch excites the battery relay through
#54 and #55 Terminals of Fuse Box A, and the
electricity from the battery power source flows to
Fuse Box A and Fuse Box B.
Electricity from the battery power source coming
out of #124 Terminal of Fuse Box A enters the
right head light relay.
Electricity from the battery power source coming
out of #121 Terminal of Fuse Box A enters the left
head light relay.
Electricity from the battery power source coming
out of #127 Terminal of Fuse Box B enters the
high beam relay.
When the head light switch is positioned at
(Head Lights), the electricity from the power
source coming out of Terminal S lights each of the
clearance lights (Refer to Clearance Light
Lighting Circuit.), and the electricity from the
power source coming out of Terminal H flows to
the high-low beam switch.
At this moment, if the high-low beam switch is
turned to Lo (Low Beam), the electricity from the
power source enters the right head light relay and
the left head light relay, and the electricity from
the battery power source enters the head lights to
light them by exciting the respective relays.
If the high-low beam switch is turned to Hi (High
Beam), the electricity from the power source
excites the high-beam relay, and the electricity
from the battery power source enters and lights
the high-beam lights. Electricity from the power
source coming out of the high-low beam switch
also enters #130 Terminal of the monitor unit, and
lights the high-beam indicators.
T2-4-22
SYSTEM/Electric System
Head Light Switch
High-Low Beam Switch
Key Switch
Lo
Hi
Fuse Box A
Monitor
Unit
High-Beam
Indicator
High-Beam Right Head Light Left Head Light
Relay
Relay
Relay
130
264
362
692
210
124
135
157
123
55
63
163
54
121
696
695
698
699
700
120
694
697
Fuse Box B
348
149
577
838
Right High-Beam Light
126
6
11
9
35
158
127
2
Right Head Light
638
34
263
7
39
42
37
381
711
Left High-Beam Light
Left Head Light
70
710
75
Fusible
Link
Battery
Battery Relay
T2-4-23
T4GB-02-03-018
SYSTEM/Electric System
TURN SIGNAL CIRCUIT
• Electricity from the battery power source also
• Electricity from the power source coming out of
flows to the flasher relay coming out of #11
Terminal of Fuse Box B.
• In case the turn signal switch is turned to left (L),
Terminal L of the turn signal switch is earthed, and
the left turn signal relay is excited.
the flasher relay enters the front and rear left turn
signal lights and #23 Terminal of the monitor unit
through the left turn signal relay.
• As a result, front and rear left turn signal lights
and the left turn signal indicators flicker.
Turn Signal Switch
Left
Turn Signal
Monitor
Unit
Right
Turn Signal
Key Switch
Left
Right
Turn Signal Relay Turn Signal
Relay
23
26
Rear Right
Turn Signal Light
Flasher
Relay
Fuse Box B
348
149
577
327
222
323
6
11
9
35
158
127
2
838
711
75
148
126
638
34
Front Right
Turn Signal
Rear Left
Turn Signal
Fusible
Link
Battery Relay
Front Left
Turn Signal
Battery
T4GB-02-03-011
T2-4-24
SYSTEM/Electric System
BRAKE LIGHT CIRCUIT
• When the key switch is turned ON, the electricity
• When the brake pedal is stepped, the brake light
from the power source coming out of Terminal M
of the key switch excites the battery relay, and the
electricity from the battery power source enters
#99 Terminal of Fuse Box A and the brake light
relay through #12 Terminal.
switch is earthed.
• As a result, the brake light relay is excited, and
the electricity from the battery power source
enters the brake lights, and light them.
Key Switch
PHOTO
Pedals
007
From #6 Terminal
of Fuse Box B
Brake Light Relay
Brake Pedal
Fuse Box A
264
362
692
210
124
135
Brake Light Switch
55
163
693
108
12
144
133
121
696
695
698
699
700
Right Brake Light
157
123
54
79
99
120
694
697
Left Brake Light
Fusible
Link
Battery
Relay
Battery
To #638 Terminal
of Fuse Box B
T4GB-02-03-012
T2-4-25
SYSTEM/Electric System
HAZARD LIGHT CIRCUIT
• Electricity from the battery power source also
• Electricity from the power source coming out of
flows to the flasher relay coming out of #11
Terminal of Fuse Box B.
• In case the hazard switch is turned ON, the
hazard switch is earthed, and the left and right
turn signal relays are excited.
the flasher relay enters all of the front and rear left
and right turn signal lights and #23 and #26
Terminals of the monitor unit through the left and
right turn signal relays.
• As a result, all of the front and rear left and right
turn signal lights and the left and right turn signal
indicators flicker.
Turn Signal Switch
Left
Turn signal
Right
Turn signal
Monitor
Unit
Diode
A
Diode
C
Diode
B
Diode
D
Left Turn
Signal Relay
Right Turn
Signal Relay
23
26
Rear Right
Turn Signal Light
Front Right
Turn Signal Light
Hazard
Switch
Flasher
Relay
Key Switch
Fuse Box B
348
149
577
327
222
323
6
11
9
35
158
127
2
838
7
39
42
37
381
711
70
148
126
638
34
263
710
75
Rear Left
Turn Signal Light
Fusible
Link
Battery Relay
Front Left
Turn Signal Light
Battery
T4GB-02-03-013
T2-4-26
SYSTEM/Electric System
HORN CIRCUIT
• When the key switch is turned ON, the electricity
from the power source coming out of Terminal M
excites the battery relay through #54 and #55
Terminals of Fuse Box A, and the electricity from
the battery power source enters #120 Terminal of
Fuse Box A and the horn relay through #133
Terminal.
• Horn switch is earthed when pushed.
• As a result, the horn relay is excited, and the
electricity from the battery power source enters
the horn, and the horn sounds.
Key Switch
From #6 Terminal
of Fuse Box B
Fuse Box A
264
362
692
210
124
135
Horn Relay
Horn
Switch
55
163
693
108
12
144
133
121
696
695
698
699
700
Horn
157
123
54
79
99
120
694
697
Battery
Relay
Fusible
Link
Battery
To #638 Terminal
of Fuse Box B
T4GB-02-03-014
T2-4-27
SYSTEM/Electric System
REVERSE LIGHT/BUZZER CIRCUIT
• When the key switch is turned ON, the electricity
from the power source coming out of Terminal M
excites the battery relay through #54 and #55
Terminals of Fuse Box A.
• Electricity from the battery power source enters
#99 Terminal of Fuse Box A, and enters the
reverse light relay through #108 Terminal.
• When the forward-reverse lever is turned to
reverse, Terminal R is earthed, and the MC earths
#109 Terminal because the electricity from the
power source flows to the forward-reverse lever
through #84 Terminal of the MC.
• As a result, the reverse light relay is excited, and
the electricity from the battery power source flows
to the reverse light and the reverse buzzer.
T2-4-28
SYSTEM/Electric System
Forward/Reverse Lever
Key Switch
From #6 Terminal
of Fuse Box B
Fuse Box A
MC
84
264
362
692
210
124
135
Reverse
Light
Relay
157
123
54
55
163
693
108
12
144
133
121
696
695
698
699
700
109
Right Reverse Light
79
99
120
694
697
Reverse Buzzer
Left Reverse Light
Fusible
Link
Battery
Relay
Battery
To #638 Terminal
of Fuse Box B
T4GC-02-04-003
T2-4-29
SYSTEM/Electric System
PARKING BRAKE CIRCUIT
• When the key switch is turned ON, the electricity
• However, as a self-exciting circuit is formed in
from the power source coming out of Terminal M
excites the battery relay through #54 and #55
Terminals of Fuse Box A.
Electricity from the power source enters #79
Terminal of Fuse Box A and Parking Brake Relay
1 through #163 Terminal of Fuse Box A.
Electricity from the power source coming out of
Terminal D of Parking Brake Relay 1 through
Terminal B of Parking Brake Relay 1 flows to
Terminal B of Parking Brake Relay 2 and Terminal
B of the parking brake switch.
Parking brake switch is composed of three circuits
of ON, NEUTRAL, and OFF, and so constructed
as to remain at ON when turned ON, but to
automatically return to NEUTRAL when turned
OFF.
When the parking brake switch is turned OFF,
electric current flows from Terminal E of the
parking brake switch to Terminal A of Parking
Brake 2 and the parking brake solenoid valve.
At this moment, if the engine is not running,
Parking Brake Relay 1 is excited because #684
Terminal of the monitor unit is earthed.
Therefore, the parking brake cannot be released
because the electricity from the power source
having been supplied through Parking Brake 1 to
Terminal B of the parking brake switch and
Terminal B of the parking brake relay is blocked.
In case the engine is running, Parking Brake
Relay 2 is excited because the electric current
from Terminal L of the alternator enters #119
Terminal of the monitor unit, releasing earthing of
#684 Terminal of the monitor unit.
As a result, a circuit in which electricity flows from
Terminal C of Parking Brake Relay 2 to Terminal A
of Parking Brake Relay 2 (self-exciting circuit) is
formed, and the parking brake solenoid valve
works, releasing the parking brake.
As the parking brake switch automatically returns
to neutral, the circuit from Terminal E of the
parking brake switch to Parking Brake Relay 2 is
blocked.
Parking Brake Relay 2, electric current keeps
flowing to the parking brake solenoid valve,
keeping the released condition of the parking
brake until the key switch is turned OFF or the
parking brake switch is turned ON.
•
•
•
•
•
•
•
•
•
IMPORTANT: Parking brake cannot be released
unless the engine is running.
T2-4-30
• When the parking brake switch is turned ON,
Terminal A of the parking brake switch is earthed,
and Parking Brake Relay 1 is excited.
• Electricity from the power source having been
supplied to Terminal B of Parking Brake Relay 2
and Terminal B of Parking Brake Switch through
Terminal D of Parking Brake Relay 2 is blocked.
• As a result, the parking brake works because
Parking Brake Relay 2 and the parking brake
solenoid valve are unexcited.
SYSTEM/Electric System
PHOTO
Cab
Key Switch
005
From #163Terminal
of Fuse Box A
From #6 terminal
of Fuse Box B
684
Monitor Unit
119
From Terminal L
of Alternator
NEUTRAL
Parking Brake
Switch
スイッチ
Parking Brake Parking Brake
Relay 2
Relay 1
OFF
AB
E F GH
A B CD E
A B CD E
684
Monitor Unit
119
To #638 Terminal
of Fuse Box B
Fuse
(100A)
157
123
54
55
163
693
108
12
144
133
121
696
695
698
699
700
(W hen forming a self-exciting circuit)
ON
Fuse Box A
264
362
692
210
124
135
Battery
Relay
79
99
120
694
697
Battery
Parking Brake
Solenoid Valve
From Terminal L
of Alternator
T4GB-02-03-016
NOTE: Illustration shows flow of electric current
when the parking brake switch remains
pushed after the parking brake switch has
been turned OFF during rotation of the
engine.
T2-4-31
SYSTEM/Electric System
EMERGENCY STEERING CHECK CIRCUIT
(OPTIONAL)
(Manual Check Circuit)
• When the key switch is turned ON, the electric
current from Terminal M the battery relay, and the
electricity from the power source enters the
emergency steering relay through #323 terminal
of Fuse Box B, and also enters Terminal B of the
emergency steering pump unit.
• When the emergency steering check switch is
turned ON, electric current flows to #179 Terminal
of the monitor unit.
• At the same time, as the monitor unit excites #180
Terminal, the emergency steering relay is excited.
• Electricity from the power unit enters Terminal C
of the emergency steering pump unit through the
emergency steering relay, exciting Terminal B,
and the emergency steering pump unit is started.
IMPORTANT: Emergency steering pump unit is
not so designed as to be operated
for a long time. When its operation
has been confirmed, turn the
emergency steering check switch
OFF by stopping pushing the switch.
(Auto Check Circuit)
• When the engine is started by turning the key
switch to the ST position, the alternator starts
generating electricity.
• When part of the electricity generation signal from
Terminal L of the alternator enters the monitor unit,
and rises to the predetermined voltage, Terminal
#180 is earthed, and the emergency steering
relay is excited.
• Electricity from the power unit enters Terminal C
of the emergency steering pump unit through the
emergency steering relay, exciting Terminal B,
and the emergency steering pump unit is started.
• The emergency steering pump unit works for
several seconds, and then the earthed circuit of
Terminal #180 is automatically cancelled and the
emergency steering pump unit stops.
• In case hydraulic oil higher than the
predetermined value has been being delivered
during operation of the emergency steering pump
unit, the emergency steering pump delivery
pressure switch is turned OFF, and the automatic
inspection operation is stopped normally.
• In case hydraulic oil higher than the
predetermined value has not been being
delivered, the emergency steering pump delivery
pressure switch remains ON, and the emergency
steering operation warning lamp on the monitor
unit flickers to notify abnormality of the
emergency steering pump unit.
T2-4-32
SYSTEM/Electric System
PHOTO
Emergency Steering
081
Key Switch
Fuse Box A
264
362
692
210
124
135
464
55
163
80
108
12
157
123
54
79
120
Emergency
Steering
Check Switch
Emergency
Steering
Relay
694
695
698
699
700
697
Fuse Box B
348
149
577
327
222
323
6
11
9
35
158
Emergency
Steering
Pump Delivery
Pressure Sensor
119
179
180
Emergency
Steering
Pump Unit
838
148
126
638
710
381
711
Monitor
Unit
75
Battery Relay
Fuse
(100A)
Battery
Alternator
T4GB-02-03-020
T2-4-33
SYSTEM/Electric System
(Blank)
T2-4-34
SECTION 3
COMPONENT OPERATION
Group 1 Pump Device
CONTENTS
Group 5 Steering Valve
Outline ...................................................... T3-1-1
Outline ...................................................... T3-5-1
Main Pump ............................................... T3-1-2
Operation .................................................. T3-5-4
Regulator.................................................. T3-1-4
Steering Overload Relief Valve ................. T3-5-8
Priority Valve .......................................... T3-1-18
Pilot Pump,Pump Delivery
Pressure Switch .................................. T3-1-19
Steering Main Relief Valve...................... T3-1-20
Group 2 Control Valve
Group 6 Pilot Valve
Outline (Two Lever Type Pilot Valve for
Front Attachment) ................................... T3-6-1
Operation .................................................. T3-6-2
Electromagnetic Detent............................. T3-6-6
Outline ...................................................... T3-2-1
Outline (Joystick Type Pilot Valve for
Hydraulic Circuit ..................................... T3-2-14
Front Attachment) ................................... T3-6-7
Main Relief Valve.................................... T3-2-22
Operation .................................................. T3-6-8
Overload Relief Valve ............................. T3-2-26
Electromagnetic Detent........................... T3-6-12
Restriction Valve..................................... T3-2-31
Outline (Lever Type Pilot Valve for
Negative Control Valve ........................... T3-2-32
Additional Circuit) (Optional) ................. T3-6-13
Flow Rate Control Valve ......................... T3-2-34
Operation ................................................ T3-6-14
Outline (Joystick Type Pilot Valve for
Group 3 Hydraulic Fan Motor
Outline ...................................................... T3-3-1
Operation ................................................. T3-3-4
Additional Circuit) (Optional) ................... T3-6-17
Operation ................................................ T3-6-18
Flow Control Valve.................................... T3-3-6
Reverse Control Valve .............................. T3-3-8
Fun Pump ............................................... T3-3-10
Group 4 Pilot Valve
Outline ...................................................... T3-4-1
Construction ............................................. T3-4-2
Operation ................................................. T3-4-3
4GBT-3-1
Group 7 Charging Block
Group 11 Brake Valve
Outline .....................................................T3-7-1
Outline ................................................... T3-11-1
Priority Valve ............................................T3-7-6
Operation ............................................... T3-11-4
Pilot Relief Valve ......................................T3-7-7
Pump Torque Control Proportional
Solenoid Valve .......................................T3-7-8
Group 12 Others
Pilot Shutoff Valve ..................................T3-12-1
Propeller Shaft .......................................T3-12-2
Service Brake Accumulator,
Pilot Accumulator ...................................T3-7-9
Emergency Steering Check Block ...........T3-12-3
Parking Brake Solenoid Valve ................T3-7-10
Emergency Steering Pump (Optional) .....T3-12-4
Service Brake Pressure Sensor..............T3-7-12
Parking Brake Pressure Sensor .............T3-7-12
Group 8 Ride Control Valve
Outline .....................................................T3-8-1
Operation .................................................T3-8-4
Charge Cut Spool .....................................T3-8-6
Over Load Relief Valve .............................T3-8-8
Ride Control Accumlator .........................T3-8-10
Drain Plug .............................................. T3-8-11
Group 9 Drive Unit
Outline .....................................................T3-9-1
Torque Converter .....................................T3-9-2
Transmission............................................T3-9-4
Transmisson Regulator Valve .................T3-9-26
Transmission Control Valve ....................T3-9-28
Manual Spool (Emergency Travel
Spool ....................................................T3-9-36
Proportional Solenoid Valve....................T3-9-38
Group 10 Axle
Outline ...................................................T3-10-1
Differential..............................................T3-10-2
Torque Proportioning Differential (TPD) ..T3-10-6
Limited Slip Differential (LSD) ................T3-10-8
Service Brake....................................... T3-10-10
Final Drivel Axle Shaft .......................... T3-10-12
4GCT-3-2
COMPONENT OPERATION / Pump Device
OUTLINE
Pump device has a main pump (1) and a pilot pump (2),
and main pump (1) has a built-in priority valve (6).
Driving force of the engine is transmitted to the shaft
(3) through the transmission input shaft, and actuates
main pump (1) and pilot pump (2).
Main pump (1) is a swash-plate type variable displacement axial plunger pump.
Pilot pump (2) is a gear pump.
Pump delivery pressure switch (4) is provided for controlling the main pump.
PHOTO
1
2
Hydraulic System
114
5
6
3
4
T4GB-03-01-001C
1 - Main Pump
3 - Shaft
5-
2 - Pilot Pump
4 - Pump Delivery Pressure
Switch
6-
T3-1-1
Steering Main Relief
Valve
Priority Valve
COMPONENT OPERATION / Pump Device
MAIN PUMP
Main pump supplies pressure oil for operating the cylinders and other hydraulic components. Also, the pump
is provided with a regulator for controlling the delivery
flow.
Shaft (5) is connected with the cylinder block (1), and
shaft (5) and cylinder block (1) corotate.
1
2
When cylinder block (1) rotates, plungers (2) reciprocate inside the cylinder block because of the tilting of
swash plate (4), and delivers the hydraulic oil.
Control of the main pump delivery is made by changing
the tilting angle of swash plate (4) with servo piston 1
(3) and servo piston 2 (6) which increase or decrease
the stroke of plungers (2).
3
4
5
6
8
7
T4GB-03-01-002C
1 - Cylinder Block
2 - Plunger
34-
Servo Piston 1 (2 pieces)
Swash Plate
56-
T3-1-2
Shaft
Servo Piston 2
78-
Feed Back Lever
Link
COMPONENT OPERATION / Pump Device
Increase and Decrease Operations of Delivery
Flow
Tilting angle variation of swash plate (4) is made by
the movement of servo piston 1 (3) and servo piston
2 (6).
Movement of the servo pistons is controlled by the
regulator. Also, the feed back of the swash plate
movement is given to the regulator by feed back lever
(7) and link (8).
7
8
6
3
4
NOTE: Refer to the following pages for operation of
the regulator.
• Tilting Change Operation
Tilting center of the swash plate is located at A in the
drawings right.
Pilot pressure is always applied to servo piston 2 (6).
Therefore, when the circuit of servo piston 1’s (3) is
connected to the hydraulic oil tank, swash plate (4)
tilts clockwisw around A.
Conversely, as there are two servo piston 1’s (3),
when pilot pressure is applied to both of servo piston
1’s (3) and servo piston 2, the swash plate (4) tilts
counterclockwise around A.
T4GB-03-01-022C
A
Minimum Tilting
6
3
4
• Feed Back Operation
End of feed back lever (7) is inserted into the boss
on the side face of the swash plate (4). When swash
plate (4) tilts, the boss also moves, and feed back
lever (7) moves together.
For example, if swash plate (4) tilts to the maximum
tilting position from the minimum tilting position, the
center of feed back lever (7) moves from B to C.
This movement of feed back lever (7) moves link (8),
and feed back is given to the regulator.
Housing
Maximum Tilting
8
7
T4GB-03-01-023
A
4
Boss
Housing
C
T3-1-3
B
T4GB-03-01-024
COMPONENT OPERATION / Pump Device
REGULATOR
Regulator controls flow of the main pump, receiving
various kinds of signal pressure.
The regulator includes the spring (1), sleeve 1 (2),
sleeve 2 (7), spool 1 (3), spool 2 (6), piston (4), load
piston (5), inner spring (8), and outer spring (9).
Regulator opens and closes the circuit leading to servo
piston 1 (10) by receiving various kinds of signal
pressure, and controls delivery flow of the pump by
varying the tilting angle of swash plate (11).
NOTE: Pilot primary pressure (Pg) is always applied to Servo Piston 2 (12).
3
2
Pi1
T
Air
Vent
1
4
Pi2
Pg
ST
T
Pd1
T
5
7
6
10
8、9
Large
Small
Tilting Angle
12
T4GB-03-01-006C
Pd1 - Pump Delivery Pressure
(Self Delivery Pressure)
ST - Pump Torque Control
Pressure
TReturn Line to Hydraulic
Oil Tank
T3-1-4
Pi1 - Pump Control Pressure 1
Pi2 - Pump Control Pressure 2
Pg - Pilot Primary Pressure
(From Pilot Pump)
COMPONENT OPERATION / Pump Device
2
5
4
3
6
7
10
4 - Piston
5 - Load Piston
6 - Spool 2
8
9
11
T4GB-03-01-007C
12
1 - Spring
2 - Sleeve 1
3 - Spool 1
1
7 - Sleeve 2
8 - Inner Spring
9 - Outer Spring
T3-1-5
10 - Servo Piston 1(2 pieces)
11 - Swash Plate
12 - Servo Piston 2
COMPONENT OPERATION / Pump Device
Control Function of Regulator
Regulator has the following three control functions.
• Control by Pump Control Pressure
Pump flow control valve inside the control valve
controls the pump control pressure (Pi1 - Pi2) in
response to the operating stroke of the control lever.
By receiving this pump control pressure (Pi1 - Pi2),
the regulator increases or decreases the pump delivery flow in response to the pressure.
When the control lever is operated, pump control
pressure (Pi1 - Pi2) lowers, and the regulator increases the pump delivery flow. If the control lever is
returned to neutral, pump control pressure (Pi1 Pi2) rises, and the regulator decreases the pump
delivery flow.
Flow (Q)
0
Pump Control Pressure (Pi1-Pi2)
• Control by Pump Delivery Pressure (Self Delivery
Pressure)
Pump Delivery Pressure (Self Delivery Pressure)
Pd1 enters the regulator. In case this pump pressure
exceeds the set P - Q line, the pump delivery flow is
decreased to return the pressure to the P - Q line.
Flow (Q)
Pressure Increase
Flow Decrease
• Control by Pilot Pressure from Torque Control Solenoid Valve
MC (Main Controller) makes arithmetic operations of
the operating conditions of the vehicle body, and
transmits signals to the pump torque control solenoid valve to obtain needed pump torque.
Pump torque control solenoid valve transmits Pump
Torque Control Pressure ST corresponding to this
signal to the regulator. Regulator, receiving the pilot
pressure, decreases the pump delivery flow.
0
Flow (Q)
0
T3-1-6
Pressure (P)
Pressure (P)
COMPONENT OPERATION / Pump Device
(Blank)
T3-1-7
COMPONENT OPERATION / Pump Device
Control by Pump Control Pressure
Flow Decrease
1. When the control lever stroke is reduced, pressure difference arising before and after the flow
control valve (difference between pressure Pi1
and Pi2) in the control valve is enlarged.
2. Pump Control Pressure Pi1 pushes Spool 1 (3),
and Spool 1 (3) moves toward the arrow.
3. This movement causes Pilot Primary Pressure Pg
to be led to servo piston 1 (10) also.
4. As there are two servo piston 1’s (10), the swash
plate (11) tilts toward the flow decreasing direction.
5. Movement of swash plate (11) is conveyed to
sleeve 1 (2) through feed back lever link (13).
Sleeve 1 (2) moves toward the movement of
spool 1 (3).
6. Pilot pressure having been led to servo piston 1
(10) is blocked when sleeve 1 (2) has moved the
same distance as spool 1 (3). This causes servo
piston 1’s (10) to stop and the flow decrease is
completed.
Flow (Q)
0
Pump Control Pressure (Pi1-Pi2)
3
2
Pi1
1
Air
Vent
T
4
Pi2
Pg
ST
T
Pd1
T
13
10
Small
Large
12
Tilting Angle
T4GB-03-01-006C
1234-
Spring
Sleeve 1
Spool 1
Piston
Pd1 ST T-
T3-1-8
10 11 12 13 -
Pump Delivery Pressure
(Self Delivery Pressure)
Torque Control Pressure
Return Line to Hydraulic
Oil Tank
Servo Piston 1
Swash Plate
Servo Piston 2
Feed Back Lever Link
Pi1 Pi2 Pg -
Pump Control Pressure 1
Pump Control Pressure 2
Pilot Primary Pressure
(From Pilot Pump)
COMPONENT OPERATION / Pump Device
Pump
Control Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
3
2
4
1
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
13
Self Delivery
Pressure Pd1
12
11
10
T4GB-03-01-008
Pump
Control Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
3
2
4
1
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
Self Delivery
Pressure Pd1
13
12
10
11
T4GB-03-01-009
T3-1-9
COMPONENT OPERATION / Pump Device
Flow Increase
1. When the control lever stroke is enlarged, pressure difference arising before and after the flow
control valve (difference between pressure Pi1
and Pi2) in the control valve is reduced.
2. Spool 1 (3) moves back by spring force (1).
3. This movement causes the circuit of servo piston
1’s (10) to be led to the hydraulic oil tank.
4. As Pilot Primary Presuure Pg is always applied to
servo piston 2 (12), the swash plate (11) tilts toward the flow increasing direction.
5. Movement of the swash plate (11) is transmitted
to sleeve 1 (2) through the feed back lever link
(13). Sleeve 1 (2) moves toward the movement of
spool 1 (3).
6. When sleeve 1 (2) has moved the same distance
as spool 1 (3) did, communication of servo piston
1’s (10) with the hydraulic tank is stopped, and
this causes servo piston 1’s (10) to stop and the
flow increase is completed.
Flow (Q)
0
Pump Control Pressure (Pi1-Pi2)
3
2
Pi1
1
Air
Vent
T
4
Pi2
Pg
ST
T
Pd1
T
13
10
Large
Small
12
Tilting Angle
T4GB-03-01-006C
1234-
Spring
Sleeve 1
Spool 1
Piston
10 11 12 13 -
Pd1 - Pump Delivery Pressure
(Self Delivery Pressure)
ST - Pump Torque Control
Pressure
TReturn Line to Hydraulic
Oil Tank
T3-1-10
Servo Piston 1
Swash Plate
Servo Piston 2
Feed Back Lever Link
Pi1 Pi2 Pg -
Pump Control Pressure 1
Pump Control Pressure 2
Pilot Primary Pressure
(From Pilot Pump)
COMPONENT OPERATION / Pump Device
Pump
Control Pressure
Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
3
2
4
1
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
13
Self Delivery Pressure Pd1
12
10
11
T4GB-03-01-010
Pump
Control Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
3
2
4
1
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
13
Self Delivery
Pressure Pd1
10
12
11
T4GB-03-01-011
T3-1-11
COMPONENT OPERATION / Pump Device
Control by Pump Delivery Pressure
(Self Delivery Pressure)
Flow Decrease
1. When load is applied to the pump by making one
operation or another, Pump Delivery Pressure
Pd1 rises. (As done during an operation, the
pump control pressure (Pi1 - Pi2) remains lowered.)
2. Load piston (5) pushes spool 2 (6), the inner
spring (8), and the outer spring (9), and Spool 2
(6) moves toward the arrow.
3. This movement causes Pilot Primary Pressure Pg
to be led to servo piston 1’s (10) also.
4. As there are two servo piston 1 (10), the swash
plate (11) tilts toward the flow decreasing direction.
5. This movement of the swash plate (11) is conveyed to sleeve 2 (7) through the feed back lever
link (13). Sleeve 2 (7) moves toward the movement of spool 2 (6).
6. Pilot pressure having been led to servo piston 1
(10) is blocked when sleeve 2 (7) has moved the
same distance as spool 2 (6). This causes servo
piston 1’s (10) to stop and the flow decrease is
completed.
Flow (Q)
0
Pressure (P)
Pi1
Air
Vent
T
Pi2
Pg
ST
T
Pd1
T
5
7
6
10
8、9
Large
Small
Tilting Angle
12
13
T4GB-03-01-006C
56789-
Load Piston
Spool 2
Sleeve 2
Inner Spring
Outer Spring
Pd1 - Pump Delivery Pressure
(Self Delivery Pressure)
ST - Pump Torque Control
Pressure
TReturn Line to Hydraulic
Oil Tank
T3-1-12
10 11 12 13 -
Servo Piston 1
Swash Plate
Servo Piston 2
Feed Back Lever Link
Pi1 Pi2 Pg -
Pump Control Pressure 1
Pump Control Pressure 2
Pilot Primary Pressure
(From Pilot Pump)
COMPONENT OPERATION / Pump Device
Pump
Control Pressure
Pi1
5
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
6
7
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
8
9
13
Self Delivery Pressure Pd1
12
10
11
T4GB-03-01-012
5
Pump
Control
Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
6
7
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
8
13
Self Delivery Pressure Pd1
9
12
10
11
T4GB-03-01-013
T3-1-13
COMPONENT OPERATION / Pump Device
Flow Increase
1. When the pump load is reduced, Self Delivery
Pressure Pd1 lowers. (As done during an operation, the pump control pressure (Pi1 - Pi2) remains lowered.)
2. Load piston (5) and spool 2 (6) are pushed by
inner spring (8) and outer spring (9), and spool 2
(6) moves toward the arrow.
3. This movement causes the circuit of servo piston
1’s (10) to be led to the hydraulic oil tank.
4. As Pilot Primary Presuure Pg is always applied to
servo piston 2 (12), swash plate (11) tilts toward
the flow increasing direction.
5. Movement of swash plate (11) is conveyed to
sleeve 2 (7) through feed back lever link (13).
sleeve 2 (7) moves toward the movement of spool
2 (6).
6. When sleeve 2 (7) has moved the same distance
as spool 2 (6), the openings of spool 2 (6) and
sleeve 2 (7) close, stopping communication of
servo piston 1’s (10) with the hydraulic tank, and
this causes servo piston 1’s (10) to stop and the
flow increase is completed.
Flow (Q)
0
Pressure (P)
Pi1
Air
Vent
T
Pi2
Pg
ST
T
Pd1
T
5
7
8、9
6
10
12
Large
Small
Tilting Angle
13
T4GB-03-01-006C
56789-
Load Piston
Spool 2
Sleeve 2
Inner Spring
Outer Spring
Pd1 - Pump Delivery Pressure
(Self Delivery Pressure)
ST - Pump Torque Control
Pressure
TReturn Line to Hydraulic
Oil Tank
T3-1-14
10 11 12 13 -
Servo Piston 1
Swash Plate
Servo Piston 2
Feed Back Lever Link
Pi1 Pi2 Pg -
Pump Control Pressure 1
Pump Control Pressure 2
Pilot Primary Pressure
(From Pilot Pump)
COMPONENT OPERATION / Pump Device
5
Pump
Control
Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
6
7
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
8
13
Self Delivery Pressure Pd1
9
12
10
11
T4GB-03-01-014
5
Pump
Control Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
6
7
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
Self Delivery Pressure Pd1
13
12
10
11
T4GB-03-01-015
T3-1-15
COMPONENT OPERATION / Pump Device
Control of Torque Control Solenoid Valve by Pilot
Pressure
Flow Decrease
1. Command from the MC (main controller) drives
the pump torque control solenoid valve, and
Pump Torque Control Pressure ST enters the
regulator.
2. Adding to Self Delivery Pressure Pd1, Pump
Torque Control Pressure ST works on load piston
(5).
3. Load piston (5) pushes spool 2 (6), inner spring
(8), and outer spring (9), and spool 2 (6) moves
toward the arrow.
4. This movement causes Pilot Primary Pressure Pg
to be led to servo piston 1’s (10) also.
5. As there are two servo piston 1 (10), swash plate
(11) tilts toward the flow decreasing direction.
6. This movement of swash plate (11) is conveyed to
sleeve 2 (7) through feed back lever link (13).
sleeve 2 (7) moves toward the movement of spool
2 (6).
7. Pilot pressure having been led to servo piston 1
(10) is blocked when sleeve 2 (7) has moved the
same distance as spool 2 (6). This causes servo
piston 1’s (10) to stop and the flow decrease is
completed.
Flow (Q)
0
Pressure (P)
Pi1
Air
Vent
T
Pi2
Pg
ST
T
Pd1
T
5
7
8、9
6
10
Large
Small
Tilting Angle
12
13
T4GB-03-01-006C
56789-
Load Piston
Spool 2
Sleeve 2
Inner Spring
Outer Spring
Pd1 - Pump Delivery Pressure
(Self Delivery Pressure)
ST - Pump Torque Control
Pressure
TReturn Line to Hydraulic
Oil Tank
T3-1-16
10 11 12 13 -
Servo Piston 1
Swash Plate
Servo Piston 2
Feed Back Lever Link
Pi1 Pi2 Pg -
Pump Control Pressure 1
Pump Control Pressure 2
Pilot Primary Pressure
(From Pilot Pump)
COMPONENT OPERATION / Pump Device
5
Pump
Control
Pressure Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
6
7
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
8
9
13
Self Delivery Pressure Pd1
12
10
11
T4GB-03-01-016
5
Pump
Control Pressure
Pi1
To Hydraulic
Oil Tank
Pilot
Primary
Pressure Pg
6
7
Pump
Control Pressure
Pi2
Pump Torque
Control Pressure
ST
8
13
Self Delivery Pressure Pd1
9
12
10
11
T4GB-03-01-017
T3-1-17
COMPONENT OPERATION / Pump Device
PRIORITY VALVE
(Refer to the Main Curcuit in the SYSTEM /
Hydraulic System)
Main pump has a built-in priority valve.
Priority valve is installed for effectively distributing the
main pump delivery oil to the steering valve and the
control valve.
PHOTO
Hydraulic System
Operation
1. Before Steering Operation
Pressure oil from the main pump tends to flow to
the steering valve through Port CF, but flows to
the both ends of the priority valve spool because
Port CF is blocked.
Pressure oil on one end of the spool flows from
Port LS to the hydraulic oil tank through the
steering valve, and its pressure is lowered. The
spool to both ends of which different pressures
are applied moves toward Port LS, overcoming
the the spring force. Therefore, the majority of the
main pump pressure oil flows to the control valve
through Port EF.
2. In Steering Operation
If steering is operated, and the steering valve
spool moves, pressure at Port LS rise in response
to the amount of the steering valve spool movement. The spool is pushed up by the pressure at
Port LS and the spring force. Therefore, the main
pump pressure oil flows to both Port EF and Port
CF. When the steering valve spool moves to the
maximum stroke, the majority of the main pump
pressure oil flows to the steering valve through
Port CF.
114
Before Steering Operation
Port
CF
To Steering Valve
From Main Pump
To Control Valve
Port
EF
Spool
Spring
Port LS
To Hydraulic
Oil Tank
T4GB-03-01-018C
In Steering Operation
Port
CF
To Steering Valve
From Main Pump
To Control Valve
Spool
Port
EF
Spring
Port LS
T3-1-18
T4GB-03-01-019C
COMPONENT OPERATION / Pump Device
PILOT PUMP
Drive gear (1) is driven throught the shaft of the main
pump, and the diven gear (2) geared to this also rotates.
1 - Drive Gear
Suction Port
1
2
2 - Driven Gear
PHOTO
Hydraulic System
114
Delivery Port
T137-02-03-005C
PUMP DELIVERY PRESSURE SWITCH
Pump delivery pressure necessary for various kinds of
control is sensed. Hydraulic pressure is received by
the diaphragm (9), and deformation of the diaphragm
is sensed as an electric signal.
6 - Earth
7 - Output
8 - Electric Source (5V)
9 - Pressure-applied Part
(Diaphragm)
6
T3-1-19
7
8
9
T157-02-03-010C
COMPONENT OPERATION / Pump Device
STEERING MAIN RELIEF VALVE
Main pump has a built-in steering main relief valve.
When the steering circuit pressure exceed the set
pressure, pressure oil is returned to the hydarulic oil
tank through inside of the main pump housing.
Before Operation
ILLUSTRATION
T4GB-01-02-009
Steering Circuit Pressure for
up to Set Pressure
Operation
In case steering circuit pressure exceed the set
pressure, the puppet is pushed toward the spring,
and pressure is returned to the hydraulic oil tank
through inside of the main pump housing.
NOTE: When the steering relief valve is operated,
the spool of the priority valve moves to the
Port LS end, and the majority of the pressure oil from the main pump flows to the
control valve through Port EF. (Refer to
T3-1-18.)
T4GB-03-01-020C
In Operation
Steering Circuit Pressure for
less than Set Pressure
To Main Pump
Housing
T4GB-03-01-021C
T3-1-20
COMPONENT OPERATION / Control Valve
OUTLINE
Control valve controls pressure, flow, and direction of
oil in the hydraulic circuit.
The control valve includes the main relief valve, overload relief valves, pump control valve, restriction valves,
flow control valve, and spools, and its operation is of
the hydraulic pilot type.
PHOTO
Main Control Valve
ZW250
ZW220
Lift Arm
089
090
Lift Arm
Bucket
Bucket
T4GB-03-02-001C
T4GB-03-02-002C
T3-2-1
COMPONENT OPERATION / Control Valve
Component Layout
ZW220
1
2
3
4
11
5
6
7
7
10
9
T3-2-2
8
T4GB-03-02-003C
COMPONENT OPERATION / Control Valve
ZW220
A
7
6
8
9
7
5
B
C
D
E
4
2
3
T4GB-03-02-004C
1 - Bucket Flow Control Valve
2 - Pump Control Valve
3 - Overload Relief Valve
(Bucket: Bottom End)
4 - Overload Relief Valve
(Bucket: Rod End)
5 - Overload Relief Valve
(Lift Arm: Bottom End)
6 - Make-up Valve
(Lift Arm: Rod End)
7 - Restriction Valve
8 - Low-pressure Relief Valve
9 - Main Relief Valve
T3-2-3
10 - Load Check Valve
(Arm Lift Circuit)
11 - Load Check Valve
(Bucket Circuit)
COMPONENT OPERATION / Control Valve
ZW220
1
2
3
4
11
5
6
7
7
10
9
T3-2-4
8
T4GB-03-02-003C
COMPONENT OPERATION / Control Valve
ZW220
8
9
Section A
*
7
7
2
T4GB-03-02-005C
Section B*
8
9
T4GB-03-02-006C
1 - Bucket Flow Control Valve
2 - Pump Control Valve
3 - Overload Relief Valve
(Bucket: Bottom End)
4 - Overload Relief Valve
(Bucket: Rod End)
5 - Overload Relief Valve
(Lift Arm: Bottom End)
6 - Make-up Valve
(Lift Arm: Rod End)
7-
Restriction Valve
8-
Low-pressure Relief Valve
9-
Main Relief Valve
* Refer to T3-2-3.
T3-2-5
10 - Load Check Valve
(Arm Lift Circuit)
11 - Load Check Valve
(Bucket Circuit)
COMPONENT OPERATION / Control Valve
ZW220
1
2
3
4
11
5
6
7
7
10
9
T3-2-6
8
T4GB-03-02-003C
COMPONENT OPERATION / Control Valve
ZW220
Section C*
6
10
7
7
5
*
Section D
1
11
4
3
Section E
*
2
T4GB-03-02-007C
1 - Bucket Flow Control Valve
2 - Pump Control Valve
3 - Overload Relief Valve
(Bucket: Bottom End)
4 - Overload Relief Valve
(Bucket: Rod End)
5 - Overload Relief Valve
(Lift Arm: Bottom End)
6 - Make-up Valve
(Lift Arm: Rod End)
7-
Restriction Valve
8-
Low-pressure Relief Valve
9-
Main Relief Valve
* Refer to T3-2-3.
T3-2-7
10 - Load Check Valve
(Arm Lift Circuit)
11 - Load Check Valve
(Bucket Circuit)
COMPONENT OPERATION / Control Valve
ZW250
1
2
3
4
5
6
8
7
8
9
11
10
T4GB-03-02-008C
T3-2-8
COMPONENT OPERATION / Control Valve
ZW250
D
10
C
6
7
8
8
A
E
5
4
3
T4GB-03-02-009C
1 - Flow Control Valve
(Poppet)
2 - Flow Control Valve
(Changeover Valve)
3 - Pump Control Valve
4 - Overload Relief Valve
(Bucket: Bottom End)
5 - Overload Relief Valve
(Bucket: Rod End)
6 - Overload Relief Valve
(Lift Arm: Bottom End)
7 - Make-up Valve
(Lift Arm: for Rod)
8 - Restriction Valve
9 - Low-pressure Relief Valve
T3-2-9
10 - Main Relief Valve
11 - Load Check Valve
(Lift Arm Circuit)
COMPONENT OPERATION / Control Valve
ZW250
1
2
3
4
5
6
8
7
8
9
11
10
T4GB-03-02-008C
T3-2-10
COMPONENT OPERATION / Control Valve
ZW250
Section A*
11
7
6
8
8
Section B*
1
2
5
4
T4GB-03-02-010C
1 - Flow Control Valve
(Poppet)
2 - Flow Control Valve
(Changeover Valve)
3 - Pump Control Valve
4-
Overload Relief Valve
(Bucket: Bottom End)
5 - Overload Relief Valve
(Bucket: Rod End)
6 - Overload Relief Valve
(Lift Arm: Bottom End)
7-
Make-up Valve
(Lift Arm: for Rod)
8 - Restriction Valve
9-
* Refer to T3-2-9.
T3-2-11
Low-pressure Relief Valve
10 - Main Relief Valve
11 - Load Check Valve
(Lift Arm Circuit)
COMPONENT OPERATION / Control Valve
ZW250
1
2
3
4
5
6
8
7
8
9
10
11
T4GB-03-02-008C
T3-2-12
COMPONENT OPERATION / Control Valve
ZW250
Section C:*
10
9
Section D*
C
3
E
Section E
*
3
T4GB-03-02-011C
1 - Flow Control Valve
(Poppet)
2 - Flow Control Valve
(Changeover Valve)
3 - Pump Control Valve
4-
Overload Relief Valve
(Bucket: Bottom End)
5 - Overload Relief Valve
(Bucket: Rod End)
6 - Overload Relief Valve
(Lift Arm: Bottom End)
7-
Make-up Valve
(Lift Arm: for Rod)
8 - Restriction Valve
9-
* Refer to T3-2-9.
T3-2-13
Low-pressure Relief Valve
10 - Main Relief Valve
11 - Load Check Valve
(Lift Arm Circuit)
COMPONENT OPERATION / Control Valve
HYDRAULIC CIRCUIT
ZW220
Main Circuit
Main circuit contains a parallel circuit, which enables
compound operations.
Main circuit (between the pump and the cylinders) is
provided with the main relief valve. The main relief
valve prevents pressure inside the main circuit from
increasing over the set pressure during operation
(when any control lever is operated).
Front circuit (between the control valve and the cylinders) of the lift arm and bucket is provided with the
overload relief valves. Overload relief valve prevents
surge pressure from being developed be external
loads in the front circuit and from increasing over the
set pressure at neutral position of the spool (neutral
position of the control lever).
T3-2-14
COMPONENT OPERATION / Control Valve
Bucket Cylinder
Lift Arm
Cylinder
Control Valve
Bucket
Overload
Relief Valve
Lift Arm
Parallel Circuit
Main
Relief Valve
Main Pump
T4GB-03-02-012C
T3-2-15
COMPONENT OPERATION / Control Valve
ZW250
Main Circuit
Main circuit contains a parallel circuit, which enables
compound operations.
Main circuit (between the pump and the cylinders) is
provided with the main relief valve. The main relief
valve prevents pressure inside the main circuit from
increasing over the set pressure during operation
(when any control lever is operated).
Front circuit (between the control valve and the cylinders) of the lift arm and bucket is provided with the
overload relief valves. Overload relief valve prevents
surge pressure from being developed be external
loads in the front circuit and from increasing over the
set pressure at neutral position of the spool (neutral
position of the control lever).
T3-2-16
COMPONENT OPERATION / Control Valve
Bucket Cylinder
Lift Arm
Cylinder
Control Valve
Overload
Valve
Bucket
Lift Arm
Parallel Circuit
Main Relief Valve
Main Pump
T4GB-03-02-023C
T3-2-17
COMPONENT OPERATION / Control Valve
Pilot Operation Circuit
ZW220
Pressure oil from the pilot valve (shown in numerals)
works on the spools of the control valve, and moves
the spools.
• Pressure oil is being sent to the bucket spool for
dumping and crowding operations.
• Pressure oil is being sent to the lift arm spool for
raising and lowering operations.
Spool for lowering is two-staged, and the first
stage is for lowering the lift arm, while the second
stage is for floating the lift arm.
T3-2-18
COMPONENT OPERATION / Control Valve
PHOTO
Bucket
Pilot Valve
Lift Arm
Pilot Valve
Pilot Valve
018
1
2
3
4
Pilot Pump
Control Valve
Bucket
1
2
Lift Arm
4
3
Main Pump
T4GB-03-02-013
1 - Bucket Crowding
2 - Bucket Dumping
34-
Lift Arm Lowering
Lift Arm Raising
T3-2-19
COMPONENT OPERATION / Control Valve
ZW250
Pressure oil from the pilot valve (shown in numerals)
works on the spools of the control valve, and moves
the spools.
• Pressure oil is being sent to the bucket spool for
dumping and crowding operations.
• Pressure oil is being sent to the lift arm spool for
raising and lowering operations.
Spool for lowering is two-staged, and the first
stage is for lowering the lift arm, while the second
stage is for floating the lift arm.
T3-2-20
COMPONENT OPERATION / Control Valve
Bucket
Pilot Valve
Lift Arm
Pilot Valve
PHOTO
Pilot Valve
1
2
3
4
018
Pilot Pump
Control Valve
PHOTO
Main Control Valve
089
Bucket
2
1
4
Lift Arm
3
4
Main Pump
T4GB-03-02-024
1 - Bucket Crowding
2 - Bucket Dumping
3 - Lift Arm Lowering
4 - Lift Arm Raising
T3-2-21
COMPONENT OPERATION / Control Valve
MAIN RELIEF VALVE
Main relief valve prevents pressure inside the main
circuit from increasing over the set pressure during
operation of the cylinder.
This prevents oil leakage from the hoses and piping
fittings as well as cylinder breakage.
ZW220
Operation of Relief Valve
1. Pressure at port HP (in the main circuit) works on
the pilot poppet through orifice A of the main
poppet and orifice B of the seat.
2. When the pressure at Port HP rises to the setting
force of spring B, the pilot poppet opens, and
pressure oil flows to port LP (in the hydraulic oil
tank) passing through passage A and the periphery of the sleeve.
3. At this time, pressure difference arises between
port HP and the spring chamber, caused by orifice
A.
4. When this pressure difference reaches the value
corresponding to the set force of spring A, the
main poppet opens, and the pressure oil at port
HP flows to port LP.
5. As a result, pressure in the main circuit lowers.
6. If the main circuit pressure lowers to the set
pressure, the main poppet is closed by the force
of spring A.
T3-2-22
COMPONENT OPERATION / Control Valve
In Normal Condition:
Main Poppet
Orifice A
Orifice B
Seat
Passage A
Spring B
HP
Sleeve
LP
Spring Cham- Spring A
ber
T4GB-03-02-034C
Pilot Poppet
When Relieving:
Main Poppet
Orifice A Orifice B
Seat
Passage A
Spring B
HP
Sleeve
LP
Spring
Chamber
Spring A
T3-2-23
Pilot Poppet
T4GB-03-02-035C
COMPONENT OPERATION / Control Valve
ZW250
Operation of Relief Valve
1. Pressure at port HP (in the main circuit) works on
the pilot poppet through orifice A of the main
poppet and orifice B of the seat.
2. When the pressure at port HP rises to the setting
force of spring B, the pilot poppet opens, and
pressure oil flows to port LP (in the hydraulic oil
tank) passing through passage A and the periphery of the sleeve.
3. At this time, pressure difference arises between
port HP and the spring chamber, caused by orifice
A.
4. When this pressure difference reaches the value
corresponding to the set force of spring A, the
main poppet opens, and the pressure oil at port
HP flows to port LP.
5. As a result, pressure in the the main circuit lowers.
6. If the main circuit pressure lowers to the set
pressure, the main poppet is closed by the force
of spring A.
T3-2-24
COMPONENT OPERATION / Control Valve
In Normal Condition:
Orifice A Main Poppet Orifice B Seat Passage A Spring B
HP
Sleeve
LP
Spring
Chamber
Spring A
Pilot Poppet
T4GB-03-02-025C
When Relieving:
Orifice A
Main Poppet
Orifice B Seat
Passage A Spring B
HP
LP
Sleeve
Spring
Chamber
Spring A
Pilot Poppet
T4GB-03-02-026C
T3-2-25
COMPONENT OPERATION / Control Valve
OVERLOAD RELIEF VALVE
(With Make-up Function)
Overload relief valve is installed on the bottom end of
the lift arm cylinders and the bottom and rod ends of
the bucket cylinder. Overload relief valve so controls
pressure in each front circuit not to rise abnormally. It
also makes make-up operation by refilling oil from the
hydraulic oil tank for preventing cavitation.
Operation of Relief Valve in ZW220 (Port on
Bucket Rod) & ZW250 (All Ports)
Make-up Operation
1. When the pressure at port HP (in the front circuit)
lowers than the pressure at port LP (in the hydraulic oil tank), the sleeve moves right.
2. Hydraulic oil at port LP flows into port HP, and
cavitation is prevented.
3. When the pressure at port HP rises to the set
pressure, the sleeve is closed by the force of
spring C.
1. Pressure at port HP (in the front circuit) works on
the pilot poppet through the orifice of the piston.
2. When the pressure at port HP rises to the setting
force of spring B, the pilot poppet opens, and
pressure oil flows to port LP (in the hydraulic oil
tank) passing through passage A and the periphery of the sleeve.
3. At this time, pressure difference arises between
port HP and the spring chamber, caused by the
orifice.
4. When this pressure difference reaches the value
corresponding to the set force of spring A, the
piston and the main poppet open, and the pressure oil at port HP flows to port LP.
5. As a result, pressure in the the main circuit lowers.
6. If the front circuit pressure lowers to the set
pressure, the piston and the main poppet are
closed by the force of spring A.
T3-2-26
COMPONENT OPERATION / Control Valve
In Normal Condition:
Main Poppet
Spring A
Sleeve
Passage A
Spring B
HP
T4GB-03-02-030C
LP
Orifice
Piston
Spring Chamber
Pilot Poppet
Spring C
When Relieving:
Main Poppet
Sleeve
Spring A
Passage A Spring B
HP
LP
Orifice
Piston
T4GB-03-02-031C
Spring Chamber Pilot Poppet
In Make-up Operation:
Sleeve
HP
LP
R4GB-03-02-032
Spring C
T3-2-27
COMPONENT OPERATION / Control Valve
Operation of Relief Valve in ZW220 (Ports on
Bottom End of Lift Arm and Bucket)
1. Pressure at port HP (front circuit) passes the seat,
and works on the shaft.
2. When the pressure at port HP rises to the value
corresponding to the set force of spring A, the
shaft moves, and pressure oil flows to port LP.
3. As a result, the pressure in the front circuit lowers.
4. If the pressure in the front circuit lowers to the set
pressure, the shaft is moved by the force of spring
A, and the oil passage closes.
Make-up Operation
1. When the pressure at port HP (in the front circuit)
lowers than the pressure at port LP (in the hydraulic oil tank), the sleeve moves right.
2. Hydraulic oil at port LP flows into port HP, and
cavitation is prevented.
3. When the pressure at port HP rises to the set
pressure, the sleeve is closed by the force of
spring C.
T3-2-28
COMPONENT OPERATION / Control Valve
In Normal Condition:
Seat
HP
Shaft
LP
Spring B
Spring A
T4GB-03-02-027C
When Relieving:
Seat
Shaft
HP
LP
Spring B
Spring A
T4GB-03-02-028C
In Make-up Operation:
Seat
HP
Shaft
LP
Spring B
Spring A
T4GB-03-02-029C
T3-2-29
COMPONENT OPERATION / Control Valve
(Blank)
T3-2-30
COMPONENT OPERATION / Control Valve
RESTRICTION VALVE
PHOTO
Restriction valve is installed at the inlet part to the pilot
circuit on the both ends of the spool for the lift arm
cylinders.
If the pilot valve is made at the neutral position during
operation of the lift arm, the pilot pressure oil having
been supplied to the spool for the lift arm is drained
through the orifice of the check valve of the restriction
valve, and pilot pressure gradually lowers.
As a result, shock to the body occurring in operation of
the front attachment can be reduced by gradually returning the lift arm spool to the neutral position.
Check Valve
Orifice
Main Control Valve
089
Pilot
Valve End
Spool End
T4GB-03-02-014C
Orifice Size
Raise Side
1.0 mm
Lower Side
1.2 mm
T3-2-31
COMPONENT OPERATION / Control Valve
PUMP CONTROL VALVE
Control valve has a built-in negative control valve.
Pump control valve controls the main pump delivery
flow of the main pump by the flow control pressure (Pi1
and Pi2).
Pump
Control Valve
Orifice
Pi2
Operation
Pi1
• At Neutral
Pressure oil coming through the control valve
neutral circuit at neutral position of the control
valve is supplied as pilot pressure for controlling
the pump delivery flow from before and after the
orifice of the pump control valve installed at the
outlet of the control valve.
At this time, spool B moves left because differential pressure is occurring between the Pi1 and Pi2.
Therefore, pilot pressure (PS2) enters the
large-diameter chamber for the servo piston
through spool B and spool A. Pilot pressure (PS2)
also enters the small-diameter chamber for the
servo piston, but as the the large-diameter
chamber has a larger area than the
small-diameter chamber, the servo piston moves
right, and the pump delivery flow is reduced.
• In Operation
In operations handling the lift arm and the bucket,
pressure oil is not supplied to Pi1 and Pi2.
At this time, differential pressure is lowered between the Pi1 and Pi2, so the regulator for the
main pump is at neutral, and restriction of delivery
flow is not made (increase pump delivery flow).
Main Pump
Neutral
Circuit
Servo Piston
Small-Diameter
Chamber
Large-Diameter
Chamber
Spool A
Pilot Pressure
(PS2)
NOTE: Illustration shows the control valve for the
ZW220.
Spool B
T4GB-03-02-015C
Oil Flow
L/min
A
ZW220
ZW250
Pump Control Pressure
Pump Control Pressure
Flow
Flow
(Pi1-Pi2)
(Pi1-Pi2)
L/min
L/min
2
2
MPa (kgf/cm )
MPa (kgf/cm )
A
B
+0.01
+0.1
-0(4
-0)
0.39
B
1.47±0.05(15±0.5)
C
+0.01
+0.1
0.67
-0(17
-0)
C
Pump Control Pressure
(Pi1-Pi2)
MPa (kgf/cm 2)
T4GB-04-02-002
T3-2-32
271±3
+0.01
+0.1
-0(5
-0)
0.49
291±3
80±2
1.47±0.05(15±0.5)
100±2
36±3
+0.01
+0.1
0.67
-0(17
-0)
55±3
COMPONENT OPERATION / Control Valve
ZW250
ZW220
Section A *1,*2
Section D*3,*4
From Main Pump
From Main Pump
Pi2
Pi1
E
Orifice Part
Section E *1
Section E *3
Pi1
Pi1
Orifice Part
Pi2
Pi2
Negative Control
Valve
T4GB-03-02-017C
Negative Control
Valve
T4GB-03-02-016C
*1: Refer to T3-2-3.
*2: Refer to T3-2-5.
*3: Refer to T3-2-9.
*4: Refer to T3-2-13.
T3-2-33
COMPONENT OPERATION / Control Valve
FLOW CONTROL VALVE
In Compound Operation of Bucket Crowding and
Lift Arm Raising
Flow control valve is installed in the bucket circuit, and
narrows the circuit in compound operations, giving
priority to operations of the other actuators.
ZW220
In Single Operation of Bucket Crowding
1. Pressure oil from the main pump passes the lift
arm spool.
2. Pressure oil from the lift arm spool flows to the
bucket spool through check valve 1, and is supplied to the bucket cylinder.
1. Part of the pressure oil from the main pump is
supplied to the lift arm cylinders through the lift
arm spool.
2. Remainder of the pressure oil from the main
pump is supplied to the bucket spool through the
parallel circuit.
3. At that time, flow is restricted because pressure
oil passes the orifice through check valve 2.
4. Pressure oil having passed the orifice flows to the
bucket spool, and is supplied to the bucket cylinder.
5. As a result, flow to the bucket spool is restricted,
and more pressure oil is supplied to the lift arm
cylinder ends having higher pressure, and both
the bucket and the arm move.
Inlet of Pressure Oil from
Main Pump in Lift Arm
Spool Operation
Check Valve 2
Orifice
Check
Valve 1
To Bucket Spool
T4GB-03-02-020C
Inlet of Pressure Oil from
Main Pump at Neutral of Lift
Arm Spool
T3-2-34
COMPONENT OPERATION / Control Valve
ZW220
In Single Operation of Bucket Crowding
Bucket
Cylinder
Bucket Spool
Pilot Pressure
Lift Arm
Cylinders
Check
Valve 1
Lift Arm Spool
T4GB-03-02-019
In Compound Operation of Bucket Crowding and Lift Arm Raising
Bucket
Cylinder
Pilot Pressure
Bucket Spool
Check
Valve 2
Lift Arm
Cylinders
Orifice
Pilot Pressure
Lift Arm Spool
Parallel Circuit
T4GB-03-02-019
T3-2-35
COMPONENT OPERATION / Control Valve
ZW250
In Single Operation of Bucket Crowding
In Compound Operation of Bucket Crowding and
Lift Arm Raising
1. Pressure oil from the main pump flows toward the
poppet.
2. Pressure oil entering the poppet pushes the
poppet left, and flows to the bucket spool, with its
small portion also flowing to the bucket spool
through the check valve inside the poppet to be
supplied to the bucket cylinder.
1. Part of the pressure oil from the main pump is
supplied to the lift arm cylinder through the lift arm
spool.
2. Remainder of the pressure oil from the main
pump is supplied toward the bucket spool.
3. Pressure oil from the main pump passes the parallel circuit, and flows to the changeover valve
through the check valve of the poppet.
4. At this time, the changeover valve is positioned
on the orifice end because pilot pressure for
raising the lift arm is working on the changeover
valve.
5. By the effect of the orifice of the changeover valve,
pressure on the spring end of the poppet rises,
and force to push the poppet right (for closing)
arises.
6. As a result, flow to the bucket spool is restricted,
and more pressure oil is supplied to the lift arm
end having higher pressure, and both the bucket
cylinder and the arm cylinder move.
Spring A
Check Valve
Poppet
Spring B
To Bucket Spool
Pilot Presser
for Lift Arm Raising
Pressure Oil
from Main Pump
Changeover Valve
To Hydraulic Oil Tank
To Bucket Spool
T1V1-03-03-064C
T3-2-36
COMPONENT OPERATION / Control Valve
ZW250
In Single Operation of Bucket Crowding
Bucket
Cylinder
Spring A
Bucket Spool
Poppet
Pilot Pressure
Spring B
Lift Arm Spool
Check
Valve
Main Pump
T4GB-03-02-021
In Compound Operation of Bucket Crowding and Lift Arm Raising
Bucket
Cylinder
Spring A
Poppet
Bucket Spool
Pilot Pressure
Pilot Pressure
Changeover
Valve
Check
Valve
Parallel Circuit
Lift Arm Cylinders
Spring B
Lift Arm
Spool
Pilot Pressure
Main Pump
T4GB-03-02-022
T3-2-37
COMPONENT OPERATION / Control Valve
(Blank)
T3-2-38
COMPONENT OPERATION / Hydraulic Fan Motor
OUTLINE
Shaft of the fan motor is provided with the cooling fan,
and the pressure oil from the fan pump rotates the
cooling fan by driving the shaft.
Fan motor has a built-in reverse control solenoid valve,
a flow adjustment solenoid valve and others, and the
reverse control solenoid valve controls the motor
rotational direction, and the flow adjustment solenoid
valve controls rotation speed.
PHOTO
Cooling Fan Pump
039
040
Reverse Control
Solenoid Valve
Flow Adjustment
Solenoid Valve
C
A
B
B
C
A
T4GB-03-03-001C
T3-3-1
COMPONENT OPERATION / Hydraulic Fan Motor
Component Layout
Cooling Fan
Shaft
Fan Motor
Reverse Spool
Reverse Control
Solenoid Valve
Flow Control Valve
Reverse Signal
from MC
Flow Control Valve
Spring
Relief Valve
Flow Adjustment
Solenoid Valve
Fan Pump
T4GB-02-02-008C
Flow Adjustment
Command Signal
from MC
(For example)
ZW220
-1
Speed (min )
Coolant (°C)
Hydraulic Oil (°C)
T/C Oil (°C)
A/C ON (°C)
Current (mA)
500
50
50
50
-
800
500
80
70
80
-
800
1650
90
90
100
30 - 35
0
1650
100
100
110
-
0
T3-3-2
COMPONENT OPERATION / Hydraulic Fan Motor
*
Section B-B
*
Section C-C
5
6
7
8
9
10
*
Section A-A
1
2
3
4
12
11
T4GB-03-03-002C
1 - Shaft
4 - Cylinder Block
2 - Thrust Plate
3 - Piston
5 - Center Spring
6 - Valve Plate
7 - Flow Adjustment Solenoid
Valve
8 - Flow Control Valve
9 - Relief Valve
*Refer to T3-3-1
T3-3-3
10 - Reverse Control Solenoid
Valve
11 - Reverse Spool
12 - Flow Control Valve Spring
COMPONENT OPERATION / Hydraulic Fan Motor
OPERATION
Fan motor is a swash-plate type axial piston motor,
and converts the pressure oil sent from the fan motor
into rotational motion.
Operation Principle of Hydraulic Motor
1. Pressure oil from the fan motor is led to cylinder
block (4) through valve plate (6).
2. Pressure oil entering cylinder block (4) pushes
respective pistons (3).
3. This force F1 works on thrust plate (2), and is
divided into the component forces of F2 and F3
because thrust plate (2) is fixed to shaft (1) at an
angle of α°.
