6.0L V8 Gas Engine Driveability
Module 1
Table of Contents
Page
Course Outline & Objective
3
Section 1
Introduction to the 6.0L
Engine Specifications
Maintenance Schedule
Cooling System
Oil Flow Circuit
Cam Phasing
CMP Actuator Valve Operation
CMP Solenoid Magnet
Inside the Actuator
CMP Solenoid Magnet Wiring Circuit
Reluctor and Sprocket
4
5
6
7
10
11
13
14
15
16
17
Section 2
Air Induction System Description
Air Induction System
Mass Air Flow Sensor
MAF/IAT Wiring Circuit
PCV System
Throttle Actuator Control
Accelerator Pedal Position Sensor
Accelerator Pedal Position Wiring Circuit
APP Graph
Throttle Actuator Control Wiring Circuit
Throttle Position Sensor Graph
Throttle Actuator Modes
Reduced Engine Power Mode
Throttle Learn Mode
1
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Table of Contents
Page
Section 3
Fuel Injection System Description
Returnless Fuel System
Modular Fuel Pump Assembly
Fuel Pump Wiring Circuit
Fuel Injector and Fuel Rail Pressure Test Connection
Fuel Injector Control Circuits
Fuel Metering Modes
Enhanced EVAP System
Fuel Tank Pressure Sensor
32
33
34
37
38
39
40
44
46
Section 4
Electronic Ignition System Description
Electronic Ignition System
Ignition System Wiring Circuit
CKP Sensor
Reluctor Wheel
CKP Wiring Circuit
CKP System Variation Learn Procedure
CMP Sensor
CMP Wiring Circuit
Knock Sensor
Knock Sensor Circuit
47
48
49
50
51
52
53
54
55
56
57
Section 5
ECM and On-Board System Communications
Module Communications
DLC
PIM
IPC Circuits
MIL Indicator
PIM Quick Learn Procedure
ECM, Inputs, Outputs, Programming
2
58
59
60
61
62
63
64
65
6.0L V8 Gas Engine Driveability
Module 1
1. Introduction to the 6.0L
2. Air Induction System
3. Fuel Injection System
4. Ignition System
5. ECM and System Communication
Course Objectives:
After completing this course, participants will be able to identify and be
familiar with the 6.0L:
• Air induction system
• Fuel and Enhanced EVAP system
• Ignition system
• ECM inputs and outputs
• On-board computer communications including the
Powertrain Interface Module (PIM) and Instrument Panel
Cluster (IPC).
3
6.0L V8 Gas Engine Driveability
Module 1
1.
Introduction to the 6.0L
•
•
•
•
Engine Specifications
Cooling System
Oil Circuit
Cam Phasing
General Information
The Vortec 6.0 liter Gen IV is a small block V8 gasoline engine. It is available as an option in Isuzu’s Low
Cab Forward Design N Series Truck for 2012. This vehicle comes in two gross vehicle weight ratings; NPR
12,000 pounds and NPR-Heavy Duty 14,500 pounds .
This engine produces 297 horse power at 4300 rpm and 372 foot pounds of torque at 4000 rpm. The engine
is mated to a new 6L90-E 6-speed Hydramatic transmission with double overdrive and lockup torque
converter that improves both vehicle performance and fuel economy.
4
6.0L Engine Specifications
Engine Specifications
The RPO code for the 6.0 liter V8 gasoline engine is L96. The RPO code for the alternate
fuel option is LC8.
This engine features:
•
sequential fuel injection
•
coil-near-plug electronic ignition system
•
compression ratio of 9.6 to1
•
firing order 1-8-7-2-6-5-4-3
Refer to the service information for additional specifications.
5
6.0L Gas Engine Maintenance Schedule
Maintenance Schedule
Under ordinary driving conditions, engine oil and filter service intervals should be every 7,500 miles, or 12,000
km, or 12 months, whichever comes first. A vehicle operated under severe conditions, such as frequent short
trips, extended low-speed engine operation or towing requires more frequent maintenance. In this case, engine
oil and filter service intervals should be every 3,000 miles, or 4,800 km, or 3 months, whichever comes first.
The fuel filter is part of the fuel pump module and is not serviced separately.
The engine coolant service life is 50,000 miles and the ignition system has a maintenance-free 100,000 mile
service life.
The long-life timing chain for this engine is designed with a leaf-spring type dampener which maintains tension
to give the chain a smooth and quiet operation for the life of the engine.
6
The Cooling System
Cooling System
The 6.0 liter engine cooling system uses DEX-COOL.
The thermostat is located in the inlet of the water pump which reduces thermal cycling and results in a more
consistent warm-up.
The normal operating range of the thermostat is between 188°F (87°C) and 206°F (97°C).
7
Coolant Air Bleed Ports and Hose
Radiator
Entrance Port
Left
Cylinder
Head
Bleed Port
Right
Cylinder
Head Bleed
Port
Coolant Air Bleed Ports
There are two air bleed ports; one at the front of each cylinder head. Coolant flows from the cylinder heads,
through these ports, to the radiator. This helps eliminate any vapor pockets which can interfere with cooling
system performance.
8
Coolant Temperature Sensors
RCT is in
Lower
Radiator
Hose
ECT is in
left
cylinder
head near
front of
engine
Coolant Temperature Sensors
The Radiator Coolant Temperature Sensor or (RCT) is located in the lower radiator hose. The ECM uses RCT
sensor data for diagnostic purposes only.
The Engine Coolant Temperature Sensor or (ECT) is located in the left cylinder head near the front of the
engine. The ECM uses ECT Sensor data to calculate air-fuel mixture, ignition timing, and fuel injector pulse
width.
The ECT Sensor also provides information for the engine temperature gauge.
The ECT and RCT Sensors have to be within a predetermined value that is calculated internally by the ECM or
a Diagnostic Trouble Code (DTC) will set.
9
Oil Flow Circuit
Oil Flow Circuit
Engine lubrication is supplied by a gearrotor type oil pump assembly mounted on the front of the engine block
and driven directly by the crankshaft sprocket. The pressure relief valve is in the oil pump assembly and the Oil
Pressure Sensor is located at the top rear of the engine.
Pressurized oil is sent through the engine block to the full flow Oil Filter and on to the upper main oil galleys,
supplying oil throughout the engine assembly.
Oil entering the center of the camshaft at journal location #2, feeds the Camshaft Position Actuator Solenoid
Valve which controls cam phasing.
Minimum oil pressure on a hot engine should be 6 psi at 1000 rpm and 24 psi at 4000 rpm. Maximum oil
pressure is 55- 75 psi. Oil pressure readings are taken at the Oil Pressure Sensor location.
10
Camshaft Phasing
Camshaft Phasing
Cam Phasing, sometimes referred to as Variable Valve Timing, is one of the unique features of this engine.
Using the Camshaft Position (CMP) Actuator System, which is controlled by the ECM, valve timing can be
changed resulting in significant performance benefits.
•
By advancing camshaft timing, an improvement in low end torque can be achieved.
•
By retarding camshaft timing slightly, an improvement in high end power can be achieved.
•
By retarding camshaft timing significantly, an improvement in light load fuel economy can be
achieved.
11
Camshaft Phasing
Camshaft Phasing (Cont’d)
The Camshaft Position (CMP) Actuator changes valve timing relative to piston timing but does not change
duration or lift. The Actuator has a 52 degree range of control.
With the engine not running and no oil pressure to the CMP Actuator, the high tension spring positions camshaft
timing at the 7 degrees advanced spark position.
Based on performance requirements, the ECM may adjust camshaft timing, within a range from 7 degrees
advanced to 45 degrees retard.
Note that the camshaft moves in the opposite direction of Actuator.
12
CMP Actuator Valve Operation
CMP Actuator Valve
Oil flows from the camshaft into the CMP Actuator Valve inlet past an internal check ball and through a filter.
Oil exits the #2 valve port and travels within the internal passages of the camshaft into the entry ports #7 of the
Actuator.
The center oil groove of the Actuator is pressurized and oil reenters the Valve at #1 port.
The electromagnetic force on the solenoid pintle controls the Spool Valve position, directing oil out of either the
Valve advance port #3 or retard port #4 to the Actuator.
Under certain conditions, the Valve will be in a neutral position with no flow to either the advance or retard
passages of the Actuator.
Note that incorrect engine oil viscosity, aftermarket engine oil additives, or low oil level can greatly affect the
performance of the Actuator.
Engine oil that is overdue for changing may cause the Spool Valve filter to become plugged. This can cause a
performance issue and Diagnostic Trouble Codes to set.
13
CMP Actuator Solenoid Magnet
CMP Actuator Solenoid Magnet
The Camshaft Position (CMP) Actuator Magnet is located in the engine front cover and is sealed by a gasket.
The CMP Actuator Solenoid is controlled by a 12-volt, 150 Hz pulse width, 0–100 percent duty cycle signal
from the ECM. When energized, the Solenoid uses electromagnetic force on the magnet pintle to position the
Spool Valve of the CMP Actuator Valve.
CMP Actuator System Performance Diagnostics
The ECM monitors the performance of the CMP Actuator system by monitoring the calibrated desired position,
and the actual position of the camshaft. If the desired position and the actual position are to far out of range of
each other the ECM sets a Diagnostic Trouble Code (DTC).
14
Inside the Actuator
Inside the CMP Actuator
The pressurized engine oil entering the Camshaft Position (CMP) Actuator unseats the park pin, and enters the
vane and rotor assembly.
There are 5 cavities, each divided by vanes within the Actuator:
•
When the Valve is wide open, oil is directed to the retard cavities, rotating the camshaft counter
clockwise, retarding valve timing.
•
When the Valve is partially open, oil is directed to the advance cavities, rotating the camshaft
clockwise, advancing valve timing.
When the Valve is closed, oil is directed to both cavities, and the Actuator is held stationary.
15
CMP Actuator Solenoid Circuit
CMP Actuator Solenoid Circuit
The Camshaft Position Actuator Solenoid is an electro-magnetic device. The ECM sends a pulse width
modulated, 12-volt signal to the CMP Actuator Solenoid to control the amount of pressurized engine oil that
flows into the Actuator Valve. A low reference circuit or ground wire between the CMP Actuator solenoid and
the ECM completes the electrical circuit.