4. Resultant force of F3 is a rotational force, and
rotates cylinder block (4) through pistons (3).
5. Cylinder block (4) is conncted to shaft (1) by the
splines, and the output shaft rotates.
T3-3-4
COMPONENT OPERATION / Hydraulic Fan Motor
α°
F1
F3
F2
2
1
4
2
3
4
6
3
T4GB-03-03-003C
From Fan Pump
To Tank
T4GB-03-03-004C
T3-3-5
COMPONENT OPERATION / Hydraulic Fan Motor
FLOW CONTROL VALVE
In case the cooling water and oil are below the set
temperature, the flow control valve supplies necessary
amount of the pressure oil from the fan pump, and
returns redundant amount to the tank to make control
for lowering the engine load and wind noise of the
cooling fan.
Operation
1. Pressure oil flowing from port P works on the A
end as upstream pressure of flow control valve
orifice (8), and on the B end as its downstream
pressure, and the differential pressure works on
flow control valve spring (12).
2. When the pressure difference becomes larger
than the set force, flow control valve spool (8)
moves, and redundant flow flows to port T.
T3-3-6
COMPONENT OPERATION / Hydraulic Fan Motor
7
8
From Fan Pump
P
B
A
12
T
T4GB-03-03-005C
To Tank
T3-3-7
COMPONENT OPERATION / Hydraulic Fan Motor
REVERSE CONTROL VALVE
Fan motor is reversed by operations of the reverse
control solenoid valve and the reverse spool.
Operation
• At Neutral of Reverse Control Solenoid Valve
1. When reverse control solenoid valve (1) is at
neutral, the pressure oil (P) from the fan pump is
blocked by changeover valve (2).
2. As reverse spool (11) is being pushed by spring
(4), the pressure oil (P) from the fan pump flows
to port MB, and the fan motor rotates normally.
• In Operation of Reverse Control Solenoid Valve
1. When reverse control solenoid valve (1) is
operated, the pressure oil from the fan pump
flows to the right end of reverse spool (11)
through changeover valve (2).
2. When the pressure oil entering the right end of
reverse spool (11) overcomes the spring (4),
reverse spool (11) moves leftwards.
3. Pressure oil (P) from the fan pump flows to port
MA, and the fan motor makes reverse rotation.
T3-3-8
COMPONENT OPERATION / Hydraulic Fan Motor
At Neutral
1
P
OFF
2
MB
MA
4
T
3
T4GB-03-03-006C
In Operation
1
P
ON
2
MA
MB
4
T
T3-3-9
3
T4GB-03-03-007C
COMPONENT OPERATION / Hydraulic Fan Motor
FAN PUMP
Fan pump is a gear pump always supplying pressure
oil to the fan motor during the engine operation.
Fan pump is installed to the engine.
PHOTO
Cooling Fan Pump
032
1
2
3
4
5
T4GB-03-03-008C
6
1 - Drive Gear
2 - Oil Seal
3 - Bushing
4 - Body
5 - Cover
6 - Front Cover
7
8
9
7 - Gasket
8 - Driven Gear
9 - Side Plate
T3-3-10
10
10 - Gasket
COMPONENT OPERATION / Steering Pilot Valve
OUTLINE
Steering pilot valve is located between the brake/pilot
pump and the steering valve.
Steering pilot valve supplies the pressure oil from the
pilot pump to the steering valve in response to the
movement of the steering wheel. (Refer to the Steering
Curcuit in the SYSTEM / Hydraulic System)
PHOTO
Steering System
076
Port L (for Steering Left)
Port R (for Steering Right)
Steering
Wheel
T487-03-02-001C
Port T
(to Hydraulic Oil Tank)
Port P
(from Brake/Pilot Pump)
T3-4-1
COMPONENT OPERATION / Steering Pilot Valve
CONSTRUCTION
8
7
11
Steering pilot valve consists of gerotor (8), drive (7),
sleeve (3), spool (4), pin (5), housing (1), centering
springs (2) and others.
10
When the steering wheel is rotated, spool (4) rotates,
and an oil passage is generated between spool (4) and
sleeve (3). Flow of the pressure oil from the pilot pump
is controlled by spool (4) and sleeve (3), and flows to
the steering valve.
Centering springs (2) are arranged both in spool (4)
and sleeve (3), and so function as to return sleeve (3)
to the neutral position when the steering wheel is
stopped.
9
1
2
5
4
3
T1F3-03-07-002C
6
4
2
3
1
Port R
Port L
Hole
5
Port P
10
9
8
7
6
T4GB-03-04-008
1 - Housing
2 - Centering Spring
3 - Sleeve
456-
Spool
Pin
Plate
789-
T3-4-2
Drive
Gerotor
Spacer
10 - Cap
11 - Check Valve
COMPONENT OPERATION / Steering Pilot Valve
OPERATION
4
Sleeve (3), spool (4) and drive (7) are mutually
connected by pin (5). When the steering wheel (or the
spool (4)) is turned, a relative angular difference arises
between sleeve (3) and spool (4) because the hole of
spool (4) is a lengthened one.
Movement of the steering wheel is conveyed only to
spool (4), and port P (from the steering pump) is
connected to port R (to the steering valve) or port L
through sleeve (3) and spool (4).
1
3
Port L
7
Port R
Steering
Wheel
Port T
Port P
2
11
2
T4GB-03-04-007C
11
1
6
10
9
2
T1F3-03-07-002C
1
5
4
3
T3-4-3
7
8
COMPONENT OPERATION / Steering Pilot Valve
Steering Left:
4. Return oil from the steering valve enters port R,
and flows in the order of housing (1) - sleeve (3) spool (4) - sleeve (3) - port T to return to the
hydraulic oil tank.
5. When the pressure oil from the brake/pilot pump
enters gerotor (8), gerotor (8) rotates leftwards.
Rotation of gerotor (8) is transmitted to the sleeve
(3) through drive (7), and sleeve (3) rotates
leftwards similarly.
6. When sleeve (3) rotates the same amount of turns
as spool (4), passages of sleeve (3) and spool (4)
are closed, and operation of the steering valve is
stopped.
7. Therefore, gerotor (8) rotates in response to
rotation of the steering wheel, and the steering
valve is operated in response to the amount of
turns of the steering wheel.
1. When the steering wheel is turned left, spool (4)
rotates, and the pressure oil from the brake/pilot
pump flows in the order of port P - sleeve (3) spool (4) - sleeve (3) - housing (1) - gerotor (8).
2. Pressure oil from gerotor (8) flows in the order of
housing (1) - sleeve (3) - spool (4) - sleeve (3) port L - steering valve, and controls the steering
valve.
3. Steering valve drives the steering cylinders with
the pressure oil from the main pump, and directs
the vehicle body toward left.
Steering Cylinder
PHOTO
Steering System
078
Steering Valve
Main Pump
Port L
Port R
Port P
Port T
Brake/Pilot
Pump
1
8
7
4
2
3
Steering Pilot Valve
T4GB-03-04-009C
T3-4-4
COMPONENT OPERATION / Steering Pilot Valve
Steering Right
T
L
R
P
When the steering wheel is turned right, the pressure
oil from the pilot pump flows in the order of port P port R - steering cylinder, and operates the steering
valve to direct the front wheel right.
Return oil from the steering valve flows in the order of
port L - port T to return to the hydraulic oil tank.
T4GB-03-04-010C
T
Neutral
When the steering wheel is not being turned, the oil
from the pilot pump works on port P of the steering
pilot valve, but does not flow to the steering valve
because it is blocked by spool (4). Therefore, the
steering cylinders are not operated.
P
4
T4GB-03-04-011C
T3-4-5
COMPONENT OPERATION / Steering Pilot Valve
(Blank)
T3-4-6
COMPONENT OPERATION / Steering Valve
OUTLINE
Steering valve is located between the main pump and
the steering cylinder.
Steering valve supplies the pressure oil from the main
pump to the steering cylinder in response to the pilot oil
pressure of the steering pilot valve.
Steering cylinder is provided with the overload relief
valve.
PHOTO
Steering System
078
A
C
B
T4GB-03-04-001C
T3-5-1
COMPONENT OPERATION / Steering Valve
Component Layout
4
1
2
3
Port T
Port A
Port B
Port Pa
Port Pb
5
Port A: Pressure for Steering
Right
Port P: From Main Pump
6
Port DR
Port P
Port LS
Port B: Pressure for Steering
Left
Port T: Return to Hydraulic Oil
Tank
4
5
Port Pa: Pilot Pressure for
Steering Right
Port LS: To Port LS of Priority
Valve
T3-5-2
T4GB-03-04-002C
Port Pb: Pilot Pressure for
Steering Left
Port DR: Return to Hydraulic Oil
Tank
COMPONENT OPERATION / Steering Valve
Section A
*
7
Port P
Port DR
1
Port T
Section B
*
3
Port LS
Port B
Port A
2
Port Pb
Port Pa
4
5
7
Section C
*
T4GB-03-04-003C
4
6
T4GB-03-04-006C
1 - Spool
2 - Overload Relief Valve
3 - Overload Relief Valve
4 - Load Check Valve
5 - Variable Orifice
6 - Fixed Orifice
*: Refer to T3-5-1
T3-5-3
7-
Passage A
COMPONENT OPERATION / Steering Valve
OPERATION
In Neutral
1. When steering spool (1) is in the neutral position,
port A and port B of the steering cylinder are
closed.
2. Pressure oil from the main pump does not flow to
the steering cylinders because port P is closed.
T3-5-4
COMPONENT OPERATION / Steering Valve
Section A
*
Port P
Port DR
Port T
Section B
:*
Port B
Port A
T4GB-03-04-004C
1
*: Refer to T3-5-1.
T3-5-5
COMPONENT OPERATION / Steering Valve
When Steering Left
1. When the steering wheel is turned left, the pilot
pressure oil is sent to port Pb from the steering
pilot valve, and spool (1) moves right.
2. Pressure oil from the main pump is sent to the
steering valve through port P, and further sent to
passage A (7) through variable orifice (5).
3. Pressure oil in passage A (7) pushes and opens
load check valve (4), and flows to the steering
cylinders through port B.
4. And the return oil from the steering cylinders
enters spool (1) through port A, and returns to the
hydraulic oil tank through port T.
5. Also, the pilot pressure oil flowing into port Pb
pushes spool (1) on port Pb end, while flowing to
port Pa after being decompressed by fixed orifice
(6). This reduces the shock caused by fast
operation of the steering wheel. (Refer to T3-5-2
and also Steering Curcuit in the SYSTEM /
Hydraulic System)
NOTE: Opening area of the variable orifice (5) is
proportional to the amount of stroke of the
spool (1) due to the pilot pressure from the
steering pilot valve. (Refer to the Steering
Curcuit in the SYSTEM / Hydraulic System)
T3-5-6
COMPONENT OPERATION / Steering Valve
Port P
1
7
5
Port T
Port LS
Port B
Port A
Port Pb
Port Pa
4
6
5
7
T3-5-7
T4GB-03-04-005
COMPONENT OPERATION / Steering Valve
STEERING OVERLOAD RELIEF VALVE
Steering overload relief valves are installed in the left
and right steering circuits. Overload relief valve
controls pressure in the respective steering circuits
from rising abnormally high when the steering cylinders
are moved by an external force.
Make-up Operation
Operation of Relief Valve
1. Pressure at port HP (in the steering circuit) works
on the pilot poppet, passing the orifice in the
piston.
2. When the pressure at port HP rises to the setting
force of spring B, the pilot poppet opens, and
pressure oil flows to port LP (in the hydraulic oil
tank), passing passage A and the periphery of the
sleeve.
3. At this moment, pressure difference arises
between port HP and the spring chamber caused
by the orifice.
4. When this pressure difference reaches the value
corresponding to the set force of spring A, the
piston and the main poppet open, and the
pressure oil at port HP flows to port LP.
5. As a result, the pressure in the steering cylinder
circuit lowers.
6. If the steering cylinder circuit pressure lowers to
the set pressure value, the piston and the main
poppet are closed by the force of spring A.
T3-5-8
1. When the pressure at port HP (in the steering
cylinder circuit) lowers than the pressure at port
LP (in the hydraulic oil tank), the sleeve moves
right.
2. Hydraulic oil flows into port HP, and cavitation is
prevented.
3. If the pressure at port HP rises to the set pressure
value, the sleeve is closed by the force of spring
C.
COMPONENT OPERATION / Steering Valve
Normally (When not Relieving):
Main
Poppet
Sleeve
Spring A
Passage A
Spring B
HP
T4GB-03-02-030C
LP
Orifice
Piston
When Relieving:
Spring Chamber
Main
Poppet
Pilot
Poppet
Sleeve
Spring A
Spring C
Passage A
Spring B
HP
LP
Orifice
Piston
T4GB-03-02-031C
Spring
Chamber
In Make-up Operation:
Pilot
Poppet
Sleeve
HP
LP
T4GB-03-02-032C
Spring C
T3-5-9
COMPONENT OPERATION / Steering Valve
(Blank)
T3-5-10
COMPONENT OPERATION / Pilot Valve
OUTLINE (TWO LEVER TYPE PILOT
VALVE FOR FRONT ATTACHMENT)
Pilot valve is a valve for controlling the pilot pressure
oil for moving the spool of the control valve. Provided
with the PPC (Pressure Proportional Control Valve)
function,
the
pilot
valve
outputs
pressure
corresponding to the control lever stroke of the control
lever, and moves the spool of the control valve.
The bi-directional, four-port type is adopted for the
front-end attachment.
Port No.
1
2
3
4
PHOTO
Control Levers
012
Bucket Crowd
Bucket Tilting Out
Lift Arm Lower
Lift Arm Raise
Hydraulic Symbol
P
1
2
3
4 T
T4GB-03-05-001C
P
T3-6-1
1
2
3
4
T
T4GB-03-05-002C
COMPONENT OPERATION / Pilot Valve
OPERATION
At Neutral (between A and B of Pusher Stroke)
1. At the neutral position of the control lever, spool
(7) is completely blocking the pressure oil of port
P. Also, the outlet port is connected to port T
through the notch part of spool (7), and the
pressure oil at the output port is equal to the
pressure in the hydraulic tank.
2. When the control lever is moved slightly, lever (1)
is tilted, and push rod (2) and pusher (3) are
pushed in. Pusher (3) and spring guide (4) remain
mutually connected, and move downward,
compressing return spring (6).
3. At this time, spool (7) is pushed by balance spring
(5), and moves downward until the clearance in
Part A becomes zero.
4. During this movement, the output port remains
connected with port T, and pressure oil is not
supplied to the output port.
NOTE: Lever stroke during the period when the
clearance (A) becomes zero is the play of
the control lever.
T3-6-2
E
Pilot
Pressure
F
D
C
A
B
Pusher Stroke
Output Diagram
T505-02-07-006
COMPONENT OPERATION / Pilot Valve
Pusher Stroke: between A and B
1
2
3
4
5
6
Port T
(Clearance of
Part A: 0)
(A)
Port P
Notch Part
7
Output Port
1 - Lever
2 - Push Rod
3 - Pusher
4 - Spring Guide
T4GB-03-05-004C
T4GB-03-05-003C
5 - Balance Spring
6 - Return Spring
T3-6-3
7-
Spool
COMPONENT OPERATION / Pilot Valve
During Metering or Pressure Decrease (In Pusher
Stroke between C and D)
Full Stroke (Pusher Stroke between E and F)
1. When the control lever is further tilted, the ouput
port is connected with port P through spool (7).
2. Pressure oil from Port P flows into the output port
through spool (7), and the pressure at the output
port is raised.
3. Pressure at the output port works on face B of
spool (7), and tends to push up spool (7).
4. In case the force tending to push up the spool (7)
is smaller than the spring force of balance spring
(5), balance spring (5) is not compressed.
Therefore, port P and the output port remain
connected, and the pressure at the output port
keeps rising.
5. When the pressure at the output port rises further,
the force tending to push spool (7) up increases. If
this force becomes larger than the force of
balance spring (5), spool (7) moves upwards,
compressing the balance spring (5).
6. When spool (7) moves upward, the output port is
not connected any longer, and pressure oil stops
flowing from port P to the output port.
And pressure increase at the output port is
stopped.
7. In this way, balance spring (5) is compressed by
the amount spool (7) is pushed down, and the
pressure at the output port is the balanced
pressure working on the spring force and spool
(7).
T3-6-4
1. When the control lever is fully stroked, pusher (3)
moves downward until spring guide (4) contacts
the shoulder part of the casing.
2. At this time, spool (7) is directly pushed by the
bottom of pusher (3). Therefore, the output port
remains connected with port P through the notch
part of spool (7) because even if the pressure at
the output port is raised, spool (7) does not move
upward.
3. As a result, the pressure on the output port end is
equal to the pressure at port P.
Stroke amount C of the pusher determines the
total stroke of the lever.
E
Pilot
Pressure
F
D
C
A
B
Pusher Stroke
Output Diagram
T505-02-07-006
COMPONENT OPERATION / Pilot Valve
Pusher Stroke: between C and D
Pusher Stroke: between E and F
3
5
(C)
Port T
4
Notch Part
Face B
Port P
Port P
7
7
Output Port
3-
Pusher
4-
Spring Guide
Output Port
T4GB-03-05-005C
5-
T3-6-5
Balance Spring
7-
Spool
T4GB-03-05-006C
COMPONENT OPERATION / Pilot Valve
Electromagnetic Detent
Coil for detent is installed at the push rod part of the
pilot valve.
3. Adsorbed condition is retained until the coil
assembly is unexcited or until adsorption is
forcefully cancelled by moving the control lever
the other way around.
1. When one of the control levers is tilted, push rod
(2) and plate (8) of the other are pushed upwards
by the spring force.
2. If the control lever is operated until its stroke end,
plate (8) of the other is adsorbed by coil assembly
(10).
2
10
8
T4GB-03-05-007C
2-
Push Rod
8-
Plate
10 - Coil Assembly
T3-6-6
COMPONENT OPERATION / Pilot Valve
OUTLINE (JOYSTICK TYPE PILOT VALVE
FOR FRONT ATTACHMENT)
Port No.
1
2
3
4
Bucket Crowd
Bucket Tilting Out
Lift Arm Lower
Lift Arm Raise
Hydraulic Symbol
PHOTO
Control Lever
011
1
2
3
4
018
P
T
T4GB-03-05-001C
2
3
T
1
4
P
T3-6-7
T4GB-03-05-008C
COMPONENT OPERATION / Pilot Valve
OPERATION
At Neutral
1. At neutral, spool (7) completely blocks the
pressure oil at port P. Also, the output port is
connected with port T through the fine control
hole of spool (7).
For this reason, the pressure at the output port is
equal to the pressure at port T.
2. If the control lever is tilted slightly, disc (1) is tilted,
and push rod (2) and piston (3) are pushed in.
Piston (3) pushes down spring guide (4) and
balance spring (5), and moves downward.
3. At this time, spool (7) is pushed by spring (5), and
moves downward until the clearance at part A
becomes zero.
4. During this movement, the output port remains
connected with port T, and pressure oil is not
supplied to the output port.
NOTE: Lever stroke during the period when the
clearance (A) becomes zero is the play of
the control lever.
T3-6-8
COMPONENT OPERATION / Pilot Valve
At Neutral
1
2
3
4
5
6
Port T
(A)
Port P
(Clearance of Part A: 0)
Fine Control Hole
7
Output Port
T4GB-03-05-009C
12-
Disc
Push Rod
3 - Piston
4 - Spring Guide
T4GB-03-05-010C
56-
T3-6-9
Balance Spring
Return Spring
7 - Spool
COMPONENT OPERATION / Pilot Valve
During Metering or Pressure Decrease
Full Stroke
1. When the control lever is further tilted, the ouput
port is connected with port P through the fine
control hole of spool (7).
2. Pressure oil from port P flows into the output port
through spool (7), and the pressure at the output
port is raised.
3. Pressure at the output port works on spool (7),
and tends to push up spool (7).
4. In case the force tending to push up spool (7) is
smaller than the spring force of balance spring (5),
balance spring (5) is not compressed. Therefore,
port P and the output port remain connected, and
the pressure at the output port keeps rising.
5. When the pressure at the output port rises further,
the force tending to push spool (7) up increases. If
this force becomes larger than the force of
balance spring (5), spool (7) moves upwards,
compressing the balance spring (5).
6. When spool (7) moves upward, the output port is
not connected any longer, and pressure oil stops
flowing from port P to the output port.
And pressure increase at the output port is
stopped.
7. In this way, balance spring (5) is compressed by
the amount spool (7) is pushed down, and the
pressure at the output port is the balanced
pressure working on the spring force and spool
(7).
1. When the control lever is fully stroked, disc (7)
pushes down push rod (2) and piston (3), and
spring guide (4) pushes down spool (7).
2. Output port is connected with port P through the
fine control hole of spool (7).
3. Spool (7) is being pushed down by spring guide
(4), and the output port remains connected
through the fine control hole of spool (7) because
even if the pressure at the output port is raised,
spool (7) does not move upward.
4. As a result, the pressure on the output port end is
equal to the pressure at Port P.
T3-6-10
COMPONENT OPERATION / Pilot Valve
During Metering or Pressure Decrease
Full Stroke
2
3
4
5
Fine Control Hole
Port P
Fine Control Hole
Port P
7
7
Output Port
Output Port
T4GB-03-05-011C
23-
Push Rod
Piston
45-
Spring Guide
Balance Spring
T4GB-03-05-012C
7-
T3-6-11
Spool
COMPONENT OPERATION / Pilot Valve
ELECTROMAGNETIC DETENT
Coils for detents are installed at the push rod part of
the pilot valve.
3. Adsorption condition is retained until coil
assembly (8) is unexcited or until adsorption is
forcefully cancelled by operating the control lever
toward the other direction.
1. When one of the control levers is tilted, push rod
(2) and plate (9) of the other are pushed upwards
by the spring force.
2. If the control lever is operated until its stroke end,
plate (9) of the other is adsorbed by coil assembly
(8).
2
8
9
T4GB-03-05-013C
2-
Push Rod
8-
Coil Assembly
9-
T3-6-12
Plate
COMPONENT OPERATION / Pilot Valve
OUTLINE (LEVER TYPE PILOT VALVE
FOR ADDITIONAL CIRCUIT) (OPTIONAL)
Port No.
1
2
Optional
Optional
T
T
Hydraulic Symbol
P
P
T
P
1
1
2
2
T554-02-07-009C
T1LA-03-04-001C
1
T3-6-13
2
COMPONENT OPERATION / Pilot Valve
OPERATION
At Neutral (between A and B of Pusher Stroke)
1. At the neutral position of the control lever, spool
(7) is completely blocking the pressure oil of port
P. Also, the outlet port is connected to port T
through the notch part of spool (7), and the
pressure oil at the output port is equal to the
pressure in the hydraulic tank.
2. When the control lever is moved slightly, cam (1)
is tilted, and pusher (2) and spring guide (4) are
pushed in. Pusher (3) and spring guide (4) move
downward, remaining mutually connected, and
compressing return spring (6).
3. At this time, spool (7) is pushed by balance spring
(5), and moves downward until the clearance in
Part A becomes zero.
4. During this movement, the output port remains
connected with port T, and pressure oil is not
supplied to the output port.
5. When the pressure at the output port rises further,
the force tending to push spool (7) up increases. If
this force becomes larger than the force of
balance spring (5), spool (7) moves upwards,
compressing balance spring (5).
6. When spool (7) moves upward, the notch part
closes, and pressure oil stops flowing from port P
to the output port. And pressure increase at the
output port is stopped.
7. In this way, balance spring (5) is compressed by
the amount the spool (7) is pushed down, and the
pressure at the output port is the balanced
pressure working on the spring force and spool
(7).
NOTE: Lever stroke during the period when Part A
becomes zero is the play of the control
lever.
Pilot
Pressure
D
During Metering or Pressure Decrease (In Pusher
Stroke between C and D)
1. When the control lever is further tilted, the hole
part of spool (7) is connected with notch part (B).
2. Pressure oil from port P flows into the output port
through notch part (B) and the hole part of spool
(7), and the pressure at the output port is raised.
3. Pressure at the output port works on the bottom of
spool (7), and tends to push up spool (7).
4. In case the force tending to push up spool (7) is
smaller than the spring force of balance spring (5),
balance spring (5) is not compressed. Therefore,
port P and the output port remain connected, and
the pressure at the output port keeps rising.
T3-6-14
C
A
B
Pusher Stroke
T1F3-03-09-004
Output Diagram
COMPONENT OPERATION / Pilot Valve
Between A and B of Pusher Stroke
1
2
3
4
5
Port T
6
(A)
Clearance at
Part A: 0
Port P
Hole Part
7
Passage
T1LA-03-04-002C
Output Port
T1LA-03-04-003C
Between C and D of Pusher Stroke
5
Port T
Notch Part (B)
Port P
Hole Part
7
Output Port
1 - Cam
2 - Pusher
3 - Plate
4 - Spring Guide
T1LA-03-04-004C
56-
T3-6-15
Balance Spring
Return Spring
7 - Spool
COMPONENT OPERATION / Pilot Valve
(Blank)
T3-6-16
COMPONENT OPERATION / Pilot Valve
OUTLINE (JOYSTICK TYPE PILOT VALVE
FOR ADDITIONAL CIRCUIT) (OPTIONAL)
Port No.
1
2
3
4
Optional
Optional
Optional
Optional
P
Hydraulic
Symbol
T
P
1
3
2
4
4
T105-02-07-020C
3
1
2
T1V1-03-04-001C
T
T3-6-17
COMPONENT OPERATION / Pilot Valve
OPERATION
Head of spool (6) is hung by the top face of spring
guide (3). Spring guide (3) is lifted up by return spring
(5).
At Neutral (Output Diagram: between A and B):
1. At neutral, spool (6) completely blocks the
pressure oil at port P (from the pilot pump). Also,
the output port is connected with port T (to the
hydraulic oil tank) through the internal passage of
spool (6).
2. For this reason, the pressure at the output port (to
the control valve) is equal to the pressure at Port
T.
3. If the control lever is tilted slightly, cam (1) is tilted,
and pusher (2) is pushed in. Pusher (2) and
spring guide (3), mutually connected, push down
return spring (5), and moves downward.
4. At this time, the pressures at the output port and
port T are equal, so spool (6) moves downward
with the bottom face of its head keeping contact
with spring guide (3) by the force of balance
spring (4).
5. This condition continues until hole part (7) of
spool (6) is connected with port P.
T3-6-18
E
Pilot
Pressure
F
D
C
A B
Lever Stroke
T523-02-05-001
Output Diagram
COMPONENT OPERATION / Pilot Valve
1
1
2
2
3
3
4
4
5
5
6
7
Port P
Output Port
6
6
Port T
7
1 - Cam
2 - Pusher
Port T
7
Port P
Output Port
3 - Spring Guide
4 - Balance Spring
Port T
Port P
Output Port
T1V1-03-04-007
5 - Return Spring
6 - Spool
T3-6-19
T1V1-03-04-008
7 - Hole Part
COMPONENT OPERATION/Pilot Valve
During Metering or Pressure Decrease (Output
Diagram: between C and D)
1. When the control lever is further tilted and pusher
(2) is pushed down, hole part (7) of spool (6)
reaches port P, and the prsessure oil from port P
flows into the output port.
2. Pressure at the output port works on the bottom of
spool (6), and tends to push up spool (6).
3. In case the force working on spool (6) is smaller
than the spring force of balance spring (4),
balance spring (5) is not compressed. Therefore,
spool (6) is not pushed up, and the pressure at
the output port keeps rising.
4. When the pressure at the output port rises further,
the force tending to push spool (6) up increases. If
this force becomes larger than the force of the
balance spring (4), spool (6) moves upwards,
compressing the balance spring (4).
5. When spool (6) moves upward, hole part (7)
closes, pressure oil stops flowing from Port P to
the output port, and pressure increase at the
output port is stopped.
6. In this way, the balance spring (4) is compressed
by the amount spool (6) is pushed down, and the
pressure at the output port is the balanced
pressure working on the spring force and spool
(6).
T3-6-20
E
Pilot
Pressure
F
D
C
A B
Lever Stroke
T523-02-05-001
Output Diagram
COMPONENT OPERATION/Pilot Valve
1
1
2
2
3
3
4
4
5
5
6
6
Port T
Port T
Output Port
1 - Cam
2 - Pusher
7
Port P
7
3 - Spring Guide
4 - Balance Spring
Port P
Output Port
T1V1-03-04-009
5 - Return Spring
6 - Spool
T3-6-21
7 - Hole Part
T1V1-03-04-010
COMPONENT OPERATION/Pilot Valve
Full Stroke (Output Diagram: between E and F)
1. When the control lever is fully stroked, pusher (2)
moves downward until it contacts the shoulder
part of the casing.
2. At this time, spool (6) is directly pushed by the
bottom of the pusher (2). Therefore, even if the
pressure at the output port is raised, hole part (7)
of spool (6) is not closed.
3. As a result, the pressure on the output port end is
equal to the pressure at port P.
E
Pilot
Pressure
D
C
A
NOTE: Stroke amount E of the pusher (2)
determines the total stroke of the lever.
B
Lever Stroke
T523-02-05-001
Output Diagram
T3-6-22
F
COMPONENT OPERATION/Pilot Valve
1
2
2
3
4
5
E
6
Port T
7
Port P
Output Port
1 - Cam
2 - Pusher
3 - Spring Guide
4 - Balance Spring
T1V1-03-04-011
T1V1-03-04-007
5 - Return Spring
6 - Spool
T3-6-23
7 - Hole Part
COMPONENT OPERATION/Pilot Valve
(Blank)
T3-6-24
COMPONENT OPERATION / Charging Block
OUTLINE
Charging block is installed for supplying the pressure
oil from the pilot pump not only to the service brake
accumulator and the brake valve by giving them priority,
but also to the parking brake, the steering pilot valve,
and others.
Charging block consists of the priority valve, relief
valve, pump torque control proportional solenoid valve,
pilot relief valve, check valve, and others.
PHOTO
Charging Block
To Steering
Pilot Valve
Port for Attaching
Service Brake
Accumulator
(Rear)
To Rear
Service Brake
To Front
Service Brake
Check Valve
073
Port for Attaching
Service Brake
Accumulator
(Front)
Port for
Service Brake
Sensor
Pump Torque Control
Proportional Solenoid
Valve
Pilot Relief
Valve
(3.9 MPa)
072
Relief Valve
(14.7 MPa)
To Steering
Pilot Valve
Check
Valve
Parking Brake
Solenoid Valve to
be adopted in EU
specification
To Ride
Control Valve
Port for Attaching
Pilot Accumulator
T4GB-03-06-001C
T3-7-1
COMPONENT OPERATION / Charging Block
Component Layout
1
2
3
4
5
6
7
Relief Valve
14.7 MPa)
8
22
9
10 Pilot Relief Valve
(3.9 MPa)
11
21
12
13
14
20
15
16
17
18
4
19
1 - Service Brake Accumulator
(Rear)
2 - Adaptor
9-
Priority Valve
3 - Port M2
(To Rear End of Brake Valve)
4 - Check Valve
5 - Port M1
(To Front End of Brake Valve
and Parking Brake)
6 - Service Brake Accumulator
(Front)
7 - Service Brake Pressure Sensor
11 - Port DR (To Hydraulic Oil Tank)
10 - Pilot Relief Valve
12 - Port DR2 (To Hydraulic Oil Tank)
13 - Port PS1
(To Steering Pilot Valve)
14 - Port X
(To Main Pump Regulator)
15 - Port S3 (To be adopted in EU
Specification Machines)
8 - Port P (From Pilot Pump)
T3-7-2
T4GB-03-06-002C
16 - Port BR3 (to be adopted in EU
Specification Machines)
17 - Port PS2
(To Main Pump Regulator
and Ride Control Valve (Optional))
18 - Pilot Accumulator
19 - Port PP (To Pilot Shutoff Valve)
20 - Parking Brake Solenoid Valve
(To be adopted in EU Specification
Machines)
21 - Pump Torque Control Proportional
Solenoid Valve
22 - Relief Valve
COMPONENT OPERATION / Charging Block
11
Section V-V*
10
Section U-U
*
14
12
21
Section T-T
15
*
16
20
Section S-S
19
*
18
4
T4GB-03-06-003C
4
*Refer to T3-7-1.
T3-7-3
COMPONENT OPERATION / Charging Block
Component Layout
1
2
3
4
5
6
7
8
22
9
10
11
21
12
13
14
20
15
16
17
18
4
19
1 - Service Brake Accumulator
(Rear)
2 - Adaptor
9-
Priority Valve
3 - Port M2
(To Rear End of Brake Valve)
4 - Check Valve
5 - Port M1
(To Front End of Brake Valve
and Parking Brake)
6 - Service Brake Accumulator
(Front)
7 - Service Brake Pressure Sensor
11 - Port DR (To Hydraulic Oil Tank)
10 - Pilot Relief Valve
12 - Port DR2 (To Hydraulic Oil Tank)
13 - Port PS1
(To Steering Pilot Valve)
14 - Port X
(To Main Pump Regulator)
15 - Port S3 (To be adopted in EU
Specification Machines)
8 - Port P (From Pilot Pump)
T3-7-4
T4GB-03-06-002C
16 - Port BR3 (To be adopted in EU
Specification Machines)
17 - Port PS2
(To Main Pump Regulator
and Ride Control Valve (Optional))
18 - Pilot Accumulator
19 - Port PP (To Pilot Shutoff Valve)
20 - Parking Brake Solenoid Valve
(To be adopted in EU Specification
Machines)
21 - Pump Torque Control Proportional
Solenoid Valve
22 - Relief Valve
COMPONENT OPERATION / Charging Block
Section Z-Z*
6
1
4
7
Section Y-Y*
8
Section X-X*
4
Section W-W
*
22
9
*Refer to T3-7-1.
T3-7-5
T4GB-03-06-004C
COMPONENT OPERATION / Charging Block
PRIORITY VALVE (REFER TO THE PILOT
CIRCUIT IN THE SYSTEM / HYDRAULIC
SYSTEM)
1. Pressure oil from the pilot pump flows in through
port P, and works on the both ends of the plunger
of the priority valve.
2. Same pressure is applied to the both ends of the
plunger, so the plunger does not move, and a
restricted amount of pressure oil is supplied to the
other pilot circuits.
3. When the service brake accumulator is
accumulated exceeding the set pressure, the
piston of the relief valve pushes the needle valve.
4. Pressure oil in the spring chamber of the plunger
flows to the hydraulic oil tank through port DR.
5. Plunger is pushed toward the spring chamber to
stroke because the spring chamber is
decompressed.
6. A larger amount of the pressure oil from the pilot
pump is supplied to the other pilot circuits through
the priority valve.
Below Set Pressure of Service Brake Accumulator
Relief Valve
From Port P
Plunger
(Section W-W)
T4GB-03-06-005C
To Service Brake Circuit
To Other
Pilot Circuits
Above Set Pressure of Service Brake Accumulator
Needle Valve
Piston
Service Brake
Accumulator
Pressure
To Port Dr
From Port P
Plunger
Spring Chamber
(Section W-W)
T4GB-03-06-006C
To Other Pilot Circuits
T3-7-6
COMPONENT OPERATION / Charging Block
PILOT RELIEF VALVE
1. Pilot relief valve prevents the pressure in the pilot
circuit from increasing over the set pressure
during operations of the actuators like the pilot
valve.
2. When the pilot circuit pressure is above the set
pressure, pressure oil works on the poppet of the
pilot relief valve.
3. Poppet works toward the spring to be connected
with port DR.
4. Pressure oil in the pilot circuit returns to the
hydraulic oil tank through port DR.
5. When the pilot circuit pressure is below the set
pressure to the spring force, the poppet moves
left, closing connection of port DR.
Normally
Poppet
(Section V-V)
From Port P
T4GB-03-06-007C
When Relieving
Poppet
Port DR
(Section V-V)
Spring
T3-7-7
T4GB-03-06-008C
COMPONENT OPERATION / Charging Block
PUMP TORQUE CONTROL PROPORTIONAL SOLENOID VALVE (REFER TO THE
PILOT CIRCUIT IN THE SYSTEM /
HYDRAULIC SYSTEM)
Pilot pressure supplied to the main pump regulator
for controlling the pump delivery flow is controlled by
the operation of the pump torque control proportional
solenoid valve.
Not in Operation of Solenoid Valve
To Main Pump
Regulator
Port X
1. When there is no signal from the MC (Main
Controller), the spool of the solenoid valve is
being pushed by the spring.
2. Pilot pressure oil is supplied to port ST of the main
pump regulator through port X.
3. When signal is transmitted from the MC, the spool
moves toward the spring in response to the signal
of the spool, and the amount of the pilot pressure
oil flowing out of Port X is lowered.
4. When the signal from the MC becomes the
maximum value, the spool fully strokes toward the
spring, and the pilot pressure oil is blocked by the
spool.
5. Port X and port DR2 are connected, and the pilot
pressure oil at port X is lost.
Spring
(Section U-U)
Pilot Pressure Oil
T4GB-03-06-009C
In Operation of Solenoid Valve
Port X
Port
DR2
Spool
Spring
(Section U-U)
Pilot Pressure Oil
T4GB-03-06-010C
T3-7-8
COMPONENT OPERATION / Charging Block
SERVICE BRAKE ACCUMULATOR /
PILOT ACCUMULATOR
Accumulator is installed in the pilot circuit leading to
the service brake and the pilot valve.
High-pressure nitrogen gas is contained in the
accumulator, and the pilot pressure oil compresses the
nitrogen gas through the diaphragm.
Circuit pressure oil is retained by compression of the
nitrogen gas.
IMPORTANT: Construction of the accumulator
does not allow disassembly.
Replace the whole assembly, when
necessary.
PHOTO
Charging Block
073
Seal Ring
Retainer
Shell
Diaphragm
Valve Poppet
T4GB-03-06-011C
T3-7-9
COMPONENT OPERATION / Charging Block
PARKING BRAKE SOLENOID VALVE
Pressure oil from the pilot pump is accumulated in the
pilot accumulator, and its pressure always works on
the outlet of the parking brake solenoid valve.
When the parking brake solenoid valve is operated,
the pilot accumulator enters the parking brake through
the spool, and releases the parking brake.
Parking Brake
Solenoid Valve
Port for Attaching
Pilot Accumulator
T3-7-10
T4GB-03-07-004C
COMPONENT OPERATION / Charging Block
Not in Operation
Parking Brake
Pressure Sensor
Parking Brake
Drain Port
Spool
Spring
Parking Brake
Solenoid Valve
(Section T-T)
Pilot Accumulator
Pressure
T4GB-03-07-005C
In Operation
Parking Brake
Pressure Sensor
Parking Brake
Spool
Spring
Parking Brake
Solenoid Valve
(Section T-T)
Pilot Pressure
Accumulator
Pressure
T3-7-11
T4GB-03-07-006C
COMPONENT OPERATION / Charging Block
SERVICE BRAKE PRESSURE SENSOR
Brake pressure necessary for the service brake is
sensed. Sensor is installed in the service brake circuit
of the charging block, and senses the oil pressure of
the service brake accumulator.
1 - Earth
2 - Output
3 - Electric Power Source
(5V)
4 - Pressure Applied Part
(Diaphragm)
1
2
4
3
T4GB-03-06-012C
PARKING BRAKE PRESSURE SENSOR
Brake pressure oil necessary for the parking brake is
sensed. Sensor is installed in the parking brake circuit
of the charging block, and senses the oil pressure of
the pilot accumulator.
3 - Pressure-applied Part
5 - (Diaphragm)
6 - Earth
7-
Output
8-
Electric Source (5V)
5
6
7
8
T176-03-01-023C
T3-7-12
COMPONENT OPERATION / Ride Control Valve
OUTLINE
(Refer to the SYSTEM / Control System)
Ride control valve enables stable traveling by
absorbing the force generated in the lift arm cylinders
in traveling.
Ride control valve consists of the ride control solenoid
valve, spool, charge-cut spool, overload relief valve
and others.
PHOTO
Ride Control System
099
Overload
Relief Valve
A
B
Ride Control
Solenoid Valve
T4GB-03-08-001C
T3-8-1
COMPONENT OPERATION / Ride Control Valve
Component Layout
Lift Arm
Cylinder
Ride Control
Accumulator
2.9 MPa
5
Ride Control Valve
SP
3
39.2 MPa
Pi
1
4
B
A
2
11.3 MPa
To Hydraulic Oil Tank
T
From Charging
Block
T4GB-03-08-002C
1 - Ride Control Solenoid Valve
2 - Charge-cut Spool
34-
Overload Relief Valve
Spool
5-
T3-8-2
Drain Plug
COMPONENT OPERATION / Ride Control Valve
*
Section A
Port Pi
To Ride Control
Accumulator
Port SP
1
3
Port B
Port A
Port T
T4GB-03-08-003C
2
*Refer to T3-8-1.
T3-8-3
4
COMPONENT OPERATION / Ride Control Valve
OPERATION
1. At neutral, port Pi and the ouput port are not
connected, blocked by the spool.
2. When the signal from the MC (Main Controller)
enters the solenoid, the solenoid is excited.
3. Solenoid pushes the spool with the force
corresponding to the signal from the MC, so port
Pi and the output port are connected, and pilot
pressure oil pushes the main spool.
4. When the main spool is pushed toward spring 2,
port A (on the bottom ends of the lift arm cylinder)
and the ride control accumulator are connected,
and port B (on the rod end of the lift arm cylinder)
and port T are connected.
5. As a result, the accumulator absorbs the pushing
force of the lift arm cylinders, and the load
generated by the pushing up force is absorbed by
sucking up the hydraulic oil from the tank port.
Section A*
Pilot Pressure
Spool
To Ride Control
Accumulator
Port Pi
Port A
Port B
Spring 1
Output Port
Spring 2
T4GB-03-08-006C
Tank Port
Main Spool
*Refer to T3-8-1.
T3-8-4
COMPONENT OPERATION / Ride Control Valve
(Blank)
T3-8-5
COMPONENT OPERATION / Ride Control Valve
CHARGE-CUT SPOOL
Charge-cut spool accumulates the pressure oil in the
lift arm cylinders in the ride control accumulator, and
shuts down the pressure oil from the lift arm cylinders
when the ride control accumulator is accumulated to
the set pressure.
1. When the ride control is not in operation, the
pressure oil on the lift arm cylinder bottom ends
flows to port X, passing the orifice through port A.
2. Pressure oil flowing into port X passes in the
spool of the charge-cut spool, and opening the
check valve, flows into port Y to be accumulated
in the ride control accumulator.
3. As Spool Sectional Area M is larger than Spool
Sectional Area N, when the ride control
accumulator is accumulated to the set pressure,
the pressure oil from port X pushes the spool
toward the spring.
4. When the spool moves toward the spring, the
passage of the pressure oil from the spool to port
Y is closed, and accumulating the ride control
accumulator is stopped.
T3-8-6
COMPONENT OPERATION / Ride Control Valve
During Accumulation of Accumulator
Orifice
Spring
Port A
Spool
Port X
To Ride Control
Accumulator
Port Y
Check Valve
T4GB-03-08-007C
After Accumulation of Accumulator
Sectional Area M
Sectional Area N
T3-8-7
T4GB-03-08-008C
COMPONENT OPERATION / Ride Control Valve
OVERLOAD RELIEF VALVE
Overload relief valve is installed for preventing hoses
and the ride control accumulator from being damaged
in case the pressure in the bottom end circuit of the lift
arm cylinders is suddenly raised by an external force
or something during operation of the lift arm cylinders.
Operation
1. Pressure at port HP (in the main circuit) works on
the pilot poppet, passing orifice A of the main
poppet and orifice B of the seat.
2. When the pressure at port HP rises to the setting
force of spring B, the pilot poppet opens, and
pressure oil flows to port LP, passing passage A
and the periphery of the sleeve.
3. At this moment, pressure difference arises
between port HP and the spring chamber caused
by orifice A.
4. When this pressure difference reaches the value
corresponding to the set force of spring A, the
main poppet opens, and the pressure oil at port
HP flows to port LP.
5. As a result, the pressure in the actuator circuit
lowers.
6. If the actuator circuit pressure lowers to the set
pressure, the main poppet is closed by the force
of spring A.
IMPORTANT: Never disassemble or adjust the
overload relief valve. Replace the
whole assembly, when necessary.
T3-8-8
COMPONENT OPERATION / Ride Control Valve
Normally:
Sleeve
Make-up Valve
Main Poppet
Orifice A
Orifice B
Seat
Passage A Spring B
HP
LP
Spring C
T176-03-03-012C
Spring Chamber
Spring A
Pilot
Poppet
When Relieving:
Sleeve
Main Poppet
Orifice A
Orifice B
Seat
Passage A
Spring B
HP
LP
T176-03-03-013C
Spring
Chamber
Spring A
T3-8-9
Pilot
Poppet
COMPONENT OPERATION / Ride Control Valve
RIDE CONTROL ACCUMULATOR
Ride control accumulator is installed in the
accumulation circuit of the ride control.
High-pressure nitrogen gas is contained in the
accumulator, and the pressure oil compresses the
nitrogen gas through the piston.
Compression of the nitrogen gas dampens shock of
the pressure oil due to pitching and the like of the lift
arm cylinder raising circuit.
IMPORTANT: Construction of the ride control
accumulator
does
not
allow
disassembly. Replace the whole
assembly, when necessary.
T4GB-03-08-009C
T3-8-10
COMPONENT OPERATION / Ride Control Valve
DRAIN PLUG
Ride control valve is provided with the drain plug for
returning the pressure oil of the ride control
accumulator to the oil tank at the time of maintenance
or something.
When necessary, connect the accumulator port (port
SP) and the tank port (port T) by loosening the lock nut
first and the drain plug later.
CAUTION: Excessive loosening (More than 2
turns) of the drain plug can result in oil burst
due to removal of the drain plug itself.
Section B*
Port SP
Lock Nut
Drain Plug
Relief Plug
Port T
*Refer to T3-8-1.
T3-8-11
T4GB-03-08-010C
COMPONENT OPERATION / Ride Control Valve
(Blank)
T3-8-12
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COMPONENT OPERATION / Axle
OUTLINE
Axle consists of the differential, final drive, axle shaft,
brakes and others.
Power from the transmission is transmitted to the front
axle and the rear axle through the propeller shaft. Inside the axle, power is transmitted to the differential,
and divided into left and right, and drives the axle
shaft and the wheels through the final drive.
PHOTO
Propeller Shaft and Axle
111
066
068
Axle Shaft
Final
Drive
Differential
Brake
Brake
T4GB-03-10-001C
T3-10-1
COMPONENT OPERATION / Axle
DIFFERENTIAL
Differential enables the left and the right drive wheels
to rotate at different rotating speeds in steering of the
vehicle body or traveling on bumpy roads.
4
5
6
7
8
9
10
11
3
2
12
1
13
14
15
16
17
18
19
20
21
T4GB-03-10-002C
123456-
Brake Ring
Brake Disc
Piston
Side Gear
Case A
Ring Gear
78910 11 12 -
Pinion Gear
Spider
Case B
Roller Bearing
Differential Body
Gear & Shaft
13 14 15 16 17 18 -
T3-10-2
Adjusting Nut
Bearing Retainer
Pinion Shaft
Roller Bearing
Bearing Cage
Spacer
19 - Roller Bearing
20 - Oil Seal
21 - Flange
COMPONENT OPERATION / Axle
Function
• Purpose of Differential
When the vehicle body is steered, the inner wheel
turns with a smaller radius, so the outer wheel
needs to rotate faster for smooth steering.
Suppose driving the rear wheel by directly installing
the gear to the propeller shaft with a shaft having no
differential.
In this case, the outer wheel and the rear wheel rotate the same amount. In other words, when the
vehicle body is steered, the outer wheel cannot rotate more than the inner wheel, and as a result,
skidding sideways or tire wear takes place. Also,
the axle shaft is subjected to torsional stress, resulting in unstable transmission of drive force.
On the other hand, in case a differential is installed,
the inner and the outer wheels can rotate at different speeds, and the problem mentioned above can
be eliminated.
Extension Line of
Rear Wheel Centers
In Turning of Vehicle Body
In Traveling of Vehicle Body on Rough Roads
T202-03-05-005
T3-10-3
COMPONENT OPERATION / Axle
• Principle of Differential
Operation principle of the differential is explained
here comparing it to the racks and the pinion gear
in the drawing.
When the load W is equally applied to the racks A
and B, if C is moved upward by the distance of H,
the racks A and B both move by the same distance
of H in unison with the pinion.
If moved by removing the load to the rack B, the
pinion rotates on the rack A (with load applied), and
moves the rack B upward. At this time, the distance
the rack B moves is longer than the distance the
pinion moves rotating.
Distance the rack B moves can be calculated using
the equation of H+H=2H. This principle is applied to
the differential.
W
W
W
C
C
H
H
H
2H
Rack (A)
Rack (B)
Rack (A)
Pinion
• Operation of Differential
Rack (B)
Pinion
T202-03-05-006
In Traveling Straight
In case resistances applied to the axle shafts (7)
and (8) connected by spline to the differential side
gears (2) and (3) are the same, or in case the vehicle body is traveling straight on plane roads, the differential pinion gears (1) and (4) remain unrotated.
Differential pinion gears (1) and (4) and the side
gears (2) and (3) remain fixed by being mutually
geared, and rotate in unison with the housing (6)
connected with the ring gear (9).
In case the constituent portion of the whole is rotating solidly like this, the differential function of the
differential does not work, but gears (1), (2), (3),
and (4) play only the role of joints for connecting the
axle shafts (7) and (8).
10
9
1
8
2
3
4
7
6
T487-03-06-014
T3-10-4
COMPONENT OPERATION / Axle
In Steering
When the vehicle body swings, uneven resistances
are applied to the drive wheels. Therefore, caused by
the difference of the resistances applied to the inner
and outer wheels, the differential pinion gears (1) and
(4) begin revolving on the side gears (2) and (3), each
rotating round the pinion shaft. As a result, in case the
resistance force applied to the shaft (7) is large, the
pinion gears (1) and (4) rotate in the same direction
as the rotational direction on the side gear (2) of the
shaft (7). And the speed of the shaft (7) is lowered,
and the amount of the speed reduction is applied to
the shaft (8), working the differential function.
Suppose the ring gear (9) is driven by the drive pinion
(10) at the speed of 100. In the condition of the vehicle body traveling straight, the drive wheels on the
both sides rotate at the same speed.
However, in case the vehicle body swings, and the
speed of the right drive wheel is lowered to 90, the left
wheel turns at the speed of 100+(100−90)=110 because the speed of 10(100−90=10) is added to the
speed of the left wheel.
If the ring gear (9) rotates at 100, the summation of
the speeds of the left and right wheels becomes always 200 regardless of movement of the respective
wheels.
T3-10-5
10
9
1
8
2
3
4
7
6
T487-03-06-014
COMPONENT OPERATION / Axle
TORQUE PROPORTIONING DIFFERENTIAL (TPD)
Wheel loader is operated mostly on roads of bad conditions. In case of skidding, working efficiency and tire
lives are lowered. In order to avoid lowering of working efficiency and tire lives, the axle is provided with
the torque proportioning differential.
Differential pinion gear of the torque proportioning differential has an odd number of teeth, and the differential pinion gear and the side gear have special tooth
profiles. Therefore, the difference of the road resistances to the left and right tires causes deviation of
the gearing locations between the differential pinion
gear and the left and right side gears, and the drive
force transferred to the left and right tires changes.
Differential Pinion Gear
Right Side Gear
Left Side Gear
Forward Rotation
T3-10-6
T487-03-06-015C
COMPONENT OPERATION / Axle
Traveling Straight with the Same Resistances to
Left and Right Tires
In case resistances to the left and right tires are the
same, the distances ‘a’ and ‘b’ from the differential
pinion gear center to the respective contact points of
the left and right side gears are the same. Therefore,
the differential pinion gear and the left and right side
gears solidly rotate toward forward, and the drive
forces of the left and right tires become the same.
Differential
Pinion Gear
Left Side Gear
Right Side Gear
T487-03-06-016C
Traveling on Soft Roads (Different Resistances to
Left and Right Tires)
In traveling on soft roads, if the left tire skids, the
side gear on the left tire receiving little resistance
tends to rotate more forward than the right side gear.
This rotation causes deviation of the contact points
of the differential pinion gear and the left and right
side gears in the torque proportioning differential.
In case the left side gear rotates slightly more forward than the right side gear, the distance ‘a’ of the
contact point of the differential pinion gear and the
left side gear is lengthened. Correlation of the forces
at this time is as follows. a×TA (force applied to the
left side gear) = b×TB (force applied to the right side
gear).
Until the difference of the road resistances exceeds
certain value, the differential pinion gear does not
roate, but the left and right side gears rotate at the
same speed solidly. Besides, the left tire does not
rotate reduntantly, and does not skid. (Right tire can
have drive force larger than the left tire.) Therefore,
tire lives are prolonged, and working efficiency is improved.
Differential
Pinion Gear
Left Side Gear
T3-10-7
Right Side Gear
T487-03-06-017C
COMPONENT OPERATION / Axle
LIMITED SLIP DIFFERENTIAL (LSD)
(Optional)
Operation Principle
Wheel loader, as required by the kind of work, must
be operated in places where skidding takes place
easily like sand and muddy soil. In places like these,
Tires can slip even if the torque proportioning differential (TPD) is installed. Rotation is transmitted to the
slipping tire, but not to the tires contacting the earth,
so not only the funtion of the wheel loader is worsened, but the tire lives are shortened.
In order to avoid this, the limited slip differential (LSD)
provided with the differential movement restriction device for avoiding different movement of the left and
right wheels is adopted. Drive force transmitted to the
left and right tires further changes.
LSD is so constructed that the clutch disc is inserted
between the pressure ring supporting the spider with
the cam and the case, which makes restriction of different movement by keeping the tire speeds the
same by the resistances of the friction surfaces. Also,
the variation of the dive force transmitted to the left
and right tires is made larger than the TPD.
Ring Gear
Pressure Ring
Side Gear
Pressure Plate
Clutch Disc
Case
Spider
Pinion Gear
T4GB-03-10-003C
T3-10-8
COMPONENT OPERATION / Axle
Traveling Straight with the Same Road Resistances to Left and Right Tires
As the differential pinion gear and the left and right
pinion gears rotate solidly, the drive forces of the left
and right tires are the same similarly to the TPD.
Traveling on Soft Roads (Different Road Resistances to Left and Right Tires)
Drive force is transmitted to the case, pressure ring,
and spider through the ring gear. At this time, the
spider having the cam construction pushes the
pressure ring with the thrust P. Clutch disc is geared
with the case through the pressure ring. Side gears
fitted to the clutch disc by spline rotate solidly with
the case, and the left and right gears rotate at the
same speed.
Like this, the left and right axle shafts fitted to the
side gears by spline tend to rotate solidly with the
case, and the differential movement restriction works.
In case the drive force provided for the skidding tire
is larger than the road resistance, part of the torque
of the skidding tire is added to the tire contacting the
road by the differential movement restriction (because of the same speed of the left and right tires),
and the tire contacting the road is provided with
more torque.
Until the difference of the resistances between the
left and right tires exceeds certain value (until the
clutch disc begins to slip), the left and right gears
solidly rotate at a constant speed. On such soft
roads, the drive force increases by 1.5 times the
value for the TPD if the LSD is provided.
T3-10-9
Clutch Disc
Pressure Plate
Spider
Pressure Ring
T4GB-03-10-004C
COMPONENT OPERATION / Axle
SERVICE BRAKE
Brake adopted is the wet type multi-disc brake, and is
assembled in the differential body of the axle. Four
wheels of this vehicle has all this disc brake.
• In Operation of Brake
Oil pressure from the brake valve works on the
back of brake piston (5) to move brake piston(5),
and brake disc (3) and brake ring (2) is compressed.
Inner surface of brake disc (3) is fitted by spline to
shaft (8) through disk hub (7). Also, the outer surface of brake ring (2) is fixed to differential body (4).
Therefore, the rotation of the pushed and compressed brake disc (3) stops, restricting the vehicle.
• In Release of Brake
When the oil pressure from the brake valve is decreased, brake piston(5) is returned by return
spring (6), and brake disc (3) is freed. Restriction of
the vehicle is released.
T3-10-10
COMPONENT OPERATION / Axle
1
2
2
3
3
2
Brake Oil
Pressure
4
5
6
7
8
T4GB-03-10-005C
1 - End Plate
2 - Brake Ring
34-
Brake Disc
Differential Body
56-
• Operation
1
2
Brake Piston
Return Spring
78-
Disc Hub
Shaft
• Release
3
2
3
2
From
Brake Valve
1
5
2
3
2
3
2 To
Brake Valve
5
6
6
T4GB-03-10-007C
T3-10-11
T4GB-03-10-008C
COMPONENT OPERATION / Axle
FINAL DRIVE / AXLE SHAFT
Final drive is the device for finally decreasing the
speed in the power transmission system, and of the
planetary gear type. As for power transmission, the
power from the differential, transmitted from the shaft,
rotates the three planetary gears in the ring gear, and
transmits rotation of the planetary carrier to the axle
shaft through the planetary carrier.
Final
Drive
Axle Shaft
Ring Gear
Shaft
Housing
Planetary Carrier
Planetary Gear
T4GB-03-10-006C
T3-10-12
COMPONENT OPERATION / Brake Valve
OUTLINE
Brake valve is operated by the brake pedals. (Refer to
the Brake Circuit of SYSTEM/Hydraulic System)
Brake valve sends pilot pressure depending on the
extent of stepping the brake pedal, and operates the
front wheel or rear wheel service brake.
PHOTO
Service Brake
006
105
Brake Pedal
Brake Valve
T4GB-03-11-001C
T3-11-1
COMPONENT OPERATION / Brake Valve
Component Layout
1
2
3
4
Port T
5
6
Port BR1
Port M1
11
7
Port BR2
Port M2
10
8
9
T4GB-03-11-002C
1 - Pedal
2 - Roller
3 - Spool Input
4 - Spring
5 - Spring
6 - Spring
7 - Spool
8 - Spool
9 - Spring
T3-11-2
10 - Plunger
11 - Plunger
COMPONENT OPERATION / Brake Valve
PHOTO
1
Service Brake
105
5
7
From Port M2
of Charging Block
M1
From Port M2
of Charging Block
M2
BR1
BR2
T
To Front
Service Brake
To Rear
Service Brake
8
9
T4GB-03-11-003C
T3-11-3
COMPONENT OPERATION / Brake Valve
OPERATION
Not in Operation of Brake
1. When the brake valve is not in operation, the ports
(BR1 and BR2) are connected with the tank port
(T) because the spring (9) returns the spools (7
and 8) to the non-operating position.
2. Ports (M1 and M2) and the brake ports (BR1 and
BR2) are blocked by the spools (7 and 8), and the
pressure oil in the service brake accumulator is
retained.
Port T
T4GB-03-11-002C+
T3-11-4
COMPONENT OPERATION / Brake Valve
In Operation of Brake
1. When the brake valve is stepped, spool input (3)
is pushed through roller (2).
Spool input moves the spools (7 and 8) forward
through the spring (5).
2. When the spools (7 and 8) moves forward, ports
(BR1 and BR2) and port (T) are disconnected.
When spools (7 and 8) are further moved forward,
the ports (BR1 and BR2) and the ports (M1 and
M2) are connected, and the pressure oil of the
accumulator flows out from the ports (BR1 and
BR2), beginning braking operation.
3. Pressure oil on the ports (BR1 and BR2) end
passes the orifices installed in spools (7 and 8),
and works on the built-in plungers (10 and 11) of
spools (7 and 8) as the return force (oil pressure
rection force) of the spools (7 and 8). Summation
of this oil pressure reaction force and the load of
spring (9) balances with the load of spring (5), and
controls the brake oil pressure on the brake ports
(BR1 and BR2) end.
4. Deflection and load of spring (5) are fed back as
the stroke and operating force of the brake pedal,
and provides the operator with virtual operation
feeling.
2
3
5
T
BR1
M1
7
11
BR2
M2
8
10
9
T4GB-03-11-005C
T3-11-5
COMPONENT OPERATION / Brake Valve
In Brake Release
1. When the operating force is released, spool input
(3) is pushed back by spring (4).
2. Compression of spring (5) is released, and spools
(7 and 8) are returned to the non-operation
position by the summation of the oil pressure
reaction force working on the plunger and load of
the spring (9).
3. At this time, the ports (BR1 and BR2) and the port
(M1 and M2) are blocked by the spools (7 and 8),
and the ports (BR1 and BR2) are relieved to the
port (T).
Pressure oil on the ports (BR1 and BR2) end is
discharged to the port (T), and the brake operation
is released.
3
4
T
5
BR1
M1
7
BR2
M2
8
9
T4GB-03-11-006
T3-11-6
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Pilot Shutoff Valve
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Front Propeller Shaft
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Rear Propeller Shaft
111
8QLYHUVDO-RLQW
7*%&
7
COMPONENT OPERATION / Others
EMERGENCY STEERING CHECK BLOCK
A: from main pump
B: from emergency steering pump
C: pressure sensor port
D: to steering valve
E: to hydraulic oil tank
Emergency steering check block is installed between
the main pump and steering valve.
Built-in check valve is provided for preventing the
delivery oil of the emergency steering pump from
flowing to the main pump.
PHOTO
A
T/C Cooler Check Valve
B
032
Section X-X
B
A
C
Y
D
Section Y-Y
A
Y
E
C
D
E
X
X
T4GB-03-12-007C
T3-12-3
COMPONENT OPERATION / Others
EMERGENCY STEERING PUMP
(OPTIONAL)
Emergency steering pump is installed to be started in
case supply of the pressure oil from the main pump is
suddenly stopped for one reason or another, and for
supplying pressure oil to the steering valve in place of
the main pump until the time when the vehicle body is
moved to a safe place.
Emergency steering pump consists of the gear pump,
electric motor, relief valve, and check valve.
PHOTO
Emergency
Steering
081
Electric Motor Part
Gear Pump Part
Relief Valve
Check Valve
T4GB-03-12-008C
T3-12-4
INTRODUCTION
TO THE READER
• This manual is written for an experienced technician
to provide technical information needed to maintain
and repair this machine.
• Be sure to thoroughly read this manual for correct product information and service procedures.
• If you have any questions or comments, at if you
found any errors regarding the contents of this
manual, please contact using “Service Manual
Revision Request Form” at the end of this manual.
(Note: Do not tear off the form. Copy it for usage.):
Publications Marketing & Product Support
Hitachi Construction Machinery Co. Ltd.
TEL: 81-29-832-7084
FAX: 81-29-831-1162
ADDITIONAL REFERENCES
• Please refer to the materials listed below in addition
to this manual.