To calculate the optimum valve timing, the ECM uses the following inputs:
•
Engine speed (RPM)
•
Manifold Absolute Pressure (MAP/BARO)
•
Mass Air Flow (MAF)
•
Accelerator Pedal Position (APP)
•
Throttle Position (TP) angle
•
Camshaft Position (CMP) Sensor
•
Crankshaft Position (CKP) Sensor
•
Engine Coolant Temperature (ECT)
•
Engine Oil Pressure (EOP)
16
CMP Actuator Solenoid Circuit
Reluctor and Sprocket
It’s important to keep the Reluctor and Sprocket together after removing from engine. The Reluctor wheel is
mounted to the Actuator body with three (3) roll pins. Install tie wrap to retain the Reluctor wheel to the
Sprocket.
17
6.0L V8 Gas Engine Driveability
Module 1, Section 2
2.
Air Induction System
•
•
•
•
Intake Air Flow
Mass Air Flow Sensor
Positive Crankcase Ventilation
Throttle Actuator Control
18
Air Induction System
Throttle
Body
MAF/IAT
Sensor
Air Induction System
Outside air is drawn in through the air cleaner assembly, then routed through the Mass Air Flow (MAF) Sensor
to the throttle body, then to the intake manifold on its way to the cylinders. The Intake Air Temperature (IAT)
Sensor is integrated into the MAF Sensor.
19
Mass Air Flow (MAF) Sensor
IAT
Sensor
Mass Air Flow Sensor
The MAF Sensor measures the amount of air entering the engine. The ECM uses the MAF Sensor signals to
provide the correct fuel delivery for all engine speeds and loads.
A faulty MAF Sensor Signal due to loose connections, bad grounds, high resistance in the circuit, or an open in
the circuit can cause the following symptoms:
•
A no start condition
•
Stalls at idle
•
Surging idle
•
Extended crank time when engine is cold
•
Hesitation, Stumble, or Chuggle
•
Poor fuel economy
The ECM uses the Manifold Absolute Pressure (MAP), Intake Air Temperature (IAT), Engine Coolant
Temperature (ECT) Sensors and engine RPM, to calculate a predicted mass air flow value and compares it to the
actual MAF Sensor signal. If it is not within a predetermined range, a Diagnostic Trouble Code (DTC) will set.
Note: When installing the MAF, be sure the arrow is pointing in the direction of air flow, towards the engine.
20
MAF and IAT Sensor Circuits
MAF and IAT Sensor Circuits
The Mass Air Flow (MAF) Sensor has a five wire connector. The 12 volt feed powers the Sensor which
produces a frequency signal based on air flow. There is a 5 volt MAF Signal wire and ground connecting to the
ECM.
There is also a 5 volt signal and ground wire for the Intake Air Temperature (IAT) Sensor. This is a variable
resistor sensor which measures the temperature of the air entering the engine.
21
Positive Crankcase Ventilation
PCV
Port
Intake
manifold
PCV
Port
Positive Crankcase Ventilation System
This engine uses a closed crankcase ventilation system to provide a more complete scavenging of crankcase
vapors. The Positive Crankcase Ventilation (PCV) System controls the blow-by gasses as they are drawn into
the intake manifold and burned, instead of vented to the atmosphere.
There is no PCV check valve and filter, only a calibrated orifice in the valve cover.
The PCV should be inspected and cleaned at recommended maintenance intervals. If the PCV system clogs, it
will affect crankcase pressures, cause oil consumption and possible engine performance concerns.
22
Throttle Actuator Control
•
Senses throttle pedal position
•
Positions throttle blade
•
Senses throttle position
•
Cruise control
Throttle Actuator Control
Throttle Actuator Control (TAC) system delivers improved throttle response and eliminates the need for a
mechanical cable. The system consists of:
•
The Accelerator Pedal Position (APP) Sensors, which sends the pedal position information to the ECM.
•
The Throttle Actuator Control (TAC) Motor, which is controlled by the ECM and positions the throttle
blade to meet driver and engine demand.
•
The Throttle Position (TP) Sensors, which are an additional input to the ECM to assure accuracy and
reliability.
The System also controls the functions of Cruise Control. The ECM commands the TAC Motor to maintain the
vehicle speed “set” by the driver.
23
Accelerator Pedal Position Sensor
Accelerator Pedal Position Sensor
The Accelerator Pedal Position (APP) Sensor is mounted on the accelerator pedal assembly. The APP Sensor
consists of two individual sensors within one housing and is used to determine accelerator pedal angle and
driver input.
24
Accelerator Pedal Position Circuit
Accelerator Pedal Position Sensor Circuit
The Accelerator Pedal Position (APP) sensors 1 and 2 are both potentiometer type sensors.
Each sensor has three wires: a 5-volt reference circuit supplied by the ECM, a low reference circuit (Ground)
and the signal circuit.
25
Output volts
APP Sensor Graph
Throttle Opening %
Accelerator Pedal Position Sensor Graph
The Accelerator Pedal Position (APP) Sensor 1 voltage increases as the accelerator pedal is depressed, from
below 1.0 volt at 0 pedal travel to above 4 volts at 100 percent pedal travel. APP Sensor 2 voltage increases at
half the rate of APP Sensor 1, from above 0.43 volts at 0 pedal travel to above 2 volts at 100 percent pedal
travel.