• The Operator’s Manual
• The Parts Catalog
• The Engine Manual
• Parts Catalog of the Engine
• Hitachi Training Material
MANUAL COMPOSITION
• This manual consists of three portions: the Technical Manual (Operational Principle), the Technical
Manual (Troubleshooting) and the Workshop Manual.
• Information included in the Technical Manual
(Operational Principle):
technical information needed for redelivery and
delivery, operation and activation of all devices
and systems.
• Information included in the Technical Manual
(Troubleshooting):
technical information needed for operational performance tests, and troubleshooting procedures.
• Information included in the Workshop Manual:
technical information needed for maintenance
and repair of the machine, tools and devices
needed for maintenance and repair, maintenance
standards, and removal/installation and assemble/disassemble procedures.
PAGE NUMBER
• Each page has a number, located on the center
lower part of the page, and each number contains
the following information:
Example : T 1-3-5
Consecutive Page Number for Each Group
Group Number
Section Number
T: Technical Manual
W: Workshop Manual
IN-01
INTRODUCTION
SAFETY ALERT SYMBOL AND HEADLINE
NOTATIONS
In this manual, the following safety alert symbol and
signal words are used to alert the reader to the
potential for personal injury of machine damage.
This is the safety alert symbol. When you see this
symbol, be alert to the potential for personal injury.
Never fail to follow the safety instructions prescribed
along with the safety alert symbol.
The safety alert symbol is also used to draw attention
to component/part weights.
To avoid injury and damage, be sure to use appropriate lifting techniques and equipment when lifting
heavy parts.
•
CAUTION:
Indicated potentially hazardous situation which
could, if not avoided, result in personal injury or
death.
• IMPORTANT:
Indicates a situation which, if not conformed to the
instructions, could result in damage to the machine.
•
NOTE:
Indicates supplementary technical information or
know-how.
UNITS USED
• SI Units (International System of Units) are used in
Example : 24.5 MPa (250 kgf/cm2, 3560 psi)
this manual.
MKSA system units and English units are also
indicated in parenthheses just behind SI units.
Quantity
Length
Volume
Weight
Force
Torque
To Convert
From
mm
mm
L
L
m3
kg
N
N
N⋅m
N⋅m
Into
in
ft
US gal
US qt
yd3
lb
kgf
lbf
kgf⋅m
lbf⋅ft
A table for conversion from SI units to other system
units is shown below for reference purposees.
Quantity
Multiply By
0.03937
0.003281
0.2642
1.057
1.308
2.205
0.10197
0.2248
1.0197
0.7375
Pressure
Power
Temperature
Velocity
Flow rate
IN-02
To Convert
From
MPa
MPa
kW
kW
°C
km/h
min-1
L/min
mL/rev
Into
kgf/cm2
psi
PS
HP
°F
mph
rpm
US gpm
cc/rev
Multiply By
10.197
145.0
1.360
1.341
°C×1.8+32
0.6214
1.0
0.2642
1.0
SAFETY
RECOGNIZE SAFETY INFORMATION
• These are the SAFETY ALERT SYMBOLS.
• When you see these symbols on your machine or
in operator`s manual, be alert to the potential for
personal injury.
• Follow recommended precautions and safe operating practices.
001-E01A-0001
SA-688
UNDERSTAND SIGNAL WORDS
• On machine safety signs, signal words designating
the degree or level of hazard - DANGER, WARNING,
or CAUTION - are used with the safety alert symbol.
• DANGER indicates an imminently hazardous
situation which, if not avoided, will result in death
or serious injury.
• WARNING indicates a potentially hazardous
situation which, if not avoided, could result in
death or serious injury.
• CAUTION indicates a potentially hazardous
situation
• which, if not avoided, may result in minor or
moderate injury.
• DANGER or WARNING safety signs are located
near specific hazards. General precautions are
listed on CAUTION safety signs.
• Some safety signs don’t use any of the designated signal words above after the safety alert
symbol are occasionally used on this machine.
• To avoid confusing machine protection with personal safety messages, a signal word IMPORTANT indicates a situation which, if not avoided,
could result in damage to the machine.
•
NOTE indicates an additional explanation for
an element of information.
002-E01A-1223
SA-1
SA-1223
SAFETY
FOLLOW SAFETY INSTRUCTIONS
• Carefully read and follow all safety signs on the
•
•
•
•
•
machine and all safety messages in operator`s
manual.
Safety signs should be installed, maintained and
replaced when necessary.
• If a safety sign or operator`s manual is damaged
or missing, order a replacement from your authorized dealer in the same way you order other
replacement parts (be sure to state machine
model and serial number when ordering).
Learn how to operate the machine and its controls
correctly and safely.
Allow only trained, qualified, authorized personnel to
operate the machine.
Keep your machine in proper working condition.
• Unauthorized modifications of the machine may
impair its function and/or safety and affect machine life.
• Do not modify any machine parts without authorization.
Failure to do so may deteriorate the part safety,
function, and/or service life. In addition, personal
accident, machine trouble, and/or damage to
material caused by unauthorized modifications
will void Hitachi Warranty Policy.
• Do not use attachments and/or optional parts or
equipment not authorized by Hitachi. Failure to do
so may deteriorate the safety, function, and/or
service life of the machine. In addition, personal
accident, machine trouble, and/or damage to
material caused by using unauthorized attachments and/or optional parts or equipment will void
Hitachi Warranty Policy.
The safety messages in this SAFETY chapter are
intended to illustrate basic safety procedures of
machines. However it is impossible for these safety
messages to cover every hazardous situation you
may encounter. If you have any questions, you
should first consult your supervisor and/or your authorized dealer before operating or performing
maintenance work on the machine.
SA-003
003-E01B-0003
PREPARE FOR EMERGENCIES
• Be prepared if a fire starts or if an accident occurs.
• Keep a first aid kit and fire extinguisher on hand.
• Thoroughly read and understand the label attached on the fire extinguisher to use it properly.
• To ensure that a fire-extinguisher can be always
used when necessary, check and service the
fire-extinguisher at the recommended intervals as
specified in the fire-extinguisher manual.
• Establish emergency procedure guidelines to
cope with fires and accidents.
• Keep emergency numbers for doctors, ambulance service, hospital, and fire department
posted near your telephone.
004-E01A-0437
SA-2
SA-437
SAFETY
WEAR PROTECTIVE CLOTHING
• Wear close fitting clothing and safety equipment
appropriate to the job.
You may need:
A hard hat
Safety shoes
Safety glasses, goggles, or face shield
Heavy gloves
Hearing protection
Reflective clothing
Wet weather gear
Respirator or filter mask.
Be sure to wear the correct equipment and clothing
for the job. Do not take any chances.
SA-438
• Avoid wearing loose clothing, jewelry, or other
items that can catch on control levers or other
parts of the machine.
• Operating equipment safely requires the full attention of the operator. Do not wear radio or music
headphones while operating the machine.
005-E01A-0438
PROTECT AGAINST NOISE
• Prolonged exposure to loud noise can cause impairment or loss of hearing.
• Wear a suitable hearing protective device such as
earmuffs or earplugs to protect against objectionable or uncomfortably loud noises.
006-E01A-0434
SA-434
NSPECT MACHINE
• Inspect your machine carefully each day or shift by
walking around it before you start it to avoid personal injury.
• In the walk-around inspection be sure to cover all
points described in the “PRE-START INSPECTION” chapter in the operator’s manual.
007-E01A-0435
SA-435
SA-3
SAFETY
GENERAL PRECAUTIONS FOR CAB
• Before entering the cab, thoroughly remove all dirt
•
•
•
•
•
•
and/or oil from the soles of your work boots. If any
controls such as a pedal is operated while with
dirt and/or oil on the soles of the operator’s work
boots the operator’s foot may slip off the pedal,
possibly resulting in a personal accident.
Do not leave parts and/or tools lying around the
operator’s seat. Store them in their specified locations.
Avoid storing transparent bottles in the cab. Do
not attach any transparent type window decorations on the windowpanes as they may focus
sunlight, possibly starting a fire.
Refrain from listening to the radio, or using music
headphones or mobile telephones in the cab
while operating the machine.
Keep all flammable objects and/or explosives
away from the machine.
After using the ashtray, always cover it to extinguish the match and/or tobacco.
Do not leave cigarette lighters in the cab. When
the temperature in the cab increases, the lighter
may explode.
524-E01A-0000
SA-4
SAFETY
USE HANDHOLDS AND STEPS
• Falling is one of the major causes of personal injury.
• When you get on and off the machine, always
face the machine and maintain a three-point
contact with the steps and handrails.
• Do not use any controls as hand-holds.
• Never jump on or off the machine. Never mount or
dismount a moving machine.
• Be careful of slippery conditions on platforms,
steps, and handrails when leaving the machine.
008-E01A-0439
SA-439
ADJUST THE OPERATOR'S SEAT
• A poorly adjusted seat for either the operator or for
the work at hand may quickly fatigue the operator
leading to misoperations.
• The seat should be adjusted whenever changing
the operator for the machine.
• The operator should be able to fully depress the
pedals and to correctly operate the control levers
with his back against the seat back.
• If not, move the seat forward or backward, and
check again.
• Adjust the rear view mirror position so that the
best rear visibility is obtained from the operator’s
seat. If the mirror is broken, immediately replace it
with a new one.
009-E01A-0462
ENSURE SAFETY BEFORE RISING FROM
OR LEAVING OPERATOR’S SEAT
• Before rising from the operator’s seat to open/close
either side window or to adjust the seat position, be
sure to first lower the front attachment to the ground
and then move the pilot control shut-off lever to the
LOCK position. Failure to do so may allow the machine to unexpectedly move when a body part unintentionally comes in contact with a control lever,
possibly resulting in serious personal injury or death.
• Before leaving the machine, be sure to first lower
the front attachment to the ground and then move
the pilot control shut-off lever to the LOCK position. Turn the key switch OFF to stop the engine.
• Before leaving the machine, close all windows,
doors, and access covers and lock them up.
SA-5
SA-462
SAFETY
FASTEN YOUR SEAT BELT
• If the machine should overturn, the operator may
become injured and/or thrown from the cab. Additionally the operator may be crushed by the overturning machine, resulting in serious injury or death.
• Prior to operating the machine, thoroughly examine webbing, buckle and attaching hardware. If
any item is damaged or worn, replace the seat
belt or component before operating the machine.
• Be sure to remain seated with the seat belt securely fastened at all times when the machine is
in operation to minimize the chance of injury from
an accident.
• We recommend that the seat belt be replaced
every three years regardless of its apparent condition.
SA-237
010-E01A-0237
MOVE AND OPERATE MACHINE SAFELY
• Bystanders can be run over.
• Take extra care not to run over bystanders. Confirm the location of bystanders before moving, or
operating the machine.
• Always keep the travel alarm and horn in working
condition (if equipped). It warns people when the
machine starts to move.
• Use a signal person when moving, swinging, or
operating the machine in congested areas. Coordinate hand signals before starting the machine.
• Use appropriate illumination. Check that all lights
are operable before operating the machine. If any
faulty illumination is present, immediately repair it.
SA-398
011-E01A-0398
HANDLE STARTING AIDS SAFELY
Starting fluid:
• Starting fluid is highly flammable.
• Keep all sparks and flame away when using it.
• Keep starting fluid well away from batteries and
cables.
• Remove container from machine if engine does
not need starting fluid.
• To prevent accidental discharge when storing a
pressurized container, keep the cap on the container, and store it in a cool, well-protected location.
• Do not incinerate or puncture a starting fluid container.
036-E01A-0293-3
SA-6
SA-293
SAFETY
OPERATE
SEAT
ONLY
FROM
OPERATOR'S
• Inappropriate engine starting procedures may cause
the machine to runaway, possibly resulting in serious injury or death.
• Start the engine only when seated in the operator's seat.
• NEVER start the engine while standing on the
track or on ground.
• Do not start engine by shorting across starter
terminals.
• Before starting the engine, confirm that all control
levers are in neutral.
• Before starting the engine, confirm the safety
around the machine and sound the horn to alert
bystanders.
SA-431
012-E01B-0431
JUMP STARTING
• Battery gas can explode, resulting in serious injury.
• If the engine must be jump started, be sure to
•
•
•
•
follow the instructions shown in the “OPERATING
THE ENGINE” chapter in the operator’s manual.
The operator must be in the operator’s seat so
that the machine will be under control when the
engine starts.
Jump starting is a two-person operation.
Never use a frozen battery.
Failure to follow correct jump starting procedures
could result in a battery explosion or a runaway
machine.
SA-032
S013-E01A-0032 SA-032
SA-7
SAFETY
INVESTIGATE JOB SITE BEFOREHAND
• When working at the edge of an excavation or on a
road shoulder, the machine could tip over, possibly
resulting in serious injury or death.
• Investigate the configuration and ground conditions of the job site beforehand to prevent the
machine from falling and to prevent the ground,
stockpiles, or banks from collapsing.
• Make a work plan. Use machines appropriate to
the work and job site.
• Reinforce ground, edges, and road shoulders as
necessary. Keep the machine well back from the
edges of excavations and road shoulders.
• When working on an incline or on a road shoulder,
employ a signal person as required.
• Confirm that your machine is equipped a FOPS
cab before working in areas where the possibility
of falling stones or debris exist.
• When the footing is weak, reinforce the ground
before starting work.
• When working on frozen ground, be extremely
alert. As ambient temperatures rise, footing becomes loose and slippery.
• Beware the possibility of fire when operating the
machine near flammable objects such as dry
grass.
015-E01B-0447
SA-8
SA-447
SAFETY
EQUIPMENT OF HEAD GUARD, ROPS,
FOPS
In case the machine is operated in areas where the
possibility of falling stones or debris exist, equip a
head guard, ROPS, or FOPS according to the potential hazardous conditions. (The standard cab for this
machine corresponds to ROPS and FOPS.)
ROPS: Roll-Over Protective Structure
FOPS: Falling Object Protective Structure
SA-521
PROVIDE SIGNALS FOR JOBS INVOLVING MULTIPLE NUMBERS OF MACHINES
• For jobs involving multiple numbers of machines,
provide signals commonly known by all personnel
involved. Also, appoint a signal person to coordinate
the job site. Make sure that all personnel obey the
signal person’s directions.
018-E01A-0481
SA-481
SA-9
SAFETY
KEEP RIDERS OFF MACHINE
• Riders on machine are subject to injury such as being struck by foreign objects and being thrown off
the machine.
• Only the operator should be on the machine.
Keep riders off.
• Riders also obstruct the operator’s view, resulting
in the machine being operated in an unsafe
manner.
014-E01B-0427
SA-427
DRIVE SAFELY
• Beware of the possibility of slipping and/or turning
over the machine when driving on a slope.
• When driving on level ground, hold the bucket at
mark (A) 400 to 500 mm above the ground as illustrated.
• Avoid driving over any obstacles.
• Drive the machine slowly when driving on rough
terrain.
• Avoid quick direction changes. Failure to do so
may cause the machine to turn over.
• If the engine stops while driving, the steering
function becomes inoperative. Immediately stop
the machine by applying the bake to prevent
personal accident.
SA-448
019-E07A-0448
DRIVE MACHINE SAFELY (WORK SITE)
• Before driving the machine, always confirm that the
steering wheel/F-N-R lever direction corresponds to
the direction you wish to drive.
• Be sure to detour around any obstructions.
• Driving on a slope may cause the machine to slip or
overturn, possibly resulting in serious injury or
death.
• When driving up or down a slope, keep the bucket
facing the direction of travel, approximately 200 to
300 mm (approximately 8 to 12 in) (A) above the
ground.
• If the machine starts to skid or becomes unstable,
immediately lower the bucket to the ground and
stop.
SA-449
SA-450
• Driving across the face of a slope or steering on a
slope may cause the machine to skid or overturn. If
the direction must be changed, move the machine to
level ground, then, change the direction to ensure
safe operation.
019-E05B-0515
SA-451
SA-10
SAFETY
DRIVE SAFELY WITH BUCKET LOADED
• If the machine is incorrectly operated while driving
with the bucket loaded, turning over of the machine
may result. Be sure to follow all the instructions indicated below.
• When driving the machine on a job site with the
bucket loaded, hold the bucket as low as possible
to keep the machine balanced and to have good
visibility.
• Do not exceed the rated load capacity. Always
operate the machine within the rated load capacity.
• Avoid fast starts, stops, and quick turns. Failure to
do so may result in personal injury and/or death.
• Avoid rapid drive direction changes which could
possibly cause personal injury and/or death.
SA-400
051-E02A-0400
DRIVE ON SNOW SAFELY
• Beware of the possibility of slipping or turning over
the machine when driving on frozen snow surfaces.
• The machine may slip more easily than expected
on frozen snow surfaces even if the inclination is
small. Reduce speed when driving. Avoid fast
starts, stops and quick turns.
• Road shoulder and/or set-up utilities covered with
snow are difficult to locate. Be sure where they
are before removing snow.
• Be sure to use tire chains when driving on snow.
• Avoid applying the brake for quick stops on snow.
If a quick stop is required, lower the bucket to the
ground.
SA-452
052-E02A-0452
TRAVEL ON PUBLIC ROADS SAFELY
• This machine is not allowed to drive on public loads
with the bucket loaded.
• Be sure to empty the bucket.
• Hold the bucket at mark (A) 400 to 500 mm above
the road surface as illustrated.
053-E02A-0453
SA-453
SA-11
SAFETY
AVOID INJURY FROM ROLLAWAY ACCIDENTS
• Death or serious injury may result if you attempt to
mount or stop a moving machine.
To avoid rollaways:
• Select level ground when possible to park machine.
• Do not park the machine on a grade.
• Lower the bucket to the ground.
• Place the F-N-R lever in neutral, and put the park
brake switch in the ON (parking brake) position.
• Run the engine at slow idle speed without load for
5 minutes to cool down the engine.
• Stop the engine and remove the key from the key
switch.
• Pull the lock lever to LOCK position.
• Block both tires and lower the bucket to the
ground.
• Position the machine to prevent rolling.
• Park a reasonable distance from other machines.
SA-457
020-E02A-0516
SA-458
SA-12
SAFETY
AVOID ACCIDENTS FROM BACKING UP
AND TURNING
• Make sure no one is working under or close to the
machine before backing up or turning the machine
to avoid personal injury and/or death by being run
over or entangled in the machine.
• Keep all personnel away from the machine by
sounding the horn and/or using hand signals. Use
extra care to be sure no one is in from the articulation area before turning the machine.
• Keep windows, mirrors, and lights in good condition.
• Reduce travel speed when dust, heavy rain, fog,
etc., reduce the visibility.
• In case good visibility is not obtained, use a signal
person to guide you.
SA-383
021-E02A-0517
SA-312
SA-13
SAFETY
AVOID POSITIONING
ANYONE
BUCKET
OVER
• Never allow the bucket to pass over co-workers
and/or the dump truck operator’s cab. Falling soil
from the bucket or contact with bucket may cause
serious personal accidents and/or damage to the
machine.
• Avoid carrying the bucket over the co-workers to
ensure safe operation.
023-E02A-0518
SA-518
AVOID TIPPING
DO NOT ATTEMPT TO JUMP CLEAR OF TIPPING
MACHINE. MACHINE WILL TIP OVER FASTER
THAN YOU CAN JUMP FREE, POSSIBLY RESULTING IN SERIOUS PERSONAL INJURY OR
DEATH. IF TIPPING OVER OF THE MACHINE IS
PREDICTED, SECURELY HOLD THE STEERING
WHEEL TO PREVENT YOUR BODY FROM BEING
THROWN OUT OF THE MACHINE.
MACHINE WILL TIP OVER FASTER THAN YOU
CAN JUMP FREE
FASTEN YOUR SEAT BELT
• The danger of tipping is always present when operating on a grade, possibly resulting in serious injury
or death.
To avoid tipping:
• Be extra careful before operating on a grade.
• Prepare machine operating area flat.
• Keep the bucket low to the ground and close to
the machine.
• Reduce operating speeds to avoid tipping or slipping.
• Avoid changing direction when traveling on
grades.
• NEVER attempt to travel across a grade steeper
than 5 degrees if crossing the grade is unavoidable.
• Reduce swing speed as necessary when swinging loads.
• Be careful when working on frozen ground.
• Temperature increases will cause the ground to
become soft and make ground travel unstable.
SA-14
SA-463
SAFETY
NEVER UNDERCUT A HIGH BANK
• The edges could collapse or a land slide could occur
causing serious injury or death.
026-E01A-0519
SA-519
DIG WITH CAUTION
Before digging, check the location of cables, gas lines,
and water lines.
027-E01A-0396
SA-396
PERFORM TRUCK LOADING SAFELY
• Do not operate the machine involuntarily. Unexpected machine movement may cause personal injury and/or death.
• Do not lower the bucket with the loader control
lever in the FLOAT position. The bucket may free
fall, possibly causing personal injury and/or death.
• Always select a level surface for truck loading.
028-E01A-397
SA-397
SA-15
SAFETY
AVOID POWER LINES
Serious injury or death can result from contact with
electric lines.
Never move any part of the machine or load closer to
any electric line than 3 m (10 ft) plus twice the line
insulator length.
29-E01A-0455
SA-455
PRECAUTIONS FOR OPERATION
• If the front attachment or any part of the machine
comes in contact with an overhead obstacle, both
the machine and the overhead obstacle may become damaged, and personal injury may result.
• Take care to avoid coming in contact with overhead obstacles with the bucket or arm during operation.
PRECAUTIONS FOR LIGHTENING
• The machine is vulnerable to lighting strikes.
• In the event of an electrical storm, immediately
stop operation, and lower the bucket to the
ground. Evacuate to a safe place far away from
the machine.
• After the electrical storm has passed, check all of
the machine safety devices for any failure. If any
failed safety devices are found, operate the machine only after repairing them.
OBJECT HANDLING
• If a lifted load should fall, any person nearby may be
struck by the falling load or may be crushed underneath it, resulting in serious injury or death.
• When using the machine for craning operations,
be sure to comply with all local regulations.
• Do not use damaged chains or frayed cables,
sables, slings, or ropes.
• Before craning, position the upperstructure with
the position of the bucket support located on the
chassis at the front.
• Move the load slowly and carefully. Never move it
suddenly.
• Keep all persons well away from the load.
• Never move a load over a person's head.
• Do not allow anyone to approach the load until it
is safely and securely situated on supporting
blocks or on the ground.
• Never attach a sling or chain to the bucket teeth.
They may come off, causing the load to fall.
032-E01A-0132
SA-16
SA-132
SAFETY
PROTECT AGAINST FLYING DEBRIS
• If flying debris hit eyes or any other part of the body,
serious injury may result.
• Guard against injury from flying pieces of metal or
debris; wear goggles or safety glasses.
• Keep bystanders away from the working area
before striking any object.
031-E01A-0432
SA-432
PARK MACHINE SAFELY
To avoid accidents:
• Park machine on a firm, level surface.
• Lower bucket to the ground.
• Place the F-N-R lever in neutral, and put the park
brake switch in the ON (parking brake) position.
• Run engine at slow idle speed without load for 5
minutes.
• Turn key switch to OFF to stop engine.
• Remove the key from the key switch.
• Lower the lock lever to the LOCK position.
• Close windows, roof vent, and cab door.
• Lock all access doors and compartments.
033-E07B-0456
SA-17
SA-456
SAFETY
STORE ATTACHMENTS SAFELY
• Stored attachments such as buckets, hydraulic
hammers, and blades can fall and cause serious
injury or death.
• Securely store attachments and implements to
prevent falling. Keep children and bystanders
away from storage areas.
504-E01A-0034
SA-034
TRANSPORT SAFELY
• Take care the machine may turn over when loading
or unloading the machine onto or off of a truck or
trailer.
• Observe the related regulations and rules for safe
transportation.
• Select an appropriate truck or trailer for the machine to be transported.
• Be sure to use a signal person.
• Always follow the following precautions for loading or unloading:
1. Select solid and level ground.
2. Always use a ramp or deck strong enough to
support the machine weight.
3. Use the low speed gear.
4. Never steer the machine while on the ramp. If the
traveling direction must be changed while the
ramp, unload the machine from the ramp, reposition the machine on the ground, then try loading
again.
5. After loading, install the lock bar to securely hold
the articulation mechanism.
6. Wedge the front and rear of tires. Securely hold
the machine to the truck or trailer deck with wire
ropes.
Be sure to further follow the details described in the
TRANSPORTING section.
035-E07A-0454
SA-18
Less than 15°
SA-454
SAFETY
HANDLE FLUIDS SAFELY-AVOID FIRES
• Handle fuel with care; it is highly flammable. If fuel
ignites, an explosion and/or a fire may occur, possibly resulting in serious injury or death.
• Do not refuel the machine while smoking or when
near open flame or sparks.
• Always stop the engine before refueling the machine.
• Fill the fuel tank outdoors.
• All fuels, most lubricants, and some coolants are
flammable.
• Store flammable fluids well away from fire hazards.
• Do not incinerate or puncture pressurized containers.
• Do not store oily rags; they can ignite and burn
spontaneously.
• Securely tighten the fuel and oil filler cap.
SA-018
034-E01A-0496
SA-019
SA-19
SAFETY
PRACTICE SAFE MAINTENANCE
To avoid accidents:
• Understand service procedures before starting
work.
• Keep the work area clean and dry.
• Do not spray water or steam inside cab.
• Never lubricate or service the machine while it is
moving.
• Keep hands, feet and clothing away from
power-driven parts.
Before servicing the machine:
1. Park the machine on a level surface.
2. Lower the bucket to the ground.
3. Turn the auto-idle switch off.
4. Run the engine at slow idle speed without load for
5 minutes.
5. Turn the key switch to OFF to stop engine.
6. Relieve the pressure in the hydraulic system by
moving the control levers several times.
7. Remove the key from the switch.
8. Attach a “Do Not Operate” tag on the control
lever.
9. Lower the lock lever to the LOCK position.
10. Lock bar connects the front and rear frames.
11. Allow the engine to cool.
SA-028
• If a maintenance procedure must be performed
•
•
•
•
•
•
with the engine running, do not leave machine
unattended.
Never work under a machine raised by the lift
arm.
Inspect certain parts periodically and repair or replace as necessary. Refer to the section discussing that part in the “MAINTENANCE” chapter of
operator`s manual.
Keep all parts in good condition and properly installed.
Fix damage immediately. Replace worn or broken
parts. Remove any buildup of grease, oil, or debris.
When cleaning parts, always use nonflammable
detergent oil. Never use highly flammable oil such
as fuel oil and gasoline to clean parts or surfaces.
Disconnect battery ground cable (-) before making adjustments to electrical systems or before
performing welding on the machine.
SA-312
SA-134
500-E02C-0520
SA-527
SA-20
SAFETY
• Sufficiently illuminate the work site. Use a maintenance work light when working under or inside
the machine.
• Always use a work light protected with a guard. In
case the light bulb is broken, spilled fuel, oil, antifreeze fluid, or window washer fluid may catch fire.
SA-037
WARN OTHERS OF SERVICE WORK
• Unexpected machine movement can cause serious
injury.
• Before performing any work on the machine, attach a “Do Not Operate” tag on the control lever.
This tag is available from your authorized dealer.
501-E01A-0287
SS2045102
SUPPORT MACHINE PROPERLY
• Never attempt to work on the machine without securing the machine first.
• Always lower the attachment to the ground before
you work on the machine.
• If you must work on a lifted machine or attachment, securely support the machine or attachment. Do not support the machine on cinder
blocks, hollow tires, or props that may crumble
under continuous load. Do not work under a machine that is supported solely by a jack.
519-E01A-0527
SA-527
STAY CLEAR OF MOVING PARTS
• Entanglement in moving parts can cause serious
injury.
• To prevent accidents, care should be taken to
ensure that hands, feet, clothing, jewelry and hair
do not become entangled when working around
rotating parts.
502-E01A-0026
SA-026
SA-21
SAFETY
SUPPORT MAINTENANCE PROPERLY
• Explosive separation of a tire and rim parts can
cause serious injury or death.
• Do not attempt to mount a tire unless you have
the proper equipment and experience to perform
the job. Have it done by your authorized dealer or
a qualified repair service.
• Always maintain the correct tire pressure. DO
NOT inflate tire above the recommended pressure.
• When inflating tires, use a chip-on chuck and extension hose long enough to allow you to stand to
one side and not in front of or over the tire assembly. Use a safety cage it available.
• Inspect tires and wheels daily. Do not operate with
low pressure, cuts bubbles, damaged rims, or
missing lug bolts and nuts.
• Never cut or weld on an inflated tire or rim assembly. Heat from welding could cause an increase in pressure and may result in tire explosion.
SA-249
521-E02A-0249
PREVENT PARTS FROM FLYING
• Travel reduction gears are under pressure.
• As pieces may fly off, be sure to keep body and
face away from AIR RELEASE PLUG to avoid
injury.
• GEAR OIL is hot. Wait for GEAR OIL to cool, then
gradually loosen AIR RELEASE PLUG to release
pressure.
503-E03A-0344
SA-344
SA-22
SAFETY
PREVENT BURNS
Hot spraying fluids:
• After operation, engine coolant is hot and under
pressure. Hot water or steam is contained in the
engine, radiator and heater lines.
Skin contact with escaping hot water or steam can
cause severe burns.
• To avoid possible injury from hot spraying water.
DO NOT remove the radiator cap until the engine
is cool. When opening, turn the cap slowly to the
stop. Allow all pressure to be released before
removing the cap.
• The hydraulic oil tank is pressurized. Again, be
sure to release all pressure before removing the
cap.
SA-039
Hot fluids and surfaces:
• Engine oil, gear oil and hydraulic oil also become
hot during operation.
The engine, hoses, lines and other parts become
hot as well.
• Wait for the oil and components to cool before
starting any maintenance or inspection work.
SA-225
505-E01B-0498
REPLACE
CALLY
RUBBER
HOSES
PERIODI-
• Rubber hoses that contain flammable fluids under
pressure may break due to aging, fatigue, and
abrasion. It is very difficult to gauge the extent of
deterioration due to aging, fatigue, and abrasion of
rubber hoses by inspection alone.
• Periodically replace the rubber hoses. (See the
page of “Periodic replacement of parts” in the operator’s manual.)
• Failure to periodically replace rubber hoses may
cause a fire, fluid injection into skin, or the front attachment to fall on a person nearby, which may result in severe burns, gangrene, or otherwise serious
injury or death.
S506-E01A-0019
SA-23
SA-019
SAFETY
AVOID HIGH-PRESSURE FLUIDS
• Fluids such as diesel fuel or hydraulic oil under
pressure can penetrate the skin or eyes causing serious injury, blindness or death.
• Avoid this hazard by relieving pressure before
disconnecting hydraulic or other lines.
• Tighten all connections before applying pressure.
• Search for leaks with a piece of cardboard; take
care to protect hands and body from
high-pressure fluids. Wear a face shield or goggles for eye protection.
• If an accident occurs, see a doctor familiar with
this type of injury immediately. Any fluid injected
into the skin must be surgically removed within a
few hours or gangrene may result.
SA-031
507-E03A-0499
SA-292
SA-044
SA-24
SAFETY
PREVENT FIRES
Check for Oil Leaks:
• Fuel, hydraulic oil and lubricant leaks can lead to
fires.
• Check for oil leaks due to missing or loose clamps,
kinked hoses, lines or hoses that rub against each
other, damage to the oil-cooler, and loose
oil-cooler flange bolts.
• Tighten, repair or replace any missing, loose or
damaged clamps, lines, hoses, oil-cooler and
oil-cooler flange bolts.
• Do not bend or strike high-pressure lines.
• Never install bent or damaged lines, pipes, or
hoses.
Check for Shorts:
• Short circuits can cause fires.
• Clean and tighten all electrical connections.
• Check before each shift or after eight(8) to ten(10)
hours operation for loose, kinked, hardened or
frayed electrical cables and wires.
• Check before each shift or after eight(8) to ten(10)
hours operation for missing or damaged terminal
caps.
• DO NOT OPERATE MACHINE if cable or wires
are loose, kinked, etc..
Clean up Flammables:
• Spilled fuel and oil, and trash, grease, debris, accumulated coal dust, and other flammables may
cause fires.
• Prevent fires by inspecting and cleaning the machine daily and by removing spilled or accumulated flammables immediately.
Check Key Switch:
• If a fire breaks out, failure to stop the engine will
escalate the fire, hampering fire fighting.
Always check key switch function before operating
the machine every day:
1. Start the engine and run it at slow idle.
2. Turn the key switch to the OFF position to confirm
that the engine stops.
• If any abnormalities are found, be sure to repair
them before operating the machine.
508-E02B-0019
Check Heat Shields:
• Damaged or missing heat shields may lead to fires.
• Damaged or missing heat shields must be repaired or replaced before operating the machine.
508-E02A-0393
SA-25
SA-019
SAFETY
EVACUATING IN CASE OF FIRE
• If a fire breaks out, evacuate the machine in the following way:
• Stop the engine by turning the key switch to the
OFF position if there is time.
• Use a fire extinguisher if there is time.
• Exit the machine.
518-E01A-0393
SA-393
BEWARE OF EXHAUST FUMES
• Prevent asphyxiation. Engine exhaust fumes can
cause sickness or death.
• If you must operate in a building, be sure there is
adequate ventilation. Either use an exhaust pipe
extension to remove the exhaust fumes or open
doors and windows to bring enough outside air
into the area.
509-E01A-0016
SA-016
PRECAUTIONS
GRINDING
FOR
WELDING
AND
• Welding may generate gas and/or small fires.
• Be sure to perform welding in a well ventilated
and prepared area. Store flammable objects in a
safe place before starting welding.
• Only qualified personnel should perform welding.
Never allow an unqualified person to perform
welding.
• Grinding on the machine may create fire hazards.
Store flammable objects in a safe place before
starting grinding.
• After finishing welding and grinding, recheck that
there are no abnormalities such as the area surrounding the welded area still smoldering.
523-E01A-0818
SA-26
SA-818
SAFETY
AVOID HEATING NEAR PRESSURIZED
FLUID LINES
• Flammable spray can be generated by heating near
pressurized fluid lines, resulting in severe burns to
yourself and bystanders.
• Do not heat by welding, soldering, or using a torch
near pressurized fluid lines or other flammable
materials.
• Pressurized lines can be accidentally cut when
heat goes beyond the immediate flame area. Install temporary fireresistant guards to protect
hoses or other materials before engaging in
welding, soldering, etc..
SA-030
AVOID APPLYING HEAT TO LINES CONTAINING FLAMMABLE FLUIDS
• Do not weld or flame cut pipes or tubes that contain flammable fluids.
• Clean them thoroughly with nonflammable solvent
before welding or flame cutting them.
510-E01B-0030
REMOVE PAINT BEFORE WELDING OR
HEATING
• Hazardous fumes can be generated when paint is
heated by welding, soldering, or using a torch. If
inhaled, these fumes may cause sickness.
• Avoid potentially toxic fumes and dust.
• Do all such work outside or in a well-ventilated
area. Dispose of paint and solvent properly.
• Remove paint before welding or heating:
1. If you sand or grind paint, avoid breathing the dust.
Wear an approved respirator.
2. If you use solvent or paint stripper, remove stripper with soap and water before welding. Remove
solvent or paint stripper containers and other
flammable material from area. Allow fumes to
disperse at least 15 minutes before welding or
heating.
511-E01A-0029
SA-27
SA-029
SAFETY
BEWARE OF ASBESTOS DUST
• Take care not to inhale dust produced in the work
site. Inhalation of asbestos fibers may be the cause
of lung cancer.
• Depending on the wok site conditions, the risk of
inhaling asbestos fiber may exist. Spray water to
prevent asbestos from becoming airborne. Do not
use compressed air.
• When operating the machine in a work site where
asbestos might be present, be sure to operate the
machine from the upwind side and wear a mask
rated to prevent the inhalation of asbestos.
• Keep bystanders out of the work site during operation.
• Asbestos might be present in imitation parts. Use
only genuine Hitachi Parts.
SA-029
PREVENT BATTERY EXPLOSIONS
• Battery gas can explode.
• Keep sparks, lighted matches, and flame away
from the top of battery.
• Never check battery charge by placing a metal
object across the posts. Use a voltmeter or hydrometer.
• Do not charge a frozen battery; it may explode.
Warm the battery to 16 °C (60 °F) first.
• Do not continue to use or charge the battery when
electrolyte level is lower than specified. Explosion
of the battery may result.
• Loose terminals may produce sparks. Securely
tighten all terminals.
SA-032
• Battery electrolyte is poisonous. If the battery should
explode, battery electrolyte may be splashed into
eyes, possibly resulting in blindness.
• Be sure to wear eye protection when checking
electrolyte specific gravity.
512-E01B-0032
SERVICE AIR CONDITIONING SYSTEM
SAFELY
• If spilled onto skin, refrigerant may cause a cold
contact burn.
• Refer to the instructions described on the container for proper use when handling the refrigerant.
• Use a recovery and recycling system to avoid
leaking refrigerant into the atmosphere.
• Never touch the refrigerant.
513-E01A-0405
SA-28
SA-405
SAFETY
HANDLE CHEMICAL PRODUCTS SAFELY
• Direct exposure to hazardous chemicals can cause
serious injury. Potentially hazardous chemicals used
with your machine include such items as lubricants,
coolants, paints, and adhesives.
• A Material Safety Data Sheet (MSDS) provides
specific details on chemical products: physical
and health hazards, safety procedures, and
emergency response techniques.
• Check the MSDS before you start any job using a
hazardous chemical. That way you will know exactly what the risks are and how to do the job
safely. Then follow procedures and use recommended equipment.
• See your authorized dealer for MSDS’s (available
only in English) on chemical products used with
your machine.
SA-309
515-E01A-0309
DISPOSE OF WASTE PROPERLY
• Improperly disposing of waste can threaten the environment and ecology. Potentially harmful waste
used with HITACHI equipment includes such items
as oil, fuel, coolant, brake fluid, filters, and batteries.
• Use leakproof containers when draining fluids. Do
not use food or beverage containers that may
mislead someone into drinking from them.
• Do not pour waste onto the ground, down a drain,
or into any water source.
• Air conditioning refrigerants escaping into the air
can
• damage the Earth’s atmosphere. Government
regulations may require a certified air conditioning
service center to recover and recycle used air
conditioning refrigerants.
• Inquire on the proper way to recycle or dispose of
waste from your local environmental or recycling
center, or from your authorized dealer.
516-E01A-0226
SA-29
SA-226
SAFETY
BEFORE RETURNING THE MACHINE TO
THE CUSTOMER
• After maintenance or repair work is complete,
confirm that:
• The machine is functioning properly, especially
the safety systems.
• Worn or damaged parts have been repaired or
replaced.
S517-E01A-0435
SA-435
SA-30
SECTION AND GROUP
CONTENTS
TECHNICAL MANUAL
(Troubleshooting)
SECTION 4 OPERATIONAL
PERFORMANCE TEST
Group
Group
Group
Group
Group
Group
1 Introduction
2 Standard
3 Engine Test
4 Wheel Loader Test
5 Component Test
6 Adjustment
SECTION 5 TROUBLESHOOTING
Group
Group
Group
Group
Group
Group
Group
Group
1 Diagnosing Procedure
2 Dr-ZX
3 e-Whell
4 Component Layout
5 Troubleshooting A
6 Troubleshooting B
7 Troubleshooting C
8 Electrical System Inspection
TECHNICAL MANUAL (Operational Principle)
All information, illustrations and specifications in this manual are based on
the latest product information available
at the time of publication. The right is
reserved to make changes at any time
without notice.
COPYRIGHT (C) 2006
Hitachi Construction Machinery Co., Ltd.
Tokyo, Japan
All rights reserved
SECTION 1 GENERAL
SECTION 3 COMPONENT OPERATION
Group 1 Specification
Group 1 Pump Device
Group 2 Component Layout
Group 2 Control Valve
Group 3 Component Specifications Group 3 Hydraulic Fan Motor
SECTION 2 SYSTEM
Group 4 Steering Pilot Valve
Group 5 Steering Valve
Group 1 Control System
Group 6 Pilot Valve
Group 2 ECM System
Group 3 Hydraulic System
Group 7 Charging Block
Group 4 Electrical System
Group 8 Ride Control Valve
Group 9 Drive Unit
Group 10 Axle
Group 11 Brake Valve
Group 12 Others
WORKSHOP MANUAL
SECTION 1 GENERAL INFORMATION
Group 1 Precautions for Disassembling
and Assembling
Group 2 Tightening Torque
Group 3 Painting
Group 4 Bleeding Air from Hydraulic
Oil Tank
SECTION 2 BASE MACHINE (UPPER
STRUCTURE)
Group 1 Cab
Group 2 Counterweight
Group 3 Frame
Group 4 Pump Device
Group 5 Control Valve
Group 6 Pilot Valve
Group 7 Ride Control Valve
Group 8 Pilot Shutoff Valve
Group 9 Hydraulic Fan Motor
SECTION 3 BASE MACHINE (TRAVEL
SYSTEM)
Group 1 Tire
Group 2 Drive Unit
Group 3 Axle
Group 4 Propeller Shaft
Group 5 Brake Valve
Group 6 Charging Block
Group 7 Steering Pilot Valve
Group 8 Steering Valve
Group 9 Steering Cylinder
Group 10 Emergency Steering Pump Unit
(Optional)
SECTION 4 FRONT ATTACHMENT
Group 1 Front Attachment
Group 2 Cylinder
SECTION 5 ENGINE
SECTION 4
OPERATIONAL
PERFORMANCE TEST
CONTENTS
Group 1 Introduction
Group 4 Wheel Loader Test
Operational Performance Tests ................... T4-1-1
Travel Speed.................................................T4-4-1
Preparation for Performance Tests .............. T4-1-2
Service Brake Function Check .....................T4-4-2
Service Brake Wear Amount ........................T4-4-3
Group 2 Standard
Parking Brake Function Check.....................T4-4-4
Bucket and Bell Crank Stopper
Operational Performance
Standard Table ........................................... T4-2-1
Clearances ..................................................T4-4-6
Main Pump P-Q Curve............................... T4-2-11
Hydraulic Cylinder Cycle Time .....................T4-4-8
Sensor Activating Range............................ T4-2-13
Cylinder Drift Check................................... T4-4-10
Bucket Levelness .......................................T4-4-11
Group 3 Engine Test
Control Lever Operating Force.................. T4-4-12
Engine Speed............................................... T4-3-1
Control Lever Stroke.................................. T4-4-13
Engine Compression Pressure .................... T4-3-3
Valve Clearance Adjustment ........................ T4-3-4
Lubricant Consumption ................................ T4-3-7
4GCT-4-1
Group 5 Component Test
Primary Pilot Pressure ................................. T4-5-1
Secondary Pilot Pressure ............................ T4-5-3
Solenoid Valve Set Pressure ....................... T4-5-4
Main Pump Delivery Pressure ..................... T4-5-6
Main Relief Valve Set Pressure ................... T4-5-8
Steering Relief Pressure ............................ T4-5-12
Overload Relief Valve Set Pressure .......... T4-5-14
Main Pump Flow Rate................................ T4-5-16
Regulator Adjustment................................. T4-5-20
Service Brake Pressure (Front and Rear) . T4-5-22
Parking Brake Pressure ............................. T4-5-24
Brake Accumulated Pressure .................... T4-5-26
Brake Warning Set Pressure (Decrease) .. T4-5-28
Brake Warning Set Pressure (Increase) .... T4-5-30
Transmission Clutch Pressure ................... T4-5-32
Torque Converter Pressure
(Inlet and Outlet)..................................... T4-5-33
Group 6 Adjustment
Transmission Learning................................. T4-6-1
Lift Arm Angle Sensor
Learning (Optional)................................... T4-6-6
Drive Belt Tension Adjustment ..................... T4-6-8
4GCT-4-2
OPERATIONAL PERFORMANCE TEST / Introduction
OPERATIONAL PERFORMANCE TESTS
Use operational performance test procedure to quantitatively check all system and functions on the machine.
Purpose of Performance Tests
1. To comprehensively evaluate each operational
function by comparing the performance test data
with the standard values.
2. According to the evaluation results, repair, adjust,
or replace parts or components as necessary to
restore the machine’s performance to the desired
standard.
3. To economically operate the machine under optimal conditions.
The machine performance does not always deteriorate as the working hours increase. However, the
machine performance is normally considered to reduce in proportion to the increase of the operation
hours. Accordingly, restoring the machine performance by repair, adjustment, or replacement shall consider the number of the machine’s working hours.
Definition of “Performance Standard”
1. Operation speed values and dimensions of the
new machine.
2. Operational performance of new components
adjusted to specifications. Allowable errors will be
indicated as necessary.
Kinds of Tests
1. Base machine performance test is to check the
operational performance of each system such as
engine, travel, swing, and hydraulic cylinders.
2. Hydraulic component unit test is to check the operational performance of each component such
as hydraulic pump, motor, and various kinds of
valves.
Performance Standards
“Performance Standard” is shown in tables to evaluate the performance test data.
Precautions for Evaluation of Test Data
1. To evaluate not only that the test data are correct,
but also in what range the test data are.
2. Be sure to evaluate the test data based on the
machine operation hours, kinds and state of work
loads, and machine maintenance conditions.
T4-1-1
OPERATIONAL PERFORMANCE TEST / Introduction
PREPARATION
TESTS
FOR
PERFORMANCE
Observe the following rules in order to carry out
performance tests accurately and safely.
THE MACHINE
1. Repair any defects and damage found, such as
oil or water leaks, loose bolts, cracks and so on,
before starting to test.
TEST AREA
1. Select a hard and flat surface.
2. Secure enough space to allow the machine to
run straight more than 200 m (656 ft 2 in), and to
operate steering.
3. If required, rope off the test area and provide
signboards to keep unauthorized personnel
away.
PRECAUTIONS
1. Before starting to test, agree upon the signals to
be employed for communication among coworkers. Once the test is started, be sure to communicate with each other using these signals, and to
follow them without fail.
2. Operate the machine carefully and always give
first priority to safety.
3. While testing, always take care to avoid accidents due to landslides or contact with
high-voltage power lines. Always confirm that
there is sufficient space for full swings.
4. Avoid polluting the machine and the ground with
leaking oil. Use oil pans to catch escaping oil.
Pay special attention to this when removing hydraulic pipings.
MAKE PRECISE MEASUREMENT
1. Accurately calibrate test instruments in advance
to obtain correct data.
2. Carry out tests under the exact test conditions
prescribed for each test item.
3. Repeat the same test and confirm that the test
data obtained can be produced repeatedly. Use
mean values of measurements if necessary.
T4-1-2
T105-06-01-003
OPERATIONAL PERFORMANCE TEST / Standard
OPERATIONAL PERFORMANCE
STANDARD TABLE
• ZW220
Acceletor Pedal
: Full Stroke
Driving Mode Switch
: H Mode
Work Mode Switch : N Mode
Hydraulic Oil Temperature : 50±5 °C (122±41 °F)
The standard performance values are listed in the
table below. Refer to the Group T4-3 or later for
performance test procedures.
The following switch positions shall be selected and
the hydraulic oil temperature shall be maintained as
indicated below as the preconditions of performance
tests unless otherwise instructed in each performance
test procedure:
PERFORMANCE TEST DESIGNATION
ENGINE SPEED (FAN SPEED min/max) min-1
Slow Idle Speed (without load)
Fast Idle Speed (without load)
Fast Idle Speed (with engine stalled)
Fast Idle Speed (with engine stalled and
relieved)
ENGINE COMPRESSION PRESSURE
2
MPa (kgf/cm , psi)
VALVE CLEARANCE (IN, EX)
mm
LUBRICANT CONSUMPTION
(Rated output)
mL/h
DRIVE BELT BEND
mm
RADIATOR CAP OPENING PRESSURE
2
kPa (kgf/cm , psi)
Performance
Standard
840±25
2230/2220±25
1990/1900±50
1760/1750±50
3.04 (31.0, 442)
0.4
45 or less
6 to 8
49 (0.5, 7)
T4-2-1
NOTE: 1 mm=0.03937 in
Reference
Remarks
Page
T4-3-1
Value indicated on Dr. ZX
↑
↑
↑
Engine speed: 200min-1
T4-3-3
With the engine cold
Hour meter: 2000 hours or
less
T4-3-4
T4-3-7
T4-6-8
-
OPERATIONAL PERFORMANCE TEST / Standard
PERFORMANCE TEST DESIGNATION
TRAVEL SPEED
km/h
First Gear (Forward/Reverse)
Second Gear (Forward/Reverse)
Third Gear (Forward/Reverse)
Fourth (Forward/Reverse)
SERVICE BRAKE CAPACITY
m
SERVICE BRAKE WEAR
mm
Brake Disc
Brake Ring (t=15)
Brake Ring (t=5)
PARKING BRAKE CAPACITY
mm/5 min
PARKING BRAKE WEAR
mm
Brake Disc
Brake Ring
BUCKET STOPPER CLEARANCE
mm
BELL CRANK STOPPER CLEARANCE
mm
FRONT PIN WEAR
mm
(to new pin outer diameter)
FRONT BUSHING WEAR
mm
(to new pin outer diameter)
CLEARANCE BETWEEN FRONT PIN
AND BUSHING
mm
BUCKET BUMP
mm
HYDRAULIC CYLINDER CYCLE TIME sec
Lift Arm Raise
Lift Arm Lower (Float)
Bucket Roll-Out
Steering (engine: neutral)
Steering (engine: full)
DIG FUNCTION DRIFT CHECK mm/15 min
Lift Arm Cylinder
Bucket Cylinder
Bucket Bottom
Performance
Standard
7.0/7.1±0.7
12.3/12.3±1.2
22.0/22.0±2.2
34.5/34.5±3.6
5.0 or less
Remarks
Reference
Page
T4-4-1
Value indicated on Dr. ZX
↑
↑
↑
T4-4-2
T4-4-3
6.2
15.0
5.0
0
Allowable Limit: 5.3
Allowable Limit: 13.5
Allowable Limit: 4.3
2.2
2.4
0
Allowable Limit: 1.9
Allowable Limit: 2.2
T4-4-4
-
T4-4-6
T4-4-6
2
-
Allowable Limit: -1.0
-
-
Allowable Limit: -1.5
-
0.3
14
T4-4-11
T4-4-8
5.3±0.3
2.9±0.3
1.2±0.3
2.8±0.3
2.5±0.3
T4-4-10
45 or less
15 or less
150 or less
T4-2-2
OPERATIONAL PERFORMANCE TEST / Standard
PERFORMANCE TEST DESIGNATION
Performance Standard
CONTROL LEVER OPERATING FORCE
N (kgf, lbf)
Lift Arm Raise (STD/MF)
Lift Arm Raise Detent (STD/MF)
Lift Arm Raise Detent Release (STD/MF)
Lift Arm Lower (STD/MF)
Lift Arm Lower Float (STD/MF)
Lift Arm Lower Float Release (STD/MF)
Bucket Lever Tilt (STD/MF)
Bucket Lever Tilt Detent (STD/MF)
Bucket Lever Tilt Detent Release (STD/MF)
Bucket Lever Dump (STD/MF)
Steering Wheel (Right/Left)
11 (1.1, 2.5)/
19 (1.9, 4.3) or less
17 (1.7, 3.8)/
30 (3.1, 6.8) or less
40 (4.1, 9)/
20(2.0, 4.5) or less
11 (1.1, 2.5)/
19 (1.9, 4.3) or less
17 (1.7, 3.8)/
30 (3.1, 6.8) or less
40 (4.1, 9)/
20 (2.0, 4.5) or less
12 (1.2, 2.7)/
22 (2.2, 5) or less
18 (1.8, 4)/
33 (3.3, 7.4) or less
40 (4.1, 9)/
20 (2.0, 4.5) or less
17(1.7, 3.8)/
28 (2.9, 6.3) or less
17 (1.7, 3.8)/
17 (1.7, 3.8) or less
Forward/Reverse Lever
11.8+1-2
(1.2+0.1-0.2, 2.7+0.2-0.5)/
11.8+1-2
(1.2+0.1-0.2, 2.7+0.2-0.5)
Accelerator Pedal
25.0±3.5
(3. 6±0.4, 5.6±0.8)
Brake Pedal Right
318+65-45
(32.4+6.6-4.6, 71.6+14.6-10.1)
Inching Pedal Left
288+80-30 (29.4+8.2-3.1,
64.8+18-6.8)
NOTE: STD: Standard Lever (Two-Lever)
MF: Multi-Function Lever (Joystick Lever)
T4-2-3
Remarks
Reference
Page
T4-4-12
OPERATIONAL PERFORMANCE TEST / Standard
Performance
Standard
PERFORMANCE TEST DESIGNATION
CONTROL LEVER STROKE
mm
Lift Arm Raise Position (STD/MF)
Lift Arm Raise Detent Position (STD/MF)
Lift Arm Lower Position (STD/MF)
Lift Arm Lower Float Position (STD/MF)
Bucket Lever Tilt Position (STD/MF)
Bucket Lever Tilt Detent Position (STD/MF)
Bucket Lever Dump Position (STD/MF)
Steering Wheel Rotation
(Right Max. to Left Max.)
Forward/Reverse Lever (F/R)
Accelerator Pedal Depressing Angle
(without play)
Brake Pedal (Right) Depressing Angle
(without play)
Inching Pedal (Left) Depressing Angle
(without play)
Steering Wheel Play
Brake Pedal Play
ELECTROLYTE DENSITY
(Specification at 20 °C)
2
TIRE INFLATION
kPa (kgf/cm , psi)
Remarks
Reference
Page
T4-4-13
34±5/63±10
54±5/80±10
34±5/63±10
54±5/80±10
34±5/63±10
54±5/80±10
54±5/80±10
3.5 to 4.0
50±5/50±5
18.0°±1.5
18.4°±1.0
17.4°±1.0
5 to 15
12 to 20
1.26
375 (3.83, 55)
NOTE: STD: Standard Lever (Two-Lever)
MF: Multi-Function Lever (Joystick Lever)
T4-2-4
Allowable Limit: 1.16
-
OPERATIONAL PERFORMANCE TEST / Standard
PERFORMANCE TEST DESIGNATION
PRIMARY PILOT PRESSURE
2
MPa (kgf/cm , psi)
SECONDARY PILOT PRESSURE
2
MPa (kgf/cm , psi)
Performance
Standard
4.0+1.0-0.5
+10
(41 -5, 580+142-71)
3.7+0.5-0.3
+5
(38 -3, 538+73-64)
Remarks
Reference
Page
T4-5-1
T4-5-3
SOLENOID VALVE SET PRESSURE
2
MPa (kgf/cm , psi)
Solenoid Valve Unit Set Pressure
MAIN PUMP DELIVERY PRESSURE
2
MPa (kgf/cm , psi)
Value indicated on Dr.
ZX±0.2 (2, 28)
2.0+1.0-0.5
+10
(20 -5, 100+142-71)
Value indicated on Dr.
ZX
In neutral, Value indicated on Dr. ZX
T4-5-4
T4-5-6
T4-5-8
MAIN RELIEF VALVE PRESSURE
2
MPa (kgf/cm , psi)
Lift Arm (Relief operation)
Bucket (Relief operation)
OVERLOAD RELIEF PRESSURE
2
MPa (kgf/cm , psi)
Lift Arm Raise
Bucket Roll-In
Bucket Roll-Out
MAIN PUMP FLOW RATE
STEERING RELIEF PRESSURE
(L/min)
2
MPa (kgf/cm , psi)
SERVICE BRAKE PRESSURE
2
(Forward/Reverse)
MPa (kgf/cm , psi)
PARKING BRAKE PRESSURE
2
MPa (kgf/cm , psi)
27.4+2.0-0.5
(280+20-5, 3983+284-71)
27.4+2.0-0.5
(280+20-5, 3983+284-71)
(Reference values at
50 L/min)
34.3+1.0-0
(350+10-0, 4987+142-0)
30.4+1.0-0
(310+10-0, 4420+142-0)
30.4+1.0-0
(310+10-0, 4420+142-0)
+2.0
27.4 -0.5
(280+20-5, 3983+291-73)
4.18±0.85
(42.7±8.7, 608±124)
3.7+0.5-0.3
+5
(38 -3, 538+73-44)
BRAKE ACCUMULATOR PRESSURE
Value indicated on Dr.
ZX
Value indicated on Dr.
ZX
T4-5-14
Value indicated on Dr.
ZX
at Brake Pedal (Right)
T4-5-16
T4-5-12
T4-5-22
T4-5-24
T4-5-26
2
MPa (kgf/cm , psi)
Service Brake
Parking Brake
BRAKE WARNING PRESSURE
2
(Pressure-Decreasing)
MPa (kgf/cm , psi)
BRAKE WARNING PRESSURE
2
(Pressure-Increasing)
MPa (kgf/cm , psi)
TRANSMISSION CLUTCH PRESSURE
2
MPa (kgf/cm , psi)
TORQUE CONVERTER PRESSURE
2
(Inlet/Outlet)
MPa (kgf/cm , psi)
14.7±1.0
(150±10, 2137±145)
3.7+0.5-0.3
+5
(38 -3, 538+73-44)
8±0.5
(82±5, 1163±73)
10±0.5
(102±5, 1454±73)
2.2 to 2.4
(22 to 24, 320 to 349)
0.84 to 0.94 (8.6 to 9.6,
122 to 137)/ 0.32 to
0.42 (3.3 to 4.3, 47 to
61)
T4-2-5
T4-5-28
T4-5-30
T4-5-32
T4-5-33
OPERATIONAL PERFORMANCE TEST / Standard
• ZW250
The standard performance values are listed in the
table below. Refer to the Group T4-3 or later for
performance test procedures.
Acceletor Pedal
: Full Stroke
Driving Mode Switch
: H Mode
Work Mode Switch : N Mode
Hydraulic Oil Temperature : 50±5 °C (122±41 °F)
The following switch positions shall be selected and
the hydraulic oil temperature shall be maintained as
indicated below as the preconditions of performance
tests unless otherwise instructed in each performance
test procedure:
PERFORMANCE TEST DESIGNATION
ENGINE SPEED (FAN SPEED min/max) min-1
Slow Idle Speed (without load)
Fast Idle Speed (without load)
Fast Idle Speed (with engine stalled)
Fast Idle Speed (with engine stalled and
relieved)
ENGINE COMPRESSION PRESSURE
2
MPa (kgf/cm , psi)
VALVE CLEARANCE (IN, EX)
mm
LUBRICANT CONSUMPTION
(Rated output)
mL/h
DRIVE BELT BEND
mm
RADIATOR CAP OPENING PRESSURE
2
kPa (kgf/cm , psi)
Performance
Standard
840±25
2300/2290±25
2040/1960±50
1790/1770±50
3.04 (31.0, 442)
0.4
45 or less
6 to 8
49 (0.5, 7)
T4-2-6
NOTE: 1 mm=0.03937 in
Reference
Remarks
Page
T4-3-1
Value indicated on Dr. ZX
↑
↑
↑
Engine speed: 200min-1
T4-3-3
With the engine cold
Hour meter: 2000 hours or
less
T4-3-4
T4-3-7
T4-6-8
-
OPERATIONAL PERFORMANCE TEST / Standard
PERFORMANCE TEST DESIGNATION
TRAVEL SPEED
km/h
First Gear (Forward/Reverse)
Second Gear (Forward/Reverse)
Third Gear (Forward/Reverse)
Fourth (Forward/Reverse)
SERVICE BRAKE CAPACITY
m
SERVICE BRAKE WEAR
mm
Brake Disc
Brake Ring (t=15)
Brake Ring (t=5)
PARKING BRAKE CAPACITY
mm/5 min
PARKING BRAKE WEAR
mm
Brake Disc
Brake Ring
BUCKET STOPPER CLEARANCE
mm
BELL CRANK STOPPER CLEARANCE
mm
FRONT PIN WEAR
mm
(to new pin outer diameter)
FRONT BUSHING WEAR
mm
(to new pin outer diameter)
CLEARANCE BETWEEN FRONT PIN
AND BUSHING
mm
BUCKET BUMP
mm
HYDRAULIC CYLINDER CYCLE TIME sec
Lift Arm Raise
Lift Arm Lower (Float)
Bucket Roll-Out
Steering (engine: neutral)
Steering (engine: full)
DIG FUNCTION DRIFT CHECK mm/15 min
Lift Arm Cylinder
Bucket Cylinder
Bucket Bottom
Performance
Standard
7.1/7.1±0.7
12.3/12.3±1.2
21.9/21.9±2.2
34.5/34.5±3.5
5.0 or less
Remarks
Reference
Page
T4-4-1
Value indicated on Dr. ZX
↑
↑
↑
T4-4-2
T4-4-3
6.2
15.0
5.0
0
Allowable Limit: 5.3
Allowable Limit: 13.5
Allowable Limit: 4.5
2.2
2.4
0
Allowable Limit: 1.9
Allowable Limit: 2.2
T4-4-4
-
T4-4-6
T4-4-6
2
-
Allowable Limit: -1.0
-
-
Allowable Limit: -1.5
-
0.3
14
T4-4-11
T4-4-8
5.3±0.3
2.9±0.3
1.1±0.3
2.8±0.3
2.5±0.3
T4-4-10
45 or less
15 or less
150 or less
T4-2-7
OPERATIONAL PERFORMANCE TEST / Standard
PERFORMANCE TEST DESIGNATION
Performance Standard
CONTROL LEVER OPERATING FORCE
N (kgf, lbf)
Lift Arm Raise (STD/MF)
Lift Arm Raise Detent (STD/MF)
Lift Arm Raise Detent Release (STD/MF)
Lift Arm Lower (STD/MF)
Lift Arm Lower Float (STD/MF)
Lift Arm Lower Float Release (STD/MF)
Bucket Lever Tilt (STD/MF)
Bucket Lever Tilt Detent (STD/MF)
Bucket Lever Tilt Detent Release (STD/MF)
Bucket Lever Dump (STD/MF)
Steering Wheel (Right/Left)
11 (1.1, 2.5)/
19 (1.9, 4.3) or less
17 (1.7, 3.8)/
30 (3.1, 6.8) or less
40 (4.1, 9)/
20(2.0, 4.5) or less
11 (1.1, 2.5)/
19 (1.9, 4.3) or less
17 (1.7, 3.8)/
30 (3.1, 6.8) or less
40 (4.1, 9)/
20 (2.0, 4.5) or less
12 (1.2, 2.7)/
22 (2.2, 5) or less
18 (1.8, 4)/
33 (3.3, 7.4) or less
40 (4.1, 9)/
20 (2.0, 4.5) or less
17(1.7, 3.8)/
28 (2.9, 6.3) or less
17 (1.7, 3.8)/
17 (1.7, 3.8) or less
Forward/Reverse Lever
11.8+1-2
(1.2+0.1-0.2, 2.7+0.2-0.5)/
11.8+1-2
(1.2+0.1-0.2, 2.7+0.2-0.5)
Accelerator Pedal
25.0±3.5
(3. 6±0.4, 5.6±0.8)
Brake Pedal Right
318+65-45
(32.4+6.6-4.6, 71.6+14.6-10.1)
Inching Pedal Left
288+80-30 (29.4+8.2-3.1,
64.8+18-6.8)
NOTE: STD: Standard Lever (Two-Lever)
MF: Multi-Function Lever (Joystick Lever)
T4-2-8
Remarks
Reference
Page
T4-4-12
OPERATIONAL PERFORMANCE TEST / Standard
Performance
Standard
PERFORMANCE TEST DESIGNATION
CONTROL LEVER STROKE
mm
Lift Arm Raise Position (STD/MF)
Lift Arm Raise Detent Position (STD/MF)
Lift Arm Lower Position (STD/MF)
Lift Arm Lower Float Position (STD/MF)
Bucket Lever Tilt Position (STD/MF)
Bucket Lever Tilt Detent Position (STD/MF)
Bucket Lever Dump Position (STD/MF)
Steering Wheel Rotation
(Right Max. to Left Max.)
Forward/Reverse Lever (F/R)
Accelerator Pedal Depressing Angle
(without play)
Brake Pedal (Right) Depressing Angle
(without play)
Inching Pedal (Left) Depressing Angle
(without play)
Steering Wheel Play
Brake Pedal Play
ELECTROLYTE DENSITY
(Specification at 20 °C)
2
TIRE INFLATION
kPa (kgf/cm , psi)
Remarks
Reference
Page
T4-4-13
34±5/63±10
54±5/80±10
34±5/63±10
54±5/80±10
34±5/63±10
54±5/80±10
54±5/80±10
3.5 to 4.0
50±5/50±5
18.0°±1.5
18.4°±1.0
17.4°±1.0
5 to 15
12 to 20
1.26
375 (3.75, 47.3)
NOTE: STD: Standard Lever (Two-Lever)
MF: Multi-Function Lever (Joystick Lever)
T4-2-9
Allowable Limit: 1.16
-
OPERATIONAL PERFORMANCE TEST / Standard
PERFORMANCE TEST DESIGNATION
PRIMARY PILOT PRESSURE
2
MPa (kgf/cm , psi)
SECONDARY PILOT PRESSURE
2
MPa (kgf/cm , psi)
Performance
Standard
4.0+1.0-0.5
+10
(41 -5, 580+142-71)
3.7+0.5-0.3
+5
(38 -3, 538+73-64)
Remarks
Reference
Page
T4-5-1
T4-5-3
SOLENOID VALVE SET PRESSURE
2
MPa (kgf/cm , psi)
Solenoid Valve Unit Set Pressure
MAIN PUMP DELIVERY PRESSURE
2
MPa (kgf/cm , psi)
Value indicated on Dr.
ZX±0.2 (2, 28)
2.0+1.0-0.5
+10
(20 -5, 100+142-71)
Value indicated on Dr.
ZX
In neutral, Value indicated on Dr. ZX
T4-5-4
T4-5-6
T4-5-8
MAIN RELIEF VALVE PRESSURE
2
MPa (kgf/cm , psi)
Lift Arm (Relief operation)
Bucket (Relief operation)
OVERLOAD RELIEF PRESSURE
2
MPa (kgf/cm , psi)
Lift Arm Raise
Bucket Roll-In
Bucket Roll-Out
MAIN PUMP FLOW RATE
STEERING RELIEF PRESSURE
(L/min)
2
MPa (kgf/cm , psi)
SERVICE BRAKE PRESSURE
2
(Forward/Reverse)
MPa (kgf/cm , psi)
PARKING BRAKE PRESSURE
2
MPa (kgf/cm , psi)
29.4+2.0-0.5
(300+20-5, 4274+284-71)
29.4+2.0-0.5
(300+20-5, 4274+284-71)
(Reference values at
50 L/min)
36.8+1.0-0
(375+10-0, 5350+142-0)
32.5+1.0-0
(332+10-0, 4725+142-0)
32.5+1.0-0
(332+10-0, 4725+142-0)
+2.0
29.4 -0.5
(300+20-5, 4274+291-73)
4.18±0.85
(42.7±8.7, 608±124)
3.7+0.5-0.3
+5
(38 -3, 538+73-44)
BRAKE ACCUMULATOR PRESSURE
Value indicated on Dr.
ZX
Value indicated on Dr.
ZX
T4-5-14
Value indicated on Dr.
ZX
at Brake Pedal (Right)
T4-5-16
T4-5-12
T4-5-22
T4-5-24
T4-5-26
2
MPa (kgf/cm , psi)
Service Brake
Parking Brake
BRAKE WARNING PRESSURE
2
(Pressure-Decreasing)
MPa (kgf/cm , psi)
BRAKE WARNING PRESSURE
2
(Pressure-Increasing)
MPa (kgf/cm , psi)
TRANSMISSION CLUTCH PRESSURE
2
MPa (kgf/cm , psi)
TORQUE CONVERTER PRESSURE
2
(Inlet/Outlet)
MPa (kgf/cm , psi)
14.7±1.0
(150±10, 2137±145)
3.7+0.5-0.3
+5
(38 -3, 538+73-44)
8±0.5
(82±5, 1163±73)
10±0.5
(102±5, 1454±73)
2.2 to 2.4
(22 to 24, 320 to 349)
0.94 to 1.04 (9.6 to
10.6, 137 to 151)/ 0.34
to 0.44 (3.5 to 4.5, 49
to 64)
T4-2-10
T4-5-28
T4-5-30
T4-5-32
T4-5-33
OPERATIONAL PERFORMANCE TEST / Standard
MAIN PUMP P-Q CURVE
P-Q Control (Torque Control)
(REFERENCE: Measured at Test Stand)
• Rated Pump Speed:
ZW220: 2170 min-1 (rpm)
ZW250: 2240 min-1 (rpm)
• Hydraulic Oil Temperature: 50±5 °C (122±41 °F)
L/min
A
B
C
D
Flow
Rate
Delivery Pressure
MPa (kgf/cm2)
ZW220
A
B
C
D
T4GB-04-02-001
ZW250
Delivery Pressure
MPa (kgf/cm2, psi)
Flow Rate
L/min (gpm)
Delivery Pressure
MPa (kgf/cm2, psi)
Flow Rate
L/min (gpm)
4.9 (50, 712)
19.6 (200, 2849)
24.5 (250, 3562)
27.4 (280, 3983)
271±3 (72±0.8)
270±3 (71±0.8)
240±6 (63±1.6)
210±6 (55±1.6)
4.9 (50, 712)
19.6 (200, 2849)
25.5 (260, 3707)
29.4 (300, 4274)
291±3 (77±0.8)
290±3 (77±0.8)
275±6 (73±1.6)
225±6 (59±1.6)
T4-2-11
OPERATIONAL PERFORMANCE TEST / Standard
P-Q Control by Pump Control Pilot Pressure
Signal
(REFERENCE: Measured at Test Stand)
• Rated Pump Speed:
ZW220: 2170 min-1 (rpm)
ZW250: 2240 min-1 (rpm)
• Hydraulic Oil Temperature: 50±5 °C (122±41 °F)
L/min
A
Flow
Rate
B
C
Pump Control Pressure
MPa (kgf/cm2)
T4GB-04-02-002
Pi1-Pi2
ZW220
A
B
C
ZW250
Pump Control Pressure
(Pi1-Pi2)
MPa (kgf/cm2, psi)
Flow Rate
L/min (gpm)
Pump Control Pressure
(Pi1-Pi2)
MPa (kgf/cm2, psi)
Flow Rate
L/min (gpm)
0.39+0.01-0 (4+0.1-0, 57+1.5-0)
1.47±0.05 (15±0.5, 214±7)
1.67+0.01-0 (17+0.1-0, 243+1.5-0)
271±3 (172±0.8)
80±2 (21±0.5)
36±3 (10±0.8)
0.49+0.01-0 (5+0.1-0, 71+1.5-0)
1.47±0.05 (15±0.5, 214±7)
1.67+0.01-0 (17+0.1-0, 243+1.5-0)
291±3 (77±0.8)
100±2 (26±0.5)
55±3 (15±0.8)
T4-2-12
OPERATIONAL PERFORMANCE TEST / Standard
SENSOR ACTIVATING RANGE
1. Checking Method
• Hydraulic Oil Temperature: 50 ± 5 °C (122±41 °F)
• Unless specified:
Engine
Speed
Fast Idle
Work Mode
Switch
N
• Monitor each sensor by using Dr. ZX.
2. Sensor Activating Range
• ZW220
Item
Pump Delivery Pressure
Implement Pressure
Parking Brake Pressure
Service Brake Pressure
Specification
MPa (kgf/cm2, psi)
Neutral
1.2 to 2.6 (12 to 27, 174 to 378)
Relieved
26.7 to 30.0 (272 to 306, 3882 to 4361)
Neutral
1.2 to 2.6 (12 to 27, 174 to 378)
Implement Lever: Relieved
26.7 to 30.0 (272 to 306, 3882 to 4361)
Parking Brake Switch: ON
0 to 0.1 (0 to 1, 0 to 15)
Parking Brake Switch: OFF
3.6 to 4.3 (37 to 44, 523 to 625)
Brake Pedal: Neutral
0 to 0.1 (0 to 1, 0 to 15)
Brake Pedal: Fully De- 3.3 to 5.0 (34 to 51, 480 to 727)
pressed
Operation
• ZW250
Item
Pump Delivery Pressure
Implement Pressure
Parking Brake Pressure
Service Brake Pressure
Specification
MPa (kgf/cm2, psi)
Neutral
1.2 to 2.6 (12 to 27, 174 to 378)
Relieved
28.7 to 32.0 (293 to 327, 4172 to 4652)
Neutral
1.2 to 2.6 (12 to 27, 174 to 378)
Implement Lever: Relieved
28.7 to 32.0 (293 to 327, 4172 to 4652)
Parking Brake Switch: ON
0 to 0.1 (0 to 1, 0 to 15)
Parking Brake Switch: OFF
3.6 to 4.3 (37 to 44, 523 to 625)
Brake Pedal: Neutral
0 to 0.1 (0 to 1, 0 to 15)
Brake Pedal: Fully De- 3.3 to 5.0 (34 to 51, 480 to 727)
pressed
Operation
T4-2-13
OPERATIONAL PERFORMANCE TEST / Standard
(Blank)
T4-2-14
OPERATIONAL PERFORMANCE TEST / Engine Test
ENGINE SPEED
Summary
1. Measure the engine speed by using the monitor
unit or Dr. ZX.
2. Measure the engine speeds in each mode.
NOTE: If the engine speed is not adjusted correctly, all other performance data will be
unreliable. Consequently, measure the engine speed before performing all other
tests in order to check that the engine
speed meets specification.
Preparation:
1. Select the monitor which is started on the service
mode or Engine Actual Speed on the MC screen
by Dr.ZX.
2. Warm up the machine until coolant temperature
reaches 50 °C (122 °F) or more, hydraulic oil
temperature is 50±5 °C (122±41 °F) and Transmission oil temperature is 85±5 °C (185±41 °F).
M4GB-01-039
Measurement:
1. Measure the items as followings: slow idle with
no load), fast idle (with no load), fast idle (when
engine stalls) and fast idle (when engine stalls
and is relieved).
2. When measuring, set the switch and test condition as shown in the table below in response to
the engine speed to be measured.
Forward/Reverse Lever Accelerator Pedal Travel Mode Switch
Slow Idle
N
No depression
M
(with no load)
Fast Idle
Forward third/fourth gear Full depression
M
(with no load)
Fast Idle
N
Full depression
M
(when engine stalls)
Fast Idle
(when engine stalls Forward third/fourth gear Full depression
M
and is relieved)
T4-3-1
Work Mode Switch
N
N
N
N
OPERATIONAL PERFORMANCE TEST / Engine Test
Slow Idle
(with no load)
Fast Idle
(with no load)
Fast Idle
(when engine
stalls)
Fast Idle
(when engine stalls
and is relieved)
Clutch Cut Position
Switch
Brake Pedal
Parking Brake
Switch
-
-
ON
S
Full depression
ON
OFF
Full depression
OFF
Transporting position
No control lever operation
OFF
Full depression
OFF
Transporting position
Bucket is raised and
relieved.
Evaluation:
Refer to Operational Performance Standard in Group
T4-2.
Remedy:
Refer to Troubleshooting in Section T5.
T4-3-2
Control Lever (Bucket)
Transporting position
No control lever operation
Transporting position
No control lever operation
OPERATIONAL PERFORMANCE TEST / Engine Test
ENGINE COMPRESSION PRESSURE
Summary:
1. Measure compression pressure in the cylinders
and check for a decline in engine power.
2. Check exhaust gas color. Keep track of engine oil
consumption.
3. Check for abnormalities in the intake system, including the air filter.
Preparation:
1. Confirm that valve clearances are correct.
2. Confirm that the batteries are charged properly.
3. Run the engine until the coolant temperature
gauge reaches the operating range.
4. Remove all the glow plugs from each cylinder.
: 20 N⋅m (2.0 kgf⋅m, 14.8 lbf⋅ft)
IMPORTANT: If disconnecting the connector of
injector, fuel cannot be jetted.
Therefore, ECM judges that the fuel
system is faulty and the fault code
is displayed. After measurement,
delete the displayed fault code.
5. Disconnect the connector of injector which is installed to the lower head cover.
6. Install the negative terminal of battery.
7. Turn the starter. Exhaust foreign subjects from
the cylinder.
8. Install a pressure gauge and an adaptor (Isuzu
EN-46722) to the glow plug mounting part. (Sufficiently install them in order to prevent air leakage.)
Injector
Lower Head Cover
Connector
T1V7-04-03-002
Measurement:
1. Turn the starter and measure compression pressure of each cylinder.
2. Repeat the measurement three times and calculate the mean values.
Evaluation:
Refer to Operational Performance Standard in Group
T4-2.
Remedy:
Refer to the engine shop manual.
T4-3-3
T1V1-04-03-005
OPERATIONAL PERFORMANCE TEST / Engine Test
VALVE CLEARANCE
Terminal Nut
Summary:
1. Perform the measurement when the engine is
cold.
2. Before starting any work, clean the head cover
mounting area and avoid contamination in the
engine.
Preparation:
1. Remove the head cover.
2. Remove the terminal nut which secures the harness to the injector.
: 2 N⋅m (0.2 kgf⋅m, 1.5 lbf⋅ft)
3. Remove the harness assembly from the injector.
4. Remove the leak off pipe.
Harness
: 12 N⋅m (1.2 kgf⋅m, 8.9 lbf⋅ft)
5. Rotate the crank pulley. Align the top dead center
(TDC) mark on crank pulley with the top mark
located on timing gear case.
Injector
T1V1-04-03-008
NOTE: When rotating the crank pulley, remove the
fan guard. Then, rotate the fan while holding the fan belt. If it is difficult to rotate,
remove all glow plugs and release
compression pressure.
6. Check if piston No.1 (or piston No.4) is now positioned at the TDC in the compression stroke.
Leak Off Pipe
NOTE: Move push rods for the intake and exhaust
valves on the No.1 cylinder up and down
by hand. If any clearances on the both
ends of the push rods are found, piston
No.1 is positioned at TDC in the compression stroke. (If the exhaust valve of cylinder No.1 is pushed down, piston No.4 is
positioned at TDC in the compression
stroke.
T1V1-04-03-007
Top Mark
Crank Pulley
7. Start measurement from the cylinder (No.1 or
No.6) positioned at TDC in the compression
stroke.
TDC Mark
T4-3-4
T1V7-04-03-001
OPERATIONAL PERFORMANCE TEST / Engine Test
Measurement:
1. Insert a thickness gauge into the clearance between rocker arm and bridge cap end and measure the valve clearance.
Adjusting Screw
NOTE: The cylinders are aligned from No.1 to
No.6 in that order, as viewed from the fan
side. Injection Order: 1-5-3-6-2-4
2. When measurement is started from No.1 cylinder,
perform the same measurement to all valves indicated with the mark “○” in the table below.
(When measurement is started from No.6 cylinder, perform the measurement in the valves
shown with mark “×”.)
Cylinder No.
Valve locations
When the measurement is
started from No.1 cylinder
When the measurement is
started from No.6 cylinder
No.1
I
E
{
{
No.2
I
E
{
×
No.3
I
E
{
×
3. Rotate the crankshaft 360°. Align the TDC mark
with the pointer. Continue measurement of other
valves in the same way.
Bridge Cap
T4GB-04-03-003
No.4
I
E
{
×
No.5
I
E
No.6
I
E
{
×
×
×
Rocker Arm
Evaluation:
Refer to Operational Performance Standard in Group
T4-2.
T4GB-04-03-004
T4-3-5
OPERATIONAL PERFORMANCE TEST / Engine Test
Adjustment:
If the measurement results are out of specification,
adjust the valve clearance in the same order of
measurement.
Adjusting
Screw
Rocker Arm
IMPORTANT: Touch the bridge to the end of valve
heads (2 used) horizontally and adjust the valve clearance carefully.
1. Loosen the lock nuts (12 used) and adjusting
screws (12 used), which secure the bridge and
rocker arm.
2. Insert a thickness gauge into the clearance between rocker arm and bridge cap.
3. Tighten the adjusting screw of rocker arm until
condition for the thickness gauge is proper.
4. Tighten the lock nut of rocker arm.
: 22 N⋅m (2.2 kgf⋅m, 16.2 lbf⋅ft)
5. Tighten the adjusting screw of bridge until the
bridge comes in contact with the valve head.
6. Tighten the lock nut of bridge.
: 22 N⋅m (2.2 kgf⋅m, 16.2 lbf⋅ft)
7. Check the valve clearance after the lock nuts are
tightened.
T1V1-04-03-002
Lock Nut
Bridge
Bridge Cap
T1V1-04-03-003
Valve Head
T4-3-6
Bridge
OPERATIONAL PERFORMANCE TEST / Engine Test
LUBRICANT CONSUMPTION
Measuring Method
1. Place the machine on level firm ground and leave
the machine for at least one hour in order to let
the lubricant lower to the oil pan when the engine
stops.
At this time, confirm that the machine is level by
using a leveler.
2. Record read-out A (unit: hour) of the hour meter.
3. Replenish the lubricant up to the high-level
gauge.
4. Operate the machine for at least 100 hours or until the oil level lowers to the low-level gauge.
IMPORTANT: Keep the machine-leaving time in
Step 1 above.
5. Place the machine on level firm ground and leave
the machine for at least one hour in order to let
the lubricant lower to the oil pan when the engine
stops.
At this time, confirm that the machine is level by
using a leveler.
6. Record read-out B (unit: hour) of the hour meter.
7. Replenish the lubricant up to the high-level
gauge while measuring the oil-replenishing volume C.
NOTE: When measuring, use a high-precision
measuring cylinder or the like.
8. Determine lubricant consumption from the following equation:
Oil replenishing volume (C) [mL] / Operating
hours (B-A) [hr]
Evaluation:
Refer to Operational Performance Standard in Group
T4-2.
T4-3-7
OPERATIONAL PERFORMANCE TEST / Engine Test
(Blank)
T4-3-8
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
TRAVEL SPEED
6. Convert the measurement value to be expressed
in km/h.
Measurement value (seconds) = S (sec)
Converted value (hourly speed) = A (km/h)
Summary:
1. The overall performance of the travel drive system
(torque converter through transmission) is judged
by measuring the time necessary for traveling 50
m (164 ft).
A=
Preparation:
1. Adjust air pressure of the tires evenly in advance.
Air pressure:375 kPa (3.83 kgf/cm2, 55 psi)
2. On a firm level and uniform supporting surface,
prepare a 50 m (164 ft) straight travel course, and
70 m (230 ft) forward and backward runways. (For
measurement at Speed 4, a forward runway of
300 m (984 ft) is needed.)
3. Empty the bucket, and hold the lift arm afloat 0.4
to 0.5 m (1 ft 4 in to 1 ft 8 in) above the ground.
4. Keep the hydraulic oil temperature at 50±5 °C
(122±41 °F). Warm the axle oil satisfactorily by
repeating travel and brake operations.
Make a warm up operation so that the indicators
of the engine water temperature monitor and the
torque converter oil temperature monitor rise
above the horizontal positions.
50 × 600
S × 1000
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
Remedy:
Refer to the Trouble Shooting in Section T5.
0.4 to 0.5 m
(1’4” to 1’8”)
Ending Point
Travel Course
Runway
Starting Point
T4GB-04-04-001
Measurement
CAUTION: Avoid measurement at reverse for
fear of dangers involved.
1. Make measurement for each mode (Speeds 1 to
4).
2. Select the switches as follows.
Parking Brake
Accelerator
Shift Switch
Switch
Pedal
Speed 1
Speed 1
OFF
Full depression
Speed 2
Speed 2
OFF
Full depression
Speed 3
Speed 3
OFF
Full depression
Speed 4
Speed 4
OFF
Full depression
3. Put the forward-reverse lever at the F (Forward)
position. From the runway, travel by depression
the accelerator pedal to the stroke end.
4. Measure the travel speed (sec) of each travel
mode.
5. Make measurement three times, and determine
the measurement value by obtaining their mean
values.
T4-4-1
Travel Mode
Switch
H
H
H
H
Work Mode
Switch
N
N
N
N
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
SERVICE BRAKE FUNCTION CHECK
Summary:
1. The overall performance of the service brake is
judged.
2. The braking capability of the brake is an item of
safety control. Be sure to conduct the performance test.
Preparation:
1. Adjust air pressure of the tires evenly in advance.
Air pressure: 375 kPa (3.83 kgf/cm2, 55 psi)
2. On a paved dry road, prepare a 100 m (328 ft)
straight travel course (a 50 m (164 ft) of runway
and a 50 m (164 ft) of measurement road), and
set the brake starting point.
3. Empty the bucket, and hold the lift arm afloat 0.4
to 0.5 m (1 ft 4 in to 1 ft 8 in) above the ground.
4. Keep the hydraulic oil temperature at 50±5 °C
(122±41 °F). Warm the axle oil satisfactorily by
repeating travel and brake operations.
Make a warm up operation so that the indicators
of the engine water temperature monitor and the
torque converter oil temperature monitor rise
above the horizontal positions.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
Remedy:
Refer to the Trouble Shooting in Section T5.
0.4 to 0.5 m
(1’4” to 1’8”)
Stopping Distance
Stopping Point
Brake Starting
Point
T4GB-04-04-002
Measurement
CAUTION: Avoid measurement at reverse for
fear of dangers involved. (Forward-reverse
lever: F)
1. Make measurement for high-speed mode.
2. Select the switches as follows.
Shift Switch
Parking Brake Switch
Speed 4
OFF
Accelerator
Pedal
Full depression
3. Put the forward-reverse lever at the F (Forward)
position. From the runway, travel at 20 km/h (12
mph) by depression the accelerator pedal to the
stroke end.
4. Depression the brake at the brake starting point,
and completely stop the vehicle. (Right Service
Brake Pedal)
5. Measure the distance from the brake starting
point to the point where the front tire is contacting.
6. Make measurement three times, and determine
the measurement value by obtaining their mean
values.
T4-4-2
Travel Mode
Switch
Work Mode
Switch
Clutch Cut Position
Switch
H
N
OFF
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
SERVICE BRAKE WEAR AMOUNT
1
Summary:
The extent of wear of the brake disc at the service
brake of the axle is judged by the wear gauge.
Preparation:
1. Clean the inspection plug (1) of the axle, and
loosen it.
2. In the case of the rear axle, the inspection plug (1)
is located below the center line of the differential,
so loosen the inspection plug (1) after draining the
axle oil.
T4GB-04-04-004
2
Measurement:
1. Operate the service brake by depression the
brake pedal.
2. Insert the wear gauge (2) into the inspection port
until it contacts the brake disc (6) between the
brake ring (3) and the brake ring (4).
Inspection Port
T4GB-04-04-005
Evaluation:
1. In case the wear gauge (2) has entered between
the brake rings (3 and 4), and the model scale of
the wear gauge (2) and the housing face (5) have
coincided, the wear amount of the brake disc (6)
is not reached the maximum allowable limit of use.
In case the wear gauge (2) has not entered between the brake rings (3 and 4), and the model
scale is sticking above the housing face (5), the
brake disc (6) is worn in excess of the maximum
allowable limit of use.
2. In the method above, in case the maximum allowable limit of use has not reached, or in case
the service brake portion has been assembled,
refer to the Performance Standard Table in Group
T4-2.
Distance between Housing Face (5) and Brake
Disc (6)
Model
Dimensions (L) mm
ZW220
52
ZW250
54
T4-4-3
5
2
L
6
3
4
T4GB-04-04-006
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
PARKING BRAKE FUNCTION CHECK
Summary:
1. The function of the parking brake on a determined
slope is measured.
2. The braking capability of the brake is an item of
safety control. Be sure to conduct the performance test.
Preparation:
1. Make measurement on a plane slope of 11.31 °
(20 %).
2. Empty the bucket, and hold the lift arm afloat 0.4
to 0.5 m (1’4” to 1’8”) above the ground.
3. Keep the hydraulic oil temperature at 50±5 °C
(122±41 °F).
4. Warm the axle oil satisfactorily by repeating travel
and brake operations.
Make a warm up operation so that the indicators
of the engine water temperature monitor and the
torque converter oil temperature monitor rise
above the horizontal positions.
0.4 to 0.5 m
(1’4” to 1’8”)
11.31° (20%)
T4GB-04-04-003
Measurement:
1. Travel up the slope, and put the parking brake
switch at the P position.
2. Stop the engine.
3. After the body has stopped, put a mark (white
line) on the tire and the ground surface respectively.
4. After Five minutes have passed, measure the
amount of movement of the white line of the tire
from that of the ground surface.
5. Make measurement three times, and determine
the measurement value by obtaining their mean
values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
T4-4-4
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
(Blank)
T4-4-5
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
BUCKET STOPPER AND BELL CRANK
CLEARANCE
Summary;
Wear and deformation conditions of the bucket
stopper (dump end and crowd end) and the clearance between the bell crank stopper and the cross
tube are measured.
Preparation:
Stop the vehicle on a plane road surface, and operate the parking brake.
Bucket Dump
Stopper
Bell Crank Stopper
Measurement:
1. Bucket dump stopper
1-1. Raise the lift arm to the highest lifting position,
and stop the engine.
1-2. At stop of the engine, dump calmly until the
buket contacts the dump stopper. At this time,
measure the Strokes (A and B) of the bucket
cylinder and the lift arm and the dump angle (C)
of the bucket. In addition, measure the clearance between the bell crank stopper and the
cross tube.
1-3. At the same time, make measurement of the
contact conditions of the bucket dump stoppers
(left and right).
2. Bucket crowd stopper
1-1. Raise the lift arm until the lift arm cylinder stroke
(E) becomes the length of the standard dimension.
1-2. Set the engine at idling speed, and make
crowding operation until the bucket calmly contacts the bucket crowd stopper.
1-3. At this time, measure the strokes (D and E) of
the bucket cylinder and the lift arm cylinder and
the crowd angle (F) of the bucket. In addition,
measure the height (G) from the ground to the
bucket lowest portion.
1-4. Also measure the contact conditions of the
bucket crowd stoppers (left and right).
T4GB-04-04-008
Bucket Crowd
Stopper
T4GB-04-04-010
T4-4-6
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
Evaluation:
1. Bucket Dumper Stopper
1-1. Cylinder Stroke Strokes A and B
Bucket Cylinder
Lift Arm Cylinder
Model
A (mm)
B (mm)
ZW220
362±1.5
1120±2
ZW250
373±1.5
1180±2
2. Bucket Crowd Stopper
2-1. Cylinder Strokes D and E
Bucket Cylinder
Model
D (mm)
ZW220
690
ZW250
719
1-2. Bucket Dump Angle C
Model
C (°)
ZW220
50±2
ZW250
50±2
2-2. Bucket Crowd Angle (F)
Model
F (°)
ZW220
50
ZW250
50
1-3. Clearance between Bell Crank Stopper and
Cross Tube
Clearance between Bell Crank
Model
Stopper and Cross Tube
(mm)
Standard
2.0
ZW220
Limit
Standard
2.0
ZW250
2-3. Height from Ground to Bucket Lowest Portion
(G)
Model
G (mm)
ZW220
450
ZW250
425
Limit
1-4. Clearance between Bucket Dump Stopper and
Lift Arm
Clearance at Longitudinal and
Unsymmetrical Lateral Clearance
Model
Contact
of a Stopper
(mm)
(mm)
Standard
0
0
ZW220
Limit
0.5
1.0
Standard
0
0
ZW250
Limit
0.5
1.0
2-4. Clearance between Bucket Dump Stopper and
Lift Arm
Clearance at Longitudinal and
Unsymmetrical Lateral Clearance
Model
Contact
of a Stopper
(mm)
(mm)
Standard
0
0
ZW220
Limit
0.5
1.0
Standard
0
0
ZW250
Limit
0.5
1.0
Clearance at Unsymmetrical Contact
Clearance Limit
Left
Clearance at Unsymmetrical Contact
Right
Longitudinal and Lateral Clearance of a Stopper
Clearance Limit
Left
Lift Arm Cylinder
E (mm)
360
371
Clearance Limit
Right
Left
Right
T4GB-04-04-009
Longitudinal and Lateral Clearance of a Stopper
Clearance Limit
Left
Right
T4GB-04-04-009
T4-4-7
NOTE: Standard dimensions indicate those of a
new tire at the designated air pressure.
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
HYDRAULIC CYLINDER CYCLE TIME
Lift Arm Cylinder:
Summary:
1. The overall performance of the cylinders drive
system (main pump through each cylinder) is
judged by measuring the operating time of the
cylinders for the lift arm, bucket, and steeering.
2. The bucket is made empty in advance.
(for Lifting)
Preparation:
1. Measurement is made for the following positions.
1-1. Measurement of Lift Arm Cylinder (for Liftig)
Fully crowd the bucket, and lower the lift arm.
1-2. Measurement of Lift Arm Cylinder (for Lowering)
Lower the lift arm until the bucket bottom face
touches the ground horizontally.
1-3. Measurement of Bucket Cylinder
Lift the lift arm to the highest position.
1-4. Measurement of Steering Cylinder
Empty the bucket, and take the travel forward
position.
T4GB-04-04-016
(for Lowering)
2. Keep the hydraulic oil temperature at 50±5 °C
(122±41 °F).
CAUTION: Select ground filled with sand or
something so that the bucket contacts the
ground with buffer.
T487-04-03-005
Bucket Cylinder:
T487-04-03-006
Travel Position
0.4 to 0.5 m
(1’4” to 1’8”)
M4GB-04-001
T4-4-8
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
Measurement:
1. Select the pedal, switches, and forward-reverse
lever as follows.
Parking Brake
Accelerator Pedal
Switch
Lift Arm
Full Stroke
ON
(for Lifting)
(Engine Maximum Speed)
Lift Arm
Neutral
ON
(for Lowering)
(Engine Minimum Speed)
Full Stroke
Bucket
ON
(Engine Maximum Speed)
Neutral
Steering
OFF
(Engine Minimum Speed)
Full Stroke
Steering
OFF
(Engine Maximum Speed)
2. Make measurement operation as follows.
(including the buffer range)
2-1. Measurement of Lift Arm Cylinder (for Lifting)
Operate the lift arm lever to the stroke end, and
measure the time of movement of the lift arm
from the lowest position to the highest position.
2-2. Measurement of Lift Arm Cylinder (for Lowering)
Lower the bucket to the ground in the horizontal
position, and lift the lift arm to the highest position.
Keep the lift arm lever at the afloat position, and
measure the time of movement of the bucket
reaching the ground.
2-3. Measurement of Bucket Cylinder
Operate the bucket lever to the stroke end, and
measure the time of movement of the bucket
from the full crowd position to the full dump position.
2-4. Measurement of Steering Cylinder
Operate the steering wheel to the stroke end,
and measure the time of movement of the
steering wheel from the right to the left end, and
from the left to the right end.
CAUTION: Before measurement, confimr
that there are no human beings or obstacles
in the steering range.
3. Make measurement three times, and determine
the measurement value by obtaining their mean
values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
Remedy:
Refer to the Trouble Shooting in Section T5.
T4-4-9
Forward-reverse
Lever
Work Mode
Switch
N
N
N
N
N
N
N
N
N
N
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
CYLINDER DRIFT CHECK
Summary:
1. Internal leakage of the lift arm, bucket cylinders,
and control valves when the buket is loaded with
load equivalent to the standard load is judged by
the settlement (shrinkage) of the cylinder rod.
2. Measurement is made in the standard front condition (standard bucket).
3. In case measurement is made immediately after
the cylinder replacement, conduct air venting of
the cylinder before measurement by operating the
cylinders slowly to the stroke ends several times.
Preparation:
1. Load the bucket with weight or sand equivalent to
the standard load
ZW220: 5085 kg (11210 lb)
ZW250: 5600 kg (12346 lb)
2. In the front position, extend the lift arm to the
maximum reach, and hold the bucket at an agle of
about 5° declined forward from full crowding.
Bucket Cylinder
CAUTION: Never allow any personnel to be
under the bucket.
1. Keep the hydraulic oil temperature at 50±5 °C
(122±41 °F).
Measurement of
Settlement
Lift Arm
Cylinder
Measurement:
1. Stop the engine.
2. After 15 minutes have passed, measure the
shrinkage of the lift arm cylinder, shrinkage of the
bucket cylinder, and the settlement of the bucket
bottom respectively.
3. Make measurement three times, and determine
the measurement value by obtaining their mean
values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
T4GB-04-04-014
B
A
T4GB-04-04-015
Remedy:
Refer to the Trouble Shooting in Section T5.
T4-4-10
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
BUCKET LEVELNESS
Summary:
Left and right inclinations of the bucket are checked
in order to prevent uneven wear of the cutting edge
of the bucket.
Preparation:
1. Place the unloaded base machine on a horizontal
bed on rhe ground. (In case a bed is not available,
place it on a horizontal flat concrete on the ground.
Deal with the measurement values as guide
lines.)
2. Adjust the tire air pressure to the designated
value.
3. Have the bucket bottom contact the ground horizontally.
Cutting Edge
Measurement:
1. Have the bucket bottom float slightly above the
bed.
2. Measure the vertical distance from the bed and
the bottom face of the cutting edge on the left and
right ends, and confirm the difference.
3. Make measurement three times, and determine
the measurement value by obtaining their mean
values.
CAUTION: Never put hands, feet, and measuring instruments under the bucket.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
T4-4-11
T4GB-04-04-011
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
CONTROL LEVER OPERATING FORCE
Summary
1. Operating conditions of the levers, pedals, and
steering wheel are confirmed, and their operating
force are measured.
2. Maximum operating force of the levers, pedals,
and steering wheel are measured.
3. Measurement of each of the operating levers is
made at the center of the grip.
Measurement of each of the pedals is made at
150 mm (6 in) from the pedal support.
Travel Position
Preparation:
1. In the front position, empty the bucket in advance.
2. Keep the hydraulic oil temperature at 50±5 °C
(122±41 °F).
Measurement
1. Make measurement for each of the operating
levers, pedals, and steering wheel.
2. Select the pedal, switches, and forward-reverse
lever as follows.
Parking
Forward-reverse
Accelerator Pedal
Brake Switch
Lever
Neutral
(Engine Minimum
ON
N
Speed)
0.4 to 0.5 m
(1’4” to 1’8”)
M4GB-04-001
CAUTION: Before measurement, confimr
that there are no human beings or obstacles
in the steering range.
3. Apply a spring balance scale (tension type) to
each of the lift arm, bucket, and froward-reverse
lever, and measure their maximum operating efforts by operating them to the stroke end.
4. In the case of the pedals, apply a spring balance
scale (compression type) or a load cell to them,
and measure their operating efforts when they are
stepped slightly.
5. For the steering wheel, apply a spring balance
scale (tension type) to the knob, and measure the
maximum operating effort when it is moved.
6. Make measurement three times, and determine
the measurement value by obtaining their mean
values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
T4-4-12
T4GB-04-04-013
Knob
M4GB-01-004
Brake Pedal
Accelerator Pedal
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
CONTROL LEVER STROKE
Summary:
1. Plays and operating conditions of operating levers,
pedals, and steering wheel are confirmed, and
their strokes are measured.
2. Measurement of each of the operating levers is
made at the tip of the grip.
Measurement of each of the pedals is made at the
top of the pedal.
3. In the case of existence of play at neutral, make
measurement by dividing it on both sides evenly.
Preparation:
1. Keep the hydraulic oil temperature at 50±5 °C
(122±40 °F).
Measurement:
1. Measurement of Operating Lever
1-1. Have the bucket bottom contact the ground.
1-2. Stop the engine.
1-3. Measure the stroke from the neutral position to
the stroke end of each of the lift arm, bucket,
and forward-reverse operating levers at the top
center of the grip.
2. Measurement of Pedal
2-1. Have the bucket contact the ground.
2-2. Stop the engine.
2-3. Measure the stroke from the neutral position to
the stroke end of the pedal at the top of the
pedal.
3. Measurement of Steering Wheel
3-1. Start the engine. (Low idling)
3-2. Have the bucket float slightly above the ground.
3-3. Measure the number of times of rotation required for reaching the left stroke end from the
right, and vice versa of the steering wheel.
4. make measurement corresponding to a straight
line.
5. Make measurement three times, and determine
the measurement value by obtaining their mean
values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
T4-4-13
OPERATIONAL PERFORMANCE TEST / Wheel Loader Test
(Blank)
T4-4-14
OPERATIONAL PERFORMANCE TEST / Component Test
PRIMARY PILOT PRESSURE
(Including Brake Circuit)
CAUTION: If air is mixed in the brake system,
the brake function is reduced, and serious
hazard may occur. Bleed air from the brake
system after removing and installing the pipe
lines and replacing hydraulic oil.
Refer to Troubleshooting B in Group T5-6.
IMPORTANT: Primary pilot pressure circuit shuts
off a circuit connecting to pilot relief
valve if pressure in the accumulator
is insufficient, and delivers primary
pilot pressure to accumulator circuit.
At this time, primary pilot pressure
reaches 15 MPa (153 kgf/cm2, 2180
psi) or high, so use a pressure
gauge capable of measuring 15 MPa
(153 kgf/cm2, 2180 psi) or higher.
Hose
(3/4-16UNF)
Preparation:
1. Stop the engine.
2. Push the air bleed valve on top of the hydraulic
oil tank and release any remaining pressure.
3. Remove the hose end from the pilot filter inlet or
outlet port. Install adapter (13/16-16UNF), nipple,
pressure gauge and coupling.
: 22 mm, 24 mm, 27 mm
Pilot Filter
T4GB-04-05-001
4. Start the engine. Check for any oil leaks at the
pressure gauge connection.
5. Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F).
Measurement:
1. Set engine speed at fast idle. Depress the accelerator pedal fully.
2. Measure pilot pressure without load by using a
pressure gauge.
3. Repeat the measurement three times and calculate the average values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
NOTE: When pressure in the service brake accumulator is reduced during measurement
of primary pilot pressure, the measured
valve is increased to 15 MPa (153 kgf/cm2,
2180 psi) for several seconds.
T4-5-1
T1F3-04-05-001
OPERATIONAL PERFORMANCE TEST / Component Test
Primary Pilot Pressure Adjustment Procedure
Adjustment:
Adjust the relief valve set-pressure in charging block
as necessary.
1. Remove plug (1) from the relief valve.
: 30 mm
2. Remove shim (2) from the relief valve.
3. Install the estimated number of shim (2).
4. Install shim (2) to the relief valve.
Tighten plug (1).
: 98.0±9.8 N⋅m
(960±95 kgf⋅m, 710±71 lbf⋅ft)
Charging Block
M4GB-07-100
5. Check the set-relief pressure.
Charging Block
NOTE: Standard Change in Pressure (Reference)
Set the thickness of shims at less than 1.5 mm.
Shim Thickness
Change in Pressure
(mm)
kPa
(kgf/cm2)
(psi)
0.2
61.8
(0.63)
(9)
0.4
124.6
(1.27)
(18)
0.8
249.2
(2.54)
(36)
1
X
X
T4GB-04-05-002
Section X-X
1
T4GB-04-05-003
2
T4-5-2
OPERATIONAL PERFORMANCE TEST / Component Test
SECONDARY PILOT PRESSURE
Preparation:
1. Stop the engine.
2. Push the air bleed valve on top of the hydraulic
oil tank and release any remaining pressure.
3. Measure pressure at the location between pilot
valve and main valve.
Remove the pilot hose to be measured. Install
the hose (9/16-18UNF length: approx. 400 mm)
to the signal control valve side. Install a tee and a
pressure gauge between the hoses.
: 17 mm, 19 mm, 22 mm
Pilot Valve
4. Start the engine. Check for any oil leaks at the
pressure gauge connection.
5. Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F).
Measurement:
1. Set engine speed at fast idle. Depress the accelerator pedal fully.
2. Measure pilot pressure by using a pressure
gauge with the corresponding control lever operated full stroke.
3. Repeat the measurement three times and calculate the average values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
Remedy:
Refer to Troubleshooting in Section T5.
T4-5-3
Pilot Hose
Signal Control
Valve
Pressure Gauge
Tee
T4GB-04-05-004
OPERATIONAL PERFORMANCE TEST / Component Test
SOLENOID VALVE SET PRESSURE
Measure solenoid valve set pressure by using both Dr.
ZX and the pressure gauge.
Preparation:
1. Stop the engine.
2. Push the air bleed valve on top of the hydraulic
oil tank and release any remaining pressure.
3. Remove the line from port X in the charging block.
Install a tee, a hose and adapter (ST 6461). Install pressure gauge (ST 6942).
: 17 mm, 19 mm, 22 mm
Install Dr. ZX and select the monitoring function.
4. Start the engine. Check for any oil leaks at the
pressure gauge connection.
5. Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F).
Charging Block
Solenoid
Valve
Measurement:
1. Set engine speed at fast idle.
2. Measure without depressing the accelerator
pedal.
Measure with the accelerator pedal fully depressed.
3. Read the values on both Dr. ZX and the pressure
gauge.
4. Repeat the measurement three times and calculate the average values.
Port X
T4GB-04-05-005
Pressure Gauge
Evaluation:
Refer to the performance Standard Table in Group
T4-2.
To Port X
T4GB-04-05-006
Hose
T4-5-4
Tee
Adapter
OPERATIONAL PERFORMANCE TEST / Component Test
Solenoid Valve Set Pressure Adjustment Procedure
IMPORTANT: O-ring on the threads may come off
the sealing surface and oil leak may
occur. Do not loosen and tighten the
adjusting screw excessively.
Do not loosen the adjusting screw
more than 1.2 turns. Do not tighten
the adjusting screw more than 2
turns.
1. Loosen lock nut (1). Turn adjusting screw (2) and
adjust set pressure of the solenoid valve.
2. Retighten lock nut (1).
: 18 mm
: 19.6 N⋅m (2 kgf⋅m, 14 lbf⋅ft)
: 6 mm
1
2
T4GB-04-05-007
Charging Block
3. Check the set pressure of solenoid valve.
NOTE: Standard Change in Pressure (Reference)
Adjusting Screw
1/4
1/2
3/4
1
Turns
kPa
39.2
80.4
120
160
Change in
(kgf/cm2) (0.4) (0.82) (1.22) (1.63)
Pressure
(psi)
(6)
(12)
(17)
(23)
T4GB-04-05-002
2
Pressure
Increase
Pressure
Decrease
W107-02-05-129
T4-5-5
OPERATIONAL PERFORMANCE TEST / Component Test
MAIN PUMP DELIVERY PRESSURE
The main pump delivery pressure can also be measured by using Dr. ZX.
Summary:
Measure the main pump delivery pressure in order to
check performance of the main pump.
Pressure
Gauge
Preparation:
1. Stop the engine.
2. Push the air bleed valve on top of the hydraulic
oil tank and release any remaining pressure.
3. Remove the plug from the main pump delivery
port. Install an adapter, a hose and a pressure
gauge.
: 6 mm
(If Dr. ZX is used, install Dr. ZX and select the
controller function diagnosing.)
4. Start the engine. Check for any leaks at the pressure gauge connection.
5. Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F).
Measurement:
1. Set engine speed at fast idle. Depress the accelerator pedal fully.
2. Measure pressure without load (with the control
levers in neutral).
3. Repeat the measurement three times and calculate the average values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
Remedy:
Refer to Troubleshooting in Section T5.
T4-5-6
Pressure
Check Port
T4GB-04-05-008
Adapter
OPERATIONAL PERFORMANCE TEST / Component Test
(Blank)
T4-5-7
OPERATIONAL PERFORMANCE TEST / Component Test
MAIN RELIEF PRESSURE
The main relief pressure can also be measured by
using Dr. ZX.
Summary:
Measure the main relief valve set pressure at the
main pump delivery port in order to check performance of the main relief valve.
Preparation:
1. Stop the engine.
2. Push the air bleed valve on top of the hydraulic
oil tank and release any remaining pressure.
3. Remove the plug from the main pump delivery
port. Install an adapter, a hose and a pressure
gauge.
: 6 mm
(If Dr. ZX is used, install Dr. ZX and select the
controller function diagnosing.)
4. Start the engine. Check for any oil leaks at the
pressure gauge connection.
5. Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F).
Measurement:
1. Set engine speed at fast idle. Depress the accelerator pedal fully.
2. Slowly operate the lift arm or bucket control levers to the stroke end (extend or retract) and relieve each function.
3. Repeat the measurement three times and calculate the average values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
T4-5-8
Pressure
Gauge
Pressure
Check Port
T4GB-04-05-008
Adapter
OPERATIONAL PERFORMANCE TEST / Component Test
Main Relief Valve Pressure Adjustment Procedure
•ZW220
1. Secure lock nut (1). Remove nut (3).
: 17 mm
2. Secure adjusting screw (2). Loosen lock nut (1).
: 17 mm
3. Turn adjusting screw (2) and adjust the relief
pressure to the specification.
4. Secure adjusting screw (2). Tighten lock nut (1).
: 19.5 N⋅m (2 kgf⋅m, 14 lbf⋅ft)
5. Secure lock nut (1). Tighten nut (3).
6. Check the relief set pressure.
T4GB-04-05-009
NOTE: Standard Change in Pressure (Reference)
Adjusting Screw
1/4
1/2
3/4
1
Turns
MPa
2.79
5.59
8.36
11.2
Change in
(kgf/cm2) (28.5)
(57)
(85.2)
(114)
Pressure
(psi)
(406) (813) (1215) (1628)
3
1
2
T4GB-04-05-010
2
Pressure
Increase
Pressure
Decrease
T105-06-05-002
T4-5-9
OPERATIONAL PERFORMANCE TEST / Component Test
•ZW250
1. Loosen lock nut (1).
: 17 mm
2. Turn adjusting screw (2) and adjust the relief
pressure to the specification.
: 6 mm
3. Tighten lock nut (1).
: 29.4 N⋅m (3 kgf⋅m, 22 lbf⋅ft)
4. Check the relief set pressure.
1
2
T4GB-04-05-011
NOTE: Standard Change in Pressure (Reference)
Adjusting Screw
1/4
1/2
3/4
1
Turns
Change in
Pressure
MPa
(kgf/cm2)
(psi)
4.5
(46)
(654)
8.9
(91)
(1294)
13.4
(137)
(1948)
17.8
(182)
(2588)
2
Pressure
Increase
Pressure
Decrease
W107-02-05-129
T4-5-10
OPERATIONAL PERFORMANCE TEST / Component Test
(Blank)
T4-5-11
OPERATIONAL PERFORMANCE TEST / Component Test
STEERING RELIEF PRESSURE
The steering relief pressure can also be measured by
using Dr. ZX.
Pressure Gauge
Summary:
Measure the steering relief valve set pressure at the
main pump delivery port in order to check performance of the steering relief valve.
Preparation:
1. Stop the engine.
2. Pusht the air bleed valve on top of the hydraulic
oil tank and release any remaining pressure.
3. Remove the plug from the main pump delivery
port. Install an adapter, a hose and a pressure
gauge.
: 6 mm
(If Dr.ZX is used, install Dr.ZX and select the controller function diagnosing.)
4. Start the engine. Check for any oil leaks at the
pressure gauge connection.
5. Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F).
Measurement:
1. Set engine speed at fast idle. Depress the accelerator pedal fully.
2. Install the articulation lock bar. Slowly operate the
steering handle and relieve the steering.
3. Repeat the measurement three times and calculate the average values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
T4-5-12
Pressure
Check Port
Adapter
T4GB-04-05-008
OPERATIONAL PERFORMANCE TEST / Component Test
Steering Relief Valve Pressure Adjustment Procedure
1. Secure lock nut (1). Remove nut (3).
: 24 mm
2. Secure adjusting screw (2). Loosen lock nut (1).
: 24 mm
3. Turn adjusting screw (2) and adjust the relief
pressure to the specification.
4. Secure adjusting screw (2). Tighten lock nut (1).
: 37 N⋅m(3.8 kgf⋅m, 27 lbf⋅ft)
5. Secure lock nut (1). Tighten nut (3).
: 37 N⋅m(3.8 kgf⋅m, 27 lbf⋅ft)
6. Check the relief set pressure.
Steering Relief
Valve
T4GB-04-05-012
3
1
NOTE: Standard Change in Pressure (Reference)
Adjusting Screw
1/4
1/2
3/4
1
Turns
Change in
Pressure
MPa
(kgf/cm2)
(psi)
3.8
(39)
(552)
7.5
(77)
(1050)
11.3
(155)
(1643)
15.0
(153)
(2181)
2
T4GB-04-05-013
2
Pressure
Increase
Pressure
Decrease
T105-06-05-002
T4-5-13
OPERATIONAL PERFORMANCE TEST / Component Test
OVERLOAD
PRESSURE
RELIEF
VALVE
SET
Summary:
1. The circuit pressure must be increased by
applying an external force while blocking the
return circuit from the control valve. This
measuring method is hazardous and the results
obtained with this method are unreliable.
2. The oil flow rate used to set the overload relief
pressure is far less than that used to set the main
relief pressure. Therefore, measuring the overload
pressure in the main circuit by increasing the main
relief set-pressure more than the overload valve
set-pressure is not a proper method. In addition, in
case a main relief valve designed to leak a small
quantity of oil before reliving is used, its
pre-leaking start pressure must be increased
more than the overload relief valve set-pressure.
However, the pre-leaking start pressure is not
always increased more than the overload relief
valve set-pressure as the adjustable upper limit of
the main relief valve set-pressure is provided.
Accordingly, the overload relief valve assembly
should be removed from the machine and
checked on a specified test stand at a correct oil
flow rate. Some overload relief valves come in
contact with the control valve body to block the oil
passage. When this type of overload relief valve is
checked, the control valve body must be precisely
finished as the test unit. Provide one control valve
other than that on the machine as a test kit.
4. Install Dr. ZX and select the monitoring function.
Start the engine. Check for any oil leaks at the
pressure gauge connection.
5. Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F).
Measurement:
1. Set engine speed at fast idle. Depress the
accelerator pedal fully.
2. Slowly operate the control levers (lift arm or
bucket) corresponding to the overload relief valve
to be measured to the stroke ends (extend and
retract) and relieve each function.
3. Read the pressures on the pressure gauge at this
time.
4. Repeat the measurement three times and
calculate the average values.
Evaluation:
Performance of the overload relief valves are normal if
the measured main relief pressures are within the
specified value range.
Refer to the Performance Standard Table in Group
T4-2.
Pressure
Gauge
3. If the overload relief valve performance must be
checked on the machine, however, measure the
main relief pressure while releasing each front
function respective to the measuring overload
relief valve. And, assume that the overload relief
valve is functioning correctly if the obtained main
relief pressure is within the specified value range.
Measure the main pressure of the front functions
by using Dr. ZX.
Preparation:
1. Stop the engine.
2. Push the air bleed valve on top of the hydraulic oil
tank and release any remaining pressure.
3. Remove the plug from the main pump delivery
port. Install an adapter, a hose and a pressure
gauge.
: 6 mm
T4-5-14
Pressure
Check Port
Adapter
T4GB-04-05-008
OPERATIONAL PERFORMANCE TEST / Component Test
Overload Relief
Procedure
Valve
Pressure
Adjusting
NOTE: In principle, adjust the overload relief valve
pressure on a test stand.
Adjust the pressure setting of the overload relief valve
with adjusting screw (2) after loosening lock nut (1).
1
1. Loosen lock nut (1).
: 17 mm
2. Turn adjusting screw (2) and adjust the pressure.
: 6 mm
3. Tighten lock nut (1).
: 17 mm
: 29.5 N⋅m (3.0 kgf⋅m, 22 lbf⋅ft)
2
W107-02-05-128
4. Check the set pressure.
NOTE: Standard Change in Pressure (Reference)
Adjusting Screw
1/4
1/2
3/4
1
Turns
MPa
5.2
10.6
15.9
21.1
Change in
(kgf/cm2) (54)
(108)
(162)
(216)
Pressure
(psi)
(770) (1540) (2300) (3070)
2
Pressure
Increase
Pressure
Decrease
W107-02-05-129
T4-5-15
OPERATIONAL PERFORMANCE TEST / Component Test
MAIN PUMP FLOW RATE
• P-Q Control (Torque Control)
Summary:
Main pump performance is checked by measuring
the pump flow rate by using a hydraulic tester
installed at the main pump delivery port to be
measured. Use Dr. ZX and a pressure gauge at the
same time.
IMPORTANT: This measurement procedure is a
simple method. The measured data
will be lower by approx. 5 % than the
accurately measured value. In order
to measure accurately, disconnect
the return circuit from the control
valve and connect it to the hydraulic
oil tank.
Preparation:
1. Stop the engine. Push the air bleed valve and
release any remaining pressure. Install a vacuum
pump to the oil filler port.
NOTE: Operate the vacuum pump while
connecting the pump flow rate test line.
2. Remove the delivery hose from the main pump.
Install pipe (1) to split flange (8) in the removed
hose with the bolt.
: 41 mm
: 10 mm
3. Connect pipe (1) to hydraulic tester (4) with test
hose (2) and adapter (3). Install adapter (5), joint
(6) and flange (7).
: 41 mm
: 10 mm
4. Connect flange (7) to the delivery hose with split
flange (8) and bolt (9).
: 10 mm
5. Install a pressure gauge to the main pump. (Refer
to the page on Main Pump Relief Pressure.)
: 6 mm
6. Remove hose (11) from the regulator. Install plug
(G1/4) to the hole on hose (11).
: 17 mm
7. Remove the vacuum pump. Loosen plug (10) on
top of the pump casing. Bleed air from the pump
casing until oil only comes out of the plug
clearance.
8. Fully open the loading valve of hydraulic tester.
9. Start the engine. Check for any oil leaks at the
pressure gauge connection. Install Dr. ZX and
select the monitor display function of MC.
Measurement:
1. Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F).
2. Measure the maximum flow rate.
3. Set engine speed at fast idle. Depress the
accelerator pedal fully.
4. Adjust the main relief valve set pressure in the
control valve to each pressure point specified
along the main pump P-Q curve. (Refer to T4-2.)
Slowly close the loading valve of the hydraulic
tester while relieving the pressure in the bucket
crowd circuit. Measure the flow rates and engine
speeds at the pressure points specified in the P-Q
curve.
5. Repeat the measurement three times and
calculate the average values.
T4-5-16
OPERATIONAL PERFORMANCE TEST / Component Test
Evaluation:
1. Convert the measured flow rates to those at the
specified pump speed by using the following
formulas:
2. Standard Flow Rate
Refer to the Performance Standard Table in Group
T4-2.
Qc = (Ns × Q) ⁄ Ne
Qc : Converted Flow Rate
Q : Measured Flow Rate
Ns : Specified Engine Speed: ZW220: 2170 min-1
ZW250: 2240 min-1
Ne : Measured Engine Speed:
Value by Dr. ZX
1
2
3
5
4
6
7
8
9
Delivery Hose
(To Control Valve)
T1F3-04-05-010
10
11
T4GB-04-05-014
1 - Pipe
2 - Test Hose
3 - Adapter (PF1× UNF1-7/8)
456-
Hydraulic Tester
Adapter (PF1×UNF1-7/8)
Joint
789-
T4-5-17
Flange
Split Flange
Bolt (4 Used)
10 - Plug
11 - Hose
OPERATIONAL PERFORMANCE TEST / Component Test
• Pilot Characteristics
Summary:
Main pump performance is checked by measuring
the pump flow rate by using a hydraulic tester
installed at the main pump delivery port to be
measured. Use Dr. ZX and a pressure gauge at the
same time.
IMPORTANT: This measurement procedure is a
simple method. The measured data
will be lower by approx. 5 % than the
accurately measured value. In order
to measure accurately, disconnect
the return circuit from the control
valve and connect it to the hydraulic
oil tank.
Preparation:
1. Refer to steps 1 to 4 on page T4-5-16. Install a
hydraulic tester to the main pump.
2. Remove the hose from regulator port Pi1 of the
pump. Install a plug to the removed hose.
: 19 mm
3. Install adapters (13) (3 used) to pressure reducing
valve (14). Remove the hose from port P of the
orbit roll. Insert tee (10), adapter (11) and hose
(12) between orbit roll and charging block.
Install hose (12) to port P1 on reducing valve (14).
: 19 mm
4. Install tee (15) to port P2 on pressure reducing
valve (14). Install pressure gauge (16) and hose
(12) to tee (15). Install hose (12) to regulator port
Pi1.
: 19 mm
5. Install hose (12) and adapter (13) to port T on
pressure reducing valve (14). Remove plug L
from the return pipe. Install hose (12).
: 19 mm
6. Connect regulator port Pi2 to the hydraulic oil tank.
As for the emergency steering, install tee (17),
adapter (18) and hose (19) to port E in the
emergency steering block. Install hose (19) to
regulator port Pi2.
7. Remove the vacuum pump. Loosen the plug on
top of the pump casing. Bleed air from the pump
casing until oil only comes out of the plug
clearance.
8. Fully open the loading valve of the hydraulic
tester.
9. Start the engine. Check for any oil leaks at the
pipe connection.
Measurement:
1. Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F)
2. The pump flow rate in response to the external
command pilot pressure is measured.
3. Set engine speed at fast idle. Depress the
accelerator pedal fully
4. Adjust the pressure reducing valve set pressure
to each pressure point specified along the main
pump P-Q curve. (Pilot Characteristics) (Refer to
T4-2.) Measure the flow rates and engine speeds
at the pressure points specified in the P-Q curve.
5. Repeat the measurement three times and
calculate the average values.
Evaluation:
1. Convert the measured flow rates to those at the
specified pump speed by using the following
formulas:
Qc = (Ns × Q) / Ne
Qc : Converted Flow Rate
Q : Measured Flow Rate
Ns : Specified Engine Speed : ZW220: 2170 min-1
ZW250: 2240 min-1
Ne : Measured Engine Speed
Value by Dr. ZX
2. Standard Flow Rate
Refer to the Performance Standard Table in
Group T4-2.
T4-5-18
OPERATIONAL PERFORMANCE TEST / Component Test
1
2
3
5
4
6
7
8
9
Delivery Hose
(To Control Valve)
T1F3-04-05-010
Port Pi2
Port Pi1
Pilot Steering Valve
Port P
Pilot Steering
Valve Port P Hose
T4GB-04-05-025
Charging Block
T4GB-04-05-026
Pressure Reducing
Valve Port Position
Emergency
Steering
Check Block
Return Pipe
T
17
L
P1
P2
19
13
To Regulator
Port Pi2
12
16
13
To Hydraulic
Oil Tank
To Port P in Pilot
Steering Valve
To Regulator
Port Pi1
12
Charging
Block
15
13
6 - Test Hose
2 - Test Hose
7 - Flange
3 - Adapter (G1 × UNF1-7/8)
(ST 6146)
4 - Hydraulic Tester
8 - Split Flange (4085560)
12
13
14
1 - Pipe
5 - Adapter (G1 × UNF1-7/8)
(ST 6146)
18
Port E
9 - Bolt (J781240) (4 Used)
10 - Tee 7/16-20UNF x G1/4
11
10
11 - Adapter (9/16 UNF x G1/4)
(A852123)
12 - Hose (9/16 UNF)
(4304905)
13 - Adapter (9/16 UNF x G3/8)
(A852133)
14 - Pressure Reducing Valve
(4325439)
15 - Tee (9/16 UNF x G1/4)
T4-5-19
T1F3-04-05-009
16 - Pressure Gauge
17 - Tee
18 - Adapter
19 - Hose
OPERATIONAL PERFORMANCE TEST / Component Test
REGULATOR ADJUSTMENT
6
5
1
2
7
8
4
3
9
10
T4GB-04-05-016
1 - Lock Nut (For Minimum
Flow Rate)
2 - Adjusting Screw (For
Minimum Flow Rate)
3 - Lock Nut (For Maximum
Flow Rate)
Adjustment Item
1. Maximum Flow Rate
4 - Adjusting Screw (For
Maximum Flow Rate)
5 - Lock Nut
(For Pilot Pressure
Characteristic)
6 - Adjusting Screw
(For Pilot Pressure
Characteristic)
7 - Lock Nut
(For P-Q Control)
8 - Adjusting Screw
(For P-Q Control)
9-
Lock Nut
(For P-Q Control)
10 - Adjusting Screw
(For P-Q Control)
Adjustment Procedure
Remarks
ZW220
1) Do not turn adjusting screw (6) more
Loosen lock nut (5) and turn
than two turns.
adjusting screw (6).
2) Do not increase the maximum flow
Rotate adjusting screw (6) 1/4 a
rate.
turn clockwise and the maximum
In other words, do not turn adjusting
pump flow rate decreases by
screw (6) counterclockwise.
11.26 cm3/rev. (0.69 in3/rev).
3) Secure tighten lock nut (5) after the
: 32 mm
adjustment.
: 40 N⋅m
(4.1 kgf⋅m, 30 lbf⋅ft)
ZW250
1) Do not turn the adjusting screw (4)
Loosen lock nut (3) and turn
more than two turns.
adjusting screw (4).
2) Do not increase the maximum flow
Rotating adjusting screw (4) 1/4
rate.
a turn clockwise and maximum
In other words, do not turn adjusting
pump flow rate decreases by
screw (4) counterclockwise.
12.58 cm3/rev. (0.77 in3/rev).
3) Securely retighten lock nut (3) after
: 22 mm
the adjustment.
: 20 N⋅m
(2 kgf⋅m, 15 lbf⋅ft)
T4-5-20
OPERATIONAL PERFORMANCE TEST / Component Test
Adjustment Item
Adjustment Procedure
Remarks
2. Pilot Pressure Characteristics Loosen lock nut (1) and turn 1) Do not turn the adjusting screw (2)
adjusting screw (2).
more than one turn.
Rotate adjusting screw (2) 1/4 a 2) Securely tighten lock nut (1) after
turn clockwise and the pump flow
the adjustment.
Q
rate decreases by X cm3/rev. (X
in3/rev).