The additional sensor is redundant. The ECM constantly compares the two values. If there is a discrepancy the
ECM sets a Diagnostic Trouble Code (DTC).
26
Throttle Actuator Control Circuit
Throttle Position Sensor and Throttle Actuator Control Circuits
There are two separate sensors to signal the throttle position as well. The Throttle Position (TP) Sensors are
potentiometer type sensors and provide the ECM with information about the actual throttle plate angle.
The ECM supplies a 5 volt reference that is shared by Throttle Position Sensors 1 and 2. The Sensors also have
a shared ground to the ECM. Each sensor sends a separate signal back to the ECM.
The ECM determines the driver’s intent by way of the Accelerator Pedal Position (APP) Signals and then
calculates the appropriate throttle response. The ECM provides a pulse width modulated voltage to the Throttle
Actuator Control Motor to position the throttle to the desired position. The TP Sensors provide feedback that
the position is correct.
27
Output volts
TP Sensor Graph
Throttle Opening %
Throttle Position Sensor Graph
The Throttle Position (TP) Sensors provide the ECM with a signal voltage proportional to throttle plate
movement. TP sensor 1 signal voltage at closed throttle is approx. 3.5 volts and decreases as the throttle plate is
opened.
The TP sensor 2 signal voltage at closed throttle is approx. 1.5 volts and increases as the throttle plate is opened.
The ECM constantly compares the two values, if there is a discrepancy the ECM sets a Diagnostic Trouble Code
(DTC).
28
Throttle Actuator Modes
Throttle Actuator Modes
The throttle body functions similar to a conventional throttle body even though an electric motor opens and
closes the throttle blade, instead of a cable.
The throttle blade is spring loaded in both directions and the default position is slightly open.
At key-up, the ECM updates the learned minimum throttle value position. To do this the throttle blade is
momentarily moved to the fully closed position when the ignition key is first turned to the on position.
If the throttle is not able to reach a predetermined minimum throttle position, the Ice Break Mode is entered. In
this mode, the ECM commands the maximum pulse width several times to the Throttle Actuator Control (TAC)
Motor in the closing direction.
Warning: To avoid injury, keep fingers away from the throttle blade when the harness is connected to the
TAC Motor.
Battery Saver Mode - When the ECM does not receive an engine RPM signal after a predetermined time, the
ECM removes the voltage from the TAC motor circuit. This eliminates the current draw used to maintain the
idle position and allows the throttle to return to the spring loaded default position.
29
Reduced Engine Power Mode
Reduced Engine Power Mode
When the ECM detects a fault with the Throttle Actuator Control (TAC) System, such as a Accelerator Pedal
Position or Throttle Position Sensor malfunction, the ECM may enter a Reduced Engine Power Mode and the
instrument panel indicator light will illuminate. In this mode, one or more of the following conditions will
occur:
Acceleration limiting—The ECM will continue to use the accelerator pedal input for throttle control, however,
the vehicle acceleration is limited.
Limited throttle mode—The ECM will continue to use the accelerator pedal input for throttle control, however,
the maximum throttle opening is limited.
Throttle default mode—The ECM will turn OFF the TAC Motor and the throttle will return to the spring
loaded default position.
Forced idle mode—The ECM will perform the following actions:
•
•
Limit engine speed to idle by positioning the throttle, or by controlling the fuel and spark if the TAC
is turned OFF.
Ignore the accelerator pedal input.
Engine shutdown —The ECM will disable fuel and de-energize the TAC.
30
Throttle Learn Mode
6.0L V8 Gas Engine Driveability
Module 1, Section 3
3.
Fuel Injection System
•
•
•
•
•
•
Returnless Fuel System
Fuel Pump Module
Fuel Injector
Fuel Pump Circuit
Fuel Injection Modes
Enhanced Evaporative Emissions Control
Throttle Learn Mode
The ECM learns the airflow through the throttle body to ensure the correct idle. The learned airflow values are
stored within the ECM. These values are learned to adjust for production variation and continuously learned
during the life of the vehicle to compensate for reduced airflow due to coking. Anytime the throttle body
airflow rate changes, for example due to cleaning or replacing, the values must be relearned.
A new ECM will have values set to zero and will also have to go through a learning procedure. If the learned
values do not match the actual airflow, the idle may be unstable or a Diagnostic Trouble Code (DTC) may set.
It may take several drive cycles for the ECM to “learn” the correct values.
Throttle Learn Procedure
To accelerate the process, use the scan tool to perform the Throttle Learn Procedure.
To perform Throttle Learn Procedure without a scan tool, run the engine in park for 3 minutes. After a 3
minute run time the engine should be idling normally.
If the engine idle speed has not been learned, the vehicle will need to be driven at speeds above 44 mph or 70
km/h with several decelerations and extended idles. After following this drive cycle, the engine should be
idling normally.
31
6.0L V8 Gas Engine Driveability
Module 1, Section 3
2.