ZW220: X=8.08 (0.49)
ZW250: X=9.22 (0.56)
: 17 mm
: 20 N⋅m
(2 kgf⋅m, 15 lbf⋅ft)
Pi
3. P-Q Control
(Torque Adjustment)
Q
A
Pd
A: Loosen lock nut (7) and turn 1) Do not turn the adjusting screws (8,
adjusting screw (8).
10) more than one turn.
Rotating adjusting screw (8) 2) Rotate the adjusting screws (8, 10)
1/4 a turn clockwise increases
while
watching
the
engine
and the pump flow rate
performance.
increase by Y cm3/rev. (Y 3) Securely tighten lock nuts (7, 9)
after the adjustment.
in3/rev.).
ZW220: Y=13.6 (0.83)
ZW250: Y=15.5 (0.95)
: 30 mm
: 30 N⋅m
(3.1 kgf⋅m, 22 lbf⋅ft)
Q
B
Pd
B: Loosen lock nut (9) and turn
adjusting screw (10).
Rotating adjusting screw (10)
1/4 a turn clockwise and the
pump flow rate increases by Z
cm3/rev. (Z in3/rev).
ZW220: Z=3.9 (0.24)
ZW250: Z=4.2 (0.26)
: 13 mm
: 10 N⋅m
(1 kgf⋅m, 7.5 lbf⋅ft)
T4-5-21
OPERATIONAL PERFORMANCE TEST / Component Test
SERVICE BRAKE PRESSURE (FRONT
AND REAR)
(The pressure can be measured by using Dr. ZX.)
CAUTION: If air is mixed in the brake system,
the brake function is reduced and serious
hazard may occur. Bleed air from the brake
system after removing and installing the pipe
lines and replacing hydraulic oil.
Refer to Troubleshooting B in Group T5-6.
Summary:
Measure the pressure at the brake valve pressure
check port when the brake pedal is depressed.
Preparation:
CAUTION: Set the block onto the front and
rear tires in order not to move the machine.
Keep away from the machine.
1. Stop the engine.
2. Push the air bleed valve on top of the hydraulic oil
tank and release any remaining pressure.
3. Depress the brake at least 50 strokes in order to
reduce the accumulated pressure left in the brake
circuit.
4. Install the measuring devices to the front and rear
wheel brake circuits.
4-1. Front wheel brake circuit pressure: Remove
plug (1) from the pressure check port in brake
valve. Install a nipple and a pressure gauge to
the pressure check port.
: 19 mm, 22 mm
: 6 mm
4-2. Rear wheel brake circuit pressure: Remove
plug (2) from the pressure check port in brake
valve. Install a nipple and a pressure gauge to
the pressure check port.
: 19 mm, 22 mm
: 6 mm
5. Start the engine. Check for any oil leaks at the
pressure gauge connection.
6. Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F).
T4GB-04-05-017
Block
Brake Valve
T4-5-22
1
2
T4GB-04-05-018
OPERATIONAL PERFORMANCE TEST / Component Test
Conditions for Measurement:
1. Set engine speed at fast idle.
2. Depress the accelerator pedal fully.
Measurement:
1. Measure the pressure when fully depressing the
brake pedal at left side to the floor.
2. Repeat the measurement three times and
calculate the average values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
Remedy:
Refer to Troubleshooting B in Group T5-6.
Normally, the front and rear wheel brake pressures
become equal. If not, malfunction of the brake valve
and dirt caught in the valve are suspected.
T4-5-23
OPERATIONAL PERFORMANCE TEST / Component Test
PARKING BRAKE PRESSURE
CAUTION: If air is mixed in the brake system,
the brake function is reduced and serious
hazard may occur. Bleed air from the brake
system after removing and installing the pipe
lines and replacing hydraulic oil.
Refer to Troubleshooting B in Group T5-6.
Summary:
1. Measure the parking brake release pressure in
the parking brake release circuit.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
Remedy:
Refer to Troubleshooting B in Group T5-6.
Preparation:
1.
2.
3.
4.
5.
CAUTION: Set the block onto the front and
rear tires in order not to move the machine.
Keep away from the machine.
Stop the engine.
Push the air bleed valve on top of the hydraulic oil
tank and release any remaining pressure.
Remove brake hose (1) from the parking brake
side. Install a pressure gauge to the removed
hose.
: 19 mm, 22 mm
Start the engine. Check for any oil leaks at the
pressure gauge connection.
Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F).
T4GB-04-05-017
Block
1
Conditions for Measurement:
1. Set engine speed at fast idle.
2. Depress the accelerator pedal fully.
Measurment:
1. Release the parking brake and measure the
pressure at this time.
2. Repeat the measurement three times and
calculate the average values.
M4GB-06-004
T4-5-24
OPERATIONAL PERFORMANCE TEST / Component Test
(Blank)
T4-5-25
OPERATIONAL PERFORMANCE TEST / Component Test
BRAKE ACCUMLATED PRESSURE
(The pressure can be measured by using Dr. ZX.)
CAUTION: If air is mixed in the brake system,
the brake function is reduced serious hazard
may occur. Bleed air from the brake system
after removing and installing the pipe lines
and replacing hydraulic oil.
Refer to the Troubleshooting B in Group T5-6.
Summary:
The accumulated brake pressure is measured at
output port of the accumulator. The accumulated
brake pressure varies according to operation of the
brake. Record the maximum value.
Preparation:
T4GB-04-05-017
CAUTION: Set the block onto the front and
rear tires in order not to move machine. Keep
away from the machine.
1. Stop the engine.
2. Push the air bleed valve on top of the hydraulic oil
tank and release any remaining pressure.
3. Depress the brake at least 50 strokes in order to
reduce the accumulated pressure left in the brake
circuit.
4. Remove plug (1) from the pressure check port of
charging block in bottom of the cab.
Install a nipple and a pressure gauge to the
pressure check port.
: 19 mm, 22 mm
: 6 mm
5. Start the engine. Check for any oil leaks at the
pressure gauge connection.
6. Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F).
Block
1
T4GB-04-05-019
T4-5-26
OPERATIONAL PERFORMANCE TEST / Component Test
Conditions for Measurement:
1. Set engine speed at fast idle.
2. Depress the accelerator pedal fully.
Measurement:
1. Measure maximum pressure when depressing
the brake pedal slowly several times.
2. Repeat the measurement three times and
calculate the average values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
Remedy:
Refer to Troubleshooting B in Group T5-6.
T4-5-27
OPERATIONAL PERFORMANCE TEST / Component Test
BRAKE WARNING
(DECREASE)
SET
PRESSURE
(The pressure can be measured by using Dr. ZX.)
CAUTION: If air is mixed in the brake system,
the brake function is reduced serious hazard
may occur. Bleed air from the brake system
after removing and installing the pipe lines
and replacing hydraulic oil.
Refer to the Troubleshooting B in Group T5-6.
Summary:
When the warning buzzer sounds by reducing the
accumulated brake pressure, measure the pressure
at the output port of accumulator.
Preparation:
CAUTION: Set the block onto he front and
rear tires in order not to move the machine.
Keep away from the machine.
1. Stop the engine.
2. Push the air bleed valve on top of the hydraulic oil
tank and release any remaining pressure.
3. Depress the brake at least 50 strokes in order to
reduce the accumulated pressure left in the brake
circuit.
4. Remove plug (1) from the charged pressure
check port in brake valve. Install a nipple and a
pressure gauge to the pressure check port.
: 19 mm, 22 mm
: 6 mm
5. Start the engine. Check for any oil leaks at the
pressure gauge connection.
6. Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F).
T4GB-04-05-017
Block
Blake Valve
1
T4GB-04-05-018
T4-5-28
OPERATIONAL PERFORMANCE TEST / Component Test
Conditions for Measurement:
1. Select the following switch positions.
Forward/Reverse Lever Parking Brake Switch
N
P (Parking)
Measurement:
1. Stop the engine. Turn the key switch to ON
position.
2. Measure the pressure when warning buzzer
sounds by slowly depressing the brake pedal
several times.
3. Repeat the measurement three times and
calculate the average values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
Remedy:
Refer to Troubleshooting B in Group T5-6.
T4-5-29
OPERATIONAL PERFORMANCE TEST / Component Test
BRAKE WARNING SET PRESSURE
(INCREASE)
(The pressure can be measured by using Dr. ZX.)
CAUTION: If air is mixed in the brake system,
the brake function is reduced serious hazard
may occur. Bleed air from the brake system
after removing and installing the pipe lines
and replacing hydraulic oil.
Refer to the Troubleshooting B in Group T5-6.
Summary:
When sounding of the warning buzzer stops by
increasing the accumulated brake pressure, measure
the pressure at the output port of accumulator.
Preparation:
CAUTION: Set the block onto the front and
rear tires in order not to move machine. Keep
away from the machine.
4. Stop the engine.
5. Push the air bleed valve on top of the hydraulic oil
tank and release any remaining pressure.
6. Depress the brake at least 50 strokes in order to
reduce the accumulated pressure left in the brake
circuit.
5. Remove plug (1) from the charged pressure
check port in brake valve. Install a nipple and a
pressure gauge to the pressure check port.
: 19 mm, 22 mm
: 6 mm
6. Start the engine. Check for any oil leaks at the
pressure gauge connection.
5. Maintain the hydraulic oil temperature at 50±5 °C
(122±41 °F).
T4GB-04-05-017
Block
Blake Valve
1
T4GB-04-05-018
T4-5-30
OPERATIONAL PERFORMANCE TEST / Component Test
Conditions for Measurement:
1. Select the following switch positions.
Forward/Reverse Lever Parking Brake Switch
N
ON
Measurement:
1. Stop the engine. Turn the key switch to ON
position.
2. Set the engine control dial to slow idle.
3. Depress the brake pedal several times and make
the warning buzzer sound.
4. Start the engine. Measure the pressure when
sounding of the warning buzzer stops. Notice that
it is difficult to read the gauge as the pressure
increases rapidly.
5. Repeat the measurement three times and
calculate the average values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
Remedy:
Refer to Troubleshooting B in Group T5-6.
T4-5-31
OPERATIONAL PERFORMANCE TEST / Component Test
TRANSMISSION CLUTCH PRESSURE
Summary:
Measure each operating pressure of the tansmission
clutch at each port of the transmission control valve.
Reverse Clutch
Pressure
Forward Clutch
Pressure
First Gear Clutch
Pressure
Preparation:
1. Stop the engine.
2. Remove the plug from the port. Install a hose, an
adapter and a pressure gauge.
: 8 mm
: 21 mm
3. Start the engine. Check for any oil leaks at the
pressure gauge connection.
4. Maintain the torque converter oil temperature at
60 to 80 °C (140 to 176 °F).
Second Gear
Clutch Pressure
Third Gear
Clutch Pressure
Fourth Gear
Clutch Pressure
Measurement:
CAUTION: Set the block onto the front and
rear tires in order not to move machine. Keep
away from the machine.
1. Select the following switch positions.
T4GB-04-05-023
Accelerator
Pedal
Fully
Depressed
Brake Pedal
Travel Mode
Clutch Cut-Off
Position Switch
Parking Brake
Switch
Fully
Depressed
M
OFF
OFF
2. Operate the forward/reverse lever and the shift
switch. Measure each clutch pressure.
Travel Switch
Forward/Reverse
Lever
Shift Switch
F
R
1st
2nd
3rd
4th
F
R
N
N
N
N
4
4
1
2
3
4
3. Repeat the measurement three times and
calculate the average values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
T4-5-32
OPERATIONAL PERFORMANCE TEST / Component Test
TORQUE CONVERTER PRESSURE (INLET
AND OUTLET)
Torque Converter
Inlet Pressure
Check Port
Summary:
Measure inlet pressure and outlet pressure of the
torque converter pressure at the port of torque
converter housing.
Preparation:
1. Stop the engine.
2. Inlet pressure:
Remove the plug from the port of regulator valve
(1). Install a hose, an adapter and a pressure
gauge to the open part.
: 6 mm
Outlet pressure:
Remove the plug from the port of torque converter
housing (2). Install a hose, an adapter and a
pressure gauge to the open part.
: 6 mm
3. Start the engine. Check for any oil leaks at the
pressure gauge connection.
4. Maintain the torque converter oil temperature at
60 to 80 °C (140 to 176 °F).
1
2
Torque Converter
Outlet Pressure
Check Port
Measurement:
CAUTION: Set the block onto the front and
rear tires in order not to move the machine.
Keep away from the machine.
1. Select the following switch positions:
T4GB-04-05-024
T4GB-04-05-017
Block
Accelerator
Pedal
Fully
Depressed
Brake Pedal
Travel Mode
Clutch Cut-Off
Position Switch
Parking Brake
Switch
Fully
Depressed
M
OFF
OFF
2. Set the front/reverse lever to “F” (Forward) and
the shift switch to “4” (Fourth Gear). Measure the
pressure.
3. Repeat the measurement three times and
calculate the average values.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
T4-5-33
OPERATIONAL PERFORMANCE TEST / Component Test
(Blank)
T4-5-34
OPERATIONAL PERFORMANCE TEST / Adjustment
TRANSMISSION LEARNING
Relay Box
After removing and/or replacing the components as
described below for repair, perform the transmission
learning (calibration).
• Replacement or repair of the transmission
assembly, transmission control valve or clutch
pack
• Replacement or repair of MC (Main Controller)
Preparation:
1. Start the service mode in monitor. Start the engine.
(Refer to T5-1-6.)
2. Select the transmission oil temperature on the
monitor. (Refer to T5-1-7.)
3. Heat transmission oil.
3-1. Disconnect connector (1) (6-pole, gray) in the
relay box from dummy connector.
3-2. Select or operate the switches from the left item
in the table below.
T4GB-04-06-007
1
T4GB-04-06-001
Clutch Cut-Off
Position Switch
Shift Switch
Parking Brake
Switch
Brake Pedal
OFF
Second Gear
OFF
Fully
Depressed
3-3. Stall the transmission and heat transmission oil
to 90 °C (194 °F).
3-4. When transmission oil temperature on the
monitor reaches 90 °C (194 °F), return the
forward/reverse lever to neutral (N) and stop the
engine.
T4-6-1
Accelerator
pedal
Fully
Depressed
Forward/Reverse
Lever
F
OPERATIONAL PERFORMANCE TEST / Adjustment
Learning
1. Install the calibration switch to the connector
(6-pole, gray) in relay box in 10 seconds after
turning the key switch OFF (the battery relay is
tuned OFF). At this time, return the calibration
start switch to neutral.
IMPORTANT: If the battery relay is not turned OFF,
calibration cannot be performed. It
takes 10 seconds to turn the battery
relay OFF after turning the key
switch OFF.
Calibration
Switch
Calibration Start
Switch
2. Start the service mode in monitor. Start the engine.
Set engine speed at idling speed. (Refer to
T5-1-6.)
3. Select the transmission oil temperature on the
monitor. (Refer to T5-1-7.)
IMPORTANT: Do not operate each switch and lever
until calibration finishes.
4. When transmission oil temperature reaches 75 °C
(167 °F), push T/M in the calibration start switch.
The start of learning display as illustrated in the
right is selected on the monitor.
Lift Arm
T/M
T4GB-04-06-003
Start of Learning
Oil
temperature
when starting
learning
5. When learning finishes, the end of learning
display as illusrated in the right is selected on the
monitor. Return the calibration start switch to
neutral.
6. Remove the calibration switch from the connector
and stop the engine.
T4GB-04-06-004
The speed stage during learning is displayed on the
monitor.
11 to 13: First Gear, 21 to23: Second Gear,
31 to 33: Third Gear, 41 to 43: Fourth Gear,
F1 to F3: Forward, A1 to A3: Reverse
End of Learning
T4GB-04-06-006
T4-6-2
OPERATIONAL PERFORMANCE TEST / Adjustment
Error Display
When calibration fails, the error is displayed on the
monitor.
The error consists of two types; when start of
calibration fails, when calibration is aborted during
calibration.
• Error display when start of calibration fails
If the error display as figure 1 is displayed before
starting calibration, calibration cannot be
continued. After the trouble correspoding to error
No. is solved, start calibration again.
Error
No.
2
3
4
Error Display
Figure 1
Error
The forward/reverse lever is not in “N”.
The parking brake is not in “ON”.
The machine is driving.
T/M temperature is lower than
5
specification. *1
T/M temperature is higher than
6
specification. *1
Engine speed is lower than specification.
7
*2
Engine
speed
is
higher
than
8
specification. *2
*1: Error No. and T/M temperature at this time (figure
2) are displayed alternately.
*2: Error No. and engine speed at this time (figure 3)
are displayed alternately.
NOTE: If error No. 2, 3 or 4 is displayed, set the
switch and lever corresponding to this error
to the correct position so that SR is
displayed on the monitor.
If error No. 6 is displayed, wait until
transmission oil temperature reaches
specification so that SR is displayed on the
monitor.
When SR is displayed, push the calibration
start switch again and start calibration.
Error No.
T4GB-04-06-009
Figure 2
T/M
Temperature
T4GB-04-06-010
Figure 3
Engine Speed
T4-6-3
T4GB-04-06-011
OPERATIONAL PERFORMANCE TEST / Adjustment
NOTE: If error No. 5, 7 or 8 is displayed, stop the
engine. Remove the calibration switch from
the connector and solve the trouble.
Then, start calibration again.
T4-6-4
OPERATIONAL PERFORMANCE TEST / Adjustment
• Error display when calibration is aborted during
calibration
When calibration is aborted during calibration, the error
display as illustrated in the right is selected.
After the trouble is solved, start calibration again.
Error No.
000108
000208
000308
000408
000508
000109
000209
000309
000110
000210
000310
000111
000211
000311
000112
000212
000312
000113
000213
000313
000114
000214
000314
Error
The key is turned into OFF.
Engine speed is out of specification.
The parking brake is turned into OFF.
The machine starts traveling.
The forward/reverse lever is operated.
Failure of learning at first gear.
Failure of learning at second gear.
T4GB-04-06-013
Error No.
Failure of learning at third gear.
Failure of learning at fourth gear.
Failure of learning at forward.
Failure of learning at reverse.
NOTE: Cause of the error No. display on failure of
learning (from first gear to reverse): The
clutch at the speed when the error occurs
may be out of correctable range
(malfunction of drive unit parts) or the
transmission oil temperature may be
beyond the specification.
T4-6-5
OPERATIONAL PERFORMANCE TEST / Adjustment
LIFT ARM ANGLE SENSOR LEARNING
(OPTIONAL)
After removing and/or replacing the components as
described below for repair, perform the left arm angle
learning (calibration).
• Removal and installation of angle sensor,
Replacement of angle sensor
• Replacement or repair of MC (Main Controller)
Preparation:
1. Install Dr. ZX and start the engine.
Select Boom Anlge and Angle Sensor Learning
Status on the main controller screen in Dr. ZX.
1
2
2. Raise the lift arm to the highest position.
At this time, check if voltage at Boom Angle on the
display in Dr. ZX is 3.78±0.5 V.
3. If voltage 3.78±0.5 V is not displayed, the
followings may be caused. Conduct the remedy.
• The rotation shaft in angle sensor (1) turns with
sensor lever (2) together.
• Angle sensor (1) failure
4. Set control lever lock (3) to LOCK position and
stop the engine.
T4GB-04-06-008
3
LOCK
M4GB-01-050
T4-6-6
OPERATIONAL PERFORMANCE TEST / Adjustment
5. Install calibration switch (5) to connector (4)
(6-pole, gray) in relay box in 10 seconds after
turning the key switch OFF (the battery relay is
tuned OFF). At this time, return calibration start
switch (6) to neutral.
IMPORTANT: If the battery relay is not turned OFF,
calibration cannot be performed. It
takes 10 seconds to turn the battery
relay OFF after turning the key
switch OFF.
Relay Box
6. Lay down calibration start switch (6) to the lift arm
side. Start the engine at idling speed.
7. If “Finish” in Angle Sensor Learning Status on Dr.
ZX is turned into black, learning finishes. Return
calibration start switch (6) to OFF (neutral).
If “Failed” or “Not Learn” in Angle Sensor Learning
Status on Dr. ZX is turned into black, repeat the
procedures from step 1.
T4GB-04-06-007
4
8. Return the control lever lock to UNLOCK. Lower
the lift arm onto the ground. Stop the engine.
9. After learning of the lift arm angle sensor, set the
stop position of lift arm. (Refer to the Operator’s
Manual.)
T4GB-04-06-001
5
6
Lift Arm
T/M
T4GB-04-06-003
T4-6-7
OPERATIONAL PERFORMANCE TEST / Adjustment
DRIVE BELT TENSION ADJUSTMENT
Summary:
If the drive belt is loosened, the charge is defective of
the battery or wear-out at early stage of drive belt
occurs.
If the drive belt is too tense, the water pump and the
bearing of alternator are damaged.
Adjust the drive belt within specification.
Measurement:
Push the drive belt between water pump (1) and
alternator (2) pulley by finger. Measure slack of the
drive belt.
1
Push Here
Pushing force: Approx. 98 N (10 kgf, 72 lbf)
CAUTION: As soon as the machine is
operated, the engine is too hot. When
measureing, take a good care.
2
Evaluation:
Slack of drive belt: 6 to 8 mm (0.24 to 0.31 in)
M4GB-07-082
Adjustment:
1. Loosen nut (3) and bolt (5).
2. Adjust tension of the drive belt to specification with
bolt (4).
3. Tighten nut (3) and bolt (5).
After tightening, check slack of the drive belt.
3
4
NOTE: When the drive belt is replaced with the
new one, the drive belt does not fit first.
After the engine is running at slow idle for 3
to 5 minutes, check slack of the drive belt.
5
T4-6-8
T4GB-04-03-001
MEMO
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SECTION 5
TROUBLESHOOTING
CONTENTS
Group 1 Diagnosing Procedure
Group 3 e-Wheel
Introduction ..............................................T5-1-1
Outline .....................................................T5-3-1
Diagnosing Procedure ..............................T5-1-2
List of Daily Report Data...........................T5-3-2
How to Operate Service Made of
List of Frequency Distribution Data ...........T5-3-3
Monitor ....................................................T5-1-6
List of Total Operationg Hours ..................T5-3-4
Display List of Monitor Service Mode ........T5-1-7
List of Alarm .............................................T5-3-5
List of failure ............................................T5-3-6
Group 2 Dr.ZX
Outline .....................................................T5-2-1
Operation .................................................T5-2-2
Self-Diagnosing Result ............................T5-2-4
Select Controller.......................................T5-2-6
Main Controller .......................................T5-2-7
Main Menu Monitor Display (Main
Controller) ................................................T5-2-8
Setting (Main Controller).........................T5-2-12
Record Data Display (Main Controller)....T5-2-19
How to Download and Upload Data of
ICF ...........................................................T5-3-7
Various Setup if ICF and Satellite
Communication Terminal by Using
Dr.ZX......................................................T5-3-10
List of ICF Fault Code ............................T5-3-22
List of Fault Code of Sattellite
Communication Terminal ........................T5-3-23
Group 4 Component Layout
Password Change (Main Controller) .......T5-2-20
Main Component Layout (Overview) .........T5-4-1
Engine Controller ...................................T5-2-21
Main Component Layout (Upper-
Monitor Display (Engine Controller) ........T5-2-22
structure)..................................................T5-4-2
Recorded Data Display (Engine
Main Component Layout (Travel
Controller) ..............................................T5-2-26
System) ....................................................T5-4-3
Password Change (Engine Controller) ....T5-2-27
Electric Component Layout (Overview) .....T5-4-4
ICF Controller.........................................T5-2-29
Electrical System (Cab) ............................T5-4-5
ICF Various Setup (ICF Controller) .........T5-2-30
Engine and Fan Pump ............................T5-4-10
Save Data Check (ICF Controller) ..........T5-2-40
Pump Device, Drive Unit......................... T5-4-11
Password Change (ICF Controller) .........T5-2-41
Control Valve ..........................................T5-4-12
Monitor Unit............................................T5-2-43
Ride Control Valve ,Charging Block,
Monitoring (Monitor Unit) ........................T5-2-44
Fan Motor...............................................T5-4-13
Various Settings (Monitor Unit) ...............T5-2-46
Steering Valve, Emergency
Internal Hour Meter Synchronization.......T5-2-47
Steering Pump (Optional) .......................T5-4-14
Password Change (Monitor Unit) ............T5-2-48
Components in Control Valve..................T5-4-16
Components in Steering Valve ................T5-4-28
4GCT-5-1
Components in Charging Block ..............T5-4-32
Transmission Failure
Components in Ride Control Valve .........T5-4-38
MC Fault Code 11600 ...........................T5-5-86
Front View of Transmission ....................T5-4-42
MC Fault Code 11601 ...........................T5-5-87
Side View of Transmission .....................T5-4-43
MC Fault Code 11602 ...........................T5-5-88
Rear View of Transmission .....................T5-4-44
MC Fault Code 11904 ...........................T5-5-89
Cross-Sectional Drawing of
MC Fault Code 11905 ...........................T5-5-90
Torque Converter ...................................T5-4-45
CAN Data Reception Failure
Cross-Sectional Drawing of
MC Fault Codes 11910, 11920................T5-5-91
Transmission..........................................T5-4-46
CAN Harness Check
(MC Fault Codes 11910, 11920) .........T5-5-92
Cross-Sectional Drawing of
Clutch Shaft ...........................................T5-4-47
MC Fault Code 11914 .............................T5-5-95
Cross-Sectional Drawing of
CAN Harness Check
(MC Fault Code 11914) ......................T5-5-96
Transmission Regulator Valve ................T5-4-48
Cross-Sectional Drawing of
Other Failures
Transmission Control Valve ....................T5-4-49
MC Fault Code 11901 .............................T5-5-99
Proportional Solenoid Valve Truble
Group 5 Troubleshooting A
Troubleshooting A Procedure....................T5-5-1
MC Fault Code List...................................T5-5-2
ECM Fault Code List ..............................T5-5-22
ICF Fault Code List ................................T5-5-46
Satellite Terminal Fault Code List ...........T5-5-48
Monitor Unit Fault Code List ...................T5-5-50
Controller Hardware Failure
MC Fault Codes 11000 to 11002.............T5-5-51
MC Fault Code 11003.............................T5-5-52
MC Fault Code 11004.............................T5-5-53
CAN Harness Check ..............................T5-5-54
Engine Failure
MC Fault Code 11103 .............................T5-5-75
MC Fault Code 11105 .............................T5-5-76
Pump Failure
MC Fault Code 11204.............................T5-5-77
MC Fault Code 11209.............................T5-5-78
Pilot Failure
MC Fault Code 11312.............................T5-5-79
MC Fault Code 11313.............................T5-5-80
Proportional Solenoid Valve Failure
MC Fault Code 11412.............................T5-5-81
MC Fault Code 11413.............................T5-5-82
Check...................................................T5-5-100
ECM, Sensor System
ECM Fault Codes 100, 102, 105, 108,
110, 157, 172 .......................................T5-5-103
ECM Fault Codes 174, 636, 723,
10001 ...................................................T5-5-104
ECM, External Device System
ECM Fault Codes 651, 652, 653, 654,
655, 656, 1347, 10002..........................T5-5-105
ECM, Fuel System
ECM Fault Codes 157, 633, 1239,
1240 .....................................................T5-5-106
ECM, Engine Protection
ECM Fault Codes 110, 190 ...................T5-5-108
ECM, External Circuit System
ECM Fault Codes 987, 1485.................T5-5-108
ECM, Internal Circuit System
ECM Fault Codes 628, 1077, 1079,
1080, 10003, 10004, 10005 ..................T5-5-109
ECM Fault Codes 10006, 10007,
10008, 10009, 10010, 10011, 10013..... T5-5-110
ECM, Communication System
ECM Fault Codes 639 .......................... T5-5-111
MC Fault Code 11414, 11415, 11416,
11417, 11418, 11419 ..............................T5-5-83
4GCT-5-2
ICF, Satellite Terminal Fault Codes
Malfunction of Hazard Light Indicator......T5-7-13
14000 to 14003 .................................... T5-5-113
Malfunction of High Beam Indicator ........T5-7-14
ICF, Satellite Terminal Fault Codes
Malfunction of Working Light Indicator ....T5-7-16
14006, 14008, 14100 to 14106 ............. T5-5-117
Malfunction of Forward/Reverse
Monitor Unit Fault Codes 13306,
Switch Indicator ......................................T5-7-18
13308 ................................................... T5-5-119
Malfunction of Maintenance Indicator .....T5-7-20
Monitor Unit Fault Code 13312 ............. T5-5-120
Malfunction of Preheat Indicator .............T5-7-21
Monitor Unit Fault Code 13314 ............. T5-5-121
Malfunction of Transmission Oil
Temperature ...........................................T5-7-22
Group 6 Troubleshooting B
Malfunction of Hydraulic Oil
Troubleshooting B Procedure ...................T5-6-1
Temperature Indicator ............................T5-7-24
Relationship between Machine Trouble
Malfunction of Transmission Warning
Symptoms and Related Parts ...................T5-6-2
Indicator .................................................T5-7-26
Correlation between Trouble
Malfunction of Air Filter Restriction
Symptoms and Part Failures ..................T5-6-18
Indicator .................................................T5-7-28
Engine System Troubleshooting .............T5-6-32
Malfunction of Engine Oil Pressure
Front Attachment System
Indicator .................................................T5-7-30
Troubleshooting......................................T5-6-41
Malfunction of Overheat Indicator ...........T5-7-32
Travel System Troubleshooting ..............T5-6-60
Malfunction of Engine Warning
Brake System Troubleshooting ...............T5-6-76
Indicator .................................................T5-7-34
Steering System Troubleshooting ...........T5-6-84
Malfunction of Stop Indicator ..................T5-7-35
Other System Troubleshooting ...............T5-6-87
Malfunction of Service Indicator..............T5-7-36
Exchange Inspection ............................ T5-6-109
Malfunction of Parking Brake Indicator ...T5-7-38
Bleeding Air from Brake (Axle) ............. T5-6-111
Malfunction of Clearance Light
One Part of Data, “Daily Report
Indicator .................................................T5-7-40
Data”, “Distribution Data”, “Total
Malfunction of Brake Low Oil Pressure
Operationg Hours” and “Alarm” is
Indicator .................................................T5-7-41
Not Recorded ....................................... T5-4-112
Malfunction of Brake Low Oil Level
Indicator .................................................T5-7-42
Group 7 Troubleshooting C
Malfunction of Emergency Steering
Troubleshooting C (Trouble Shooting
for Monitor) Procedure .............................T5-7-1
Malfunction of Indicator Light Check
System .....................................................T5-7-2
Malfunction of Buzzer in Monitor...............T5-7-4
Malfunction of Coolant Temperature
Gauge ......................................................T5-7-6
Malfunction of Transmission Oil
Temperature Gauge .................................T5-7-8
Malfunction of Fuel Gauge .....................T5-7-10
Indicator (Optional).................................T5-7-44
Malfunction of Low Steering Oil
Pressure Indicator (Optional) ..................T5-7-46
Malfunction of Discharge Warning
Indicator .................................................T5-7-48
Malfunction of Monitor Display................T5-7-50
Malfunction of Ride Control Indicator ......T5-7-51
Malfunction of Engine Coolant
Temperature Display...............................T5-7-52
Malfunction of Turn Signal Indicators
(Left and Right) ......................................T5-7-12
4GCT-5-3
Group 8 Electrical System Inspection
Precautions for Inspection and
Maintenance...........................................T5-8-1
Instructions for Disconnecting
Connectors .............................................T5-8-3
Fuse Inspection........................................T5-8-6
Fusible Link Inspection .............................T5-6-8
Battery Voltage Check ..............................T5-6-9
Alternator Check ....................................T5-6-10
Continuity Check ....................................T5-6-12
Voltage and Current Measurement .........T5-6-14
Check by False Signal ............................T5-6-17
4GCT-5-4
TROUBLESHOOTING / Diagnosing Procedure
INTRODUCTION
Refer to the inspection and troubleshooting procedures after any machine trouble has occurred. The
inspection and troubleshooting procedures are presented in an orderly fashion in this section to quickly
find the cause of the machine trouble and solution.
The troubleshooting section in this manual consists of
8 groups; Diagnosing Procedure, Dr. ZX, e-Wheel,
Component Layout, Troubleshooting A (base machine
diagnosis by using fault codes), Troubleshooting B
(base machine diagnosis starting with inspection of
abnormal operational status), Troubleshooting C
(monitor diagnosis) and Electrical System Inspection.
• Dr. ZX
• Troubleshooting A (base machine diagnosis by
This group contains the operating procedures for
Dr. ZX.
using fault codes)
Refer to these procedures if any fault codes are
displayed when each controller of ICF (information controller) is diagnosed by using Dr. ZX (or
the service mode of monitor).
• e-Wheel
Refer to these procedures if any fault codes are
displayed when ICF (information controller) and
satellite communication controller are diagnosed
by using Dr. ZX. (ICF and satellite communication
controller self-diagnosing functions retain a record of the electrical signal system malfunction in
the form of fault codes. At the same time, as the
satellite communication controller sends information onto CAN, the fault code of satellite communication controller can be checked by using ICF.)
This group contains as follows.
Download data from ICF and Upload
Various setting procedures when starting satellite
communication, when installing the satellite
communication controller and when replacing
ICF
Explanation for the satellite communication system
IMPORTANT: Each
controller self-diagnosing
function retains a record of the electrical signal system malfunction in
the form of fault codes. At the same
time, as each controller sends information onto CAN, the fault code
of all controllers can be checked by
using ICF.)
ICF records the fault code of each
controller and the date when the
malfunction occurs.
• Component Layout
Refer to this group when required to check where
the components and inner parts are located.
• Troubleshooting B (base machine diagnosis
starting with inspection of abnormal operational
status)
Refer to these procedures when no fault codes
are displayed after diagnosing the machine with
Dr. ZX (or the service mode of monitor).
• Troubleshooting C (monitor diagnosis)
Refer to these procedures when gauges and/or
indicators are malfunctioning.
• Electrical System Inspection
Refer to this group when required to obtain precautions and/or information for the electrical system inspection.
T5-1-1
TROUBLESHOOTING / Diagnosing Procedure
DIAGNOSING PROCEDURE
These six basic steps are essential for efficient
troubleshooting:
1. Study the System
Study the machine’s technical manuals. Know the
system and how it works, and what the
construction, functions and specifications of the
system components are.
2. Ask the operator
Before inspecting, get the full
malfunctions from the operator below.
story
of
T4GB-05-01-001
(a) How is the machine being used? (Find out if
the machine is being operated correctly)
(b) When was the trouble noticed, and what
types of work the machine doing at that
time?
(c) What are the details of the trouble? Is the
trouble getting worse, or did it appear
suddenly for the first time?
(d) Did the machine have any other troubles
previously? If so, which parts were repaired
before?
3. Inspect the machine
Before starting the troubleshooting procedure,
check the machine’s daily maintenance points, as
shown in the operator's manual.
T4GB-05-01-002
Also, check the electrical system, including the
batteries, as troubles in the electrical system
such as low battery voltage, loose connections
and blown fuses will result in malfunction of the
controllers, causing total operational failure of the
machine.
If troubleshooting is started without checking for
blown fuses, a wrong diagnosis may result,
wasting time. Check for blown fuses before
troubleshooting. Even if a fuse looks normal by
visual inspection, a fine crack is difficult to find.
Always use a tester when checking the fuses.
T4GB-05-01-003
T5-1-2
TROUBLESHOOTING / Diagnosing Procedure
4. Operate the machine yourself
Try to identify the trouble by operating the
machine yourself.
If the trouble cannot be confirmed (this states
are repeated that the trouble is resolved later
altough the trouble sometimes occurs), stop the
engine and obtain further details of the
malfunction from the operator.
Also, check for any incomplete connections of
the wire harnesses correponding to the trouble.
NOTE: It should take time to required to find the
malfunction according to the trouble during
the troubleshooting. The malfunction may
occur due to up and down of hydraulic
temperature, weather and under the
special condition including expansion by
heat and shorted harness by moisture. The
informations of weather when the
mulfunction occurs, time from the engine
start to the trouble occurrence are also
important.
T5-1-3
TROUBLESHOOTING / Diagnosing Procedure
5. Perform troubleshooting
CAUTION: Do not disconnect harnesses or
hydraulic lines while the engine is running.
The machine may malfunction or pressurized
oil may spout, possibly resulting in personal
injury. Stop the engine before disconnecting
harnesses or hydraulic lines.
Perform diagnosis by connecting Dr. ZX to the
machine or by using the service mode of monitor.
In case any fault code has been displayed by diagnosis by using Dr. ZX or the service mode of
monitor, check the cause of the trouble by referring to Troubleshooting A in this section. In case
any fault code has been displayed by diagnosis
by using Dr. ZX or the service mode of monitor,
write the fault code. Delete the fault code once
and retry self-diagnosis again. If the fault code is
displayed again, check the cause of the trouble
by referring to Troubleshooting A in this section.
After the machine trouble has been corrected, the
fault code (displayed by the service mode of
monitor) will be deleted. Therefore, in case problems which are not easily re-predicable are encountered (this states are repeated that the
trouble is resolved later altough the troubole
sometimes occurs), check the fault code by using
Dr. ZX.
NOTE: As for teach controller, the fault code and
date when the trouble occurred, which are
recorded by ICF, are effective in order to
resolve the problem which are not easily
re-predicable. (Refer to e-Wheel in this
section.)
T4GB-05-01-004
T4GB-05-01-005
In case the fault code is not displayed, check
operating condition of each component by referring to Troubleshooting B in this section and by
using Dr.ZX or the service mode of monitor.
T4GB-05-01-006
T5-1-4
TROUBLESHOOTING / Diagnosing Procedure
Note that the fault codes displayed do not
necessarily indicate machine trouble. The
controller stores even temporary electrical
malfunctions, such as a drop in battery output
voltage or disconnections of the switches,
sensors, etc., for inspections.
For this reason, the “RETRIAL” is required to
erase the accumulated fault codes from the
controller memory and to confirm if any fault
codes are indicated after the “RETRIAL”.
6. Trace possible causes
Before reaching a conclusion, check the most
likely causes again. Try to identify the actual
cause of the trouble.
Based on your conclusion, make a plan for
appropriate repairs to avoid consequent
malfunctions.
T5-1-5
TROUBLESHOOTING / Diagnosing Procedure
HOW TO OPERATE SERVICE MODE OF
MONITOR
In case the engine starts in normal, the monitor is
started in normal mode and only the items, which can
be displayed in normal mode, are displayed on the
liquid crystal display (LCD). (Refer to the next page.)
How to Used Monitor in Service Mode
1. Whenever pushing the monitor display selector
(up) in the monitor, the display in information display is changed.
When the monitor is started in service mode according to the following procedures, the items which can
be displayed in normal mode, the fault code and one
part of monitor items can be displayed. (Refer to the
next page.)
NOTE: The fault code is indicated in the display
order 11. All fault codes can be indicated.
In case more than one fault code is indicated, they will be displayed with an interval of 1 second in order. After the machine
malfunction has been repaired, the fault
codes are automatically deleted. Accordingly, if any trouble, which is not reproducible, is encountered (this states are
repeated that the trouble is resolved later
altough the troubole sometimes occurs), it
is recommended to use Dr. ZX in order to
check the fault code history.
How to Start Monitor in Service Mode
1. Push the monitor display selector (up) and
(down) in the monitor at the same time and the
key switch is turned ON.
NOTE: The engine can start in normal.
Liquid Crystal
Display (LCD)
Information
Display
T4GB-01-02-001
Monitor Display
Selector (Down)
Monitor Display
Selector (Up)
T5-1-6
Mode Selection
Switch
TROUBLESHOOTING / Diagnosing Procedure
DISPLAY LIST OF MONITOR SERVICE MODE
Display
Order
1
2
3
4
4-1
Description
Model
Clock (24 hour)
Hour Meter
Fuel
Consumption
Amount
Average Fuel Consumption Amount
Monitored Result
{{{{{{
{{:{{
{{{{{.{ h
{{{{{.{
Unit
hh:mm
hour
L/h
{{{{{.{
L/h
Remark
Service Mode
Normal Mode
Normal Mode
Normal Mode
Normal Mode (Displayed
when pushing the monitor
display selector (down) with
“4” displayed, Re-set when
pushing the mode selection
switch)
Normal Mode
Normal Mode (Displayed
when pushing the monitor
display selector down) with
“5” displayed)
Normal Mode (Displayed
when pushing the monitor
display selector (down) with
“5-1” displayed)
Normal Mode (Displayed
when pushing the monitor
display selector (down) with
“5-2” displayed)
Normal Mode (Displayed
when pushing the monitor
display selector (down) with
“5-3” displayed)
Normal Mode (Displayed
when pushing the monitor
display selector (down) with
“5-4” displayed)
Normal Mode (Displayed
when pushing the monitor
display selector (down) with
“5-5” displayed)
Normal Mode (Displayed
when pushing the monitor
display selector (down) with
“5-6” displayed)
Service Mode (“Mile” is displayed when pushing the
mode selection switch.)
Service Mode
Service Mode
Service Mode
5
5-1
Other Information
Remainder Time when
Hydraulic Oil can be
used
InFo
{{{{{.{
hour
5-2
Remainder Time when
Hydraulic Oil Filter can
be used
{{{{{.{
hour
5-3
Remainder Time when
Transmission Oil can be
used
{{{{{.{
hour
5-4
Remainder Time when
Transmission Oil Filter
can be used
{{{{{.{
hour
5-5
Remainder Time when
Engine Oil can be used
{{{{{.{
hour
5-6
Remainder Time when
Engine Oil Filter can be
used
{{{{{.{
hour
5-7
Remainder Time when
Fuel Filter can be used
{{{{{.{
hour
6
Odometer
{{{{{{
km or mile
7
8
9
Engine Speed
Coolant Temperature
Transmission Oil Temperature
Hydraulic Oil Temperature
Fault Code
{{{{{
{{{{{
{{{{{
min-1
°C
°C
{{{{{
°C
Service Mode
ERROR
Service Mode
10
11
{{{{{{
T5-1-7
TROUBLESHOOTING / Diagnosing Procedure
(Blank)
T5-1-8
TROUBLESHOOTING / Dr. ZX
OUTLINE
Dr. ZX is used for diagnosis of electrical system
including MC (main controller), ECM (engine control
module), ICF (information controller) and monitor unit.
Dr. ZX is connected to ICF and failure of each
controller and each sensor is displayed as a fault code.
(Self-Diagnostic Result)
Dr. ZX displays the input status of sensors and
switches connected to each controller and the output
status to actuator including solenoid valve from
controller with the machine operated in real time.
(Controller Diagnosis)
T5-2-1
TROUBLESHOOTING / Dr. ZX
Operation
1. Connect Palm (Dr. ZX) to the diagnosing
connector in the cab by using the Hot Sync cable
and connecting harness.
2. Turn the key switch ON or start the engine.
3. When turning Palm ON, the following screen is
displayed on the display of Palm.
1-1. Initial Screen
Select Dr. ZX icon.
Fuse Box
Dr. ZX Connector
1-2. Password Setup Screen (When the password
has unset)
Set the password.
1-3. Service Software Selection Screen
+ Select ZX-3 Mid.
T4GB-05-01-007
1-4. Function Selection Screen
+ Self-Diagnostic Result
+ Select Controller
4. Select Self-Diagnostic Result and operate
according to the instruction under display screen.
Palm
(Dr. ZX)
Hot Sync Cable
Download
Cable for
Portable
Communication
T1V1-05-07-002
T5-2-2
TROUBLESHOOTING / Dr. ZX
Start
Initial Screen
Password Setup Screen
• Input Password
Input
the
former
password (6 characters
or more).
Next time, input the
same password in order
to check and push OK.
When the password has unset
Communication
Error
• Check Communication Harness
• Check Fuse
When the password
has set
Service Software
Selection Screen
Select ZX-3 Mid
Self-Diagnostic
Result Function
Self-Diagnostic
Result of Each
Controller
Select
Function
Record
T1V7-05-03-165
Select Controller
Main
Controller
Main Menu
• Monitor Display
• Setup
Disp. Record
Select Controller
Engine
Controller
Main Menu
• Monitor Display
Disp. Record
Password Change
Password Change
Op. Manual.
Monitor
Controller
ICF
Controller
Main Menu
• Information
C/U
Various Setup
• Data Download
• Save Data Check
Password Change
Retry B
Self-Diagnostic
Result
T5-2-3
Main Menu
• Monitoring
• Various Setup
Password Change
TROUBLESHOOTING / Dr. ZX
Self-Diagnostic Result
The self-diagnostic result of each controller is
displayed.
After starting Dr. ZX, push Self-Diagnostic Result.
Function Selection Screen
T1V7-05-03-001
T1V7-05-03-008
T4GB-05-02-052
Controller Self- Diagnosis Screen
NOTE: Main C/U:
Engine C/U:
Monitor Unit:
Information C/U:
MC
ECM
Monitor Unit
ICF
NOTE: Self-diagnosis of ICF controller is done on
the next page.
T5-2-4
TROUBLESHOOTING / Dr. ZX
Self-Diagnosis
After starting Dr. ZX,
Self-Diagnostic Result.
Push Fault of ICF Controller. In
case of no faulty, No Fault is
displayed.
push
To the
lower
T1V7-05-03-001
T4GB-05-02-052
T1V7-05-03-008
Controller Self- Diagnosis Screen
By changing the page, the forward or
backward controller is displayed.
Function Selection Screen
By changing the page, the
forward or backward fault Push Retry B and return to
code is displayed.
Controller Self-Diagnosis Screen
after executing Retry B.
Push ESC and return to Controller
Push ESC and Retry B Screen is
Self-Diagnosis Screen directly.
displayed.
Push Details, and Details of the
fault code and Corrective Action
are displayed.
Push ESC and Retry B Screen is
displayed.
Trouble
Retry B
ESC
ESC
T1V7-05-03-003
T1V7-05-03-005
Fault Code Screen
T1V7-05-03-007
Retry B Screen
If the message of Details is
long, push the arrow and
change the screen.
Retry B
ESC
T4GB-05-02-052
Controller Self- Diagnosis Screen
T5-2-5
TROUBLESHOOTING / Dr. ZX
SELECT CONTROLLER
Select the failure-diagnosis controller.
After starting Dr. ZX, push Select Controller.
T4GB-05-02-053
T1V7-05-03-001
Function Selection Screen
NOTE: Main C/U:
Engine C/U:
Monitor Unit:
Information C/U:
Controller Selection Screen
MC
ECM
Monitor Unit
ICF
T5-2-6
TROUBLESHOOTING / Dr. ZX
MAIN CONTROLLER
Main Menu
• Monitor Display
Displays the control signals of MC and the input
signals from each switch and sensor.
• Setup
Adjusts target engine idling speed, engine
warming-up speed and so on.
Title Screen
Recorded Data
Displays data recorded in MC by one day by using Dr.
ZX.
Password Change
Changes the password input when setting.
T1V7-05-03-011
Password
Change
Return to Controller
Selection Screen.
Disp. Record
Main Menu Screen
T1V7-05-03-012
Monitor Display
This function is not
available.
Setup
T5-2-7
TROUBLESHOOTING / Dr. ZX
MAIN MENU MONITOR DISPLAY
Dr. ZX displays the input signals from switches and
sensors and the control signals from MC.
MC List of Monitor Item
Item
Required Engine Speed
Hydraulic Fan Target Speed
Actual Engine Speed
Torque Converter Output Speed
Medium Gear Speed
Transmission Output speed
Engine Speed Deviation
Torque Converter Speed Ratio
Travel Speed
Pump Pressure
Pump Displacement Proportional
Valve Output
Hydraulic Drive Fan Proportional
Valve
Ride Control Proportional Valve
Output (Optional)
Pump Displacement Proportional
Valve FB
Hydraulic Drive Fan Proportional
Valve FB
Ride Control Proportional Valve
Output FB (Optional)
Accelerator Pedal
Parking Brake Pressure
Pedal Brake Pressure (Low)
Lift Cylinder Bottom Pressure
(Optional)
Lift Cylinder Rod Pressure (Optional)
Implement Pressure
Boom Angle (Optional)
Key Switch
Ride Control Switch (Optional)
A/C Clutch SW
Fan Reversing SW
FNR SW
Speed Gear SW
Implement FNR SW
Implement FNR Selector SW
USS SW
DSS SW
Speed Gear Hold SW
Selected Speed Gear
Data
Control instruction value of engine speed to ECM
Control instruction value to fan flow rate control valve
Detected valve of torque converter input speed sensor
Detected valve of torque converter output speed sensor
Detected valve of transmission medium shaft sensor
Detected valve of travel speed sensor
Difference between required engine speed and actual engine
speed
Ratio of the detected value of torque converter output rotation
sensor in that of torque converter input rotation sensor
Value converted the detected value of travel speed sensor into
speed per hour
Detected value to main pump delivery pressure sensor
Control instruction value to pump displacement proportional solenoid valve
Control instruction value to hydraulic drive fan flow rate control
solenoid valve
Control instruction value to ride control solenoid valve
Unit
min-1
min-1
min-1
min-1
min-1
min-1
min-1
No unit
Km/h
MPa
MPa
mA
MPa
Feedback value from pump displacement proportional solenoid
valve
Feedback value from hydraulic drive fan flow rate control solenoid valve
Feedback value from ride control solenoid valve
mA
Output value of accelerator pedal
Detected value of parking brake pressure sensor
Detected value of service brake pressure sensor
Detected value of lift arm cylinder bottom pressure sensor
V
MPa
MPa
MPa
Detected value of lift arm cylinder rod pressure sensor
MPa
Detected value of implement pressure sensor
Output valve of lift arm angle sensor
Key ON signal from key switch to each controller
Continuity status in ride control switch
Continuity status in air conditioner switch
Continuity status in hydraulic drive fan reversing switch
Selected status of forward/reverse lever
Selected status of shift switch
Selected status of forward/reverse switch
Continuity status in forward/reverse selector switch
Continuity status in up-shift switch
Continuity status in down-shift switch
Continuity status in hold switch
Selected speed gear
mA
mA
Actual Speed Gear
Actual speed gear
Boom Height Kickout SW (Optional)
Boom Height Kickout Setup SW
(Optional)
Ground Stop SW (Optional)
Ground Stop Setup SW (Optional)
Continuity status in lift arm auto leveler switch (raise)
MPa
V
ON OFF
ON OFF
ON OFF
ON OFF
N F R Err N
1234
N F R Err N
ON OFF
ON OFF
ON OFF
ON OFF
R4 R3 R2 R1 N
F1 F2 F3 F4
R4 R3 R2 R1 N
F1 F2 F3 F4
ON OFF
Continuity status in lift arm auto leveler switch (raise) set switch
ON
Continuity status in lift arm auto leveler switch (lower)
Continuity status in lift arm auto leveler switch (lower) set switch
ON OFF
ON OFF
T5-2-8
OFF
TROUBLESHOOTING / Dr. ZX
Item
Engine Torque Selection
Pump Torque Selection
Data
Instruction signal of engine torque selection to ECM
Selection status of work mode selection switch
Hold Mode
Option FNR Mode
Auto/Manual Selection
Auto Gear Shifting Mode
Enabled/disabled status of hold mode
Enabled/disabled status of forward/reverse switch use mode
Selected status (auto/manual) of travel mode selector switch
Selected status (gear shifting timing) of travel mode selector
switch
Selected status (ON/OFF) of clutch cut-off position switch
Selected status (clutch cut-off position) of clutch cut-off position
switch
Instruction value of forward proportional solenoid valve output
Clutch Cut-Off Switch
Clutch Cut-Off Mode
T/M Clutch Forward Proportional
Valve Output
T/M Clutch Reverse Proportional
Valve Output
T/M Clutch First Gear Proportional Valve Output
T/M Clutch Second Gear Proportional Valve Output
T/M Clutch Third Gear Proportional Valve Output
T/M Clutch Fourth Gear Proportional Valve Output
T/M Clutch Forward Proportional
Valve FB
T/M Clutch Reverse Proportional
Valve FB
T/M Clutch First Gear Proportional Valve FB
T/M Clutch Second Gear Proportional Valve FB
T/M Clutch Third Gear Proportional Valve FB
T/M Clutch Fourth Gear Proportional Valve FB
Hydraulic Drive Fan Reversing
Valve
Implement FNR Operating Light
Back Alarm
Boom Height Kickout (Optional)
Ground Stop System (Optional)
Neutral Signal
Parking brake Light
T/M Warning Light
Ambient Temperature
Hydraulic Oil Temperature
AEB Status (Main Code)
AEB Status (Sub Code)
Learning Step
ON OFF
Low Medium High
mA
Instruction value of reverse proportional solenoid valve output
mA
Instruction value of first gear proportional solenoid valve output
mA
Instruction value of second gear proportional solenoid valve output
Instruction value of third gear proportional solenoid valve output
mA
Instruction value of fourth gear proportional solenoid valve output
mA
Feedback value of forward proportional solenoid valve output
mA
Feedback value of reverse proportional solenoid valve output
mA
Feedback value of first gear proportional solenoid valve output
mA
Feedback value of second gear proportional solenoid valve output
Feedback value of third gear proportional solenoid valve output
mA
Feedback value of fourth gear proportional solenoid valve output
mA
Instruction signal to hydraulic drive fan reversing solenoid valve
ON OFF
Continuity status to enabled indicator in forward/reverse switch
Excited condition of reverse relay in MC
Excited Status of solenoid valve at lift arm raise side in pilot valve
Excited Status of solenoid valve at lift arm lower side in pilot
valve
Forward/reverse neutral signal status
Excited status of parking brake relay 1 and continuity status to
parking brake indicator
Continuity status to transmission warning indicator
Detected value of ambient temperature sensor
Detected value of hydraulic oil temperature sensor
Transmission learning process status code
Transmission learning failure position code
ON
ON
ON
ON
Learning Warning Crash
Learning detail position of transmission learning process status
each code
Learning failure detail position of transmission learning failure
position code
Crash grounds of transmission learning
Angle Sensor Learning Status
Lift arm angle sensor learning status
Learning Warning Step
Unit
1234
LD/Cry
Normal
Power
ON OFF
Acr NotAct
Manual Auto
Low Normal High
T5-2-9
mA
mA
OFF
OFF
OFF
OFF
ON OFF
ON OFF
ON OFF
°C
°C
Normal Other
Enabled Learning
Other
1 2 3
1 2 3
Ky Eng Pbrk Spd
FNR
Not Learn
Finish Failure
TROUBLESHOOTING / Dr. ZX
Monitor Display
After starting Dr. ZX, push Select
Controller.
Push OK.
Push Main C/U.
To the
lower
T4GB-05-02-053
T1V7-05-03-001
Function Selection Screen
Controller Selection Screen
Push Start.
Push Monitor Display.
T4GB-05-02-004
Main Controller Screen
To the
lower
T4GB-05-02-054
T1V7-05-03-012
T1V7-05-03-011
Title Screen
Main Menu Screen
Enter Model and Serial No. Screen
Input the model code and serial
No. and push OK. If this procedure
is not done, monitor data cannot
recorded. Push ESC and return to
Main Menu Screen.
Push the item for Monitor Display
and push OK. Refer to T5-2-8, 9 as
for the monitor item. Push ESC
and return to Main Menu Screen.
Push Hold and the monitor are
stopped temporarily. When the monitor
is started again, push Hold again.
Push ESC and return to Display Item
Selection Screen.
T4GB-05-02-008
T4GB-05-02-007
T4GB-05-02-055
Enter Model and Serial No. Screen
Display Item Selection Screen
Monitor Screen
To the next page
T5-2-10
TROUBLESHOOTING / Dr. ZX
Push Rec. No. and the recording
screen for Rec. No. is made.
Push Record.
To the
lower
T4GB-05-02-008
T1V7-05-03-096
Monitor Screen
If Rec. No. has already been
recorded and push Over Write,
data is overwritten. Push ESC and
return to Main Menu Screen.
If Rec. No. has not been recorded
yet and push Write, data is written
to the recording screen. Push ESC
and return to Main Menu Screen.
Select Write Data-Bank Screen
T1V7-05-03-097
Push Comment.
Push ESC and return to Main
Menu Screen.
To the
lower
T4GB-05-02-056
Recording Screen
T4GB-05-02-057
T1V7-05-03-100
Recording Screen
Input weather and person’s name
in change and push OK.
Push OK and the recording screen
(making) is finished.
T4GB-05-02-058
T4GB-05-02-059
Recording Screen (Comment
Input)
T5-2-11
Push Re-Input and return to
Recording
Screen
(Comment
Input).
Push ESC and return to Monitor
Screen.
T4GB-05-02-060
TROUBLESHOOTING / Dr. ZX
SETTING
Target engine idling speed, engine warming-up speed
and so on can be adjusted.
MC List of Parameter Change Item
Item
Unit
Request Speed Ⅰ Calibration
min-1
Warning Up Speed Calibration
min-1
Warming Up Control Deactivation
ON, OFF
Flag
Set Torque Calibration
N⋅m
Data
Adjustment of engine idling speed
Adjustment of engine warming-up speed
Selection (enable/ disable) of engine warming-up control
Adjustment of main pump target torque
MC List of Adjustment Data
Data
Request Speed Ⅰ Calibration
Warning Up Speed Calibration
Warming Up Control Deactivation
Flag
Set Torque Calibration
Adjustment
Minimum Unit
1 min-1
1 min-1
0 to 200
-200 to 200
Adjustment Value
When Delivering
0 min-1
0 min-1
-
ON or OFF
ON
3 N⋅m
-45 to 45
0 N⋅m
Adjustable Range
T5-2-12
Remark
TROUBLESHOOTING/ Dr. ZX
Setting
• Parameter Change
After starting Dr. ZX, push Select
Controller.
Push OK.
Push Main C/U.
To the
lower
T4GB-05-02-053
T1V7-05-03-001
Function Selection Screen
Controller Selection Screen
Push Start.
Push Setup.
T4GB-05-02-004
Main Controller Screen
To the
lower
T1V7-05-03-011
T1V7-05-03-012
Title Screen
Main Menu Screen
Input the password and push OK.
Push Cancel and return to Main
Menu Screen.
Push Parameter Change.
Push ESC and return to Main
Menu Screen.
T1V7-05-03-016
Refer to T5-2-12 as for the item of
Parameter Change. Push Engine
Control.
To the
Next Page
T1V7-05-03-022
Setup Password Input Screen
T4GB-05-02-014
Setup Item Selection Screen
T5-2-13
Parameter Change Selection
Screen
T4GB-05-02-015
TROUBLESHOOTING/ Dr. ZX
Parameter Input
Example: Engine Control
Correction
Input Value = Normal Value
Push Request Speed I Calibration..
Target
Speed
I
Input the value and push Exec.
Push ESC and return to Parameter
Change Selection Screen.
Check Adjustment and push Exec.
Push ESC and return to Parameter
Change Selection Screen.
To the
lower
T4GB-05-02-016
Parameter Change Selection
Screen
T4GB-05-02-017
Parameter Input Screen
Push ESC and return to Parameter
Change Selection Screen.
T1V7-05-03-107
T5-2-14
T4GB-05-02-018
TROUBLESHOOTING/ Dr. ZX
Input Value = Current Value
Push Request Speed I Calibration.
Input the value and push Exec.
Push ESC and return to Parameter
Change Selection Screen.
Push Exec. Push ESC and return
to Parameter Change Selection
Screen.
To the
lower
T4GB-05-02-016
Parameter Change Selection
Screen
T4GB-05-02-019
Parameter Input Screen
Push ESC and return to Parameter
Change Selection Screen.
T1V7-05-03-107
T5-2-15
T1V7-05-03-108
TROUBLESHOOTING/ Dr. ZX
Input Value > Maximum Value
(Input Value < Minimum Value)
Push Request Speed I Calibration.
Input the value and push Exec.
Push ESC and return to Parameter
Change Selection Screen.
Push Re-Input and return to
Parameter Input Screen. Push Max
and the maximum value is input.
Push ESC and return to Parameter
Change Selection Screen.
To the
lower
T4GB-05-02-016
Parameter Change Selection
Screen
T4GB-05-02-020
Parameter Input Screen
Push ESC and return to Parameter
Change Selection Screen.
T1V7-05-03-107
T5-2-16
T4GB-05-02-021
TROUBLESHOOTING/ Dr. ZX
When the input value cannot be divided
Example: Pump Control Set Torque Calibration
Push Set Torque Calibration.
Input the value and push Exec.
Push ESC and return to Parameter
Change Selection Screen.
Push Re-Input and return to
Parameter Input Screen. Push A or
B and the value of A or B is input.
Push ESC and return to Parameter
Change Selection Screen.
To the
lower
T4GB-05-02-022
Parameter Change Selection
Screen
T4GB-05-02-023
Parameter Input Screen
Push ESC and return to Parameter
Change Selection Screen.
T1V7-05-03-107
T5-2-17
T4GB-05-02-024
TROUBLESHOOTING/ Dr. ZX
Status Selection
Example: Engine Control Warming Up Control
Deactivation Flag
Push
Warming
Deactivation Flag.
Up
Ctrl
Push OFF and push Exec. Push
ESC and return to Parameter
Change Selection Screen.
Check contents and push Exec.
Push ESC and return to Parameter
Change Selection Screen.
To the
lower
T4GB-05-02-016
Parameter Change Selection
Screen
T4GB-05-02-025
Status Selection Screen
Push ESC and return to Parameter
Change Selection Screen.
T1V7-05-03-107
T5-2-18
T4GB-05-02-026
TROUBLESHOOTING/ Dr. ZX
Recorded Data Display
After starting Dr. ZX, push Select
Controller.
Push OK.
Push Main C/U.
To the
lower
T4GB-05-02-053
T1V7-05-03-001
Function Selection Screen
Push and select No. Push
Regeneration and the recorded
data are regenerated.Push DEL
and data of selected No. is
d l t d
Push Start to record.
Push Hold and the monitor are
stopped temporarily. Push Hold
again and restart regeneration.
Push ESC and Recorded Data
Selection Screen is displayed.
T1V7-05-03-124
T1V7-05-03-011
Title Screen
T4GB-05-02-004
Main Controller Screen
Controller Selection Screen
Recorded Data Selection Screen
T5-2-19
Recorded Data Regeneration
Screen
T4GB-05-02-027
TROUBLESHOOTING/ Dr. ZX
PASSWORD CHANGE
After starting Dr. ZX, push Select
Controller.
Push OK.
Push Main C/U.
To the
lower
Function Selection Screen
T1V7-05-03-001
Controller Selection Screen
T4GB-05-02-053
Input the registered password and
push OK.
Push Password.
Main Controller Screen
T4GB-05-02-004
Input the new password and push
OK.
To the
lower
T1V7-05-03-126
T1V7-05-03-011
Title Screen
Input the new password again and
push OK.
Push OK
Screen.
and
return
to
Title
T1V7-05-03-128
T1V7-05-03-169
T5-2-20
T1V7-05-03-127
TROUBLESHOOTING / D r. ZX
ENGINE CONTROLLER
Main Menu
• Monitor Display
Dr. ZX displays the input signals from sensors and
the control signals of ECM.
• Recorded Data Display
Data recorded in ECM is displayed by one day by
using Dr. ZX.
Password
The password can be changed.
T1V7-05-03-079
T5-2-21
TROUBLESHOOTING / D r. ZX
MONITOR DISPLAY
ECM List of Monitor Item
Item
Selecting
Engine Torque
Actual Engine Speed
(Engine Speed)
Target Engine Speed
Glow Signal
Coolant
Temperature
(Engine
Coolant
Temperature)
Fuel Temperature
Engine Oil Pressure
Fuel Flow Rate
Atmospheric Pressure
Suction
Temperature
(Intake Air Temperature)
Boost Pressure
Boost Temperature
Battery Voltage
Total Amount of Fuel Use
Unit
Monitoring
Engine Torque
%
Actual Engine
min-1
Speed
Target Engine
min-1
Speed
Glow Signal
OFF, ON
Coolant
Temperature
°C
(E)
Fuel
°C
Temperature
Engine
Oil
kPa
Pressure
Fuel Flow
L/h
Barometric
kPa
Pressure
Intake Air
°C
Temperature
Boost Pressure
kPa
Boost
°C
Temperature
Battery Voltage
V
Total
Used
L
Fuel
Data
Input signal from ECM
Input signal from crank speed sensor and cam angle
sensor
Input signal from accelerator pedal
Glow relay ON/OFF status
Input signal from coolant temperature sensor
Input signal from fuel sensor
Input signal from engine oil pressure sensor
Input signal from ECM
Input signal from atmospheric pressure sensor
Input signal from intake-air temperature sensor
Input signal from boost pressure sensor
Input signal from boost temperature sensor
Input signal from ECM
Input signal from ECM
T5-2-22
TROUBLESHOOTING / D r. ZX
(Blank)
T5-2-23
TROUBLESHOOTING / D r. ZX
Monitor Display
After starting Dr. ZX, push Select
Controller.
Push OK.
Push Engine C/U.
To the
lower
T4GB-05-02-053
T1V7-05-03-001
Function Selection Screen
Controller Selection Screen
Push Start.
Push Monitor Display.
T4GB-05-02-004
Engine Controller Screen
To the
lower
Title Screen
T4GB-05-02-028
T1V7-05-03-011
Input the model code and serial
No. and push OK. If this procedure
is not done, monitor data cannot
recorded. Push ESC and return to
Main Menu Screen.
T4GB-05-02-061
Main Menu Screen
Enter Model and Serial No. Screen
Push the item for Monitor Display
and push OK. Refer to T5-2-22 as
for the monitor item.
Push ESC and return to Main
Menu Screen.
Push Hold and the monitor are
stopped temporarily. When the
monitor is started again, push Hold
again. Push ESC and return to
Display Item Selection Screen.
Start
recoding.
To the
next page
T1V7-05-03-132
T4GB-05-02-062
Enter Model and Serial No. Screen
Display Item Selection Screen
T5-2-24
T1V7-05-03-133
Monitor Screen
TROUBLESHOOTING / D r. ZX
Push Rec. No. and the recording
screen for Rec. No. is made.
Push Record.
To the
lower
Monitor Screen
T1V7-05-03-133
If Rec. No. has already been
recorded and push Over Write,
data is overwritten.
Push ESC and return to Main
Menu Screen.
T1V7-05-03-134
If Rec. No. has not been recorded
yet and push Write, data is written
to the recording screen.
Push ESC and return to Main
Menu Screen.
Select Write Data-Bank Screen
T1V7-05-03-135
Push Comment.
Push ESC and return to Main
Menu Screen.
To the
lower
T4GB-05-02-063
Recording Screen
T4GB-05-02-030
T4GB-05-02-064
Recording Screen
Input weather and person’s name
in change and push OK.
Push OK and the recording screen
(making) is finished.
T4GB-05-02-065
T4GB-05-02-066
Recording Screen (Comment
Input)
T5-2-25
Push Re-Input and return to
Recording
Screen
(Comment
Input).
Push ESC and return to Main
Menu Screen.
T4GB-05-02-067
TROUBLESHOOTING / D r. ZX
RECORDED DATA DISPLAY
After starting Dr. ZX, push Select
Controller.
Push OK.
Push Engine C/U.
To the
lower
T4GB-05-02-053
T1V7-05-03-001
T4GB-05-02-004
Function Selection Screen
Controller Selection Screen
Engine Controller Screen
Push Disp. Record.
Push and select No. Push
Regeneration and the recorded
data is regenerated. Push DEL and
data of selected No. is deleted.
Push ESC and return to Title
Screen.
Push Hold and the monitor is
stopped temporarily
When the monitor is started again,
push Hold again.
Push ESC and return to Recored
Data Selection Screen.
T1V7-05-03-124
T1V7-05-03-011
Title Screen
Recorded Data Selection Screen
T5-2-26
T1V7-05-03-141
Recorded Data Regeneration
Screen
TROUBLESHOOTING / D r. ZX
PASSWORD CHANGE
After starting Dr. ZX, push Select
Controller.
Push Engine C/U.
Push OK.
To the
lower
T1V7-05-03-001
T4GB-05-02-053
T4GB-05-02-004
Function Selection Screen
Controller Selection Screen
Engine Controller Screen
Push Password.
Input the registered password and
push OK.
Input the new password and push
OK.
To the
lower
T1V7-05-03-126
T1V7-05-03-011
Title Screen
Input the new password again and
push OK.
Push OK
Screen.
and
return
to
Title
T1V7-05-03-128
T1V7-05-03-169
T5-2-27
T1V7-05-03-127
TROUBLESHOOTING / D r. ZX
(Blank)
T5-2-28
TROUBLESHOOTING / Dr. ZX
ICF CONTROLLER
Main Menu
• Information C/U Various Setup
Initialization of information C/U, setting of model,
serial No. and time, and initialization of control
data can be done.
• Data Download
Daily report data, frequency distribution data, total
operating hours, alarm and fault code, which are
recorded in ICF, can be downloaded to Dr. ZX.
• Save Data Check
Daily report data, frequency distribution data, total
operating hours, alarm and fault code, which are
saved in ICF, can be checked by using Dr. ZX.
Password
The password can be changed.
T1V7-05-03-166
T5-2-29
TROUBLESHOOTING / Dr. ZX
INFORMATION C/U VARIOUS SETUP
ICF List of Controller Data Setting Item
Item
Information C/U: Initialize
Enter Model and Serial No.
Range of Data
Model
Serial No.
Enter Date and Time
YY
MM
DD
HH
MM
Date
Time
Control Data: Initialize
Satellite Terminal: Initialize
Satellite Terminal No. Confirmation
Communicating State Check
ICF < = > Satellite
Terminal
Satellite Terminal
Connect
Comm.
Power
Comm.
Rod Aerial
GPS Aerial
Wave State
Un-Transmit Data Number
Last Transmitting Time
Enter Satellite Comm.
Start/Stop
T5-2-30
Initialize/ESC
ASCII (4 characters) 0 to 9, A to Z
000000 to 999999
2000 to 2100
1 to 12
1 to 31
0 to 23
0 to 59
Initialize/ESC
DEL/ESC
12 digits: 0 to 9, A to Z
Conn/UnConn
OK/NG
ON/OFF
Enable/Stop
OK/NG
OK/NG
ON/OFF
0~99
YYYY/MM/DD hh: mm: ss
Start/Stop
TROUBLESHOOTING / Dr. ZX
INFORMATION C/U: INITIALIZE
After starting Dr. ZX, push Select
Controller.
Push OK.
Push Information C/U.
To the
lower
Function Selection Screen
T1V7-05-03-001
Controller Selection Screen
Push Information
Setup.
Push Start.
C/U:
T4GB-05-02-053
Various
ICF Controller Screen
T4GB-05-02-036
Push Information C/U: Initialize.
To the
lower
Title Screen
T1V7-05-03-025
Push Init and the controller
operating data is initialied. Push
ESC and return to Information C/U:
Various Setup Screen.
Main Menu Screen
T1V7-05-03-026
T1V7-05-03-027
Information C/U: Various Setup
Screen
Push OK and return to Information
C/U: Various Setup Screen.
Push ESC and return to Main
Menu Screen.
Init
ESC
T1V7-05-03-029
T1V7-05-03-028
T1V7-05-03-027
Information C/U: Various Setup
Screen
Information C/U: Initialize Screen
T5-2-31
TROUBLESHOOTING / Dr. ZX
ENTER MODEL AND SERIAL No.
After starting Dr. ZX, push Select
Controller.
Push Information C/U.
Push OK.
To the
lower
T4GB-05-02-053
T1V7-05-03-001
T4GB-05-02-036
Function Selection Screen
Controller Selection Screen
ICF Controller Screen
Push Start.
Push Information
Setup.
Push Enter Model and Serial No.
C/U:
Various
To the
lower
T1V7-05-03-026
T1V7-05-03-025
Title Screen
Main Menu Screen
Push Exec and model and serial
No. can be input.
Push ESC and return to
Information C/U: Various Setup
Screen.
Push OK after inputting model and
serial No. and return to Enter
Model and Serial No. Screen.
Push ESC and return to
Information C/U: Various Setup
Screen.
T1V7-05-03-027
Information C/U: Various Setup
Screen
Push ESC and return to Main
Menu Screen.
ESC
Exec
ESC
OK
T4GB-05-02-068
T4GB-05-02-069
T1V7-05-03-027
Information C/U: Various Setup
Screen
Enter Model and Serial No. Screen
T5-2-32
TROUBLESHOOTING / Dr. ZX
ENTER DATE AND TIME
After starting Dr. ZX, push Select
Controller.
Push Information C/U.
Push OK.
To the
lower
Function Selection Screen
T4GB-05-02-053
T1V7-05-03-001
Controller Selection Screen
Push Information
Setup.
Push Start.
C/U:
Various
ICF Controller Screen
T4GB-05-02-036
Push Enter Date and Time.
To the
lower
T1V7-05-03-026
T1V7-05-03-025
Title Screen
T1V7-05-03-027
Information C/U: Various Setup
Screen
Main Menu Screen
Push Set and the focused item is
YY. Push ESC and return to
Information C/U: Various Setup
Screen.
YY, MM, DD, HH and MM
The focused item is displayed reversely.
At first, the focused item is YY.
-
YY, MM, DD, HH and MM
Move the focused item.
No repeat input.
T1V7-05-03-032
Enter Date and Time Screen
+
YY, MM, DD, HH and MM
Value of the focused item is increased or
decreased one by one.
In case value is beyond maximum one: Change
value into the minimum one
In case value is below minimum one: Change
value into the maximum one
No repeat input.
T5-2-33
TROUBLESHOOTING / Dr. ZX
CONTROL DATA: INITIALIZE
After starting Dr. ZX, push Select
Controller.
Push OK.
Push Information C/U.
To the
lower
Function Selection Screen
T4GB-05-02-053
T1V7-05-03-001
Controller Selection Screen
Push Information
Setup.
Push Start.
C/U:
T4GB-05-02-036
ICF Controller Screen
Various
Push Control Data: Initialize.
To the
lower
Title Screen
T1V7-05-03-025
Push Init and the controller control
data is initialied. Push ESC and
return to Information C/U: Various
Setup Screen.
T1V7-05-03-026
Main Menu Screen
Information C/U: Various Setup
Screen
Push OK and return to Information
C/U: Various Setup Screen.
Push ESC and return to Main
Menu Screen.
T1V7-05-03-027
Init
ESC
T1V7-05-03-034
T1V7-05-03-033
T1V7-05-03-027
Information C/U: Various Setup
Screen
Control Data: Initialize Screen
T5-2-34
TROUBLESHOOTING / Dr. ZX
SATELLITE TERMINAL: INITIALIZE
After starting Dr. ZX, push Select
Controller.
Push Information C/U.
Push OK.
To the
lower
T4GB-05-02-053
T1V7-05-03-001
Function Selection Screen
Push Start.
T4GB-05-02-036
Controller Selection Screen
ICF Controller Screen
Push Information
Setup.
Push T and move to the next
screen of Information C/U: Various
Setup Screen. Push Satellite
Terminal: Initialize.
C/U:
Various
To the
lower
T1V7-05-03-026
T1V7-05-03-025
Title Screen
Main Menu Screen
Push Exec.
Push
ESC
and
return
to
Information C/U: Various Setup
Screen.
Push OK and return to Information
C/U: Various Setup Screen.
T1V7-05-03-035
Information C/U: Various Setup
Screen
Exec
ESC
T1V7-05-03-145
T1V7-05-03-036
T5-2-35
Information C/U: Various Setup
Screen
T1V7-05-03-035
TROUBLESHOOTING / Dr. ZX
SATELLITE TERMINAL No. CONFIRMATION
After starting Dr. ZX, push Select
Controller.
Push OK.
Push Information C/U.
To the
lower
T4GB-05-02-053
T1V7-05-03-001
Function Selection Screen
Push Start.
T4GB-05-02-036
Controller Selection Screen
ICF Controller Screen
Push Information
Setup.
Push T and move to the next
screen of Information C/U: Various
Setup Screen. Push Satellite
Terminal No. Confirmation.
C/U:
Various
To the
lower
T1V7-05-03-026
T1V7-05-03-025
Main Menu Screen
Title Screen
Confirm serial No. (12 digits). Push
ESC and return to Information C/U:
Various Setup Screen.
T1V7-05-03-035
T1V7-05-03-037
T5-2-36
T1V7-05-03-035
Information C/U: Various Setup
Screen
TROUBLESHOOTING / Dr. ZX
COMMUNICATING STATE CHECK
After starting Dr. ZX, push Select
Controller.
Push Information C/U.
Push OK.
To the
lower
T1V7-05-03-001
Function Selection Screen
Push Start.
T4GB-05-02-053
Controller Selection Screen
ICF Controller Screen
Push Information
Setup.
Push T and move to the next
screen of Information C/U: Various
Setup
Screen.
Push
Communicating State Check.
C/U:
Various
T4GB-05-02-036
To the
lower
T1V7-05-03-026
T1V7-05-03-025
Title Screen
Main Menu Screen
Check communicating state.
Unconn: Faulty harness
NG: Faulty harness for Comm.
OFF: Faulty harness, Faulty controller
Stop: Enter Satellite Comm. Start/Stop
Push ESC and return to Information
C/U: Various Setup Screen.
Push T and move to the next
screen. Check communicating
state of Rod Aerial and GPS Aerial.
Push
ESC
and
return
to
Information C/U: Various Setup
Screen.
T1V7-05-03-035
Information C/U: Various Setup
Screen
Push ESC and return to Main
Menu Screen.
ESC
T1V7-05-03-143
T1V7-05-03-142
T1V7-05-03-035
When electrical wave of the satellite is caught,
the items are turned into OK.
Check the enclosed state.
IMPORTANT: Check this with the key of machine
ON in outdoor. According to state
of electrical wave, it may take a
little longer time.
T5-2-37
TROUBLESHOOTING / Dr. ZX
ENTER SATELLITE COMM. START / STOP
After starting Dr. ZX, push Select
Controller.
Push OK.
Push Information C/U.
To the
lower
T1V7-05-03-001
Function Selection Screen
T4GB-05-02-053
Controller Selection Screen
Push Information
Setup.
Push Start.
C/U:
Various
ICF Controller Screen
T4GB-05-02-036
Push T and move to the next
screen of Information C/U: Various
Setup Screen. Push Enter Satellite
Comm. Start/Stop.
To the
lower
Title Screen
T1V7-05-03-026
T1V7-05-03-025
When starting Satellite Comm., push
Start and push Exec. When stopping
Satellite Comm., push Stop and push
Exec.
Push ESC and return to Information
C/U: Various Setup Screen.
T1V7-05-03-035
Main Menu Screen
Information C/U: Various Setup
Screen
Push OK and return to Information
C/U: Various Setup Screen.
Push ESC and return to Main
Menu Screen.
Exec
ESC
T1V7-05-03-147
T1V7-05-03-146
T5-2-38
Information C/U: Various Setup
Screen
T1V7-05-03-035
TROUBLESHOOTING / Dr. ZX
DATA DOWNLOAD
After starting Dr. ZX, push Select
Controller.
Push OK.
Push Information C/U.
To the
lower
Function Selection Screen
T1V7-05-03-001
Push Start.
Controller Selection Screen
T4GB-05-02-053
ICF Controller Screen
T4GB-05-02-036
While downloading data, Download
Screen is displayed.
Push Data Download.
To the
lower
Title Screen
T1V7-05-03-025
When downloading is completed
normally, Normal End Screen is
displayed. Push OK and return to
Main Menu Screen.
Main Menu Screen
If pushing Cancel on Data
Download Screen, Alarm Screen is
displayed. Push OK and return to
Main Menu Screen.
Data Download Screen
Alarm Screen
T1V7-05-03-026
Main Menu Screen
T5-2-39
T1V7-05-03-038
Push ESC and return to Title
Screen.
T1V7-05-03-148
T1V7-05-03-039
Normal End Screen
T1V7-05-03-026
TROUBLESHOOTING / Dr. ZX
SAVE DATA CHECK
After starting Dr. ZX, push Select
Controller.
Push Information C/U.
Push OK.
To the
lower
T4GB-05-02-053
T1V7-05-03-001
Function Selection Screen
Push Start.
ICF Controller Screen
Push Save Data Check.
Data saved in ICF is displayed.
Push OK and return to Main Menu
Screen.
T1V7-05-03-026
T1V7-05-03-025
Title Screen
T4GB-05-02-036
Controller Selection Screen
Main Menu Screen
T5-2-40
T1V7-05-03-040
Save Data Check Screen
TROUBLESHOOTING / Dr. ZX
PASSWORD CHANGE
After starting Dr. ZX, push Select
Controller.
Push OK.
Push Information C/U.
To the
lower
T4GB-05-02-053
T1V7-05-03-001
Function Selection Screen
Controller Selection Screen
ICF Controller Screen
Push Password.
Input the registered password and
push OK.
Input the new password and push
OK.
T4GB-05-02-036
To the
lower
T1V7-05-03-126
T1V7-05-03-025
Title Screen
Input the new password again and
push OK.
Push OK
Screen.
and
return
to
Title
T1V7-05-03-128
T1V7-05-03-169
T5-2-41
T1V7-05-03-127
TROUBLESHOOTING / Dr. ZX
(Blank)
T5-2-42
TROUBLESHOOTING / Dr. ZX
MONITOR UNIT
Main Menu
• Monitoring
Dr. ZX displays the input signals from each sensor
and switch.
• Various Settings
Dr. ZX can set inner hour meter synchronization.
Password
The password can be changed.
T4GB-05-02-039
T5-2-43
TROUBLESHOOTING / Dr. ZX
MONITORING
List of Monitoring Item
Item
Radiator Coolant Temperature
Fuel Level
T/M Torque Converter Oil
Temperature
Steering Pressure
Brake Oil Level Switch of
Service Brake
Data
Signal to coolant temperature gauge
Signal to fuel gauge
Signal to transmission oil temperature gauge
Continuity status in emergency steering pressure switch
Continuity status to brake oil level indicator
Unit
°C
%
°C
ON OFF
ON OFF
Emergency Steering Pump Continuity status in emergency steering pump delivery
Pressure Switch
pressure switch
ON OFF
Service Brake Pressure
Overheat Switch
Engine Oil Pressure Switch
Air Filter Restriction
Heated
Window
Switch
(Optional)
MPa
ON OFF
ON OFF
ON OFF
ON OFF
Detected value in brake primary pressure sensor
Continuity status to overheat indicator
Continuity status to engine oil pressure indicator
Continuity status to air filter restriction indicator
Continuity status in heated window switch (optional)
Emergency
Steering Continuity status in emergency steering check switch
Operation Check Switch
Front Wiper Switch
Continuity status in front wiper switch
Engine Warning Switch
Continuity status to engine warning indicator
Engine STOP Switch
Continuity status to stop indicator
Model Selector Switch 1
Model Selector Switch 2
Glow Switch
T/M Warning Switch
Buzzer Output
Load Dump Relay Output
Emergency Steering Relay
Output
Front Wiper Relay Output
Heated Window Relay Output
Parking Brake Signal Output
Parking
Brake
Pressure
Switch
Neutral Signal
Axle Oil Temperature
ON OFF
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
Continuity status in parking brake pressure switch
ON
ON
ON
ON
OFF
OFF
OFF
OFF
Excited status in neutral relay
Detected value in axle oil temperature sensor
ON OFF
°C
Switch 1 OFF, switch 2 OFF: ZW220/250
Switch 1 ON, switch 2 OFF: ZW310
Continuity status to glow signal
Continuity status to transmission warning indicator
Continuity status to buzzer
Excited status in load dump relay
Excited status in emergency steering relay
Excited status in front wiper relay
Excited status in heated window relay
Sending status of parking brake operating signal to TCU
T5-2-44
TROUBLESHOOTING / Dr. ZX
Monitoring
After starting Dr. ZX, push Select
Controller.
Push OK.
Push Monitor Unit.
To the
lower
T4GB-05-02-053
T1V7-05-03-001
Function Selection Screen
Push Start.
T4GB-05-02-040
Controller Selection Screen
Monitor Controller Screen
Push Monitoring.
Push item for monitoring and push
OK. Refer to T5-2-44 as for the
monitoring item.
Push ESC and return to Main Menu
Screen.
To the
lower
Title Screen
T1V7-05-03-025
T1V7-05-03-042
Main Menu Screen
When pushing Hold, the monitor is
stopped temporarily.
When re-starting the monitor, push
Hold again. Push ESC and return
to Monitoring Item Selection
Screen.
T4GB-05-02-042
Monitoring Screen
T5-2-45
T4GB-05-02-041
Monitoring Item Selection Screen
TROUBLESHOOTING / Dr. ZX
VARIOUS SETTINGS
Monitor Unit List of Setup Item
Item
Internal Hour Meter Sync.
Data
Synchronization of hour meter data in both monitor unit and ICF
MC List of Adjustment Data
Data
Internal Hour Meter Sync.
Adjustment
Minimum Unit
-
Adjustable Range
T5-2-46
ON only
Adjustment
Minimum Unit
-
Remark
TROUBLESHOOTING / Dr. ZX
INTERNAL
HOUR
SYNCHRONIZATION
After starting Dr. ZX, push Select
Controller.
METER
Push Monitor Unit.
Push OK.
To the
lower
T4GB-05-02-053
T1V7-05-03-001
T4GB-05-02-040
Function Selection Screen
Controller Selection Screen
Monitor Controller Screen
Push Start.
Push Various setting.
Push Internal Hour Meter Sync.
To the
lower
T1V7-05-03-042
T1V7-05-03-025
Title Screen
Main Menu Screen
Push Sync. Push ESC and return
to the former screen.
Push ESC and return to Various
Setup Item Screen.
T1V7-05-03-086
T1V7-05-03-085
Maintenance Set Item Screen
T5-2-47
T4GB-05-02-043
Various Setup Item Screen
TROUBLESHOOTING / Dr. ZX
PASSWORD CHANGE
After starting Dr. ZX, push Select
Controller.
Push Monitor Unit.
Push OK.
To the
lower
T4GB-05-02-053
T1V7-05-03-001
T4GB-05-02-040
Function Selection Screen
Controller Selection Screen
Monitor Controller Screen
Push Password.
Input the registered password and
push OK.
Input the new password and push
OK.
To the
lower
T1V7-05-03-126
T1V7-05-03-025
Title Screen
Main Menu Screen
Input the new password again and
push OK.
Push OK
Screen.
and
return
to
Title
T1V7-05-03-128
T1V7-05-03-169
.
T5-2-48
T1V7-05-03-127
TROUBLESHOOTING / e-Wheel
OUTLINE
ICF (Information Controller) saves the input signals
from various sensors and switches of the machine as
data by using CAN bus line from each controller.
Various input signals are recorded as “list of daily
report data”, “list of frequency distribution data”, “list of
total operating hours”, “list of alarm” and “list of failure”
in ICF.
The recorded data is downloaded to the personal
computer and is uploaded to the center server via
LAN, so that the data can be used as “e-Service”.
The machine equipped with the optional satellite
communication terminal can send the data to center
server by using satellite communication. (As for the
satellite communication system, refer to T5-3-24.
T5-3-1
TROUBLESHOOTING / e-Wheel
LIST OF DAILY REPORT DATA
Item
1.
Date
2.
Fuel Level
3.
4.
5.
6.
7.
Fuel Usage Amount
Machine Hour Meter
Engine Operating Hours
Operating Distance
Manual Transmission Operating Hours
8.
Automatic Transmission Operating Hours
9.
L Mode Operating Hours
Details
Date of daily report data
The value of the final remained fuel during a day when
the engine stops
The value of fuel used during a day
Hour meter cumulative hours
Total engine operating hours during a day
Traveling distance during a day
Total manual transmission operating hours during a day
Total automatic transmission operating hours during a
day
Total hours operating L mode of work mode selection
switch during a day
Total hours operating N mode of work mode selection
switch during a day
Total hours operating P mode of work mode selection
switch during a day
The highest radiator coolant temperature during a day
The highest hydraulic oil temperature during a day
The highest intake air temperature during a day
The highest fuel temperature during a day
The highest torque converter oil temperature during a
day
Engine operating hour distribution during a day
(Operating hours are recorded only when alternator
output signal is continuously delivered for more than 10
minutes.)
10. N mode Operating Hours
11. P mode Operating Hours
12.
13.
14.
15.
Radiator Coolant Temperature
Hydraulic Oil Temperature
Intake Air Temperature
Fuel Temperature
16. Torque Converter Oil Temperature
17. Engine Operating Hour Distribution
NOTE: The daily operation in this table is
equivalent to the hours between 0:00 and
23:59:59 counted by the ICX built-in clock.
In case the engine is kept operated
beyond 0:00, such data are recorded as
those for the following day.
T5-3-2
TROUBLESHOOTING / e-Wheel
LIST OF FREQUENCY DISTRIBUTION DATA
1.
2.
3.
4.
5.
6.
Item
Fuel Temperature Distribution
Pump Load Distribution
Travel Load Distribution
Radiator Coolant Temperature Distribution
Hydraulic Oil Temperature Distribution
Torque converter oil Temperature Distribution
7.
8.
Brake Pressure Distribution
Radiator Coolant Temperature - Intake Air
Temperature Distribution
9. Hydraulic Oil Temperature - Intake Air
Temperature
10. Torque Converter Oil Temperature - Intake
Air Temperature Distribution i
11. Radiator Coolant Temperature/Intake Air
Temperature
12. Hydraulic
Oil
Temperature/Intake
Air
Temperature
13. Torque Converter Oil Temperature / Intake Air
Temperature
14. Manual Transmission Speed Distribution
15. Automatic Transmission Speed Distribution
16. Engine Load Rate
Details
Frequency distribution of fuel temperature
Frequency distribution of main pump delivery pressure
Frequency distribution of travel torque
Frequency distribution of coolant temperature
Frequency distribution of hydraulic oil temperature
Frequency distribution of torque converter oil
temperature
Frequency distribution of secondary brake pressure
Frequency distribution on temperature in which intake air
temperature is pulled from coolant temperature
Frequency distribution on temperature in which intake air
temperature is pulled from hydraulic oil temperature
Frequency distribution on temperature in which intake air
temperature is pulled from torque converter oil
temperature
Frequency distribution of coolant temperature and intake
air temperature
Frequency distribution of hydraulic oil temperature and
intake air temperature
Frequency distribution of torque converter oil
temperature and intake air temperature
Frequency distribution of speed in manual transmission
Frequency distribution of speed in automatic
transmission
Frequency distribution of engine spood and engine
torque
T5-3-3
TROUBLESHOOTING / e-Wheel
LIST OF TOTAL OPERATING HOURS
1.
2.
3.
4.
5.
6.
7.
Item
Hour Meter (ICF)
Hour Meter (Monitor Unit)
Engine Operating Hour
Traveling Distance
Manual Transmission Operating Hours
Automatic Transmission Operating Hours
L mode Operating Hours
8.
N mode Operating Hours
9.
P mode Operating Hours
Details
Hour meter’s value accumulated inside ICF
Hour meter’s value accumulated in monitor unit
Total engine operating hours
Total traveling Distance
Total manual transmission operating hours
Total automatic transmission operating hours
Total hours operating L mode of work mode selection
switch
Total hours operating N mode of work mode selection
switch
Total hours operating P mode of work mode selection
switch
T5-3-4
TROUBLESHOOTING / e-Wheel
LIST OF ALARM
1.
2.
3.
4.
5.
6.
7.
8.
9.
Item
Overheat Alarm
Engine Warning Alarm
Engine Oil Pressure Alarm
Alternator Indicator Alarm
Air Filter Restriction Alarm
Water Separator Alarm
Service Brake Oil Level Alarm
Service Brake Oil Pressure Alarm
Emergency Steering Operation Alarm
Details
Date when the overheat indicator lights
Date when the engine warning indicator lights
Date when the engine oil pressure indicator lights
Date when the alternator indicator lights
Date when the air filter restriction indicator lights
Date when the water separator indicator lights
Date when the service brake oil level indicator lights
Date when the service brake oil pressure indicator lights
Date when the emergency steering operation indicator
lights
Date when the steering oil pressure indicator lights
Date when the transmission oil temperature indicator
lights
Date when the hydraulic oil temperature indicator lights
Date when the transmission filter restriction indicator
lights
Date when the transmission failure indicator lights
10. Steering Oil Pressure Alarm
Transmission Oil Temperature Alarm
11.
12. Hydraulic Oil Temperature Alarm
Transmission Filter Restriction Alarm
13.
14. Transmission Failure Alarm
NOTE: When the alarm above is recorded, check
each item.
If the monitor is faulty, refer to
Troubleshooting C.
T5-3-5
TROUBLESHOOTING / e-Wheel
LIST OF FAILURE
When the fault code occurs, ICF records the fault
code and the date.
Use the list of failure when the malfunction, which is
difficult to identify, occurs as the remedy information.
Refer to Troubleshooting A.
If the machine is operated properly with the fault code
recorded, the machine can continue to be operated.
T5-3-6
TROUBLESHOOTING / e-Wheel
HOW TO DOWNLOAD AND UPLOAD DATA
OF ICF
After the data saved in ICF is downloaded to Dr. ZX, is
uploaded to the personal Computer, and is uploaded
to the center server by using LAN, the data can be
used as “e-Service”.
Dr.ZX Connector
How to Download Data from Machine to Dr. ZX
1. Connect Dr. ZX to the machine by using the Hot
Sync cable and download cable for portable
communication system.
2. Turn Dr. ZX ON and start downloading the data.
(Refer to the next page.)
T4GB-05-01-007
Dr. ZX
(Palm)
Hot Sync
Cable
Download Cable
for Portable
Communication
System
T1V1-05-07-002
T5-3-7
TROUBLESHOOTING / e-Wheel
Data Download
After starting Dr. ZX, push Select
Controller.
Select Function
+
Select failure-diagnosis
controller
Self-Diagnostic Result
+
Push OK.
Push ICF Controller.
Select Controller
+
Engine Controller
+
Main Controller
+
Monitor Controller
+
ICF Controller
ESC
・ ICF
controller Ver.: XXYY
・ Satellite terminal Controller
Ver.: XXYY
Is it correct?
ESC
OK
ESC
Function Selection Screen
Controller Selection Screen
ICF Controller Screen
Push Start.
Push Date Download.
While downloading data, Download
Screen is displayed.
Select Item
Password
Dr. ZX SerVice Soft
(C)Hitachi Construction
Machinery Co., ltd
Data Download
+
Information C/U: Various
Setup
+
Data Download
+
Save Data Check
Downloading.
Do not turn off the Palm or
disconnect the download
cable.
27%
+
Op. Manual
Start
Back
ESC
Cancel
Title Screen
Main Menu Screen
Data Download Screen
When downloading is completed
normally, Normal End Screen is
displayed.
Push OK and return to Main Menu
Screen.
If pushing Cancel on Data
Download Screen, Alarm Screen is
displayed. Push OK and return to
Main Menu Screen.
Push ESC and return to Title
Screen.
Select Item
i
Initialization has been
completed.
The
download
is
completed.
CAUTION
Initialization has been
The completed.
download has been
interrupted.
You may disconnect the
download cable.
No
data
has
been
transferred to the Dr. ZX
OK
Normal End Screen
To the
lower
+
Information C/U: Various
Setup
+
Data Download
+
Save Data Check
+
OK
ESC
Main Menu Screen
Alarm Screen
T5-3-8
To the
lower
TROUBLESHOOTING / e-Wheel
How to Upload Data from Dr. ZX (Palm) to
Personal Computer
1. Set Dr. ZX (Palm) to the cradle. Connect the USB
cable to the personal computer.
2. Push the Hot Sync button.
NOTE: When pushing the Hot Sync button and
uploading the data to the personal
computer, the Palm Desktop software
attached with Dr. ZX (Palm) need to be
installed.
Dr. ZX
(Palm)
Cradle
Hot Sync
Button
T178-05-07-033
T5-3-9
TROUBLESHOOTING / e-Wheel
VARIOUS SETUP OF ICF AND SATELLITE
COMMUNICATION TERMINAL BY USING
Dr. ZX
Before starting satellite communication, installing the
satellite communication terminal and replacing ICF,
perform the following procedures by using Dr. ZX.
ICF Setup Procedures
Start Dr. ZX
1.1
Select Information Controller
1.2
Select Information C/U: Various Setup
1.3
Enter Date and Time
1.4
Enter Model and Serial No.
1.5
Information C/U: Initialize
Communication
1.6
Satellite Terminal: Initialize
1.7
Satellite Terminal Serial No. Check
1.8
Satellite Terminal, Communicating State Check
No Communication
2. Self-Diagnosing
T5-3-10
TROUBLESHOOTING / e-Wheel
1.1 Select Information Controller
1.2 Select Information C/U: Various Setup
1.1 Select Information Controller
After starting Dr. ZX, push Select
Controller.
Push ICF Controller.
Push OK.
Select failure-diagnosis
controller
Select Function
+
Self-Diagnostic Result
+
Select Controller
+
Engine Controller
+
Main Controller
+
Monitor Controller
+
ICF Controller
ESC
Function Selection Screen
・ ICF
Controller Ver.: XXYY
・ Satellite Terminal
Controller Ver.: XXYY
To the
lower
Is it correct?
ESC
Controller Selection Screen
OK
ESC
ICF Controller Screen
1.2 Select Information C/U: Various Setup
Push Information
Setup.
Push Start.
C/U:
Various
Select Item
Password
+
Dr. ZX SerVice Soft
(C)Hitachi Construction
Machinery Co., ltd
+
+
Select Item
Information C/U: Various
Setup
Data Download
+
Information C/U: Initialize
+
Enter Model and Serial
No.
+
Save Data Check
+
+
Enter Date and Time
Control Data: Initialize
Op. Manual
Start
Title Screen
Back
ESC
Main Menu Screen
T5-3-11
ESC
Information C/U: Various Setup
Screen
TROUBLESHOOTING / e-Wheel
1.3 Enter Date and Time
Push Enter Date and Time.
Push ESC and return to Main
Menu Screen.
Push Set and the focused item is
YY.
Push ESC and return to Information
C/U: Various Setup Screen.
Enter Date and Time
Select Item
+
Information C/U: Initialize
YY 2004 MM
01
+
HH
01
01
+
Enter Model and Serial
No.
Enter Date and Time
+
Control Data: Initialize
MM
DD
-
Set
ESC
Information C/U: Various Setup
Screen
01
+
ESC
YY, MM, DD, HH and MM
The focused item is displayed reversely.
At first, the focused item is YY.
YY, MM, DD, HH and MM
Move the focused item.
No repeat input.
Enter Date and Time Screen
-
YY, MM, DD, HH and MM
Value of the focused item is increased or
decreased one by one.
In case value is beyond maximum one: Change
value into the minimum one
In case value is below minimum one: Change
value into the maximum one
No repeat input.
Select Item
+
Information C/U: Various
Setup
+
Data Download
+
Save Data Check
+
+
ESC
Main Menu Screen
T5-3-12
TROUBLESHOOTING / e-Wheel
1.4 Enter Model and Serial No.
Push Enter Model and Serial No.
Select Item
+
Information C/U: Initialize
+
Enter Model and Serial
No.
+
Enter Date and Time
+
Control Data: Initialize
To the
lower
ESC
Information C/U: Various Setup
Screen
After inputting model and serial No.,
push OK and return to Enter Model
and Serial No. Screen.
Push ESC and return to Information
C/U: Various Setup Screen.
Push Exec, and model and serial
No. can be input.
Push
ESC
and
return
to
Information C/U: Various Setup
Screen.
Enter Model and Serial No.
Model
Enter Model and Serial No.
04GB
Select Item
Model |
Exec
Serial No. 000001
Exec
Push ESC and return to Main
Menu Screen.
ESC
ESC
Ex. Mach.No.(HCM4GB00P00
0001) Model(04GB)
Serial No.
Ex. Mach.No.(HCM4GB00P00
0001) Serial No.(000001)
OK
ESC
ESC
OK
+
Information C/U: Initialize
+
Enter Model and Serial
No.
+
Enter Date and Time
+
Control Data: Initialize
ESC
Information C/U: Various Setup
Screen
Enter Model and Serial No.
T5-3-13
TROUBLESHOOTING / e-Wheel
1.5 Information C/U: Initialize
Push Information C/U: Initialize.
Select Item
+
Information C/U: Initialize
+
Enter Model and Serial
No.
+
Enter Date and Time
+
Control Data: Initialize
To the
lower
ESC
Information C/U: Various Setup
Screen
Push Init and the controller
operating data is initialized.
Push
ESC
and
return
to
Information C/U: Various Setup
Screen.
Push OK and return to Information
C/U: Various Setup Screen.
Information C/U: Initialize
Select Item
Is operation data erased?
Init
i
Initialization has been
completed.
Initialization has been
completed.
ESC
Init
ESC
Push ESC and return to Main
Menu Screen.
OK
+
Information C/U: Initialize
+
Enter Model and Serial
No.
+
Enter Date and Time
+
Control Data: initialize
ESC
Information C/U: Various Setup
Screen
Information C/U: Initialize Screen
T5-3-14
TROUBLESHOOTING / e-Wheel
1.6 Satellite Terminal: Initialize
Display the next screen of
Information C/U: Various Setup
Screen.
Push Satellite Terminal: Initialize.
Push ESC and return to Main
Menu Screen.
Select Item
Select Item
+ Information C/U: Initialize
+
+ Enter Model and Serial
No.
+
+ Enter Date and Time
+
+ Control Data: Initialize
+
Information C/U: Various Setup
Screen
Satellite Terminal: Initialize
Satellite Terminal: Initialize
Satellite Terminal No.
Confirmation
Communicating State
Check
Enter Satellite Comm.
Start/Stop
ESC
Push Exec.
Push
ESC
and
return
to
Information C/U: Various Setup
Screen.
ESC
Next Screen of Information C/U:
Various Setup Screen
Is Un-Transmit data erased?
Exec
ESC
Satellite Terminal: Initialize
Push OK and return to Information
C/U: Various Setup Screen.
Satellite Terminal: Initialize
Select Item
+
Un-Transmit data is erased.
+
+
+
OK
Select Item
Satellite Terminal: Initialize
Satellite Terminal No.
Confirmation
Communicating State
Check
Enter Satellite Comm.
Start/Stop
+
Information C/U: Various
Setup
+
Data Download
+
Save Data Check
+
ESC
Information C/U: Various Setup
Screen
T5-3-15
ESC
Main Menu Screen
To the
lower
TROUBLESHOOTING / e-Wheel
1.7 Satellite Terminal Serial No. Check
Push
Satellite
Terminal
No.
Confirmation.
Push ESC and return to Main
Menu Screen.
Select Item
+
+
+
+
Satellite Terminal: Initialize
Satellite Terminal No.
Confirmation
Communicating State
Check
Enter Satellite Comm.
Start/Stop
Confirm serial no. (12 digits). Push
ESC and return to Information C/U:
Various Setup Screen.
Satellite Terminal No.
Confirmation
Select Item
+
+
Serial No. 8GBDA701862
+
+
ESC
ESC
Satellite Terminal: Initialize
Satellite Terminal No.
Confirmation
Communicating State
Check
Enter Satellite Comm.
Start/Stop
ESC
Information C/U: Various Setup
Screen
Information C/U: Various Setup
Screen
Select Item
+
Information C/U: Various
Setup
+
Data Download
+
Save Data Check
+
ESC
Main Menu Screen
T5-3-16
TROUBLESHOOTING / e-Wheel
1.8 Satellite
Check
Terminal,
Push
Communicating
State
Check.
Push ESC and return to Main
Menu Screen.
Select Item
+
+
+
+
Communicating State
Check communicating state.
Communicating State Check
Satellite Terminal: Initialize
Satellite Terminal No.
Confirmation
Communicating State
Check
Enter Satellite Comm.
Start/Stop
・ Comm.
UnCon
UnCon
OK
NG
Satellite Terminal
・ Power
ON
OFF
・ Comm.
Enable
Stop
ESC
Information C/U: Various Setup
Screen
Check the enclosed state.
ICF⇔Satellite Terminal
・ Conn
UnCon: Faulty harness
NG: Faulty harness for Comm.
OFF: Faulty harness, Faulty controller
Stop: 1.9 Enter Satellite Comm. Start/Stop is
performed.
ESC
Communicating State Check
Rod Aerial
OK
NG
GPS Aerial
OK
NG
Wave State
ON
OFF
Un Transmit Data Number
0
Last Transmitting Time
When electrical wave of the satellite is caught,
the items are turned into OK.
IMPORTANT: Check this with the key of
machine ON in outdoor.
According to state of electrical
wave, it may take a little longer
time.
2004/07/01 13:50:00
ESC
Select Item
Select Item
+
Information C/U: Various
Setup
+
+
Data Download
+
+
Save Data Check
+
+
+
ESC
Satellite Terminal: Initialize
Satellite Terminal No.
Confirmation
Communicating State
Check
Enter Satellite Comm.
Start/Stop
ESC
Information C/U: Various Setup
Screen
Main Menu Screen
T5-3-17
TROUBLESHOOTING / e-Wheel
1.9 Enter Satellite Comm. Start/Stop
Push ▼ and move to the next
screen of Information C/U: Various
Setup Screen.
Push Enter Satellite Comm.
Start/Stop.
Select Item
+
+
+
+
Satellite Terminal: Initialize
Satellite Terminal No.
Confirmation
Communicating State
Check
Enter Satellite Comm.
Start/Stop
To the
lower
ESC
Information C/U: Various Setup
Screen
In normal, Start is selected. When
stopping Satellite Comm., due to
some reasons, push Stop and
push Exec.
Push
ESC
and
return
to
Information C/U: Various Setup
Screen.
Push OK and return to Information
C/U: Various Setup Screen.
Enter Satellite Comm. Start/Stop
Satellite Terminal UnTrasmit
State
Stop
Setting has been completed
ESC
Exec
ESC
Select Item
+
+
Exec
Start
Push ESC and return to Main
Menu Screen.
+
+
OK
Satellite Terminal: Initialize
Satellite Terminal No.
Confirmation
Communicating State
Check
Enter Satellite Comm.
Start/Stop
ESC
Information C/U: Various Setup
Screen
CAUTION: This procedure need not be done
in normal.
T5-3-18
TROUBLESHOOTING / e-Wheel
1.10 Control Data: Initialize
Push Control Data: Initialize.
Select Item
+
Information C/U: Initialize
+
Enter Model and Serial
No.
+
Enter Date and Time
+
Control Data: Initialize
ESC
Information C/U: Various Setup
Screen
Push Init and the controller
operating data is initialized.
Push
ESC
and
return
to
Information C/U: Various Setup
Screen.
Push OK and return to Information
C/U: Various Setup Screen.
Push ESC and return to Main
Menu Screen.
Select Item
Control Data: Initialize
+ Information C/U: Initialize
Is control data initialized?
Init
i
Initialization has been
completed.
Initialization has been
completed.
ESC
Init
ESC
+ Enter Model and Serial
No.
+ Enter Date and Time
+ Control Data: Initialize
OK
ESC
Information C/U: Various Setup
Screen
Control Data: Initialize Screen
T5-3-19
TROUBLESHOOTING / e-Wheel
2. Self-Diagnosing
After starting Dr. ZX,
Self-Diagnostic Result.
Push Fault of ICF Controller. If
there is no trouble, No Problem is
displayed.
push
Self-diagnosing of controllers
below hasn completed.
Select Function
+
Self-Diagnostic Result
+
Select Controller
Self-Diagnosing
Engine Controller
No Problem
Main Controller
Fault
To the
lower
Monitor Controller No Problem
ICF Controller
ESC
ESC
ESC
Function Selection Screen
Change the page and
the fault code in back
and forth is displayed.
Push Details, and Details and
Corrective Action are displayed.
Push ESC and Retry B Screen is
Displayed.
Push ESC and Retry B Screen is
Displayed.
ICF Controller
Problem was detected.
14000
Fault
Controller Self-Diagnosing Screen
Push Retry B and return to Controller
Self-Diagnosing Screen after controller
self-diagnsing.
Push ESC and return to Controller
Self-Diagnosing Screen.
Fault Code 14000-2
14001
Details
Details
CAN Communication Error
ESC
Corrective Action
1)Retry B
2)Check Harness
3)
Retry B
Do you want to escape?
ESC
Details
ESC
ESC
Fault Code Screen
Retry B
Retry B Screen
Execute
Retry B
Self-diagnosing of controllers
below hasn completed.
Engine Controller
Main Controller
ESC
No Problem
Fault
Monitor Controller No Problem
ICF Controller
Fault
ESC
Controller Self-Diagnosing Screen
T5-3-20
ESC
TROUBLESHOOTING / e-Wheel
(Blank)
T5-3-21
TROUBLESHOOTING / e-Wheel
LIST OF ICF FAULT CODE
Fault Code
Details
14000-2
Abnormal CAN Communication
CAN Communication Error
14001-2
Abnormal Flash Memory
Read / Write Error
14002-2
Abnormal External RAM
Read / Write Error
14003-2
Abnormal EEPROM
Sum Check Error
Remedy
Execute retry B in self-diagnosing.
If this error code is displayed after re-try, check the following
item.
• Check the CAN communication line (check the
h retry) B in self-diagnosing and execute the following
Execute
item.
• Execute 1.5 Information C/U: Initialize (T5-3-14).
Execute retry B in self-diagnosing.
If this error code is displayed after re-try, check the following
item.
1. Execute 1.4 Enter Model and Serial No. (T5-3-13).
2. Execute 1.10 Control Data: Initialize (T5-3-19).
Then, execute self-diagnosing and execute retry B.
14006-2
Communication Error
Execute retry B in self-diagnosing.
Impossible to communicate with MC If this error code is displayed after re-try, check the following
item.
• Check the communication line.
• Check the power source line of satellite terminal.
• Check the fuse.
Then, execute self-diagnosing and execute retry B.
14008-2
Abnormal RAM
Road / Write Error
Execute retry B in self-diagnosing.
If this error code is displayed after re-try, replace the
controller.
T5-3-22
TROUBLESHOOTING / e-Wheel
LIST OF FAULT CODE OF SATELLITE
COMMUNICATION TERMINAL
Fault Code
Details
14100-2
Inside Error
Abnormal EEPROM
14101-2
Inside Error
Abnormal IB/OB Queue
14102-2
Inside Error
Abnormal Local Loup Back
14103-2
Communication Error
The satellite is not found.
14104-2
Inside Error
Fail 1 of Remote Loup Back
14105-2
Communication Error
Fail 2 of Remote Loup Back
14106-2
Abnormal Harness
Sending and receiving data are
unmatched.
Remedy
Execute retry B in self-diagnosing.
If this error code is displayed after re-try, replace the
controller.
T5-3-23
TROUBLESHOOTING / e-Wheel
SATELLITE COMMUNICATION SYSTEM
The satellite communication system is used for
maintenance of the machine, “e-Service” by
transmitting various data of the machine regularly via
a low earth orbit satellite.
Communication
Aerial
GPS
Aerial
NOTE: Depending on the circumstances of the
machine (ex. in the constructions, in the
tunnel, affected by the surrounding
building and affected of noise), the data
transfer rate may become slower, or the
communication might not be established.
The satellite communication system using
a low earth orbit satellite transmits digital
data through the radio wave. If there is
excessively noise or use of electrical
equipment which causes noise near the
machine, they cause reduces data transfer
rate or communication might not be
established at worst.
The satellite communication system consists of
satellite communication terminal, GPS aerial and
communication aerial.
The functions of each equipment are:
• Satellite Communication Terminal
T4GB-05-07-001
Satellite
Communication
Terminal
Receives the data from ICF and GPS aerial, and
sends the data to the communication aerial.
• GPS Aerial
Receives location information of the machine
from a low earth orbit satellite.
• Communication Aerial
Communicates the data with a low earth orbit
satellite.
T4GB-05-07-002
T5-3-24
TROUBLESHOOTING / e-Wheel
On the machine equipped with the satellite
communication system, the data are sent according to
the condition as follows:
Kinds of data sent from the machine by using satellite
communication:
Items
Kinds of Data
Periodical
Daily Report Data, Latest
Transmission
Information, Fuel Level
Condition
Location The data are sent once a day. In order to
avoid
congested
traffic
in
the
communication line, the data is sent
randomly between 0:00 and 02:00.
Transmitting Data at Latest Location Information
The data is sent only when the machine
Engine Start
is moved more than 5 km from the place
where it is recorded lastly.
Emergency
Alarm and Error Information
The transmission starts immediately
Transmission
when the alarm and error occurs.
Hour Meter 100 Hours Frequency Distribution Information
The data is sent when the hour meter
Transmission
exceeds every 100 hours.
T5-3-25
TROUBLESHOOTING / e-Wheel
(Blank)
T5-3-26
TROUBLESHOOTING / Component Layout
MAIN COMPONENT LAYOUT (OVERVIEW)
1
2
3
4
5
6
12
7
11
10
9
T4GB-01-02-005
8
1 - Bucket
2 - Bell Crank
4 - Head Light
5 - Front Working Light
3 - Bucket Cylinder
6 - Rear Working Light
(Optional)
7 - Rear Working Light
8 - Rear Combination Light
(Turn Signal, Hazard Light
Clearance Light and Brake
Light)
9 - Turn Signal, Hazard Light
and Clearance Light
T5-4-1
10 - Lift Arm Cylinder
11 - Lift Arm
12 - Bucket Link
TROUBLESHOOTING / Component Layout
MAIN COMPONENT LAYOUT (UPPERSTRUCTURE)
1
20
2
3
4
5
21
19
18
17
16
15
6
7
8
9
10
14
13
12
11
T4GB-01-02-002
123456-
Charging Block
Pilot Valve
Brake Valve
Steering Pilot Valve
Steering Valve
Control Valve
78910 11 12 -
Stop Valve
Pilot Shutoff Valve
Engine Oil Filter
Pilot Filter
Engine
Fuel Tank
13 14 15 16 17 18 -
T5-4-2
Torque Converter Cooler
Oil Cooler
Fan Motor
Radiator
Inter Cooler
Reserve Tank
19 - Muffler
20 - Air Cleaner
21 - Hydraulic Tank
TROUBLESHOOTING / Component Layout
MAIN COMPONENT LAYOUT (TRAVEL SYSTEM)
1
2
3
4
5
6
9
8
7
T4GB-01-02-004
1 - Front Axle
2 - Propeller Shaft (Front)
3 - Steering Cylinder
45-
Pump Device
Transmission
5 - Rear Axle
6 - Propeller Shaft (Rear)
T5-4-3
7 - Steering Accumulator
8 - Brake Pressure Sensor
TROUBLESHOOTING / Component Layout
ELECTRIC COMPONENT LAYOUT (OVERVIEW)
14
Cab
(Refer to T5-4-5)
2
1
13
12
Engine and Fan Pump
(Refer to T5-4-10)
11
3
4
5
6
8
Pump Device
(Refer to T5-4-11)
Drive Unit
(Refer to T5-4-11)
10
7
9
T4GB-01-02-019
1 - Hydraulic Oil Level Switch
5-
Battery
2 - Air Filter Restriction Switch
3 - ECM
67-
Boost Pressure Sensor
Fuel Level Sensor
4 - Reverse Buzzer
8-
Hydraulic Oil
Temperature Sensor
7 - Emergency Steering
Pump Delivery Pressure
Switch
8 - Lift Arm Angle Sensor
(Optional)
9 - Bucket Proximity Switch
T5-4-4
10 - Lift Arm Proximity Switch
11 - Implement Pressure Sensor
12 - Out Side Temperature
Sensor
TROUBLESHOOTING / Component Layout
ELECTRICAL SYSTEM (CAB)
1
2
3
Monitor and Switches
(Refer to T5-4-8)
4
Right Consol
(Refer to T5-4-7)
6
5
Controller and Relays
(Refer to T5-4-6)
T4GB-01-02-006
1 - Radio
2 - Auxiliary Switch Panel
(Optional)
3 - Speaker
4 - Rear Wiper Motor
5 - Brake Lamp Switch
T5-4-5
6 - Front Wiper Motor
TROUBLESHOOTING / Component Layout
Controller and Relays
5
6
T4GB-01-02-006
10
4
1
14
15
16
17
18
2
19
20
21
22
23
11
7
12
8
13
9
3
24
25
26
27
28
29
30
31
32
33
T4GC-01-02-002
1-
Flasher Relay
2-
Option Controller
(Optional)
3 - MCF
9-
Front Window Heater
Relay
10 - Neutral Relay
11 - Rear Window Heater Relay
4-
ICF
12 - Wiper Relay (Left)
5-
Dr.ZX Connector
13 - Wiper Relay (Right)
6-
Fuse Box
7-
Fog Light Relay (Optional)
14 - Reverse Light Relay
(A-R5)
15 - Brake Light Relay (A-R4)
8-
Auxiliary
16 - High Beam Relay (A-R3)
17 - Head Light Relay (Right)
(A-R2)
T4GB-01-02-022
18 - Head Light Relay (Left)
(A-R1)
19 - Emergency Steering Relay
(A-R10)
20 - Hone Relay (A-R9)
21 - Turn Signal Relay (Right)
(A-R8)
22 - Working Light Relay (Rear)
(A-R7)
23 - Working Light Relay
(Front) (A-R8)
24 - Front Wiper Relay (B-R5)
25 - Neutral Relay (B-R4)
T5-4-6
26 - Load Dump Relay (B-R3)
27 - Parking Brake Relay
(B-R2)
28 - Parking Brake Relay
(B-R1)
29 - Fuel Pump Relay (B-R10)
30 - Main Relay (B-R9)
31 - Rear Washer Relay (B-R8)
32 - Turn Signal Relay (Left)
(B-R7)
33 - Rear Wiper Relay (B-R6)
TROUBLESHOOTING / Component Layout
Right Console
T4GB-01-02-006
2
3
4
6
5
7
1
8
9
10
18
17
16
15
14
13
12
T4GB-01-02-023
11
1 - Down Shift Switch
2 - Bucket Control Lever
3 - Lift Arm Control Lever
4 - Forward/Reverse Switch
5 - Hone Switch
6 - Auxiliary Control Lever
(Optional)
7 - Quick Coupler Switch (Optional)
8 - Lift Arm Auto Leveler Downward
Set Switch (Optional)
9 - Lift Arm Auto Leveler Upward
Set Switch (Optional)
10 - Front Control Lock Lever
11 - Emergency Steering Check
Switch
12 - Fan Reversing Switch
13 - Fog Light Switch (Optional)
15 - Forward/Reverse Selector
Switch
16 - Cigar Lighter
17 - Up-shift/Down-shift Switch
14 - Ride Control Switch
(Optional)
18 - Hold Switch
T5-4-7
TROUBLESHOOTING / Component Layout
Monitor and Switchs
1
2
T4GB-01-02-006
14
3
13
12
4
5
11
6
7
10
9
8
1 - Monitor Panel
(Refer to T5-4-9)
2 - Driving Mode Switch
T4GB-01-02-024
5 - Work Mode Selector Switch
9 - Front Wiper Switch
12 - Rear Wiper Switch
6 - Clutch Cat Position Switch
10 - Forward/Reverse Lever
and Shift Switch
11 - Air Conditioner Switch
Panel
13 - Working Light Switch
3 - Turn Signal Lever /Head Light
Switch/Dimmer Switch
7 - Key Switch
4 - Parking Brake Switch
8 - Steering Column Tilt
/Telescopic Lever
T5-4-8
14 - Hazard Light Switch
TROUBLESHOOTING / Component Layout
Monitor Panel
1
2
3
4
5
6
7
8
9
10
11
34
12
33
13
14
32
15
31
T4GB-01-02-001
30
29
28
1 - Coolant Temperature
Gauge
2 - Transmission Oil
Temperature Gauge
3 - Turn Signal Indicator
(Left)
4 - High Beam Indicator
5 - Working Light Indicator
6 - Turn Signal Indicator
(Right)
7 - Monitor Display
8 - Stop Indicator
9 - Service Indicator
27
26
25
24 23
22
10 - Parking Brake Indicator
21
20
19
18
11 - Clearance Light Indicator
19 - Lever Steering Indicator
(Optional)
20 - Monitor Mode Selector
12 - Fuel Gauge
21 - Glow Signal
13 - Brake Low Oil Pressure
Indicator
14 - Brake Low Oil Level
Indicator
15 - Emergency Steering
Indicator (Optional)
16 - Low Steering Oil Pressure
Indicator
17 - Seat Belt Indicator
22 - Monitor Display Selector (Up)
23 - Maintenance Indicator
24 - Monitor Display selector
(Down)
25 - Forward/Reverse Switch
Indicator
26 - Water Separator Indicator
18 - Discharge Warning
Indicator
T5-4-9
17
16
27 - Engine Warning Indicator
28 - Overheat Indicator
29 - Engine Low Oil Pressure
Indicator
30 - Air Filter Restriction Indicator
31 - Transmission Warning
Indicator
32 - Transmission Oil Filter
Restriction Indicator
33 - Hydraulic Oil Temperature
Indicator
34 - Transmission Oil
Temperature Indicator
TROUBLESHOOTING / Component Layout
ENGINE AND FAN PUMP
1
2
3
6
7
8
9
5
10
11
4
14
13
12
T4GB-01-02-025
1 - Glow Plug
9 - EGR Valve
12 - Crank Revolution Sensor
2 - Injector
5 - Coolant Temperature
Sensor
6 - Overheat Switch
10 - Supply Pump
3 - Cam Angle Sensor
7 - Boost Pressure Sensor
11 - Fuel Temperature Sensor
13 - Engine Oil Pressure
Sensor
14 - Common Rail Pressure
Sensor
4 - Fan Pump
8 - Boost Temperature Sensor
T5-4-10
TROUBLESHOOTING / Component Layout
PUMP DEVICE
1
2
3
6
5
T4GB-01-02-009
4
DRIVE UNIT
7
21
8
9
13
14
15
16
17
18
20
12
19
11
10
T4GC-01-02-001
1 - Main Pump
7-
2 - Regulator
Torque Converter Input
Speed Sensor
8 - Air Breather
3 - Priority Valve
9-
4 - Pump Delivery Pressure
Switch
5 - Pilot Pump
10 - Vehicle Speed
Sensor
11 - Transmission Output
Speed Sensor
Charge Pump
12 - Transmission Middle Shaft
Sensor
13 - Forward Clutch Solenoid
Valve
14 - Reverse Clutch Solenoid
Valve
15 - 1st Clutch Solenoid Valve
16 - 2nd Clutch Solenoid Valve
6 - Steering Relief Valve
T5-4-11
17 - 3rd Clutch Solenoid Valve
18 - 4th Clutch Solenoid Valve
19 - Transmission Control Valve
20 - Parking Brake Pressure
Switch
21 - Regulator Valve
TROUBLESHOOTING / Component Layout
CONTROL VALVE
ZW220
5
4
1
2
3
T4GB-01-02-027
ZW250
5
1
4
3
2
T4GB-03-02-002
1 - Over Load Relief Valve
(Lift Arm: Bottom)
2 - Over Load Relief Valve
(Bucket: Bottom)
3 - Over Load Relief Valve
(Bucket: Rod)
4 - Make-up Valve
(Lift Arm: Rod)
T5-4-12
5 - Main Relief Valve
TROUBLESHOOTING / Component Layout
RIDE CONTROL VALVE
1
2
CHARGING BLOCK
3
4
5
6
10
T4GB-01-02-014
9
8
7
T4GB-01-02-013
FAN MOTOR
10
11
12
T4GB-01-02-012
1 - Overload Relief Valve
2 - Ride Control Solenoid
Valve
3 - Ride Control Accumulator
5 - Service Brake Accumulator
(Front)
6 - Service Brake Accumulator
(Rear)
7 - Relief Valve
89-
Pilot Relief Valve
Pump Torque Control
Solenoid Valve
10 - Parking Brake Solenoid
Valve
4 - Pilot Accumulator
T5-4-13
11 - Reverse Control Solenoid
Valve
12 - Relief Valve
13 - Flow Control Solenoid
Valve
TROUBLESHOOTING / Component Layout
STEERING VALVE
1
2
T4GB-01-02-020
EMERGENCY STEERING PUMP
(OPTIONAL)
3
4
5
6
T4GB-01-02-010
1 - Overload Relief Valve
2 - Overload Relief Valve
3 - Electric Motor
4 - Gear Pump
5 - Check Valve
T5-4-14
6-
Relief Valve
TROUBLESHOOTING / Component Layout
(Blank)
T5-4-15
TROUBLESHOOTING / Component Layout
COMPONENTS IN CONTROL VALVE
ZW220
1
2
3
4
11
5
6
7
7
10
9
T5-4-16
8
T4GB-03-02-003
TROUBLESHOOTING / Component Layout
A
7
6
8
9
7
5
B
C
D
E
4
2
3
T4GB-03-02-004
1 - Bucket Flow Control Valve
2 - Negative Control Valve
3 - Overload Relief Valve
(Bucket: Bottom End)
4 - Overload Relief Valve
(Bucket: Rod End)
5 - Overload Relief Valve
(Lift Arm: Bottom End)
6 - Make-up Valve
(Lift Arm: Rod End)
7 - Restriction Valve
8 - Low-pressure Relief Valve
9 - Main Relief Valve
T5-4-17
10 - Load Check Valve
(Arm Lift Circuit)
11 - Load Check Valve
(Bucket Circuit)
TROUBLESHOOTING / Component Layout
ZW220
1
2
3
4
11
5
6
7
7
10
9
T5-4-18
8
T4GB-03-02-003
TROUBLESHOOTING / Component Layout
ZW220
8
9
Section A※
7
7
2
T4GB-03-02-005
Section B※
8
9
T4GB-03-02-006
1 - Bucket Flow Control Valve
2 - Negative Control Valve
3 - Overload Relief Valve
(Bucket: Bottom End)
4 - Overload Relief Valve
(Bucket: Rod End)
5 - Overload Relief Valve
(Lift Arm: Bottom End)
6 - Make-up Valve
(Lift Arm: Rod End)
7-
Restriction Valve
8-
Low-pressure Relief Valve
9-
Main Relief Valve
※ Refer to T5-4-17.