Fuel Injection System
•
•
•
•
•
•
Returnless Fuel System
Fuel Pump Module
Fuel Injector
Fuel Pump Circuit
Fuel Metering Modes
Enhanced Evaporative Emissions Control
32
Returnless Fuel System
Returnless Fuel System
The fuel system is a returnless, on-demand design consisting of the following:
•
Fuel Tank
•
Fuel Fill Pipe
•
Filler Cap
•
Modular Fuel Pump Assembly
•
Fuel Rail Assembly
•
Injectors
33
Modular Fuel Pump Assembly
Modular Fuel Pump Assembly
The Modular Fuel Pump Assembly consists of the following:
•
The Fuel Level Sensor and Sender
•
Fuel Pump
•
Fuel Pressure Regulator
•
Fuel Filter
•
Fuel pump Flex Lines
Note that the Fuel Pump Module is serviced as a complete unit and there is no fuel filter replacement.
34
Modular Fuel Pump Assembly Components
Fuel Pump
Fuel
Pressure
Regulator
Fuel
Filter
Fuel
Pump
Flex
Lines
Modular Fuel Pump Assembly Components
The Fuel Pump is an electric turbine style pump which supplies high pressure fuel through the fuel filter and the
feed pipe to the fuel injection system. The ECM controls fuel pump operation through a fuel pump relay.
The Flex Lines dampen fuel pulses and noise generated by the pump. The fuel pump also supplies fuel to a
venturi pump located on the bottom of the fuel sender assembly. The function of the venturi pump is to fill the
sender assembly reservoir.
The fuel pump assembly contains a reverse flow check valve. The check valve and fuel pressure regulator
maintain fuel pressure in the feed pipe and fuel rail to prevent long cranking times.
35
Modular Fuel Pump Assembly Internal View
Fuel Pump
Modular
Housing
Fuel Filter
Fuel
Pressure
Regulator
Fuel Pump
and
Strainer
Fuel Pump Assembly Internal View
The Fuel Filter, Pump and Strainer are contained in the modular fuel pump assembly housing inside the fuel
tank. There is no service interval for the fuel filter and it is not serviced separately.
The Fuel Pressure Regulator is also part of the Modular Fuel Pump assembly, eliminating the need for a return
pipe from the engine. The Fuel Pressure Regulator has a spring loaded check ball that bleeds off fuel inside the
tank to maintain the specified fuel rail pressure. With the ignition ON and engine not running, fuel pressure at
the Fuel Pressure Test Service Valve should be between 50-60 psi.
36
Fuel Pump Circuit
Fuel Pump Circuit
The ECM controls the fuel pump operation through a Fuel Pump Relay.
When the ignition switch is first turned ON, the ECM applies 12 volts to the Fuel Pump Relay, which closes the
12 volt circuit to the Fuel Pump.
The ECM enables the Fuel Pump Relay as long as the engine is cranking or running, and crankshaft reference
pulses are received. If no crankshaft reference pulses are received after 2 seconds, the ECM turns off the Fuel
Pump Relay.
The ECM also monitors the voltage on the Fuel Pump Relay control circuit. If it detects an incorrect voltage, a
DTC will set.
37
Fuel Injectors, Rail, and Pressure Test
Connection
Fuel
Injector
Fuel Pressure
Test Service
Valve
Fuel Injectors, Rail and Pressure Test Connection
The fuel injectors meter pressurized fuel for each engine cylinder. The ECM energizes the injector solenoid to
open a normally closed ball valve. This allows the fuel to flow into the top of the injector, past the ball valve,
and through a director plate at the injector outlet. The director plate has machined holes that control the fuel
flow, generating a spray of finely atomized fuel at the injector tip. Fuel from the injector tip is directed at the
intake valve, causing the fuel to become further atomized and vaporized before entering the combustion
chamber. This fine atomization improves fuel economy and emissions.
The Fuel Pressure Test Service Valve is located on the passenger side fuel rail. Fuel pressure can be checked by
attaching a gauge to this valve.
38
Fuel Injector Control Circuits
Fuel Injector Control Circuit
Each Injector has an internal Solenoid that is controlled by the ECM. The ECM energizes the Injector Solenoid
by providing a ground path for each Injector. The Fuel Injectors are sequentially controlled by the ECM.
The ECM controls the “ON” time of each Injector by pulse width modulation which allows the ECM to deliver
the precise amount of fuel needed for performance, optimum fuel economy, and reduced emissions.
The ECM uses many inputs to adjust fuel delivery. The main inputs include engine RPM, Engine Coolant
Temperature (ECT), Intake Air Temperature (IAT), Manifold Absolute Pressure (MAP), Mass Air Flow (MAF),
Accelerator Pedal Position (APP), Throttle Position (TP), and Heated Oxygen Sensors (HO2S).
39
Fuel Metering Modes
Cranking/
Starting
Mode
Run Mode
ECM
Fuel Trim
Mode
Fuel Metering Modes
The ECM monitors specific inputs to determine the correct fuel needed for different modes of engine operation.
By changing the injector pulse width, the ECM can deliver the precise amount of fuel needed for performance
and fuel economy. These fuel delivery modes are described as:
•
Cranking/Starting Mode
•
Run Mode
•
And Fuel Trim
40
Starting/ Cranking Mode
12V Ignition
Starter Relay
ECT/IAT
Fuel Pump Relay
APP/TPS
MAP/BARO
ECM
Fuel Injectors
(Pulse Width
Modulated)
Crank Signal
RPM
VTD signal
from PIM
Starting /Cranking Mode
When the ignition is turned to the ON position, before cranking, the ECM energizes the Fuel Pump Relay for 2
seconds. This allows the Fuel Pump to run and build pressure in the Fuel Rail.
The ECM takes readings from the Engine Coolant Temperature (ECT) Sensor, Throttle Position (TP) Sensor
and Manifold Absolute Pressure (MAP) Sensor, which provides a barometric pressure reading. Using these
inputs, the ECM first checks air density, then switches to the MAF Sensor to determine appropriate fuel
delivery needed for starting the engine during cranking.
Cranking Mode:
When the ignition switch is placed in the START position, a discrete 12-volt signal is supplied to the
Powertrain Interface Module (PIM) notifying it that the ignition is in the start position. The PIM then sends a
message to the ECM notifying it that CRANK has been requested. The ECM verifies proper Vehicle Theft
Deterrent (VTD) security message from the PIM and verifies from the TCM that the transmission is in Park or
Neutral. If all conditions are met the ECM then supplies a ground signal to the control circuit of the Start
Relay. When this occurs, battery positive voltage is supplied through the switch side of the Start Relay to the S
terminal of the Starter Solenoid.
41
Run Mode_Open Loop
ECT
Fuel Pump Relay
TPS
MAP
Fuel Injectors
(Pulse Width
Modulated)
ECM
MAF
RPM
Internal Timer
(
)
Run Mode – Open Loop
After start up, the fuel control mode is in Open Loop.
Once the engine is started and the engine is above a predetermined RPM, the ECM calculates fuel delivery
based on the Engine Coolant Temperature (ECT) Sensor, Throttle Position (TP) Sensor, Manifold Absolute
Pressure (MAP) Sensor and Mass Air Flow (MAF) Sensor readings.
Once the Oxygen Sensors are warmed up and providing a signal, which can occur in under 90 seconds, the
system goes into Closed Loop.
42
Run Mode_Closed Loop
ECT
Fuel Pump Relay
TPS
MAP
Fuel Injectors
(Pulse Width
Modulated)
ECM
MAF
RPM
Heated Oxygen
Sensors
Run Mode - Closed Loop
In Closed Loop, the oxygen sensors provide constant feedback to the ECM, which adjusts the fuel delivery to
maintain as close to 14.7:1 air/fuel ratio as possible. This is desired air/fuel ratio for optimum catalytic
converter operation and minimum emissions.
In this mode, the ECM constantly fine tunes the fuel delivery in response to the Oxygen Sensor signals. This is
referred to as Fuel Trim. When the ECM determines that the Fuel Trim is beyond normal operating range, a
Diagnostic Trouble Code (DTC) is set.
Fuel Trim will be covered in more detail in the 6.0 liter Driveability Diagnostic Course, Module II.
43
Enhanced EVAP System
EVAP
Purge
Solenoid
EVAP Vapor
Pipe
EVAP Test
Port
Enhanced Evaporative Emissions Control System
All vehicles are now equipped with an Enhanced Evaporative Emissions Control (EVAP) System. The
Enhanced EVAP system limits fuel vapors from escaping into the atmosphere. The system consists of a
Charcoal Canister, Purge Solenoid, Vent Solenoid and a Fuel Tank Pressure Sensor.
As fuel tank vapors build up, they are routed through the vapor lines and absorbed by charcoal pellets in the
EVAP Canister.
Under certain running conditions, the ECM will turn on the EVAP Purge Solenoid, which is normally closed,
which opens a valve and allows engine vacuum to be applied to the EVAP Canister.
44
Enhanced EVAP System
Vent
Solenoid
Valve
EVAP Canister
Vent Solenoid
Enhanced Evaporative Emissions System (EVAP) Vent Solenoid, which is normally open, remains OFF
allowing fresh air to be drawn through the Solenoid and Vent line to the EVAP Canister. This allows the fuel
vapors to be pulled from the Canister and drawn into the Intake Manifold to be burned during normal
combustion.
If excess pressure builds up in the system, it is vented through the EVAP Vent Solenoid to the atmosphere.
Note: The Solenoid is activated for diagnostic purposes only.
45
Fuel Tank Pressure Sensor
Fuel Tank
Pressure
Sensor
Fuel Tank Pressure Sensor
The Fuel Tank Pressure (FTP) sensor is located on the top of the Fuel Pump assembly unit. It measures the
difference between the pressure and vacuum in the Fuel Tank and outside air pressure.
The ECM provides a 5-volt reference and a ground to the FTP sensor. The Fuel Tank Pressure (FTP) Sensor
provides a signal voltage back to the ECM. A high sensor voltage indicates a low Fuel Tank pressure or
vacuum. A low sensor voltage indicates a high Fuel Tank pressure.
Under Certain conditions, the ECM tests the EVAP system for leaks. When the engine is running it monitors
the system for large leaks. The ECM performs a small leak test by monitoring the FTP sensor for up to 40
minutes once the ignition key is in the off position.
The system is designed to detect leaks as small as .020 in. pin hole and will cause a Diagnostic Trouble Code
(DTC) to set.
46
6.0L V8 Gas Engine Driveability
Module 1, Section 4
4.