T5-4-19
10 - Load Check Valve
(Arm Lift Circuit)
11 - Load Check Valve
(Bucket Circuit)
TROUBLESHOOTING / Component Layout
ZW220
1
2
3
4
11
5
6
7
7
10
9
T5-4-20
8
T4GB-03-02-003
TROUBLESHOOTING / Component Layout
Section C※
6
10
7
7
5
Section D※
4
1
11
3
Section E※
2
T4GB-03-02-007
1 - Bucket Flow Control Valve
2 - Negative Control Valve
3 - Overload Relief Valve
(Bucket: Bottom End)
※ Refer to T5-4-17
4 - Overload Relief Valve
(Bucket: Rod End)
5 - Overload Relief Valve
(Lift Arm: Bottom End)
6 - Make-up Valve
(Lift Arm: Rod End)
7-
Restriction Valve
8-
Low-pressure Relief Valve
9-
Main Relief Valve
T5-4-21
10 - Load Check Valve
(Arm Lift Circuit)
11 - Load Check Valve
(Bucket Circuit)
TROUBLESHOOTING / Component Layout
ZW250
1
2
3
4
5
6
8
7
8
9
11
10
T4GB-03-02-008
T5-4-22
TROUBLESHOOTING / Component Layout
D
10
C
6
7
8
8
A
E
5
4
3
T4GB-03-02-009
1 - Flow Control Valve
(Poppet)
2 - Flow Control Valve
(Changeover Valve)
3 - Negative Control Valve
4 - Overload Relief Valve
(Bucket: Bottom End)
5 - Overload Relief Valve
(Bucket: Rod End)
6 - Overload Relief Valve
(Lift Arm: Bottom End)
7-
Make-up Valve
(Lift Arm: for Rod)
8 - Restriction Valve
9-
T5-4-23
Low-pressure Relief Valve
10 - Main Relief Valve
11 - Load Check Valve
(Lift Arm Circuit)
TROUBLESHOOTING / Component Layout
ZW250
1
2
3
4
5
6
8
7
8
9
11
10
T4GB-03-02-008
T5-4-24
TROUBLESHOOTING / Component Layout
Section A※
11
7
6
8
8
Section B※
1
2
5
4
T4GB-03-02-010
1 - Flow Control Valve
(Poppet)
2 - Flow Control Valve
(Changeover Valve)
3 - Negative Control Valve
4-
Overload Relief Valve
(Bucket: Bottom End)
5 - Overload Relief Valve
(Bucket: Rod End)
6 - Overload Relief Valve
(Lift Arm: Bottom End)
7-
Make-up Valve
(Lift Arm: for Rod)
8 - Restriction Valve
9-
※ Refer to T5-4-23
.
T5-4-25
Low-pressure Relief Valve
10 - Main Relief Valve
11 - Load Check Valve
(Lift Arm Circuit)
TROUBLESHOOTING / Component Layout
ZW250
1
2
3
4
5
6
8
7
8
9
10
11
T4GB-03-02-008
T5-4-26
TROUBLESHOOTING / Component Layout
Section C※
10
9
Section D※
C
3
E
Section E※
3
T4GB-03-02-011
1 - Flow Control Valve
(Poppet)
2 - Flow Control Valve
(Changeover Valve)
3 - Negative Control Valve
4-
Overload Relief Valve
(Bucket: Bottom End)
5 - Overload Relief Valve
(Bucket: Rod End)
6 - Overload Relief Valve
(Lift Arm: Bottom End)
7-
Make-up Valve
(Lift Arm: for Rod)
8 - Restriction Valve
9-
※ Refer to T5-4-23.
T5-4-27
Low-pressure Relief Valve
10 - Main Relief Valve
11 - Load Check Valve
(Lift Arm Circuit)
TROUBLESHOOTING / Component Layout
COMPONENTS IN STEERING VALVE
4
1
2
3
Port T
Port A
Port B
Port Pa
Port Pb
5
Port A: Pressure for Steering
Right
Port P: From Main Pump
6
Port DR
Port P
Port LS
Port B: Pressure for Steering
Left
Port T: Return to Hydraulic Oil
Tank
4
5
Port Pa: Pilot Pressure for
Steering Right
Port LS: To Port LS of Priority
Valve
T5-4-28
T4GB-03-04-002
Port Pb: Pilot Pressure for
Steering Left
Port DR: Return to Hydraulic Oil
Tank
TROUBLESHOOTING / Component Layout
A
2
3
C
B
T4GB-03-04-001
1 - Spool
2 - Overload Relief Valve
3 - Overload Relief Valve
4 - Lord Check Valve
5 - Variable Orifice
6 - Fixed Orifice
T5-4-29
TROUBLESHOOTING / Component Layout
4
1
2
3
Port T
Port A
Port B
Port Pa
Port Pb
5
Port A: Pressure for Steering
Right
Port P: From Main Pump
6
Port DR
Port P
Port LS
Port B: Pressure for Steering
Left
Port T: Return to Hydraulic Oil
Tank
4
5
Port Pa: Pilot Pressure for
Steering Right
Port LS: To Port LS of Priority
Valve
T5-4-30
T4GB-03-04-002
Port Pb: Pilot Pressure for
Steering Left
Port DR: Return to Hydraulic Oil
Tank
TROUBLESHOOTING / Component Layout
Section A ※
7
Port P
Port DR
1
Port T
Section B ※
3
Port LS
Port B
Port A
2
Port Pb
Port Pa
4
5
7
Section C ※
T4GB-03-04-003
4
6
T4GB-03-04-006
1 - Spool
2 - Overload Relief Valve
3 - Overload Relief Valve
4 - Lord Check Valve
56-
※: Refer to T5-4-29.
T5-4-31
Variable Orifice
Fixed Orifice
7 - Passage A
TROUBLESHOOTING / Component Layout
COMPONENTS IN CHARGING BLOCK
1
2
3
4
5
6
7
8
22
9
10
11
21
12
13
14
20
15
16
17
18
T4GB-03-06-013
4
19
1 - Service Brake Accumulator
(Rear)
2 - Adaptor
9-
Priority Valve
3 - Port M2
(To Rear End of Brake Valve)
4 - Check Valve
5 - Port M1
(To Front End of Brake Valve)
6 - Service Brake Accumulator
(Front)
7 - Service Brake Pressure Sensor
8 - Port P (from Pilot Pump)
11 - Port DR (To Hydraulic Oil Tank)
10 - Pilot Relief Valve
12 - Port DR2 (To Hydraulic Oil Tank)
13 - Port PS1
(To Steering Pilot Valve)
14 - Port X
(To Main Pump Regulator)
15 - Parking Brake Pressure Sensor
T5-4-32
16 - Port BR3 (To Parking Brake)
17 - Port PS2
(To Main Pump Regulator
and Ride Control Valve (Optional))
18 - Pilot Accumulator
19 - Port PP (To Pilot Shutoff Valve)
20 - Parking Brake Solenoid Valve
21 - Pump Torque Control Proportional
Solenoid Valve
22 - Relief Valve
TROUBLESHOOTING / Component Layout
2
Port for Attaching
Service Brake
Accumulator (Rear)
Port for Attaching
Service Brake
Accumulator (Front)
3
5
Pump Torque
Control
Proportional
Solenoid Valve
13
Parking Brake
Solenoid Valve
17
Port for Attaching
Pilot Accumulator
T4GB-03-06-001
T5-4-33
TROUBLESHOOTING / Component Layout
1
2
3
4
5
6
7
8
22
9
10
11
21
12
13
14
20
15
16
17
18
T4GB-03-06-013
4
19
1 - Service Brake Accumulator
(Rear)
2 - Adaptor
9-
Priority Valve
3 - Port M2
(To Rear End of Brake Valve)
4 - Check Valve
5 - Port M1
(To Front End of Brake Valve)
6 - Service Brake Accumulator
(Front)
7 - Service Brake Pressure Sensor
8 - Port P (from Pilot Pump)
11 - Port DR (To Hydraulic Oil Tank)
10 - Pilot Relief Valve
12 - Port DR2 (To Hydraulic Oil Tank)
13 - Port PS1
(To Steering Pilot Valve)
14 - Port X
(To Main Pump Regulator)
15 - Parking Brake Pressure Sensor
T5-4-34
16 - Port BR3 (To Parking Brake)
17 - Port PS2
(To Main Pump Regulator
and Ride Control Valve (Optional))
18 - Pilot Accumulator
19 - Port PP (To Pilot Shutoff Valve)
20 - Parking Brake Solenoid Valve
21 - Pump Torque Control Proportional
Solenoid Valve
22 - Relief Valve
TROUBLESHOOTING / Component Layout
11
Section V-V※
10
14
Section U-U※
12
21
15
16
Section T-T※
20
19
Section S-S※
18
4
T4GB-03-06-003
※Refer to T5-4-33.
4
T5-4-35
TROUBLESHOOTING / Component Layout
1
2
3
4
5
6
7
8
22
9
10
11
21
12
13
14
20
15
16
17
18
T4GB-03-06-013
4
19
1 - Service Brake Accumulator
(Rear)
2 - Adaptor
9-
Priority Valve
3 - Port M2
(To Rear End of Brake Valve)
4 - Check Valve
5 - Port M1
(To Front End of Brake Valve)
6 - Service Brake Accumulator
(Front)
7 - Service Brake Pressure Sensor
8 - Port P (From Pilot Pump)
11 - Port DR (To Hydraulic Oil Tank)
10 - Pilot Relief Valve
12 - Port DR2 (To Hydraulic Oil Tank)
13 - Port PS1
(To Steering Pilot Valve)
14 - Port X
(To Main Pump Regulator)
15 - Parking Brake Pressure Sensor
T5-4-36
16 - Port BR3 (To Parking Brake)
17 - Port PS2
(To Main Pump Regulator
and Ride Control Valve (Optional))
18 - Pilot Accumulator
19 - Port PP (To Pilot Shutoff Valve)
20 - Parking Brake Solenoid Valve
21 - Pump Torque Control Proportional
Solenoid Valve
22 - Relief Valve
TROUBLESHOOTING / Component Layout
Section Z-Z※
6
1
4
Section Y-Y※
Section X-X※
7
8
4
Section W-W※
22
9
※Refer to T5-4-33
T5-4-37
T4GB-03-06-004
TROUBLESHOOTING / Component Layout
COMPONENTS IN RIDE CONTROL VALVE
Lift Arm
Cylinder
Ride Control
Accumulator
5
Ride Control Valve
SP
3
Pi
1
4
B
A
2
To Hydraulic Oil Tank
T
From Charging
Block
T4GB-03-08-002
1 - Ride Control Solenoid Valve
2 - Charge-cut Spool
3 - Overload Relief Valve
4 - Spool
5 - Drain Plug
T5-4-38
TROUBLESHOOTING / Component Layout
A
3
5
1
T4GB-03-08-001
T5-4-39
TROUBLESHOOTING / Component Layout
Lift Arm
Cylinder
Ride Control
Accumulator
5
Ride Control Valve
SP
3
Pi
1
4
B
A
2
To Hydraulic Oil Tank
T
From Charging
Block
T4GB-03-08-002
1 - Ride Control Solenoid Valve
2 - Charge-cut Spool
34-
Overload Relief Valve
Spool
5-
T5-4-40
Drain Plug
TROUBLESHOOTING / Component Layout
Section A※
Port Pi
To Ride Control
Accumulator
1
Port SP
3
Port B
Port A
Port T
2
※Refer to T5-4-39
T5-4-41
4
T4GB-03-08-003
TROUBLESHOOTING / Component Layout
FRONT VIEW OF TRANSMISSION
1
A
2
5
B
6
B
C
3
C
7
8
4
A
T4GC-03-09-003
1 - Breather
2 - From Oil Cooler
3 - Control Valve
4 - Oil Feed Port
5 - Charging Pump
6 - Rotation Sensor (A)
T5-4-42
7 - Rotation Sensor (B)
8 - Vehicle Speed Sensor
TROUBLESHOOTING / Component Layout
SIDE VIEW OF TRANSMISSION
2
1
3
4
3
5
6
9
10
7
8
T4GC-03-09-005
1 - Converter Inlet Pressure
Port
2 - Regulator Valve
3 - Forward Clutch Pressure
Port
4 - Reverse Clutch Pressure
Port
5 - 1st Speed Clutch Pressure
Port
6 - 2nd Speed Clutch Pressure
Port
7 - 3rd Speed Clutch Pressure
Port
8 - 4th Speed Clutch Pressure
Port
9 - Parking Brake Release
Pressure Inlet
T5-4-43
10 - Parking Brake Pressure
Switch Port
TROUBLESHOOTING / Component Layout
REAR VIEW OF TRANSMISSION
1
D
D
2
3
9
8
7
E
6
4
Detail E
5
T4GC-03-09-004
Section DD
1 - Engine Speed Sensor
2 - Suction Tube
3 - Hose
4 - Strainer
5 - To Oil Cooler
6 - Converter Outlet Boss
7 - Oil Pressure Gauge Port
8 - Safety Valve
9 - Spring
T5-4-44
TROUBLESHOOTING / Component Layout
CROSS-SECTIONAL DRAWING OF TORQUE CONVERTER
7
8
9
10
11
1
2
3
4
5
6
T4GC-03-09-001
1 - Cover Wheel
2 - Input Plate
3 - Turbine
4 - Stator
5 - Input Guide
6 - Stator Hub
7 - Impeller
8 - Impeller Hub
9 - Pump Drive Gear
T5-4-45
10 - Guide Carrier
11 - Turbine Shaft
TROUBLESHOOTING / Component Layout
CROSS-SECTIONAL DRAWING OF TRANSMISSION
1
2
14
3
4
Section BB※
13
5
12
11
10
9
Section
15
1234-
Charging Pump
Pump Drive Shaft
Forward Clutch
Distributor Cap
CC※
5678-
7
8
Section AA※
T4GC-03-09-006
16
Parking Brake
Front Output Flange
Output Shaft
Drain Plug
6
910 11 12 -
※Refer to T5-4-42
T5-4-46
Rear Output Flange
1st & 2nd Speeds Clutch
Distributor Cap
Idler Shaft
13 14 15 16 -
Torque Converter
Reverse Clutch
Distributor Cap
3rd & 4th Speeds Clutch
TROUBLESHOOTING / Component Layout
CROSS-SECTIONAL DRAWING OF CLUTCH SHAFT
1
2
3
4
5
A
6
7
8
9
10
11
B
12
13
Detail B
Detail A
1234-
Hub Gear
End Plate
Return Spring
Seal Ring (Inner)
567-
Bleed Valve
Seal Ring (Outer)
Piston
T4GC-03-09-007
8 - Disk
9 - Plate
10 - Hub Gear
T5-4-47
11 - Shaft
12 - Plug
13 - Seal Ring
TROUBLESHOOTING / Component Layout
CROSS-SECTIONAL DRAWING OF TRANSMISSION REGULATOR VALVE
Normally
Small Hole of
Regulator Spool
Regulator Spool
Spring
From
Charging Pump
T4GC-03-09-025
When overflowing
Regulator Spool
Spring
To Transmission
Control Valve
From
Charging Pump
To Torque
Converter
T5-4-48
T4GC-03-09-026
TROUBLESHOOTING / Component Layout
CROSS-SECTIONAL DRAWING OF TRANSMISSION CONTROL VALVE
1
2
3
24
4
5
23
6
7
8
22
9
21
10
11
12
20
13
14
19
15
16
17
18
T4GC-03-09-029
From
Charging Pump
1 - Solenoid Body
7 - Emergency Reverse Spool
2 - Valve Body
8 - Reverse Modulation Spool
3 - Cover
9 - Reverse Modulation Spring
4 - Emergency Forward Spool
10 - 1st Speed Modulation
Spool
11 - 1st Speed Modulation
Spring
12 - Emergency 2nd Speed
Spool
5 - Forward Modulation Spool
6 - Forward Modulation Spring
13 - 2nd Speed Modulation
Spool
14 - 2nd Speed Modulation
Spring
15 - 3rd Speed Modulation
Spool
16 - 3rd Speed Modulation
Spring
17 - 4th Speed Modulation
Spool
18 - 4th Speed Modulation
Spring
T5-4-49
19 - 4th Speed Proportional
Solenoid Valve
20 - 3rd Speed Proportional
Solenoid Valve
21 - 2nd Speed Proportional
Solenoid Valve
22 - 1st Speed Proportional
Solenoid Valve
23 - Reverse Proportional
Solenoid Valve
24 - Forward Proportional
Solenoid Valve
TROUBLESHOOTING / Component Layout
(Blank)
T5-4-50
TROUBLESHOOTING / Troubleshooting A
TROUBLESHOOTING A PROCEDURE
Refer to troubleshooting A procedure in case any fault
codes are displayed after diagnosing by using Dr. ZX
or the service mode of monitor unit.
• How to Read Troubleshooting Flow Charts
YES(OK)
・
(2)
After completing the checking and/or measuring procedures in box (1),
select YES (OK) or NO (NOT OK) and proceed to box (2) or (3).
(1)
NO(NOT OK)
・
· Key switch: ON
(3)
Instructions, reference, and/or inspection methods and/or measurements are occasionally
described under the box. If incorrectly checked or measured, not only will troubleshooting
be unsuccessful but also damage to the components may result.
・
Use Dr. ZX for descriptions in the double-line box.
・
Causes of machine problems are stated in the thick-line box. Scanning quickly through the
thick-line boxes allows you to estimate the possible causes before actually following the
flow chart.
NOTE: Harness end connector viewed from the
open end side by the all connectors image
shown in this section.
Harness
Open End
Side
Harness End Connector
T158-05-03-001
T5-5-1
TROUBLESHOOTING / Troubleshooting A
MC FAULT CODE LIST
Controller Hardware Failure
Fault
Trouble
Code
11000-2 Abnormal EEPROM
Cause
Faulty MC
All Control
Faulty MC
All Control
11001-2
Abnormal RAM
11002-2
Abnormal A/D (Analog to Digi- Faulty MC
tal) Converter
Abnormal Sensor Voltage
Faulty sensor because
shorted circuit in harness
Faulty MC
CAN Communication Error
Faulty sensor because
shorted circuit in harness
Faulty MC
11003-3
11004-2
Influenced Control
T5-5-2
All Control
of All Control
of All Pump Control
All Transmission Control
All Engine Control
Hydraulic Drive Fan Cooling
Control
Ride Control
CAN Cycle Data Communication
TROUBLESHOOTING / Troubleshooting A
Symptoms in Machine Operation When Trouble Occurs
There is something wrong with machine operation.
Remark
Retrial B
Replace MC
There is something wrong with machine operation.
Retrial B
Replace MC
As the latest, normal value AD (analog to digital) is enabled, the Retrial B
machine may be operated incorrectly or slowly.
Replace MC
Inputs from all sensors are uncertain.
Retrial B
Check Harness
Replace MC
-1
As engine speed is kept at 1000 min (1000 rpm), the work may Retrial B
be inoperable.
Check CAN Harness
Replace MC
T5-5-3
TROUBLESHOOTING / Troubleshooting A
Engine Failure
Fault
Trouble
Code
11103-3 Abnormal Accelerator
High Voltage
11103-4
Abnormal Accelerator
Low Voltage
11105-3
Abnormal Torque
Input Shaft Sensor
Cause
Influenced Control
Pedal Voltage: 4.75 V or higher
Pump Torque Decrease Control
Engine Accelerator Pedal
Control
Pedal Voltage: Less than 0.25 V
Pump Torque Decrease Control
Engine Accelerator Pedal
Control
Hydraulic Drive Fan Cooling
Control
Converter Engine speed=0 min-1
ECM engine speed>500 min-1
T5-5-4
TROUBLESHOOTING / Troubleshooting A
Symptoms in Machine Operation When Trouble Occurs
Remedy
The accelerator pedal is inoperable.
Retrial B
Engine speed kept at 1000 min-1 (1000 rpm), the work may be Check Harness
inoperable.
Replace Accelerator Pedal
Replace MC
The accelerator pedal is inoperable.
Retrial B
Engine speed kept at 1000 min-1 (1000 rpm), the work may be Check Harness
inoperable.
Replace Accelerator Pedal
Replace MC
As fan speed is controlled by temperature only, when oil and Retrial B
coolant temperature are high, the machine starts slowly.
Check Harness
Fuel consumption becomes bad.
Replace Torque Converter Input Shaft
Sensor
Replace MC
T5-5-5
TROUBLESHOOTING / Troubleshooting A
Pump Failure
Fault
Trouble
Cause
Influenced Control
Code
11204-3 Abnormal Pump Delivery Output voltage: 4.75 V or Disable Pump Torque Decrease
Pressure Sensor High Volt- higher
Control
age
11204-4
Abnormal Pump Delivery Output voltage: Less than Disable Pump Torque Decrease
Pressure Sensor Low Voltage 0.25 V
Control
11209-3
Abnormal Implement Pres- Output voltage: 4.75 V or Disable Pump Torque Decrease
sure Sensor High Voltage
higher
Control
11209-4
Abnormal Implement Pres- Output voltage: Less than Disable Pump Torque Decrease
sure Sensor Low Voltage
0.25 V
Control
T5-5-6
TROUBLESHOOTING / Troubleshooting A
Symptoms in Machine Operation When Trouble Occurs
Remedy
As the pump is controlled by pump standard torque control, work ef- Retrial B
ficiency of the front attachment becomes low.
Check Harness
Fuel consumption becomes bad.
Replace Pump Delivery Pressure Sensor
Replace MC
As the pump is controlled by pump standard torque control, work ef- Retrial B
ficiency of the front attachment becomes low.
Check Harness
Fuel consumption becomes bad.
Replace Pump Delivery Pressure Sensor
Replace MC
As the pump is controlled by pump standard torque control, work ef- Retrial B
ficiency of the front attachment becomes low.
Check Harness
Fuel consumption becomes bad.
Replace Implement Pressure Sensor
Replace MC
As the pump is controlled by pump standard torque control, work ef- Retrial B
ficiency of the front attachment becomes low.
Check Harness
Fuel consumption becomes bad.
Replace Implement Pressure Sensor
Replace MC
T5-5-7
TROUBLESHOOTING / Troubleshooting A
Pilot Failure
Fault
Trouble
Cause
Code
11312-3 Abnormal Brake Pedal Pres- Voltage: 4.75 V or higher
sure Sensor High Voltage
Influenced Control
Clutch Cut-Off Control
11312-4
Abnormal Brake Pedal Pres- Voltage: Less than 0.25 V
sure Sensor Low Voltage
Clutch Cut-Off Control
11313-3
Abnormal Parking Brake Pres- Output voltage: 4.75 V or higher
sure Sensor High Voltage
Parking Brake Indicator Control
11313-4
Abnormal Parking Brake Pres- Output voltage: Less than 0.25 Parking Brake Indicator Consure Sensor Low Voltage
V
trol
T5-5-8
TROUBLESHOOTING / Troubleshooting A
Symptoms in Machine Operation When Trouble Occurs
Remedy
As clutch cut-off control is disabled, the clutch cut-off is inoper- Retrial B
able.
Check Harness
Fuel consumption becomes bad.
Replace Brake Pedal Pressure Sensor
Replace MC
As clutch cut-off control is disabled, the clutch cut-off is inoper- Retrial B
able.
Check Harness
Fuel consumption becomes bad.
Replace Brake Pedal Pressure Sensor
Replace MC
As the parking brake is forcibly released, the machine can travel Retrial B
with the parking brake switch ON.
Check Harness
Replace Parking Brake Pressure Sensor
Replace MC
As the parking brake is forcibly released, the machine can travel Retrial B
with the parking brake switch ON.
Check Harness
Replace Parking Brake Pressure Sensor
Replace MC
T5-5-9
TROUBLESHOOTING / Troubleshooting A
Proportional Solenoid Valve Failure
Fault
Trouble
Code
11412-2 Abnormal Feedback of Hydraulic
Drive Fan Flow Rate Control Solenoid Valve
Cause
Influenced Control
The feedback current Hydraulic
to MC becomes the Control
uncertain value
Drive
Fan
Cooling
11412-3
Abnormal Feedback High Current of The feedback current Hydraulic
Hydraulic Drive Fan Flow Rate Con- to MC exceeds the Control
trol Solenoid Valve
upper limit
Drive
Fan
Cooling
11412-4
Abnormal Feedback Low Current of While the command Hydraulic
Hydraulic Drive Fan Flow Rate Con- from MC is output, the Control
trol Solenoid Valve
feedback current to MC
is 56 mA or less
Drive
Fan
Cooling
11413-2
Abnormal Feedback of Pump Torque The feedback current Pump Standard Torque Control
Control Solenoid Valve
to MC becomes the
uncertain value
11413-3
Abnormal Feedback High Current of The feedback current Pump Standard Torque Control
Pump Torque Control Solenoid Valve to MC exceeds the
upper limit
11413-4
Abnormal Feedback Low Current of While the command Pump Standard Torque Control
Pump Torque Control Solenoid Valve from MC is output, the
feedback current to MC
is 56 mA or less
11414-2
Abnormal Feedback of Transmission
Clutch First Gear Proportional Solenoid Valve
11414-3
Abnormal Feedback High Current of The feedback current All Transmission Control
Transmission Clutch First Gear to MC exceeds the
Proportional Solenoid Valve
upper limit
The feedback current All Transmission Control
to MC becomes the
uncertain value
T5-5-10
TROUBLESHOOTING / Troubleshooting A
Symptoms in Machine Operation When Trouble Occurs
Remedy
As the fan rotation is kept at maximum, the machine starts slowly.
Fuel consumption becomes bad.
Retrial B
Check Harness (Feedback line from the
flow rate control solenoid valve to MC)
Replace Hydraulic Drive Fan Flow Rate
Control Solenoid Valve
Replace MC
Retrial B
Check Harness (Feedback line from the
flow rate control solenoid valve to MC)
Replace Hydraulic Drive Fan Flow Rate
Control Solenoid Valve
Replace MC
Retrial B
Check Harness (Feedback line from the
flow rate control solenoid valve to MC)
Replace Hydraulic Drive Fan Flow Rate
Control Solenoid Valve
Replace MC
Retrial B
Check Harness (Feedback line from the
torque control solenoid valve to MC)
Replace Pump Torque Control Solenoid
Valve
Replace MC
Retrial B
Check Harness (Feedback line from the
torque control solenoid valve to MC)
Replace Pump Torque Control Solenoid
Valve
Replace MC
Retrial B
Check Harness (Feedback line from the
torque control solenoid valve to MC)
Replace Pump Torque Control Solenoid
Valve
Replace MC
Retrial B
Check Harness (Feedback line from first
gear proportional solenoid valve output to
MC)
Replace First Gear Proportional Solenoid
Valve
Replace MC
Retrial B
Check Harness (Feedback line from first
gear proportional solenoid valve output to
MC)
Replace First Gear Proportional Solenoid
Valve
Replace MC
As the fan rotation is kept at maximum, the machine starts slowly.
Fuel consumption becomes bad.
As the fan rotation is kept at maximum, the machine starts slowly.
Fuel consumption becomes bad.
As the pump is kept at minimum displacement, work efficiency of
the front attachment becomes low.
As the pump is kept at minimum displacement, work efficiency of
the front attachment becomes low.
As the pump is kept at minimum displacement, work efficiency of
the front attachment becomes low.
As speed is kept at second gear in spite of the shift switch, there
is some influence on the work.
As speed is kept at second gear in spite of the shift switch, there
is some influence on the work.
T5-5-11
TROUBLESHOOTING / Troubleshooting A
Fault
Code
11414-4
Trouble
Cause
Influenced Control
Abnormal Feedback Low Current of The feedback current All Transmission Control
Transmission Clutch First Gear to MC is 20 mA or less
Proportional Solenoid Valve
11415-2
Abnormal Feedback of Transmission
Clutch Second Gear Proportional
Solenoid Valve
The feedback current All Transmission Control
to MC becomes the
uncertain value
11415-3
Abnormal Feedback High Current of The feedback current All Transmission Control
Transmission Clutch Second Gear to MC exceeds the
Proportional Solenoid Valve
upper limit
11415-4
Abnormal Feedback Low Current of The feedback current All Transmission Control
Transmission Clutch Second Gear to MC is 20 mA or less
Proportional Solenoid Valve
11416-2
Abnormal Feedback of Transmission
Clutch Third Gear Proportional Solenoid Valve
11416-3
Abnormal Feedback High Current of The feedback current All Transmission Control
Transmission Clutch Third Gear to MC exceeds the
Proportional Solenoid Valve
upper limit
11416-4
Abnormal Feedback Low Current of The feedback current All Transmission Control
Transmission Clutch Third Gear to MC is 20 mA or less
Proportional Solenoid Valve
11417-2
Abnormal Feedback of Transmission
Clutch Fourth Gear Proportional Solenoid Valve
The feedback current All Transmission Control
to MC becomes the
uncertain value
The feedback current All Transmission Control
to MC becomes the
uncertain value
T5-5-12
TROUBLESHOOTING / Troubleshooting A
Symptoms in Machine Operation When Trouble Occurs
Remedy
As speed is kept at second gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from first gear
proportional solenoid valve output to MC)
Replace First Gear Proportional Solenoid Valve
Replace MC
As speed is kept at first gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from second gear
proportional solenoid valve output to MC)
Replace Second Gear Proportional Solenoid
Valve
Replace MC
As speed is kept at first gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from second gear
proportional solenoid valve output to MC)
Replace Second Gear Proportional Solenoid
Valve
Replace MC
As speed is kept at first gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from second gear
proportional solenoid valve output to MC)
Replace Second Gear Proportional Solenoid
Valve
Replace MC
As speed is kept at second gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from third gear
proportional solenoid valve output to MC)
Replace Third Gear Proportional Solenoid Valve
Replace MC
As speed is kept at second gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from third gear
proportional solenoid valve output to MC)
Replace Third Gear Proportional Solenoid Valve
Replace MC
As speed is kept at second gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from third gear
proportional solenoid valve output to MC)
Replace Third Gear Proportional Solenoid Valve
Replace MC
As speed is kept at second gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from fourth gear
proportional solenoid valve output to MC)
Replace Fourth Gear Proportional Solenoid
Valve
Replace MC
T5-5-13
TROUBLESHOOTING / Troubleshooting A
Fault
Code
11417-3
Trouble
Cause
Influenced Control
Abnormal Feedback High Current of The feedback current All Transmission Control
Transmission Clutch Fourth Gear to MC exceeds the
Proportional Solenoid Valve
upper limit
11417-4
Abnormal Feedback Low Current of The feedback current All Transmission Control
Transmission Clutch Fourth Gear to MC is 20 mA or less
Proportional Solenoid Valve
11418-2
Abnormal Feedback of Transmission
Clutch Forward Proportional Solenoid Valve
11418-3
Abnormal Feedback High Current of The feedback current All Transmission Control
Transmission Clutch Forward Pro- to MC exceeds the
portional Solenoid Valve
upper limit
11418-4
Abnormal Feedback Low Current of The feedback current All Transmission Control
Transmission Clutch Forward Pro- to MC is 20 mA or less
portional Solenoid Valve
11419-2
Abnormal Feedback of Transmission
Clutch Reverse Proportional Solenoid Valve
11419-3
Abnormal Feedback High Current of The feedback current All Transmission Control
Transmission Clutch Reverse Pro- to MC exceeds the
portional Solenoid Valve
upper limit
11419-4
Abnormal Feedback Low Current of The feedback current All Transmission Control
Transmission Clutch Reverse Pro- to MC is 20 mA or less
portional Solenoid Valve
The feedback current All Transmission Control
to MC becomes the
uncertain value
The feedback current All Transmission Control
to MC becomes the
uncertain value
T5-5-14
TROUBLESHOOTING / Troubleshooting A
Symptoms in Machine Operation When Trouble Occurs
Remedy
As speed is kept at second gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from fourth gear
proportional solenoid valve output to MC)
Replace Fourth Gear Proportional Solenoid
Valve
Replace MC
As speed is kept at second gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from fourth gear
proportional solenoid valve output to MC)
Replace Fourth Gear Proportional Solenoid
Valve
Replace MC
As speed is kept at second gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from forward
proportional solenoid valve output to MC)
Replace Forward Proportional Solenoid Valve
Replace MC
As speed is kept at second gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from forward
proportional solenoid valve output to MC)
Replace Forward Proportional Solenoid Valve
Replace MC
As speed is kept at second gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from forward
proportional solenoid valve output to MC)
Replace Forward Proportional Solenoid Valve
Replace MC
As speed is kept at second gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from reverse
proportional solenoid valve output to MC)
Replace Reverse Proportional Solenoid Valve
Replace MC
As speed is kept at second gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from reverse
proportional solenoid valve output to MC)
Replace Reverse Proportional Solenoid Valve
Replace MC
As speed is kept at second gear in spite of the shift switch, Retrial B
there is some influence on the work.
Check Harness (Feedback line from reverse
proportional solenoid valve output to MC)
Replace Reverse Proportional Solenoid Valve
Replace MC
T5-5-15
TROUBLESHOOTING / Troubleshooting A
Transmission Failure
Fault
Trouble
Code
11600-3 Abnormal Travel Speed Sensor
11600-4
11601-3
11602-3
11904-2
11905-2
Cause
The abnormal value below All Transmission Control
is detected with the clutch
connected.
• Travel speed sensor=0
min-1
• Middle shaft sensor>300
min-1
• Torque converter output
speed sensor>500 min-1
• Detected voltage under
the open circuit with key
ON: 4.5 V or higher
Abnormal Low Voltage of Travel Detected voltage under the
Speed Sensor
shorted circuit with key ON:
Less than 1.5 V
Abnormal Torque Converter The abnormal value below
Output Speed Sensor
is detected with the clutch
connected.
• Torque converter output
speed sensor=0 min-1
• Middle shaft sensor>300
min-1
• Travel speed sensor>300
min-1
Abnormal Transmission Middle The abnormal value below
Shaft Sensor
is detected with the clutch
connected.
• Middle shaft sensor =0
min-1
• Travel speed sensor>500
min-1
• Torque converter output
speed sensor>500 min-1
Abnormal
Forward/Reverse The forward/reverse sigLever
nals are turned ON for 80
ms or longer at the same
time.
Abnormal
Switch
Influenced Control
All Transmission Control
Pump Torque Decrease Control
All Transmission Control
All Transmission Control
Forward/Reverse The forward/reverse sig- All Transmission Control
nals are turned ON for 80
ms or longer at the same
time.
T5-5-16
TROUBLESHOOTING / Troubleshooting A
Symptoms in Machine Operation When Trouble Occurs
Remedy
As travel speed is calculated at the middle shaft sensor, Retrial B
there is no influence on the machine. Travel speed moves Check Harness
over about 2 km/h when shifting the gears.
Replace Travel Speed Sensor
Replace MC
As travel speed is calculated at the middle shaft sensor,
there is no influence on the machine. Travel speed moves
over about 2 km/h when shifting the gears.
As travel speed rate becomes 0, torque decrease control is
disabled and base torque control is operable. Work efficiency and fuel consumption may become bad. There may
be some shock when shifting the gears.
Retrial B
Check Harness
Replace Travel Speed Sensor
Retrial B
Check Harness
Replace Torque Converter Output Speed Sensor
Replace MC
As backup travel speed calculation is disabled, travel Retrial B
speed is not displayed in case of the abnormal travel speed Check Harness
sensor.
Replace Transmission Middle Shaft Sensor
Replace MC
As the forward/reverse lever is forcibly turned to neutral in Retrial B
case of the abnormal forward/reverse lever, the machine Check Harness
cannot start.
Replace Forward/Reverse Lever
Replace MC
The forward/reverse lever only is operable in case of the Retrial B
abnormal forward/reverse switch.
Check Harness
Replace Forward/Reverse Switch
Replace MC
T5-5-17
TROUBLESHOOTING / Troubleshooting A
CAN Data Reception Failure
Fault
Trouble
Cause
Code
11910-2 Actual Engine Speed Receive Faulty Harness
Error
Faulty ECM
Received from ECM
11914-2
Radiator Coolant Temperature Faulty Harness
Receive Error
Faulty Monitor Unit
Received from Monitor Unit
11920-2
Fuel Flow Rate Receive Error
Received from ECM
Faulty Harness
Faulty ECM
T5-5-18
Influenced Control
Transmission Control
(Error judgment of
pulse sensor)
engine
Hydraulic Drive Fan Cooling
Control
TROUBLESHOOTING / Troubleshooting A
Symptoms in Machine Operation When Trouble Occurs
Remedy
Error of the torque converter input speed sensor cannot be Retrial B
judged.
Check CAN Communication Line
Replace Engine Speed Sensor
Replace MC
As the fan rotation is always kept at maximum, the machine Retrial B
starts slowly.
Check CAN Communication Line
Fuel consumption becomes bad.
Replace Monitor Unit
Replace MC
The fuel consumption is not displayed on the monitor.
T5-5-19
Retrial B
Check CAN Communication Line
Replace ECM
Replace MC
TROUBLESHOOTING / Troubleshooting A
Other Failures
Fault
Trouble
Cause
Code
11901-3 Hydraulic
Oil
Temperature Voltage: 4.52 V or higher
Sensor High Voltage
11901-4
Hydraulic
Oil
Temperature Voltage: Less than 0.23 V
Sensor Low Voltage
T5-5-20
Influenced Control
Auto-Warming Up Control
Hydraulic Drive Fan Cooling
Control
Auto-Warming Up Control
Hydraulic Drive Fan Cooling
Control
TROUBLESHOOTING / Troubleshooting A
Symptoms in Machine Operation When Trouble Occurs
Remedy
When temperature is low (hydraulic oil temperature is 0 °C
(32 °F) or less), the auto-warming up control is inoperable.
Fuel consumption becomes bad.
The hydraulic oil temperature calculating part is kept at
maximum.
Retrial B
Check Harness
Replace Hydraulic Oil Temperature Sensor
Replace MC
When temperature is low (hydraulic oil temperature is 0 °C
(32 °F) or less), the auto-warming up control is inoperable.
Fuel consumption becomes bad.
The hydraulic oil temperature calculating part is kept at
maximum.
Retrial B
Check Harness
Replace Hydraulic Oil Temperature Sensor
Replace MC
T5-5-21
TROUBLESHOOTING / Troubleshooting A
ECM FAULT CODE LIST
Sensor System
Fault
Trouble
Code
636-2
Abnormal Cam Angle Sensor (No Signal)
Cause
Although the crank signal is present, the cam signal is
not present.
636-2
Abnormal Cam Angle Sensor (Abnormal The pulse of cam signal is not matched.
Signal)
723-2
Abnormal Crank Speed Sensor (No Signal)
Abnormal Crank Speed Sensor (Abnormal Signal)
Phase Mismatch of Cam Angle Sensor
723-2
636-7
172-3
172-4
110-3
Although the cam signal is present, the crank signal is
not present.
The pulse of crank signal is not matched.
The right cam pulse is not present at the gap in the
crank.
Abnormal Intake-Air Temperature Sensor Voltage at the intake-air temperature sensor is beyond
(Abnormal High Voltage)
4.95 V in 3 minutes after the engine starts.
Abnormal Intake-Air Temperature Sensor Voltage at the intake-air temperature sensor is below
(Abnormal Low Voltage)
0.1 V.
Abnormal Coolant Temperature Sensor Voltage at the coolant temperature sensor is beyond
(Abnormal High Voltage)
4.85 V in 3 minutes after the engine starts.
110-4
Abnormal Coolant Temperature Sensor Voltage at the coolant temperature sensor is below 0.1
(Abnormal Low Voltage)
V.
102-4
Abnormal Boost Pressure Sensor (Abnormal High Voltage)
Abnormal Boost Pressure Sensor (Abnormal Low Voltage)
Abnormal EGR Position (Brushless
spec.)
102-3
10001-3
108-4
108-3
174-3
174-4
Abnormal Atmospheric Pressure Sensor
(Abnormal High Voltage)
Abnormal Atmospheric Pressure Sensor
(Abnormal Low Voltage)
Abnormal Fuel Temperature Sensor (Abnormal High Voltage)
Abnormal Fuel Temperature Sensor (Abnormal Low Voltage)
Voltage at the boost pressure sensor is beyond 4.9 V.
Voltage at the boost pressure sensor is below 0.1 V
The condition which the output signal of EGR position
cannot be present in.
Voltage at the atmospheric pressure sensor is beyond
3.8 V.
Voltage at the atmospheric pressure sensor is below
0.5 V.
Voltage at the fuel temperature sensor is beyond 4.85
V in 3 minutes after the engine starts.
Voltage at the fuel temperature sensor is below 0.1 V.
T5-5-22
TROUBLESHOOTING / Troubleshooting A
Fault Code
(Tech 2)
While the engine runs, there is nothing abnormal While the engine runs, operate according P0340
with machine operation.
to standard of the crank sensor. When the
After the engine is stalled, the re-start is impossible. engine stops, the start is impossible (in
order to prevent the engine from damag- P0341
ing).
The output power may decrease, white smoke may Operate according to standard of the cam P0335
occur and vibration may occur.
sensor.
The engine may be stalled. (If the cam senor is
P0336
normal, the engine can re-start.)
Presumptive Symptoms in Real Machine Operation
Assumptive Conditions at Backup
While the engine runs, there is nothing abnormal The timing chain and the belt does not
with machine operation.
turn smoothly but turn in reverse.
After the engine is stalled, the re-start is impossible.
Nothing special
When starting: -10 °C (14 °F) (Start the
engine although what state.)
When operating: 25 °C (77 °F) (Operate
normally.)
Normal temperature: When starting, dark smoke When starting: -20 °C (-4 °F) (Start the
may occur and engine combustion sound may be- engine although what state.)
come loud.
When operating: 80 °C (176 °F) (Operate
While warming up with fresh air in low temperature: normally.)
Rough idle, engine stall or while smoke may occur.
Dark smoke occurs.
Boost pressure cannot be corrected.
P1345
P0113
P0112
P0118
P0117
P0238
P0237
There is influence to exhaust gas.
Dark smoke occurs at high altitude.
Nothing special
As the sensor input is not certain, it cannot P0487
be controlled. Exhaust gas becomes bad.
Operate the engine with EGR valve fully
close.
Atmospheric pressure 80 kPa (0.8 P0108
kgf/cm2, 12 psi) (2000 m above the sea)
O0107
When starting: -20 °C (-4 °F) (Start the P0183
engine although what state.)
When operating: 70 °C (158 °F) (Operate P0182
normally.)
T5-5-23
TROUBLESHOOTING / Troubleshooting A
Fault
Code
157-3
157-4
100-4
100-3
105-3
105-4
Trouble
Cause
Abnormal Common Rail Pressure
(Abnormal High Voltage)
Abnormal Common Rail Pressure
(Abnormal Low Voltage)
Abnormal Engine Oil Pressure
(Abnormal High Voltage)
Abnormal Engine Oil Pressure
(Abnormal Low Voltage)
Abnormal Boost Temperature
(Abnormal High Voltage)
Sensor Voltage at the common rail pressure sensor is beyond
4.5 V.
Sensor Voltage at the common rail pressure sensor is below
0.7 V.
Sensor Voltage at the engine oil pressure sensor is beyond
4.85 V.
Sensor Voltage at the engine oil pressure sensor is below 0.1
V.
Sensor Voltage at the boost temperature sensor is beyond
4.95 V over 5 minutes after the engine starts or when
coolant temperature is beyond 50 °C (122 °F).
Abnormal Boost Temperature Sensor Voltage at the boost temperature sensor is below 0.1
(Abnormal Low Voltage)
V.
T5-5-24
TROUBLESHOOTING / Troubleshooting A
Presumptive Symptoms in Real Machine Operation
Assumptive Conditions at Backup
The engine may be stalled. The output power de- The supply pump can not be controlled.
creases.
Fault Code
(Tech 2)
P0193
P0192
There is no influence when operating the machine.
Nothing special
P0523
P0522
There is no influence when operating the machine.
Nothing special
P1113
P1112
T5-5-25
TROUBLESHOOTING/ Troubleshooting A
Fault Code
636-2
636-2
723-2
723-2
636-7
172-3
172-4
110-3
110-4
102-4
102-3
10001-3
108-4
108-3
174-3
174-4
157-3
157-4
Influence to Engine
Performance
(Presumption)
Abnormal Cam Angle Sensor (No No influence during
operation
Signal)
Abnormal Cam Angle Sensor After stopping, the
re-start is impossible.
(Abnormal Signal)
output
power
Abnormal Crank Speed Sensor (No No
decrease
Signal)
Abnormal Crank Speed Sensor
(Abnormal Signal)
Phase Mismatch of Cam Angle No influence during
Sensor
operation
After stopping, the
re-start is impossible.
output
power
Abnormal Intake-Air Temperature No
decrease
Sensor (Abnormal High Voltage)
Abnormal Intake-Air Temperature
Sensor (Abnormal Low Voltage)
output
power
Abnormal
Coolant
Temperature No
decrease
Sensor (Abnormal High Voltage)
Abnormal
Coolant
Temperature
Sensor (Abnormal Low Voltage)
output
power
Abnormal Boost Pressure Sensor No
decrease
(Abnormal High Voltage)
Abnormal Boost Pressure Sensor
(Abnormal Low Voltage)
Abnormal EGR Position (Brushless No
output
power
spec.)
change
output
power
Abnormal Atmospheric Pressure No
decrease
Sensor (Abnormal High Voltage)
Abnormal Atmospheric Pressure
Sensor (Abnormal Low Voltage)
output
power
Abnormal Fuel Temperature Sensor No
decrease
(Abnormal High Voltage)
Abnormal Fuel Temperature Sensor
(Abnormal Low Voltage)
power
Abnormal Common Rail Pressure Output
decrease: 70%
Sensor (Abnormal High Voltage)
Abnormal Common Rail Pressure
Sensor (Abnormal Low Voltage)
Trouble
T5-5-26
Operating Rank
(Current State)
A B C D
○
○
○
○
○
○
○
○
○
○
○
○
○
○
○
○
○
○
○
○
○
Remark
TROUBLESHOOTING/ Troubleshooting A
Fault Code
100-4
100-3
105-3
105-4
Influence to Engine
Operating Rank
Performance
(Current State)
(Presumption)
A B C D
output
power
Abnormal Engine Oil Pressure No
○
change
Sensor (Abnormal High Voltage)
Abnormal Engine Oil Pressure
○
Sensor (Abnormal Low Voltage)
Abnormal
Boost
Temperature
○
Sensor (Abnormal High Voltage)
Abnormal
Boost
Temperature
○
Sensor (Abnormal Low Voltage)
Trouble
Operating Rank
A: Digging and travel are operable. (A few
performance decreases may occur.)
B: Machine can travel on flat and downward slope.
C: The engine can stop / start.
D: The engine cannot stop / start.
IMPORTANT: When fault code 723-2 (abnormal
crank speed sensor) is displayed
and the engine does not start, the
cam angle sensor is faulty although
fault codes 636-2 (abnormal cam
angle sensor) and 636-7 (phase
mismatch of cam angle sensor) are
not displayed.
T5-5-27
Remark
TROUBLESHOOTING/ Troubleshooting A
External Device System
Fault Code
Trouble
Cause
10002-2
Abnormal EGR valve control
Difference between the target valve lift and actual position is
beyond 20%.
1347-0
Open circuit in suction control valve The suction control valve drive current is beyond 2400 mA or
drive system, Shorted circuit in + B or below 50 mA. Or, difference between the tartget current and
GND
actual current is 1000 mA or more.
651-3
Open circuit in injection nozzle #1 No monitor input signal of injector 1.
drive system
652-3
Open circuit in injection nozzle #2 No monitor input signal of injector 2.
drive system
653-3
Open circuit in injection nozzle #3 No monitor input signal of injector 3.
drive system
654-3
Open circuit in injection nozzle #4 No monitor input signal of injector 4.
drive system
655-3
Open circuit in injection nozzle #5 No monitor input signal of injector 5.
drive system
656-3
Open circuit in injection nozzle #6 No monitor input signal of injector 6.
drive system
987-3
Abnormal check engine lamp
No monitor signal of the check engine lamp
1485-2
Abnormal main relay system
Voltage in the main relay system is 1 V or less with the main
relay coil output ON.
Although the main relay coil output is turned OFF, the main
relay is kept ON.
T5-5-28
TROUBLESHOOTING/ Troubleshooting A
Presumptive Symptoms in Real Machine
Operation
Assumptive Conditions at Backup
Fault Code
(Tech 2)
There is influence to exhaust gas.
EGR cannot be controlled.
As exhaust gas becomes bad, EGR stops.
P0488
The engine may be stalled and the rotation
speed increases automatically and abnormally
according to open or shorted circuitc ondition.
Dark smoke occurs. Output power is too large.
The supply pump cannot be controlled.
→ Prevent the engine from increasing the rotation
speed automatically and abnormally (Protect the
engine).
P0090
Vibration of the engine is large, Rough idle, #1 injector cannot be controlled.
output power decrease, faulty increasing of → Stop drive pulse output of #1 injector.
rotation speed, output power decrease
#2 injector cannot be controlled.
→ Stop drive pulse output of #2 injector.
P0201
#3 injector cannot be controlled.
→ Stop drive pulse output of #3 injector.
P0203
#4 injector cannot be controlled.
→ Stop drive pulse output of #4 injector.
P0204
#5 injector cannot be controlled.
→ Stop drive pulse output of #5 injector.
P0205
#6 injector cannot be controlled.
→ Stop drive pulse output of #6 injector.
P0206
There is no influence when operating the Nothing special
machine.
The engine cannot start.
P0202
P0650
Nothing
Electrical power is kept supplying to the Nothing
machine.
T5-5-29
P1625
TROUBLESHOOTING/ Troubleshooting A
Fuel System
Fault Code
Trouble
Cause
rail
pressure Common rail pressure is beyond 185 Mpa (1887 kgf/cm2,
26895 psi).
157-0
Abnormal common
(First stage)
157-0
Abnormal commo rail pressure
(Second stage)
The first stage “Abnormal common rail presure” is approve
and common rail pressure is beyond 190 Mpa (1938 kgf/cm2,
27622 psi)..
157-2
Abnormal common rail pressure
(Pump over-pressure)
When DUTY to the suction control valve is 40 % or more, or
target pressure to the suction control valve is 90 mm3/sec or
less, actual rail pressure is 40 MPa (410 kgf/cm2, 5820 psi)
higher than the target rail pressure.
633-7
Pressure limiter open
The pressure limiter is open.
1239-1
No pressure to pump (Fuel leakage) When pressure to the suction control valve is 900 min-1 (900
rpm) or more, actual rail pressure is 15Mpa (150 kgf/cm2,
2180 psi) or less.
T5-5-30
TROUBLESHOOTING/ Troubleshooting A
Presumptive Symptoms in Real Machine
Operation
Assumptive Conditions at Backup
Fault Code
(Tech 2)
Vibration of the engine may be large, Rough idle, Prevention the injection system (pump) from
output power decrease may occur,
faulty damage
increasing of rotation speed, dark smoke may (Protect the RP sensor by over-pressure)
occur, output power may be too large.
P0088
Vibration of the engine may be large, Rough idle, Prevention the injection system from damage
output power decrease may occur,
faulty (Pressure is too much as PR is clogged.)
increasing of rotation speed, dark smoke may
occur, output power may be too large.
P0088
Vibration of the engine may be large, Rough idle, Prevention the injection system (pump) from
output power decrease may occur,
faulty damage
increasing of rotation speed, dark smoke may (Protect the RP sensor by over-pressure)
occur, output power may be too large.
P0089
Output power decrease
P1095
Rial pressure is beyond the allowable pressure.
Vibration of the engine may be large, Rough idle, Fuel leakage is too much.
output power decrease may occur, faulty Actual rail pressure does not increase to the
increasing of rotation speed, dark smoke may required pressure.
occur, output power may be too large.
T5-5-31
P0087
P1093
TROUBLESHOOTING/ Troubleshooting A
Fault
Code
Influence to Engine
Performance
(Presumption)
Trouble
Operating Rank
(Current)
A
B
C
10002-2 Abnormal EGR valve control
1347-0
651-3
652-3
653-3
654-3
655-3
656-3
987-3
1485-2
Fault
Code
157-0
157-0
157-2
633-7
1239-1
No
output
power
○
change
Open circuit in suction control valve Output
power
drive system, Shorted circuit in + B or decrease: 50%
GND
○
Open circuit in PCV1 drive system,
shorted circuit in GND
power
Open circuit in injection nozzle # 1 Output
○
decrease: 15%
drive system
Open circuit in injection nozzle # 2 (Five cylinders drive.)
○
drive system
Open circuit in injection nozzle # 3
○
drive system
Open circuit in injection nozzle # 4
○
drive system
Open circuit in injection nozzle # 5
○
drive system
Open circuit in injection nozzle # 6
○
drive system
Abnormal check engine lamp
No
output
power
○
change
Abnormal main relay system
The engine stops.
Nothing (The engine
cannot
re-start
○
according to battery
voltage.)
Remark
D
Influence to Engine
Performance
(Presumption)
Trouble
Abnormal common rail pressure (First Output
stage)
decrease: 50%
Abnormal common rail pressure
Output
(Second stage)
decrease: 50%
Abnormal common rail pressure
Output
(Pump over-pressure)
decrease: 50%
Pressure limiter open
Output
decrease: 50%
No pressure to pump (Fuel leakage)
Operating Rank
A: Digging and travel are operable. (A few
performance decreases may occur.)
B: Machine can travel on flat and downward slope.
C: The engine can stop / start.
D: The engine cannot stop / start.
T5-5-32
power
power
power
power
○
○
Operating Rank
(Current)
A
B
○
○
○
○
○
C
D
Remark
TROUBLESHOOTING/ Troubleshooting A
(Blank)
T5-5-33
TROUBLESHOOTING/ Troubleshooting A
Engine Protection System
Fault Code
Trouble
110-0
Overheating
190-0
Overrunning
Cause
Coolant temperature is beyond 120 °C (248 °F) when
operating the engine.
In case the engine speed is beyond 2500 min-1 (2500 rpm)
T5-5-34
TROUBLESHOOTING/ Troubleshooting A
Presumptive Symptoms in Real Machine
Fault Code
Assumptive Conditions at Backup
Operation
(Tech 2)
There is no influence when operating the Nothing special (The history of overheating is
P1173
machine.
recorded.)
Engine speed of the wheel loader may not Mistake of gear change, etc.
P0219
increase 2500 min-1 (2500 rpm) or more.
T5-5-35
TROUBLESHOOTING/ Troubleshooting A
Fault
Code
Influence to Engine
Performance
(Presumption)
Trouble
110-0
Overheating
190-0
Overrunning
No
output
change
No
output
decrease
Operating Rank
A: Digging and travel are operable. (A few
performance decreases may occur.)
B: Machine can travel on flat and downward slope.
C: The engine can stop / start.
D: The engine cannot stop / start.
T5-5-36
power
power
Operating Ranke
(Current)
A
○
○
B
C
D
Remark
TROUBLESHOOTING/ Troubleshooting A
(Blank)
T5-5-37
TROUBLESHOOTING/ Troubleshooting A
Internal Circuit System
Fault Code
Trouble
Cause
10005-1
Abnormal Charge Circuit (Bank 1)
In case voltage at bank 1 of charge circuit in ECM is low
10006-1
Abnormal Charge Circuit (Bank 2)
In case voltage at bank 2 of charge circuit in ECM is low
10008-2
1077-2
Abnormal A/D Converter (Analog to A/D conversion (analog to digital) cannot be done.
Digital)
Abnormal CPU
Within 100 msec after the key switch is turned ON, failure of
main CPU is detected by sub CPU.
(Sub CPU resets CPU.)→CPU is recovered.
Within 100 msec after the key switch is turned ON, failure of
main CPU is detected by sub CPU.
(Sub CPU resets CPU.)→CPU is not recovered.
Abnormal IC for CPU Watching
No change of RUN-SUB pulse in 20 msec
628-2
Abnormal ROM
ROM is broken.
10013-2
Abnormal EEPROM
EEPROM is broken.
1079-2
Abnormal 5 V Power Source 1
Voltage
Abnormal 5 V Power Source 2
Voltage
Abnormal 5 V Power Source 3
Voltage
Abnormal 5 V Power Source 4
Voltage
Abnormal 5 V Power Source 5
Voltage
Abnormal Injection Nozzle Common
1 Drive System
Abnormal Injection Nozzle Common
2 Drive System
When battery voltage is between 16 V and 32 V, voltage
IGKEY power source is 5.5 V or more or 4.5 V or less.
When battery voltage is between 16 V and 32 V, voltage
IGKEY power source is 5.5 V or more or 4.5 V or less.
When battery voltage is between 16 V and 32 V, voltage
IGKEY power source is 5.5 V or more or 4.5 V or less.
When battery voltage is between 16 V and 32 V, voltage
IGKEY power source is 5.5 V or more or 4.5 V or less.
When battery voltage is between 16 V and 32 V, voltage
IGKEY power source is 5.5 V or more or 4.5 V or less.
No monitor input signals of injectors 1, 3, 5
10007-2
1080-2
10009-2
10010-2
10011-2
10003-2
10004-2
No monitor input signals of injectors 2, 4, 6
T5-5-38
of
of
of
of
of
TROUBLESHOOTING/ Troubleshooting A
Presumptive Symptoms in Real Machine
Operation
Vibration of the engine may be large, Rough idle,
output power decrease may occur, faulty
increasing of rotation speed may occur, the
engine may be stalled.
The injector cannot be controlled.
→ Stop output of drive signal at broken common
side
(Protect the engine from damage)
Output power decrease, dark smoke occurs.
All analogue sensor cannot be used.
P1630
Output power decrease
CPU is broken.
P0606
Assumptive Conditions at Backup
The engine cannot start.
Fault Code
(Tech 2)
P0611
P0612
P0606
Output power decrease
Sub CPU is broken.
P0606
The engine stops.
Data of ROM cannot be read.
P1601
There is no influence when operating the Data cannot be written to EEPROM.
machine.
Same as Abnormal accelerator sensor
←
P1603
Same as Abnomal atmospheric and in-take
temperature sensors
Same as Abnomal coolant temperature, fuel
temperature and hydraulic oil pressure sensors
Same as Abnomal boost pressure and boost
temperature sensors
Same as Abnomal rail pressure and EGR
position sensors
Vibration of the engine may be large, Rough idle,
output power decrease may occur, faulty
increasing of rotation speed may occur, the
engine may be stalled.
←
P1632
←
P1633
←
P1634
←
P1635
The injector cannot be controlled.
→ Stop output of drive signal at broken common
side
(Protect the engine from damage)
P1261
T5-5-39
P1631
P1262
TROUBLESHOOTING/ Troubleshooting A
Fault Code
Trouble
10005-1
10006-1
Abnormal Charge Circuit (Bank 1)
Abnormal Charge Circuit (Bank 2)
10008-2
Abnormal A/D Converter
10007-2
Abnormal CPU
1077-2
Abnormal IC for CPU watching
628-2
10013-2
Abnormal ROM
Abnormal EEPROM
1079-2
1080-2
Abnormal 5 V Power Source 1 Voltage
Abnormal 5 V Power Source 2 Voltage
10009-2
Abnormal 5 V Power Source 3 Voltage
10010-2
Abnormal 5 V Power Source 4 Voltage
10011-2
Abnormal 5 V Power Source 5 Voltage
10003-2
Abnormal Injection Nozzle Common 1
Drive System
Abnormal Injection Nozzle Common 2
Drive System
10004-2
Influence to Engine
Performance
(Presumption)
Output
power
decrease: 60%
(Three cylinders drive.)
Output
power
decrease: 50%
Output
power
decrease: 50%
The engine cannot
start.
Output
power
decrease: 50%
The engine stops.
No
output
power
decrease
Idle speed operation
No
output
power
decrease
No
output
power
change
No
output
power
decrease
Output
power
decrease: 50%
Output
power
decrease: 60%
(Three cylinders drive.)
Operating Rank
A: Digging and travel are operable. (A few
performance decreases may occur.)
B: Machine can travel on flat and downward slope.
C: The engine can stop / start.
D: The engine cannot stop / start.
T5-5-40
Operating Rank
(Current)
A B C D
○ ○
○ ○
○
○
○
○
○
○
○
○
○
○
○ ○
○ ○
○ ○
Remark
TROUBLESHOOTING/ Troubleshooting A
(Blank)
T5-5-41
TROUBLESHOOTING/ Troubleshooting A
Communication System
Fault Code
Trouble
Cause
639-2
Abnormal CAN Bus Line
Detect the bus line off.
639-3
Abnormal CAN Time Out
In case the CAN data reception is not approved in
prescribedtime
T5-5-42
TROUBLESHOOTING/ Troubleshooting A
Presumptive Symptoms in Real Machine
Operation
Speed is turnd into idle speed.
Assumptive Conditions at Backup
CAN communication is inoperable.
Fault Code
(Tech 2)
U2104
U2106
T5-5-43
TROUBLESHOOTING/ Troubleshooting A
Fault
Code
Trouble
639-2
639-3
Abnormal CAN Bus Line
Abnormal CAN Time Out
Influence to Engine
Performance
(Presumption)
Idle speed
Operating Rank
A: Digging and travel are operable. (A few
performance decreases may occur.)
B: Machine can travel on flat and downward slope.
C: The engine can stop / start.
D: The engine cannot stop / start.
T5-5-44
Operating Rank
(Current)
A B C D
○
○
Remark
TROUBLESHOOTING/ Troubleshooting A
(Blank)
T5-5-45
TROUBLESHOOTING/ Troubleshooting A
ICF FAULT CODE LIST
Fault Code
14000-2
14001-2
Trouble
Cause
Abnormal CAN Communication
Data cannot be received due to the noise on the CAN bus
line.
ICF: Flash Memory: Read / Write In case the internal memory is abnormal when the key is
Error
turned ON
14002-2
ICF: External RAM: Read / Write In case the internal memory is abnormal when the key is
Error
turned ON
14003-2
ICF: EEPROM: Sum Check Error
14006-2
14008-2
In case the internal memory is abnormal when the key is
turned ON
ICF:
Satellite
Communication In case communication to the satellite terminal cannot be
Terminal: Communication Error
done over 30 seconds.
ICF: Abnormal Internal RAM
In case the internal memory is abnormal when the key is
turned ON
T5-5-46
TROUBLESHOOTING/ Troubleshooting A
Remedy
If trouble is not resolved after retrial B, check for CAN communication bus line.