Electronic Ignition System
•
•
•
•
Coil-near-Plug
Crank Sensor
Cam Sensor
Knock Sensor
47
The Electronic Ignition System
Sequential Ignition Coils
IGN. Coil
#8
IGN. Coil
#6
IGN. Coil
#4
IGN. Coil
#2
Ignition Coil
Harness
Connector
Electronic Ignition System
The Electronic Ignition System of the 6.0L engine is known as coil-near-plug. It consists of a separate ignition
coil with a short secondary wire connected to a spark plug for each cylinder.
48
Ignition System Circuit
Ignition System Circuit
Each Ignition Coil primary circuit is connected to an ignition voltage feed and ground.
Each of the coil assemblies also has a driver module that is commanded ON and OFF by the ECM.
When the ECM turns the Ignition Circuit (IC) ON, current flows through the primary coil windings.
When the ECM commands the IC circuit OFF, this interrupts current flow through the primary coil windings.
This causes the magnetic field to collapse across the secondary coil windings, sending high voltage through the
short spark plug wire to the spark plug electrodes.
The spark plug electrodes are tipped with iridium for longer life. The recommended maintenance interval for
the spark plugs and wires is 100,000 miles.
49
Crankshaft Position Sensor
Crankshaft Position Sensor
The Crankshaft Position (CKP) Sensor is located on the right side of the block behind the starter.
The ECM uses the crankshaft and camshaft position sensors, along with various other inputs, to determine
firing sequence, dwell, and timing of the spark event. The CKP information is also used to sequence fuel
injection, detect cylinder misfire, and the camshaft to crankshaft relative position.
Note: The starter assembly must be removed to gain access to CKP sensor.
50
The Reluctor Wheel
The Reluctor Wheel
Crankshaft Reluctor Wheel is the trigger for the Crankshaft Position Sensor.
Each tooth on the Reluctor Wheel is spaced at 6 degrees apart from each other, for a total of 60-tooth spacing
around the circumference of the wheel.
The crankshaft Reluctor Wheel has two missing teeth, creating 12 degrees of spacing, which is used for the
reference or sync pulse. The sync pulse is used by the ECM to synchronize the coil firing with the crankshaft
position, while the other teeth provide cylinder location during each crankshaft revolution.
51
CKP Wiring Circuit
Crankshaft Position Sensor Circuit
The Crankshaft Position (CKP) Sensor is a three wire, hall effect type sensor.
The ECM supplies 5 volts and ground. The third wire is the low 5 volt reference output circuit that provides a
crank reference signal to the ECM
52
CKP System Variation Learn
Crankshaft Position Sensor Variation Learn
If the Crankshaft Position (CKP) Sensor or the ECM is replaced, or any engine repairs that disturb CKP to
Reluctor Wheel relationship, the CKP System Variation Learn Procedure must be performed.
This procedure must also be performed if the crankshaft or engine is replaced as well. The Variation Learn
procedure is performed using a scan tool. See the service information for more information.
It is important to follow the exact test criteria from the scan tool. The ECM needs to see brake pedal input
during the CKP Learn Procedure.
53
Camshaft Position Sensor
Camshaft Position Sensor
The Camshaft Position (CMP) Sensor is located in the front timing gear cover next to the Camshaft Position
Actuator Magnet.
The Camshaft Position information, along with the Crankshaft Position Sensor information is used to
determine the correct time and sequence for fuel injection, ignition spark events, detect cylinder misfire, and
the camshaft to crankshaft relative position.
54
CMP Wiring Circuit
Camshaft Position Sensor Circuit
The Camshaft Position Sensor is a three wire, hall effect type sensor.
The ECM supplies 5 volts and ground. The third wire is the low reference output circuit that provides the cam
reference signal to the ECM. This is the same sensor used for the Camshaft Phasing.
55
Knock Sensor
Knock Sensors
There are two Knock Sensors. Knock Sensor 1 is located on the left side and Knock Sensor 2 is located on the
right side of the engine block, in the center just above the oil pan.
56
Knock Sensor Circuit
Knock Sensor Circuits
The ECM receives the knock sensor signals through two isolated circuits. Each sensor produces an AC voltage
that varies, depending on the vibration levels detected during engine operation. The ECM monitors these
signals and adjusts the spark timing based on the amplitude and frequency of each sensor signal.
The knock sensor system enables the ECM to control the ignition timing for the best possible performance
while protecting the engine from potentially damaging levels of detonation.
57
6.0L V8 Gas Engine Driveability
Module 1, Section 5
5.
ECM and On-board System Communications
•
•
•
•
•
ECM, TCM, PIM and IPC
ECM inputs and outputs
Powertrain Interface Module
PIM Quick Learn Procedure
ECM Programming
58
Module Communications
Module Communications
This 6.0L system includes a number of modules that communicate using a serial data bus. These modules
include the ECM, Powertrain Interface Module (PIM), Transmission Control Module (TCM) and the Anti-lock
Brakes System (ABS) Module. The PIM also communicates with the Instrument Panel Cluster or IPC.
The control modules communicate with each other and the diagnostic scan tool equipment, using the ISO
15765 serial data bus. This is referred to as the CAN Bus, which stands for Controller Area Network and is a
Dual Wire, High Speed communication link.
The ABS module transmits data to the PIM via the J1939 Bus. The PIM will translate the information and
places the information on the ISO 15765 bus.
If communication is lost, a DTC specific for each individual module will set.