After initializing the information C/U by using Dr. ZX, re-try in the troubleshooting.
If the error code is displayed after re-try, ICF may be broken.
Replace ICF.
NOTE: When initialising the information C/U, all stored data is deleted.
After initializing the information C/U by using Dr. ZX, re-try in the troubleshooting.
If the error code is displayed after re-try, ICF may be broken.
Replace ICF.
NOTE: When initialising the information C/U, all stored data is deleted.
If trouble is not resolved after retrial B, ICF may be broken. Replace ICF.
Check for the items below.
1. Retrial B.
2. Check if the communication line is abnormal.
3. Check if the electrical power source of communication terminal is abnormal.
• Electrical power source
• Fuses
3. Check if the satellite terminal is broken.
Re-try in the troubleshooting by using Dr.ZX.
If the error code is displayed after re-try, ICF may be broken. Replace ICF.
T5-5-47
TROUBLESHOOTING/ Troubleshooting A
SATELLITE TERMINAL FAULT CODE LIST
Fault Code
14100-2
14101-2
14102-2
Trouble
Cause
Satellite Communication Terminal: In case internal memory is abnormal
Abnormal EEPROM
Satellite Communication Terminal: In case internal memory is abnormal
Abnormal IB/OB Queue
Satellite Communication Terminal: In case data cannot be received from the satellite terminal
Abnormal Local Loup Back
14103-2
Satellite Communication Terminal: In case the satellite terminal cannot be acquired
The satellite is not found.
14104-2
Satellite Communication Terminal:
Fail 1 of Remote Loup Back
Satellite Communication Terminal:
Fail 2 of Remote Loup Back
Satellite Communication Terminal:
Sending and receiving data are
unmatched.
14105-2
14106-2
In case communication to the satellite terminal base cannot
be done
In case communication to the satellite terminal base cannot
be done
In case sending and receiving data are unmatched
T5-5-48
TROUBLESHOOTING/ Troubleshooting A
Remedy
Retrial B.
Replace the ICF controller.
Retrial B.
Replace the ICF controller.
Retrial B.
Check the communication aerial.
Replace the ICF controller.
Retrial B.
Check the communication aerial.
Replace the ICF controller.
Retrial B.
Replace the ICF controller.
Retrial B.
Replace the ICF controller.
Retrial B.
Replace the ICF controller.
T5-5-49
TROUBLESHOOTING/ Troubleshooting A
MONITOR UNIT FAULT CODE LIST
Fault Code
Trouble
Cause
13306-2
13308-2
13312-2
Abnormal EEPROM
Abnormal CAN Communication
Abnormal
Transmission
Oil
Temperature Sensor
Service Brake Pressure Sensor High
Voltage
Service Brake Pressure Sensor Low
Voltage
When failure reading EEPROM occurs
Bus off occurs beyond five times
Shorted ground circuit in the transmission oil temperature
sensor
Voltage at the signal line in service brake pressure sensor:
4.75 V or higher
Voltage at the signal line in service brake pressure sensor:
0.25 or less
13314-3
13314-4
T5-5-50
TROUBLESHOOTING / Troubleshooting A
CONTROLLER HARDWARE FAILURE
MC FAULT CODES 11000 to 11002
Fault Code
11000-2
11001-2
11002-2
Trouble
Abnormal EEPROM
Abnormal RAM
Abnormal A/D Converter
Cause
Faulty MC
Faulty MC
Faulty MC
YES
Influenced Control
All Control
All Control
All Control
*Normal.
Check if operation of machine
is normal.
Faulty MC.
NO
* When the fault code is displayed in the result of
retrial and If operation of engine or machine is
normal, the machine can be used.
T5-5-51
TROUBLESHOOTING / Troubleshooting A
MC FAULT CODE 11003
Fault Code
11003-3
Trouble
Abnormal Sensor Voltage
Cause
Shorted circuit in harness
Faulty sensor
Faulty MC
Influenced Control
All Control
YES
Disconnect connectors of
all sensors corresponding
to the displayed fault code
and connector monitor-1B
in monitor unit. Retry.
Check if fault code
11003-3 disappears.
NO
Faulty any sensors.
Disconnect all connectors at
MC end.
Check for continuity
between terminals #1 and
#3 of harness end
connector of each sensor to
MC, terminal #1 and vehicle
frame.
Check for continuity
between terminals #27 and
#32 of connector
monitor-1B in monitor unit,
each terminal #27, #28,
#29, #30 or #31 and vehicle
frame.
YES
Shorted circuit in harness with
continuity.
Faulty MC or faulty monitor
unit.
NO
· Key switch: OFF
Connector (Harness end of connector viewed from the
open end side)
• Parking Brake Pressure Sensor
1
2
• Pump Delivery Pressure Sensor
• Implement Pressure Sensor
3
3
Monitor Unit
Connector Monitor-1B
(Harness end)
#27
#28
T4GB-05-05-002
#32 #31 #30 #29
T5-5-52
2
1
TROUBLESHOOTING / Troubleshooting A
MC FAULT CODE 11004
Fault Code
11004-2
Trouble
Cause
Abnormal
CAN Shorted
circuit
Communication
harness
Faulty MC
in
•
•
•
•
•
•
Influenced Control
All Pump Control
All Transmission Control
All Engine Control
Hydraulic Drive Fan Cooling Control
Ride Control
CAN Cycle Data Communication
GPS
Monitor Unit
Dr-ZX
ICF
ECM
CAN Harness
MC
T5-5-53
TROUBLESHOOTING / Troubleshooting A
CAN HARNESS CHECK
• Check the wiring connections first.
NO
YES Check for continuity in
CAN harness between
MC and ECM.
YES
· Key switch: OFF
· Refer to “CAN
Harness Continuity
Check” on T5-5-58.
Check for continuity in
CAN harness between
MC and ICF.
· Key switch: OFF
· Refer to “CAN
Harness Continuity
Check” on T5-5-59.
Retry by using Dr. ZX.
Check if fault code
11004-2 is displayed.
NO
Open circuit in CAN
harness between MC and
ECM.
Check for continuity
in CAN harness
YES between MC and
monitor unit.
· Key Switch: OFF
· Refer to “CAN
Harness Continuity
Check” on T5-5-60.
Open circuit in CAN
harness between MC and
ICF.
Normal.
NO
IMPORTANT: If the CAN harness is completely
opened in circuit, the controller
name is not displayed on the
diagnosing screen on Dr. ZX (refer to
T5-2-4).
T5-5-54
TROUBLESHOOTING / Troubleshooting A
Shorted circuit in CAN
harness between ground
circuit and CAN circuit.
YES
YES
Disconnect all
connectors in MC,
ICF, ECM and
monitor unit.
Check for continuity
between CAN circuit
and ground circuit in
MC, ICF, ECM and
monitor unit.
· Key switch: OFF
· Refer to “Discontinuity
Check between CAN
Circuit and Ground
Circuit” on T5-5-61 to
65.
To A
NO
Open circuit in CAN
harness between MC and
monitor unit.
NO
Shorted circuit in CAN
harness between power
circuit and CAN circuit.
YES
A
Check for continuity
between CAN circuit
and power circuit in
MC, ICF, ECM and
monitor unit.
· Key switch: OFF
· Refer to “Discontinuity
Check between CAN
Circuit and Power
Circuit” on T5-5-66 to
69.
NO
T5-5-55
Check for continuity
between CAN circuit
and key signal circuit
in MC, ICF, ECM and
monitor unit.
YES Shorted circuit in CAN
harness between key signal
circuit and CAN circuit.
NO
· Key switch: OFF
· Refer to “Discontinuity
Check between CAN
Circuit and Key Signal
Circuit” on T5-5-70 to
72.
Check for continuity
between High side
and Low side in CAN
harness.
· Key switch: OFF
· Refer to
“Discontinuity Check
in CAN Harness on
T5-5-73.
To B
TROUBLESHOOTING / Troubleshooting A
Shorted circuit in
CAN harness.
YES
B
Connect connector
YES in MC.
Check if fault code
11004-2 is
displayed.
Connect all
connectors except
connector MC-C in
MC.
Check if resistance
between terminals
#C4 and #C15 of
NO harness end of
connector MC-C is
within 60±10 Ω.
· Key switch: ON
· Key switch: OFF
NO
Connect connector in
MC. Disconnect
connector ICF-C in
ICF.
Check if resistance
between terminals
#C5 and #C11 of
harness end of
connector is within
60±10 Ω.
Faulty MC.
YES
YES
NO
MC
Connector MC-C
(Harness end)
#C4
NO
Check the
connection of ICF
and connector.
Faulty ICF.
YES
Connect connector in
ICF.
Disconnect
connector in ECM.
Check if resistance
between terminals
#18 and #37 of
harness end of
connector is within
120±10 Ω.
YES
· Key switch: OFF
NO
Connect connector
in ECM. Check if
fault code 11004-2
is displayed.
· Key switch: ON
#C15
C10
C1
C23
Connect connector
in ICF.
Check if fault code
11004-2 is
displayed.
· Key switch: ON
· Key switch: OFF
Connector
Check the
connection of MC
and connector.
NO
C31
Connect connector in
ECM.
Disconnect
connector monitor-2B
in monitor unit.
Check if resistance
between terminals
#33 and #34 of
harness end of
connector is within
120±10 Ω.
· Key switch: OFF
ICF
Connector ICF-C
(Harness end)
#C5
#C11
ECM
Connector
(Harness end)
T1V1-05-04-002
Monitor Unit
Connector Monitor-2B
(Harness end)
#18
#37
T1GR-05-04-002
T5-5-56
T4GB-05-05-002
#34
#33
TROUBLESHOOTING / Troubleshooting A
Check the connection of
ECM and connector.
NO
Faulty ECM.
YES
YES
Connect connector in
monitor unit.
Check if fault code
11004-2 is displayed.
· Key switch: ON
NO
Check the connection of
monitor unit and
connector.
Faulty monitor unit.
YES
Failure in any controller
of MC, ICF, ECM and
monitor unit.
T5-5-57
TROUBLESHOOTING / Troubleshooting A
Continuity Check in CAN Harness
IMPORTANT: Before continuity check, turn the key
switch OFF.
• Between MC and ECM
CAN Harness (High Side)
Check for continuity between terminal #C4 of
harness end of connector MC-C in MC and
terminal #18 of harness end of connector in ECM.
CAN Harness (Low Side)
Check for continuity between terminal #C15 of
harness end of connector MC-C in MC and
terminal #37 of harness end of connector in ECM.
Connector
MC
Connector MC-C
(Harness end)
#C4
C1
C23
#C15
C10
C31
ECM
Connector
(Harness end)
#18
#37
T1GR-05-04-002
T5-5-58
TROUBLESHOOTING / Troubleshooting A
• Between MC and ICF
CAN Harness (High Side)
Check for continuity between terminal #C4 of
harness end of connector MC-C in MC and
terminal #C5 of harness end of connector ICF-C
in ICF.
CAN Harness (Low Side)
Check for continuity between terminal #C15 of
harness end of connector MC-C in MC and
terminal #C11 of harness end of connector ICF-C
in ICF.
Connector
MC
Connector MC-C
(Harness end)
#C4
#C15
C10
C1
C23
C31
ICF
Connector ICF-C
(Harness end)
#C5
#C11
T1V1-05-04-002
T5-5-59
TROUBLESHOOTING / Troubleshooting A
• Between MC and Monitor Unit
CAN Harness (High Side)
Check for continuity between terminal #C4 of
harness end of connector MC-C in MC and
terminal #B33 of harness end of connector
monitor-2B in the monitor unit.
CAN Harness (Low Side)
Check for continuity between terminal #C15 of
harness end of connector MC-C in MC and
terminal #B34 of harness end of connector
monitor-2B in the monitor unit.
Connector
MC
Connector MC-C
(Harness end)
#C4
#C15
C10
C1
C23
C31
Monitor Unit
Connector Monitor-2B
(Harness end)
T4GB-05-05-002
#B34
#B33
T5-5-60
TROUBLESHOOTING / Troubleshooting A
Discontinuity Check between CAN Circuit and
Ground Circuit
IMPORTANT: Before continuity check, turn the key
switch OFF.
• In case of continuity, the circuit
between CAN circuit and ground
circuit is shorted.
• In case of discontinuity, the circuit is
normal.
Connector
Connector MC-C
(Harness end)
#C4
C10
C1
C23
• MC
Between CAN Circuit (High Side) and Ground
Circuit
Check for continuity between terminal #C4 of
harness end of connector MC-C and terminal #A2
of harness end of connector in MC-A.
C31
Connector MC-A
(Harness end)
#A2
Check for continuity between terminal #C4 of
harness end of connector MC-C and terminal
#A13 of harness end of connector in MC-A.
#A13
Check for continuity between terminal #C4 of
harness end of connector MC-C and terminal #B8
of harness end of connector in MC-B.
T183-05-04-008
Connector MC-B
(Harness end)
Check for continuity between terminal #C4 of
harness end of connector MC-C and terminal
#B18 of harness end of connector in MC-B.
#B8
#B18
T183-05-04-021
T5-5-61
TROUBLESHOOTING / Troubleshooting A
Between CAN Circuit (Low Side) and Ground
Circuit
Check for continuity between terminal #C15 of
harness end of connector MC-C and terminal #A2
of harness end of connector in MC-A.
Connector
Check for continuity between terminal #C15 of
harness end of connector MC-C and terminal
#A13 of harness end of connector in MC-A.
Check for continuity between terminal #C15 of
harness end of connector MC-C and terminal #B8
of harness end of connector in MC-B.
Check for continuity between terminal #C15 of
harness end of connector MC-C and terminal
#B18 of harness end of connector in MC-B.
Connector MC-C
(Harness end)
#C15
C10
C1
C23
C31
Connector MC-A
(Harness end)
#A2
#A13
T183-05-04-008
Connector MC-B
(Harness end)
#B8
#B18
T183-05-04-021
T5-5-62
TROUBLESHOOTING / Troubleshooting A
• ECM
Between CAN Circuit (High Side) and Ground
Circuit
Check for continuity between terminals #18 and
#1 of harness end of connector.
ECM
Connector
(Harness end)
#18
#43
Check for continuity between terminals #18 and
#3 of harness end of connector.
#4
#3
Check for continuity between terminals #18 and
#4 of harness end of connector.
#62
Check for continuity between terminals #18 and
#43 of harness end of connector.
#1
T1GR-05-04-002
#81
Check for continuity between terminals #18 and
#62 of harness end of connector.
Check for continuity between terminals #18 and
#81 of harness end of connector.
Between CAN Circuit (Low Side) and Ground
Circuit
Check for continuity between terminals #37 and
#1 of harness end of connector.
ECM
Connector
(Harness end)
#37
#43
#4
Check for continuity between terminals #37 and
#3 of harness end of connector.
Check for continuity between terminals #37 and
#4 of harness end of connector.
Check for continuity between terminals #37 and
#43 of harness end of connector.
Check for continuity between terminals #37 and
#62 of harness end of connector.
Check for continuity between terminals #37 and
#81 of harness end of connector.
T5-5-63
#3
#62
#81
#1
T1GR-05-04-002
TROUBLESHOOTING / Troubleshooting A
• ICF
Between CAN Circuit (High Side) and Ground
Circuit
ICF
Connector ICF-C
(Harness end)
Check for continuity between terminals #C5 and
#C9 of harness end of connector ICF-C.
#C5
Check for continuity between terminals #C5 and
#C14 of harness end of connector ICF-C.
Check for continuity between terminals #C5 and
#C15 of harness end of connector ICF-C.
Between CAN Circuit (Low Side) and Ground
Circuit
#C14
#C15
Check for continuity between terminals #C11 and
#C15 of harness end of connector ICF-C.
T5-5-64
T1V1-05-04-002
ICF
Connector ICF-C
(Harness end)
#C9
Check for continuity between terminals #C11 and
#C9 of harness end of connector ICF-C.
Check for continuity between terminals #C11 and
#C14 of harness end of connector ICF-C.
#C9
#C14
#C15
#C11
T1V1-05-04-002
TROUBLESHOOTING / Troubleshooting A
• Monitor Unit
Between CAN Circuit (High Side) and Ground
Circuit
Check for continuity between terminal #33 of
harness end of connector monitor-2B and terminal
#19 of harness end of connector monitor-2A in the
monitor unit.
Check for continuity between terminal #33 of
harness end of connector monitor-2B and terminal
#4 of harness end of connector monitor-1A in the
monitor unit.
Monitor Unit
Connector Monitor-2B
(Harness end)
T4GB-05-05-002
#33
Monitor Unit
Connector Monitor-2A
(Harness end)
T183-05-04-013
#19
Monitor Unit
Connector Monitor-1A
(Harness end)
#4
T183-05-04-013
Between CAN Circuit (Low Side) and Ground
Circuit
Check for continuity between terminal #34 of
harness end of connector monitor-2B and terminal
#19 of harness end of connector monitor-2A in the
monitor unit.
Check for continuity between terminal #34 of
harness end of connector monitor-2B and terminal
#4 of harness end of connector monitor-1A in the
monitor unit.
Monitor Unit
Connector Monitor-2B
(Harness end)
T4GB-05-05-002
#34
Monitor Unit
Connector Monitor-2A
(Harness end)
T183-05-04-013
#19
Monitor Unit
Connector Monitor-1A
(Harness end)
#4
T183-05-04-013
T5-5-65
TROUBLESHOOTING / Troubleshooting A
Discontinuity Check between CAN Circuit and
Power Circuit
Connector
IMPORTANT: Before continuity check, turn the key
switch OFF.
• In case of continuity, the circuit
between CAN circuit and power
circuit is shorted.
• In case of discontinuity, the circuit is
normal.
Connector MC-C
(Harness end)
#C4
C1
C23
C10
C31
• MC
Between CAN Circuit (High Side) and Power
Circuit
Check for continuity between terminal #C4 of
harness end of connector MC-C and terminal #A1
of harness end connector MC-A.
#A1
Check for continuity between terminal #C4 of
harness end of connector MC-C and terminal
#A12 of harness end connector MC-A.
#A12
Connector MC-A
(Harness end)
Check for continuity between terminal #C4 of
harness end of connector MC-C and terminal #B7
of harness end connector MC-B.
T183-05-04-008
Connector MC-B
(Harness end)
#B7
Check for continuity between terminal #C4 of
harness end of connector MC-C and terminal
#B17 of harness end connector MC-B.
#B17
T183-05-04-021
T5-5-66
TROUBLESHOOTING / Troubleshooting A
Between CAN Circuit (Low Side) and Power
Circuit
Check for continuity between terminal #C15 of
harness end of connector MC-C and terminal #A2
of harness end connector MC-A.
Connector
Connector MC-C
(Harness end)
Check for continuity between terminal #C15 of
harness end of connector MC-C and terminal
#A12 of harness end connector MC-A.
C1
Check for continuity between terminal #C15 of
harness end of connector MC-C and terminal #B7
of harness end connector MC-B.
Check for continuity between terminal #C15 of
harness end of connector MC-C and terminal
#B17 of harness end connector MC-B.
C23
#C15
C10
C31
Connector MC-A
(Harness end)
#A1
#A12
T183-05-04-008
Connector MC-B
(Harness end)
#B7
#B17
T183-05-04-021
T5-5-67
TROUBLESHOOTING / Troubleshooting A
• ECM
Between CAN Circuit (High Side) and Power
Circuit
Check for continuity between terminals #18 and
#2 of harness end of connector.
ECM
Connector
(Harness end)
#18
#5
Check for continuity between terminals #18 and
#5 of harness end of connector.
T1GR-05-04-002
#2
Between CAN Circuit (Low Side) and Power
Circuit
Check for continuity between terminals #37 and
#2 of harness end of connector.
ECM
Connector
(Harness end)
#37
#5
Check for continuity between terminals #37 and
#5 of harness end of connector.
#2
• ICF
Between CAN Circuit (High Side) and Power
Circuit
Check for continuity between terminals #C5 and
#C1 of harness end of connector ICF-C.
ICF
Connector ICF-C
(Harness end)
Check for continuity between terminals #C5 and
#C2 of harness end of connector ICF-C.
#C1
#C2
T1GR-05-04-002
#C5
T1V1-05-04-002
Between CAN Circuit (Low Side) and Power
Circuit
Check for continuity between terminals #C11 and
#C1 of harness end of connector ICF-C.
ICF
Connector ICF-C
(Harness end)
#C2
Check for continuity between terminals #C11 and
#C2 of harness end of connector ICF-C.
#C1
#C11
T5-5-68
T1V1-05-04-002
TROUBLESHOOTING / Troubleshooting A
• Monitor Unit
Between CAN Circuit (High Side) and
Circuit
Check for continuity between terminal
harness end of connector monitor–2B
monitor unit and terminal #1 of harness
connector monitor–1A in the monitor unit.
Power
#33 of
in the
end of
Monitor Unit
Connector Monitor-2B
(Harness end)
#33
T4GB-05-05-002
Monitor Unit
Connector Monitor-1A
(Harness end)
#1
T183-05-04-013
Between CAN Circuit (Low Side) and Power
Circuit
Check for continuity between terminal #34 of
harness end of connector monitor–2B in the
monitor unit and terminal #1 of harness end of
connector monitor–1A in the monitor unit.
Monitor Unit
Connector Monitor-2B
(Harness end)
#34
T4GB-05-05-002
Monitor Unit
Connector Monitor-1A
(Harness end)
#1
T183-05-04-013
T5-5-69
TROUBLESHOOTING / Troubleshooting A
Discontinuity Check between CAN Circuit and
Key Signal Circuit
Connector
IMPORTANT: Before continuity check, turn the key
switch OFF.
• In case of continuity, the circuit
between CAN circuit and key signal
circuit is shorted.
• In case of discontinuity, the circuit is
normal.
Connector MC-C
(Harness end)
#C4
C10
C1
C23
• MC
Between CAN Circuit (High Side) and Key Signal
Circuit
Check for continuity between terminal #C4 of
harness end of connector MC-C and terminal
#B16 of harness end of connector MC-B.
C31
Connector MC-B
(Harness end)
#B16
T183-05-04-021
Between CAN Circuit (Low Side) and Key Signal
Circuit
Check for continuity between terminal #C15 of
harness end of connector MC-C and terminal
#B16 of harness end of connector MC-B.
Connector
Connector MC-C
(Harness end)
#C15
C1
C23
C10
C31
Connector MC-B
(Harness end)
#B16
T183-05-04-021
T5-5-70
TROUBLESHOOTING / Troubleshooting A
• ECM
Between CAN Circuit (High Side) and Key Signal
Circuit
Check for continuity between terminals #18 and
#24 of harness end of connector.
ECM
Connector
(Harness end)
#18
#24
T1GR-05-04-002
Between CAN Circuit (Low Side) and Key Signal
Circuit
Check for continuity between terminals #37 and
#24 of harness end of connector.
ECM
Connector
(Harness end)
#37
#24
T1GR-05-04-002
• ICF
Between CAN Circuit (High Side) and Key Signal
Circuit
Check for continuity between terminals #C5 and
#C7 of harness end of connector ICF-C.
ICF
Connector ICF-C
(Harness end)
#C5
#C7
T1V1-05-04-002
Between CAN Circuit (Low Side) and Key Signal
Circuit
ICF
Connector ICF-C
(Harness end)
Check for continuity between terminals #C11
and #C7 of harness end of connector ICF-C.
#C7
#C11
T5-5-71
T1V1-05-04-002
TROUBLESHOOTING / Troubleshooting A
• Monitor Unit
Between CAN Circuit (High Side) and Key Signal
Circuit
Check for continuity between terminal #33 of
harness end of connector monitor–2B in the
monitor unit and terminal #2 of harness end of
connector monitor–1A in the monitor unit.
Monitor Unit
Connector Monitor-2B
(Harness end)
T4GB-05-05-002
#33
Monitor Unit
Connector Monitor-1A
(Harness end)
#2
T183-05-04-013
Between CAN Circuit (Low Side) and Key Signal
Circuit
Check for continuity between terminal #34 of
harness end of connector monitor–2B in the
monitor unit and terminal #2 of harness end of
connector monitor–1A in the monitor unit.
Monitor Unit
Connector Monitor-2B
(Harness end)
T4GB-05-05-002
#34
Monitor Unit
Connector Monitor-1A
(Harness end)
#2
T183-05-04-013
T5-5-72
TROUBLESHOOTING / Troubleshooting A
Discontinuity Check in CAN Harness
IMPORTANT: Before continuity check, turn the key
switch OFF.
• In case of continuity, the circuit
between CAN (high side) circuit and
CAN (low side) circuit is shorted.
• In case of discontinuity, the circuit is
normal.
• Connector MC-C
Check for continuity between terminals #C4 and
#C15 of harness end of connector MC-C in MC.
MC
Connector MC-C
(Harness end)
#C4
C1
C23
#C15
C10
C31
• Connector ECM
Check for continuity between terminals #18 and
#37 of harness end of connector in ECM.
ECM
Connector
(Harness end)
#18
#37
T1GR-05-04-002
T5-5-73
TROUBLESHOOTING / Troubleshooting A
• Connector ICF-C
Check for continuity between terminals #C5 and
#C11 of harness end of connector ICF-C in ICF.
ICF
Connector ICF-C
(Harness end)
#C5
#C11
• Connector Monitor-2B in Monitor Unit
Check for continuity between terminals #B33 and
#B34 of harness end of connector monitor-2B in
the monitor unit.
Monitor Unit
Connector Monitor-2B
(Harness end)
#B34 #B33
T5-5-74
T1V1-05-04-002
T4GB-05-05-002
TROUBLESHOOTING / Troubleshooting A
ENGINE FAILURE
MC FAULT CODE 11103
Fault Code
Trouble
Cause
11103-3 Abnormal Accelerator Pedal Voltage: 4.75 V or higher
High Voltage
11103-4
Abnormal Accelerator Pedal Voltage: Less than 0.25 V
Low Voltage
Influenced Control
Pump
Torque
Decrease
Control
Engine Accelerator Pedal
Control
Pump
Torque
Decrease
Control
Engine Accelerator Pedal
Control
Open circuit in
harness between MC
and accelerator pedal
sensor (terminal #1).
NO
Disconnect connector
MC-C in MC.
Check for continuity
between terminal #C13
YES of harness end of
connector and terminal
#1 of harness end of
connector in
accelerator pedal
sensor.
Check if voltage between
terminals #2 and #6 of
harness end of connector
in accelerator pedal sensor
is 5±0.5 V.
Check if voltage
between terminal #2 of
harness end of
connector in
accelerator pedal
NO
sensor and vehicle
frame is specigication.
· Key switch: ON
With connector of
accelerator pedal sensor
connected, insert a tester YES Faulty MC.
probe into rear of
connector of terminal #1.
Operate accelerator
YES pedal.
Faulty accelerator
Check if voltage reaches
pedal sensor.
specification.
NO
· Key switch: ON
Open circuit in
YES
· Specification: Refer to
harness between MC
the table below.
and accelerator pedal
sensor (terminal #6).
· Key switch: ON
· Specification: 5±0.5 V
Specification of Accelerator Pedal Sensor
Slow Idle
0.5 to 0.65 V
Fast Idle
4.35 to 4.5 V
Connector (Harness end of connector viewed from the
open end side)
MC
Connector MC-C
#C13
C10
C1
C23
C31
Accelerator Pedal Sensor Connector
#2
#1
4
1
8
5
#6
T5-5-75
NO
Open circuit in
harness between MC
and accelerator pedal
sensor (terminal #2).
TROUBLESHOOTING / Troubleshooting A
MC FAULT CODE 11105
Fault Code
11105-3
Trouble
Cause
Influenced Control
Abnormal Torque Converter Engine speed=0 min-1
• Hydraulic rive Fan Cooling
Input Shaft Sensor
ECM engine speed>500 min-1
Control
Replace torque
converter input shaft
sensor. Start engine in
10 seconds after key
switch is turned OFF.
Travel machine 20 m.
Retry.
Check if fault code
disappears.
· Key switch: ON
Check if voltage
between terminals #1
NO of harness end of
connector in torque
converter input shaft
sensor and vehicle
frame is 5±0.5 V.
· Key switch: ON
Disconnect connector
MC-C in MC.
Check for continuity
between terminal #C16
YES of harness end of
connector and terminal
#2 of harness end of
connector in torque
converter input shaft
sensor.
NO
Disconnect connector
MC-C in MC.
Check for continuity
between terminal #C5
of harness end of
connector and terminal
#1 of harness end of
connector in torque
converter input shaft
sensor.
YES
Connector (Harness end of connector viewed from the
open end side)
MC
Connector MC-C
#C5
C10
C1
C23
#C16
C31
Torque Converter Input
Shaft Sensor Connector
#1
#2
T5-5-76
NO
Open circuit in hranees
between MC and torque
converter input shaft
sensor (terminal #2).
Faulty MC.
YES
YES Faulty MC.
NO
Open circuit in hranees
between MC and torque
converter input shaft
sensor (terminal #1).
Faulty MC and torque
converter input shaft
sensor.
TROUBLESHOOTING / Troubleshooting A
PUMP FAILURE
MC FAULT CODE 11204
Fault Code
11204-3
11204-4
Trouble
Abnormal
Pump
Delivery
Pressure Sensor High Voltage
Abnormal
Pump
Delivery
Pressure Sensor Low Voltage
Switch pump delivery
pressure sensor with
normal pressure sensor
and retry.
Check if fault code
disappears.
Cause
Influenced Control
Output voltage: 4.75 V or • Pump
Torque
Decrease
higher
Control: Disabled
Output voltage: Less than 0.25 • Pump
Torque
Decrease
V
Control: Disabled
Disconnect connector
MC-C in MC. Check for
continuity between
terminal #C2 of
YES harness end of
connector and terminal
#2 of harness end of
connector in pump
delivery pressure
sensor.
Disconnect connector
of pump delivery
pressure sensor.
NO Check if voltage
between terminals #1
and #3 of harness end
of connector is 5±0.5
V.
· Key switch: ON.
Check if voltage
between terminal #1 of
harness end of
connector in pump
delivery pressure
sensor and vehicle
frame is specification.
· Key switch: ON
· Specification: 5±0.5 V.
NO
Connector (Harness end of connector viewed from
the open end side)
Pump Delivery
Pressure Sensor
#C2
C1
C10
3
C23
Open circuit in harnees
between MC and pump
delivery pressure sensor.
Faulty MC.
YES
YES Open circuit in harness
between MC and pump
delivery pressure sensor
(terminal #3).
NO
Open circuit in harness
between MC and pump
delivery pressure sensor
(terminal #1).
Faulty pump delivery
pressure sensor.
YES
MC
Connector MC-C
NO
2
1
C31
T5-5-77
TROUBLESHOOTING / Troubleshooting A
MC FAULT CODE 11209
Fault Code
11209-3
11209-4
Trouble
Cause
Influenced Control
Abnormal Implement Pressure Output voltage: 4.75 V or • Pump
Torque
Decrease
Sensor High Voltage
higher
Control: Disabled
Abnormal Implement Pressure Output voltage: Less than 0.25 • Pump
Torque
Decrease
Sensor Low Voltage
V
Control: Disabled
Disconnect connector
MC-C in MC.
Check for continuity
YES between terminal #C12
of harness end of
connector and terminal
#2 of harness end of
connector in implement
pressure sensor.
Disconnect connector
of implement pressure
sensor.
Check if voltage
NO
between terminals #1
and #3 of harness end
of connector is 5±0.5
V.
Switch implement
pressure sensor with
normal pressure sensor
and retry.
Check if fault code
disappears.
· Key switch: ON
NO
Check if voltage
between terminal #1 of
harness end of
connector in implement
pressure sensor and
vehicle frame is
specification.
· Key switch: ON
· Specification: 5±0.5 V
Connector (Harness end of connector viewed from the
open end side)
Implement
Pressure Sensor Connector
#C12
C1
C10
3
C23
Open circuit in harnees
between MC and
implement pressure
sensor.
Faulty MC.
YES
YES Open circuit in harness
between MC and
implement pressure
sensor (terminal #3).
NO
Open circuit in harness
between MC and
implement pressure
sensor (terminal #1).
Faulty implement
pressure sensor.
YES
MC
Connector MC-C
NO
2
1
C31
T5-5-78
TROUBLESHOOTING / Troubleshooting A
PILOT FAILURE
MC FAULT CODE 11312
Fault Code
11312-3
11312-4
Trouble
Cause
Abnormal
Brake
Pedal Voltage: 4.75 V or higher
Pressure Sensor (Service
Brake Pressure Sensor) High
Voltage
Abnormal
Brake
Pedal Voltage: Less than 0.25 V
Pressure Sensor (Service
Brake Pressure Sensor) Low
Voltage
• Clutch Cut-Off Control
Disconnect connector
MC-C in MC.
Check for continuity
YES between terminal #C1
of harness end of
connector and terminal
#2 of harness end of
connector in pressure
sensor.
Disconnect connector
of pressure sensor.
Check if voltage
between terminals #1
and #3 of harness end
of connector is 5±0.5
V.
NO
Influenced Control
• Clutch Cut-Off Control
· Key switch: ON
Check if voltage
between terminal #1
of harness end of
NO connector in pressure
sensor and vehicle
frame is specification.
· Key switch: ON
· Specification: 5±0.5 V
Switch pressure sensor
with normal pressure
sensor and retry.
Check if fault code
disappears.
NO
Open circuit in harness
between MC and
pressure sensor.
Faulty MC.
YES
Open circuit in harness
YES between MC and
pressure sensor (terminal
#3).
Open circuit in harness
between MC and
NO pressure sensor (terminal
#1).
Faulty pressure sensor.
YES
Connector (Harness end of connector viewed from the
open end side)
MC
Connector MC-C
C1
Service Brake Pressure
Sensor Connector
C10
1
#C1
C23
2
3
C31
T5-5-79
TROUBLESHOOTING / Troubleshooting A
MC FAULT CODE 11313
Fault Code
11313-3
11313-4
Trouble
Abnormal
Parking
Brake
Pressure Sensor High Voltage
Abnormal
Parking
Brake
Pressure Sensor Low Voltage
Cause
Influenced Control
Output voltage: 4.75 V or • Parking Brake Indicator Control
higher
Output voltage: Less than 0.25 • Parking Brake Indicator Control
V
Disconnect connector
MC-C in MC.
Check for continuity
YES between terminal #C23
of harness end of
connector and terminal
#2 of harness end of
connector in pressure
sensor.
Disconnect connector
of pressure sensor.
Check if voltage
between terminals #1
NO and #3 of harness end
of connector is 5±0.5
V.
· Key switch: ON
Check if voltage
between terminal #1
of harness end of
NO connector in pressure
sensor and vehicle
frame is specification.
· Key switch: ON
· Specification: 5±0.5 V
Switch pressure sensor
with normal pressure
sensor and retry.
Check if fault code
disappears.
NO
Open circuit in harnees
between MC and
pressure sensor.
Faulty MC.
YES
Open circuit in harness
YES between MC and
pressure sensor (terminal
#3).
Open circuit in harness
between MC and
NO pressure sensor (terminal
#1).
Faulty pressure sensor.
YES
Connector (Harness end of connector viewed from the
open end side)
MC
Connector MC-C
C1
Parking Brake Pressure
Sensor Connector
C10
1
C23
2
3
C31
#C23
T5-5-80
TROUBLESHOOTING / Troubleshooting A
PROPORTIONAL SOLENOID VALVE FAILURE
MC FAULT CODE 11412
Fault Code
11412-2
11412-3
11412-4
Trouble
Abnormal Feedback of Hydraulic
Drive Fan Flow Rate Control
Solenoid Valve
Abnormal
Feedback
High
Current of Hydraulic Drive Fan
Flow Rate Control Solenoid
Valve
Abnormal
Feedback
Low
Current of Hydraulic Drive Fan
Flow Rate Control Solenoid
Valve
YES
Check for continuity in
harness between MC
and hydraulic drive fan
flow rate control
solenoid valve.
· Between terminal #A32
of connector MC-A in
MC and terminal #1 of
connector in hydraulic
drive fan flow rate
control solenoid valve
· Between terminal #A29
of connector MC-A in
MC and terminal #2 of
connector in hydraulic
drive fan flow rate
control solenoid valve
Cause
Influenced Control
The feedback current to MC Hydraulic Drive Fan Cooling
becomes the uncertain value. Control
The feedback current to MC is Hydraulic Drive Fan Cooling
beyond the upper limit.
Control
While the command from MC Hydraulic Drive Fan Cooling
is output, the feedback current Control
to MC is 56 mA or less.
Switch connectors of
hydraulic drive fan flow
rate control solenoid
valve and normal
solenoid valve.
Retry.
Check if fault code
disappears.
NO
Faulty hydraulic drive fan
flow rate control solenoid
valve.
Faulty MC.
YES
Open circuit in harness.
NO
Connector (Harness end of connector viewed from the
open end side)
MC
Connector MC-A
#A32
#A29
T183-05-04-008
Hydraulic Drive Fan Flow Rate
Control Solenoid Valve Connector
1
2
T5-5-81
TROUBLESHOOTING / Troubleshooting A
MC FAULT CODE 11413
Fault Code
11413-2
11413-3
11413-4
Trouble
Abnormal Feedback of Pump
Torque Control Solenoid Valve
Abnormal Feedback High
Current of Pump Torque
Control Solenoid Valve
Abnormal
Feedback
Low
Current of Pump Torque
Control Solenoid Valve
YES
Check for continuity in
harness between MC
and pump torque
control solenoid valve.
· Between terminal #A31
of connector MC-A in
MC and terminal #1 of
connector in pump
torque control solenoid
valve
· Between terminal #A5
of connector MC-A in
MC and terminal #2 of
connector in pump
torque control solenoid
valve
Cause
Influenced Control
The feedback current to MC • Pump Standard Torque Control
becomes the uncertain value.
The feedback current to MC is • Pump Standard Torque Control
beyond the upper limit.
While the command from MC • Pump Standard Torque Control
is output, the feedback current
to MC is 56 mA or less.
Switch connectors of
pump torque control
solenoid valve and normal
solenoid valve.
Retry.
Check if fault code
disappears.
Faulty pump torque
control solenoid valve.
Faulty MC.
YES
Open circuit in harness.
NO
Connector (Harness end of connector viewed from the
open end side)
MC
Connector MC-A
#A5
#A31
T183-05-04-008
Pump Torque Control Solenoid Valve
1
NO
2
T5-5-82
TROUBLESHOOTING / Troubleshooting A
MC FAULT CODES 11414, 11415, 11416, 11417, 11418, 11419
Fault Code
11414-2
11414-3
11414-4
11415-2
11415-3
11415-4
11416-2
11416-3
11416-4
11417-2
11417-3
11417-4
Trouble
Abnormal Feedback of
Transmission Clutch First Gear
Proportional Solenoid Valve
Abnormal
Feedback
High
Current of Transmission Clutch
First Gear Proportional Solenoid
Valve
Abnormal
Feedback
Low
Current of Transmission Clutch
First Gear Proportional Solenoid
Valve
Abnormal Feedback of
Transmission Clutch Second
Gear Proportional Solenoid
Valve
Abnormal
Feedback
High
Current of Transmission Clutch
Second
Gear
Proportional
Solenoid Valve
Abnormal
Feedback
Low
Current of Transmission Clutch
Second
Gear
Proportional
Solenoid Valve
Abnormal Feedback of
Transmission Clutch Third Gear
Proportional Solenoid Valve
Abnormal
Feedback
High
Current of Transmission Clutch
Third
Gear
Proportional
Solenoid Valve
Abnormal
Feedback
Low
Current of Transmission Clutch
Third
Gear
Proportional
Solenoid Valve
Abnormal Feedback of
Transmission Clutch Fourth
Gear Proportional Solenoid
Valve
Abnormal
Feedback
High
Current of Transmission Clutch
Fourth
Gear
Proportional
Solenoid Valve
Abnormal
Feedback
Low
Current of Transmission Clutch
Fourth
Gear
Proportional
Solenoid Valve
Cause
Influenced Control
The feedback current to MC • All Transmission Control
becomes the uncertain value
The feedback current to MC • All Transmission Control
exceeds the upper limit
The feedback current to MC is • All Transmission Control
20 mA or less
The feedback current to MC • All Transmission Control
becomes the uncertain value
The feedback current to MC • All Transmission Control
exceeds the upper limit
The feedback current to MC is • All Transmission Control
20 mA or less
The feedback current to MC • All Transmission Control
becomes the uncertain value
The feedback current to MC • All Transmission Control
exceeds the upper limit
The feedback current to MC is • All Transmission Control
20 mA or less
The feedback current to MC • All Transmission Control
becomes the uncertain value
The feedback current to MC • All Transmission Control
exceeds the upper limit
The feedback current to MC is • All Transmission Control
20 mA or less
T5-5-83
TROUBLESHOOTING / Troubleshooting A
Fault Code
11418-2
11418-3
11418-4
11419-2
11419-3
11419-4
Trouble
Abnormal Feedback of
Transmission Clutch Forward
Proportional Solenoid Valve
Abnormal
Feedback
High
Current of Transmission Clutch
Forward Proportional Solenoid
Valve
Abnormal
Feedback
Low
Current of Transmission Clutch
Forward Proportional Solenoid
Valve
Abnormal Feedback of
Transmission Clutch Reverse
Proportional Solenoid Valve
Abnormal
Feedback
High
Current of Transmission Clutch
Reverse Proportional Solenoid
Valve
Abnormal
Feedback
Low
Current of Transmission Clutch
Reverse Proportional Solenoid
Valve
Cause
Influenced Control
The feedback current to MC • All Transmission Control
becomes the uncertain value
The feedback current to MC • All Transmission Control
exceeds the upper limit
The feedback current to MC is • All Transmission Control
20 mA or less
The feedback current to MC • All Transmission Control
becomes the uncertain value
The feedback current to MC • All Transmission Control
exceeds the upper limit
The feedback current to MC is • All Transmission Control
20 mA or less
T5-5-84
TROUBLESHOOTING / Troubleshooting A
NO
Switch proportional
solenoid valve with
normal one and retry.
Check if fault code
disappears.
YES
Faulty proportional
solenoid valve.
Faulty MC.
YES
Check for continuity in
harness between MC
and proportional
solenoid valve.
· Refer to tabel below.
Open circuit in harness.
NO
Connector (Harness end of connector viewed from the
open end side)
MC
Connector MC-A
#A6
#A3
#A9 #A10
#A11
#A22
#A15
#A16 #A17 #A19 #A20
T183-05-04-008
#A30
Proportional Solenoid Valve Connector
1
2
List of connection relationship between each
proportional solenoid valve connector terminal and
connector MC-A terminal
First
Gear Second Gear Third
Gear
Proportional
Proportional
Proportional
Solenoid Valve Solenoid Valve Solenoid Valve
Connector
Connector
Connector
Connector
MC-A
Fourth
Gear
Proportional
Solenoid Valve
Connector
#1
#2
#1
#2
#1
#2
#1
#2
#A10
#A6
#A22
#A16
#A20
#A3
#A11
#A17
T5-5-85
Forward
Proportional
Solenoid Valve
Connector
#1
#2
#A30 #A19
Reverse
Proportional
Solenoid Valve
Connector
#1
#2
#A9
#A15
TROUBLESHOOTING / Troubleshooting A
TRANSMISSION FAILURE
MC FAULT CODE 11600
Fault Code
11600-3
11600-4
Trouble
Abnormal Travel Speed Sensor
Cause
Influenced Control
The abnormal value below is All Transmission Control
detected with the clutch
connected.
• Travel speed sensor=0 min-1
• Middle shaft sensor>300
min-1
• Torque converter output
speed sensor>500 min-1
• Detected voltage under the
shorted circuit with key ON:
4.5 V or higher
Abnormal Low Voltage of Travel Detected voltage under the All Transmission Control
Speed Sensor
shorted circuit with key ON:
Less than 1.5 V
Connect terminals #1
and #2 of harness end
of connector in travel
speed sensor by using a
clip.
NO Disconnect connector
MC-C in MC.
Check for continuity
between terminals #C19
and #C7 of harness end
of connector MC-C.
Replace travel speed
sensor.
Turn key switch ON in 10
seconds
after key switch is
·
turned OFF. Retry.
Check if fault code
disappears.
Connect terminal #C19 of
harness end of connector
MC-C in MC to vehicle
frame.
Check for continuity
NO between terminal #2 of
harness end of connector
in travel speed sensor
and vehicle frame.
· Key switch: ON
Connector (Harness end of connector viewed from the
open end side)
MC
Connector MC-C
#C7
C23
C10
#C19
C31
Travel Speed Sensor Connector
#2
Open circuit in
YES harness between MC
and travel speed
sensor (terminal #1).
NO
Open circuit in
harness between MC
and travel speed
sensor (terminal #2).
Faulty travel speed
sensor.
YES
C1
Faulty MC.
YES
#1
T5-5-86
TROUBLESHOOTING / Troubleshooting A
MC FAULT CODE 11601
Fault Code
11601-3
Trouble
Cause
Influenced Control
Abnormal Torque Converter The abnormal value below is • Pump
Torque
Decrease
Output Speed Sensor
detected with the clutch
Control
connected.
• Torque converter output
speed sensor=0 min-1
• Middle shaft sensor>300
min-1
• Travel speed sensor>300
min-1
Connect terminals #1
and #2 of harness end
of connector in torque
converter output speed
sensor by using a clip.
YES
Disconnect connector
MC-C in MC.
Check for continuity
between terminals #C29
and #C18 of harness
end of connector MC-C.
Replace torque converter
output speed sensor.
Start engine in 10 seconds
after key switch is turned
OFF. Travel machine 20
m. Retry.
Check if fault code
disappears.
NO
· Key Switch: ON
Connector (Harness end of connector viewed from the
open end side)
MC
Connector MC-C
#C18
C23
C10
C31
#C29
Torque Converter Output Speed Sensor Connector
#2
Connect terminal #C29
of harness end of
connector MC-C in MC
to vehicle frame.
Check for continuity
between terminal #2 of
harness end of
connector in torque
converter output speed
sensor and vehicle
frame.
Open circuit in
harness between MC
YES
and torque converter
output speed sensor
(terminal #1).
NO
Open circuit in
harness between MC
and torque converter
output speed sensor
(terminal #2).
Faulty torque
converter output speed
sensor.
NO
C1
Faulty MC.
YES
#1
T5-5-87
TROUBLESHOOTING / Troubleshooting A
MC FAULT CODE 11602
Fault Code
11602-3
Trouble
Cause
Influenced Control
Abnormal Transmission Middle The abnormal value below is • All Transmission Control
Shaft Sensor
detected with the clutch
connected.
• Middle shaft sensor =0 min-1
• Travel speed sensor>500
min-1
• Torque converter output
speed sensor>500 min-1
Replace transmission
middle shaft sensor.
Start engine in 10 seconds
after key switch is turned
OFF. Travel machine 20 m.
Retry.
Check if fault code
disappears.
Connect terminals #1
and #2 of harness end of YES
connector in
transmission middle
shaft sensor by using a
YES clip.
Connect terminal #C17 of
Disconnect connector
harness end of connector
MC-C in MC.
MC-C in MC to vehicle
Check for continuity
frame.
between terminals #C17
Check for continuity
and #C6 of harness end
NO between terminal #2 of
of connector MC-C.
harness end of connector
in transmission middle
shaft sensor and vehicle
frame.
Faulty MC.
Open circuit in harness
YES between MC and
transmission middle
shaft sensor (terminal
#1).
NO
Open circuit in harness
between MC and
transmission middle
shaft sensor (terminal
#2).
· Key switch: ON
Faulty transmission
middle shaft sensor.
NO
Connector (Harness end of connector viewed from the
open end side)
MC
Connector MC-C
#C6
C1
C23
#C17
C10
C31
Transmission Middle Shaft Sensor Connector
#2
#1
T5-5-88
TROUBLESHOOTING / Troubleshooting A
MC FAULT CODE 11904
Fault Code
11904-2
Abnormal
Lever
Trouble
Cause
Influenced Control
Forward/Reverse The forward/reverse signals All Transmission Control
are turned ON for 80 ms or
longer at the same time.
YES
NO
Disconnect connector of
forward/reverse lever.
Retry.
Check if fault code
disappears.
Disconnect connector
MC-B in MC.
Check for continuity
between terminal #2 or
#4 of connector in
forward/reverse lever
and vehicle frame
respectively.
Shorted circuit in
harness between
between connector of
forward/reverse lever
and connector MC-B
in MC.
Faulty MC.
NO
· Key switch: ON
Faulty
forward/reverse lever.
YES
Connector (Harness end of connector viewed from the
open end side)
MC
Connector MC-C
T183-05-04-021
Forward/Reverse Lever Connector
#4
#2
4
1
8
5
T5-5-89
TROUBLESHOOTING / Troubleshooting A
MC FAULT CODE 11905
Fault Code
11905-2
Abnormal
Switch
Trouble
Cause
Influenced Control
Forward/Reverse The forward/reverse signals All Transmission Control
are turned ON for 80 ms or
longer at the same time.
YES
NO
Disconnect connector of
forward/reverse switch.
Retry.
Check if fault code
disappears.
Disconnect connector
MC-B in MC.
Check for continuity
between terminal #1 or
#3 of connector in
forward/reverse switch
and vehicle frame
respectively.
Shorted circuit in
harness between
between connector of
forward/reverse
switch and connector
MC-B in MC.
Faulty MC.
NO
· Key switch: ON
Faulty
forward/reverse
switch.
YES
Connector (Harness end of connector viewed from the
open end side)
MC
Connector MC-B
T183-05-04-021
Forward/Reverse Switch Connector
#3
#1
T5-5-90
TROUBLESHOOTING / Troubleshooting A
CAN DATA RECEPTION FAILURE
MC FAULT CODES 11910, 11920
Fault Code
11910-2
11920-2
Trouble
Actual Engine Speed Receive
Error
Received from ECM
Fuel Flow Rate Receive Error
Received from ECM
Cause
Faulty Harness
Faulty ECM
Influenced Control
• Pump Torque Decrease Control
• Hydraulic Drive Fan Cooling
Control
Faulty Harness
Faulty ECM
• Engine
Speed
Decrease
Control
GPS
Monitor Unit
Dr-ZX
ICF
ECM
CAN Harness
MC
T5-5-91
CAN Harness
TROUBLESHOOTING / Troubleshooting A
CAN HARNESS CHECK
MC FAULT CODES 11910, 11920
• Check the wiring connections first.
Disconnect all
connectors of MC, ICF,
ECM and monitor unit.
Check for continuity
YES between ground circuit
(MC, ICF, ECM,
monitor unit) and CAN
circuit.
NO
Check for continuity in
YES CAN harness between
MC and ECM.
· Key switch: OFF
· Refer to
“Discontinuity Check
between CAN Circuit
and Ground Circuit”
on T5-5-61 to 65.
· Key switch: OFF
· Refer to “Continuity
Check in CAN
Harness” on T5-5-59.
Retry by using Dr. ZX.
Check if fault code
11004-2 is displayed.
YES
NO
Shorted circuit in CAN
harness between ground
circuit and CAN circuit.
Check for continuity
between power
circuit MC, ICF,
ECM, monitor unit
and CAN circuit.
To A
· Key switch: OFF
· Refer to “Discontinuity
Check between CAN
Circuit and Power Circuit”
on T5-5-66 to 69.
Open circuit in CAN
harness between MC and
ECM.
Normal.
NO
Shorted circuit in CAN
harness between power
circuit and CAN circuit.
YES
Shorted circuit in CAN
harness between key
signal circuit and CAN
circuit.
YES
A
Check for continuity
between key signal
circuit in MC, ICF,
NO ECM, monitor unit
and CAN circuit.
· Key switch: OFF
· Refer to
“Discontinuity
Check between
CAN Circuit and
Key Signal Circuit”
on T5-5-70 to 72.
YES
NO
Check for continuity
between High side
and Low side in CAN
harness.
· Key switch: OFF
· Refer to
“Discontinuity Check
in CAN Harness” on
T5-5-73.
Shorted circuit in CAN
harness.
Connect all connectors
YES
except connector
MC-C in MC.
Check if resistance
Disconnect
between terminals #C4
connector in MC.
NO and #C15 of harness
Connect connector of
end of connector
harness end.
MC-C is within 60±10
NO Check if resistance
Ω.
between terminals
#18 and #37 of
· Key switch: OFF
connector in ECM is
within 120±10 Ω.
· Key switch: OFF
T5-5-92
To B
To C
TROUBLESHOOTING / Troubleshooting A
NO
Connect connector
in MC.
Check if fault code
11004-2 is
displayed.
B
Check the connections of
MC and connector.
Faulty MC.
YES
· Key switch: ON
Check the connections of
ECM and connector.
NO
Connect connector
in MC.
YES Check if fault code
11004-2 is
displayed.
Faulty ECM.
YES
· Key switch: ON
Connect connector
in ICF.
YES Check if fault code
11004-2 is
displayed.
C
Connect connector in
ECM.
Disconnect
connector ICF-C in
ICF.
Check if resistance
NO between terminals
#C5 and #C11 of
harness end of
connector is within
60±10 Ω.
· Key switch: ON
· Key switch: OFF
NO
Connect connector in
ICF.
Disconnect
connector monitor-2B
in monitor unit.
Check if resistance
between terminals
#B33 and #B34 of
harness end of
connector is within
120±10 Ω.
NO
Check the connection of
ICF and connector.
Faulty ICF.
YES
YES
Connect connector
in monitor unit.
Check if fault code
11004-2 is
displayed.
· Key switch: ON
NO
Check the connections of
monitor unit and
connector.
Faulty monitor unit.
YES
Faulty in any controller in
MC, ICF, ECM or monitor
unit.
NO
· Key switch: OFF
Connector
ECM
Connector
(Harness end)
MC
Connector MC-C
(Harness end)
#C4
C1
C23
ICF
Connector ICF
(Harness end)
#18
#C15
#37
C10
C31
T1GR-05-04-002
Monitor Unit
Connector Monitor-2B
(Harness end)
#C5
#C11
T1V1-05-04-002
T4GB-05-05-002
#B34 #B33
T5-5-93
TROUBLESHOOTING / Troubleshooting A
(Blank)
T5-5-94
TROUBLESHOOTING / Troubleshooting A
MC FAULT CODE 11914
Fault Code
11914-2
Trouble
Cause
Radiator
Coolant Faulty Harness
Temperature Receive Error Faulty Monitor Unit
Received from Monitor Unit
Influenced Control
• Hydraulic Drive Fan Cooling Control
GPS
Monitor Unit
Dr-ZX
ICF
ECM
CAN Harness
MC
T5-5-95
TROUBLESHOOTING / Troubleshooting A
CAN HARNESS CHECK
FAULT CODE 11914
• Check the wiring connections first.
Disconnect all
connectors of MC, ICF,
ECM and monitor unit.
YES Check for continuity
between ground circuit
MC, ICF, ECM,
monitor unit and CAN
circuit.
Check for continuity in
YES CAN harness between
MC and monitor unit.
· Key switch: OFF
· Refer to
“Discontinuity Check
between CAN Circuit
and Ground Circuit”
on T5-5-61 to 65.
· Key switch: OFF
· Refer to “Continuity
Check in CAN
Harness” on T5-5-60.
Retry by using Dr. ZX.
Check if fault code
11004-2 is displayed.
YES Open circuit in CAN
harness between ground
circuit and CAN circuit.
NO
Check for continuity
between power
circuit MC, ICF,
To A
ECM, monitor unit
and CAN circuit.
· Key switch: OFF
· Refer to
“Discontinuity Check
between CAN Circuit
and Power Circuit” on
T5-5-66 to 69.
Open circuit in CAN
harness between MC and
monitor unit.
NO
Normal.
NO
Shorted circuit in CAN
harness between power
circuit and CAN circuit.
YES
Shorted circuit in CAN
harness between key
signal circuit and CAN
circuit.
YES
A
Check for continuity
between key signal
circuit in MC, ICF,
NO ECM, monitor unit
and CAN circuit.
· Key switch: OFF
· Refer to
“Discontinuity
Check between
CAN Circuit and
Key Signal Circuit”
on T5-5-70 to 72.
YES
NO
Check for continuity
between High side
and Low side in CAN
harness.
· Key switch: OFF
· Refer to
“Discontinuity Check
in CAN Harness” on
T5-5-73.
NO
Shorted circuit in CAN
harness.
Connect all
connectors except
connector MC-C in
MC.
Check if resistance
between terminals
#C4 and #C15 of
harness end of
connector MC-C is
within 60±10 Ω.
· Key switch: OFF
YES
NO
To B
Connect connector in
MC.
Disconnect
connector monitor-2B
in monitor unit.
Check if resistance
between terminals
#B33 and #B34 of
harness end of
connector is within
120±10 Ω.
· Key switch: OFF
T5-5-96
To C
TROUBLESHOOTING / Troubleshooting A
NO
Check the connections of
MC and connector.
Connect connector
in MC. Check if fault
code 11004-2 is
displayed.
B
Faulty MC.
· Key witch: ON
YES
Connect connector
in monitor unit.
YES Check if fault code
11004-2 is
displayed.
NO
Check the connections of
monitor unit and
connector.
Faulty monitor unit.
YES
· Key witch: ON
Connect connector
in ECM.
YES Check if fault code
11004-2 is
displayed.
C
Connect connector in
monitor unit.
Disconnect
connector ECM.
Check if resistance
between terminals
#18 and #37 of
NO harness end of
connector is within
120±10 Ω.
· Key witch: ON
· Key witch: OFF
NO
Connect connector in
ECM.
Disconnect
connector ICF-C in
ICF.
Check if resistance
between terminals
#C5 and #C11 of
harness end of
connector is within
60±10 Ω.
NO
Check the connections of
ICF and connector.
Faulty ICF.
YES
YES
Connect connector
in ICF.
Check if fault code
11004-2 is
displayed.
· Key witch: ON
NO Check the connections of
ICF and connector.
Faulty ICF.
YES
Faulty In any controller in
MC, ICF, ECM or monitor
unit.
NO
· Key witch: OFF
Connector
ECM
Connector
(Harness end)
MC
Connector MC-C
(Harness end)
#C4
#18
#37
#C15
C1
C23
C10
T1GR-05-04-002
C31
Monitor Unit
Connector Monitor-2B
(Harness end)
ICF
Connector ICF-C
(Harness end)
#C5
#C11
T1V1-05-04-002
T4GB-05-05-002
#B34 #B33
T5-5-97
TROUBLESHOOTING / Troubleshooting A
(Blank)
T5-5-98
TROUBLESHOOTING / Troubleshooting A
OTHER FAILURES
MC FAULT CODE 11901
Fault Code
Trouble
Cause
11901-3 Hydraulic
Oil
Temperature Voltage: 4.52 V or higher
Sensor High Voltage
11901-4
Hydraulic
Oil
Temperature Voltage: Less than 0.23 V
Sensor Low Voltage
Disconnect connector of
hydraulic oil temperature
sensor.
Check if resistance at
sensor end connector is
specification.
· Specification: Refer to
the table below.
Connect terminals #1
and #2 of harness end
of connector in
hydraulic oil
temperature sensor by
YES using a clip.
Disconnect connector
MC-D from MC.
Check for continuity
between terminals #D8
and #D6 of harness
end of connector
MC-D.
Influenced Control
• Auto Warning-Up Control
• Hydraulic Drive Fan Cooling
Control
• Auto Warning-Up Control
• Hydraulic Drive Fan Cooling
Control
Faulty MC.
YES
NO
Connect terminal #D6
of harness end of
connector MC-D in
MC to vehicle frame.
Check for continuity
between terminal #2
of harness end of
connector in hydraulic
oil temperature
sensor and vehicle
frame.
NO
Open circuit in harness
between MC and
hydraulic oil temperature
sensor (terminal #2).
Faulty hydraulic oil
temperature sensor.
NO
Specification of Hydraulic Oil Temperature Sensor
Hydraulic Oil Temperature
Resistance
(°C, °F)
(kΩ)
-20, -4
16.2±1.6
0, 32
(5.88)
20, 68
2.45±0.24
40, 104
(1.14)
60, 140
(0.534)
80, 176
0.322
NOTE: If fault code 11901-4 is not displayed and
hydraulic oil temperature “-30°C” is
displayed on the monitor by using Dr. ZX,
the circuit in hydraulic oil temperature
sensor may be opened.
Connector (Harness end of connector viewed from the
open end side)
MC
Connector MC-D
Hydraulic Oil Temperature
Sensor Connector
#D8
1
#D6
Open circuit in harness
YES between MC and
hydraulic oil temperature
sensor (terminal #1).
T183-05-04-009
T5-5-99
2
TROUBLESHOOTING / Troubleshooting A
PROPORTIONAL
TROUBLE CHECK
SOLENOID
VALVE
When the harness in proportional solenoid valve is
faulty, the fault code may be not detected. If the trouble
is related to the proportional solenoid valve,
disconnect the connectors in MC and proportional
solenoid valve. Then check for continuity.
Circuit Condition in Trouble
A
B
D
C
MC
Proportional
Solenoid Valve
A
B
D
C
T1V1-05-06-008
○: Fault code can be detected.
△: Fault code can be detected according to trouble.
×: Fault code cannot be detected.
Trouble
Fault Code
Open circuit in A-B
△
Damaged Parts in MC
None
T1V1-05-06-006
A
B
D
C
None
• Open circuit in A-B
• Harness in side B is shorted to
the ground.
○
T1V1-05-06-007
A
B
D
C
FET
• Open circuit in A-B
• Harness in side A is shorted to
△
the ground.
T1V1-05-06-009
A
B
D
C
Shorted circuit in A-B
FET
○
T1V1-05-06-010
A
B
D
C
Open circuit in C-D
None
△
T1V1-05-06-011
A
B
D
C
None
• Open circuit in C-D
• Harness in side C is shorted to
the ground.
△
T1V1-05-06-012
A
B
D
C
None
• Open circuit in C-D
• Harness in side D is shorted to
○
the ground.
T1V1-05-06-013
A
B
D
C
Shorted circuit in C-D
None
△
T1V1-05-06-014
T5-5-100
TROUBLESHOOTING / Troubleshooting A
Circuit Condition in Trouble
A
B
D
C
Trouble
Fault Code
Shorted circuit in harness
×
Damaged Parts in MC
Resistance
between A-B and C-D
T1V1-05-06-015
A
B
D
C
• Open circuit in A- B
• Harness in side A is shorted to
None
△
the power source.
T1V1-05-06-016
A
B
D
C
• Open circuit in A- B
• Harness in side B is shorted to
the power source.
None
○
T1V1-05-06-017
A
B
D
C
Harness in A-B is shorted to the
power source.
None
○
T1V1-05-06-018
A
B
D
C
• Open circuit in C-D
Resistance
• Harness in side D is shorted to
the power source.
○
T1V1-05-06-019
A
B
D
C
• Open circuit in C-D
None
• Harness in side C is shorted to
△
the power