59
Data Link Connector (DLC)
Data Link Connector
The scan tool connects to the Data Link Connector or DLC and communicates with the various modules on
Pins 6 and 14 of the DLC using the ISO 15765 serial data bus.
The ABS module communicates via class 2, J1850 communication bus. The class 2 Bus is a single wire bus
communicating on Pin 2 of the DLC.
60
Powertrain Interface Module (PIM)
Power
train
Interface
Module
(PIM)
Powertrain Interface module
The Powertrain Interface module (PIM) is located behind the right side of the instrument panel, under the
glove compartment.
Discrete inputs from the ECM, Transmission Control Module (TCM) and the Antilock Brake System (ABS)
Module are routed to the PIM, which operates the appropriate lamps or gauges in the Instrument Panel Cluster
(IPC).
The PIM contains software that functions as the Vehicle Theft Deterrent (VTD). This is a password security
check that is performed by the PIM before the engine is allowed to crank. When the ignition switch has been
turned to the RUN or START position, the PIM sends a password message to the ECM over the ISO 15765
Bus. Once the ECM confirms this is the password stored in its memory, it will energize the starter and fuel
pump relays. If the password message received from the PIM does not match, the ECM will not energize the
fuel pump or starter relay and the engine will not CRANK or START.
Another function of the PIM is to provide interface for the operation of the cruise control system.
61
IPC Circuits
Instrument Panel Cluster
The Instrument Panel Cluster (IPC) circuits are hard wired to the PIM. The PIM receives messaging from the
ECM via ISO 15765 bus that commands it to turn ON the Charge, Service Vehicle Soon (SVS), Low Fuel
Indicator, Cruise Set, and the Engine Oil Pressure indicators. The PIM also controls the gauge signals for the
Engine Temperature, Fuel Level, Tachometer, and Speedometer.
The Service Vehicle Soon (SVS) Indicator is a non-emission related Indicator.
62
MIL Indicator
Malfunction Indicator Light
The Malfunction Indicator Light (MIL) is hard wired between the Instrument Panel Cluster (IPC) and ECM.
The ECM illuminates the MIL to notify the driver when an emission related Diagnostic Trouble Code (DTC)
sets.
The MIL also notifies the driver when a fault is occurring that may cause possible damage to the Catalytic
Converter, such as a cylinder misfire, by flashing continuously until the condition is no longer present. Under
this condition, a DTC will set and the MIL then reverts to a steady “ON” state at that time.
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PIM Quick Learn Procedure
Powertrain Interface Module Quick Learn Procedure
If a new PIM is installed or swapped from another vehicle or when an ECM is swapped from another vehicle, a
Relearn Procedure MUST be performed. Without this procedure, the vehicle will not crank because the
security password in the ECM and the password in the PIM do not match.
When a new ECM is installed or if the ECM is reprogrammed, there is no relearning required. The new ECM
will learn the incoming security password of the PIM immediately upon the next ignition switch from OFF to
CRANK.
To learn the password of the current vehicle PIM, there is a 30-minute relearn procedure as well as a Quick
Learn using the IDSS.
64
Engine Control Module
Engine Control Module
The ECM is located on the left side frame, below the Cab. It is designed to maintain exhaust emissions levels
while maintaining driveability and fuel efficiency. The ECM is designed to process the various input
information and then sends the necessary electrical responses to control fuel delivery, spark timing and other
emissions control systems. The ECM controls the following operations:
• Fuel control
• Ignition control
• Enhanced Evaporative emissions purge, Cruise control enable
• Generator
• A/C clutch control
• On-board diagnostics
65
ECM Input
Inputs
Outputs
•
•
•
Crankshaft Position (CKP) Sensor
Camshaft Position (CMP) Sensor
Engine Coolant Temperature (ECT) Sensor
•
•
•
•
•
Manifold Absolute Pressure (MAP) Sensor
Mass Air Flow (MAF) Sensor
•
•
•
•
•
•
•
•
•
Intake Air Temperature (IAT) Sensor
Throttle Position (TP) Sensor
4 Heated Oxygen Sensors (HO2S)
Accelerator Pedal Position (APP) Sensor
Fuel Level Sensor
Fuel Tank Pressure (FTP) Sensor
Radiator Coolant Temperature (RCT)
Sensor
Powertrain Interface Module (PIM)
Transmission Control Module (TCM)
•
•
•
•
•
•
•
8 Fuel Injectors
8 Ignition Coil/Driver Modules
Throttle Actuator Control (TAC)
System
Camshaft Position Actuator Solenoid
Enhanced EVAP Emissions Vacuum
Purge Solenoid
Transmission Functions
A/C Compressor Clutch
Fuel Pump Relay
ISO 15765 (SERIAL DATA)
Malfunction Indicator Lamp (MIL)
ECM Inputs
The ECM constantly monitors input signals from various sensors and switches to manage fuel, ignition,
emissions, and diagnostics. Input components may include, but are not limited to, the following:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Crankshaft Position (CKP) Sensor
Camshaft Position (CMP) Sensor
Engine Coolant Temperature (ECT) Sensor
Manifold Absolute Pressure (MAP) Sensor
Mass Air Flow (MAF) Sensor
Intake Air Temperature (IAT) Sensor
Throttle Position (TP) Sensor
4 Heated Oxygen Sensors (HO2S)
Accelerator Pedal Position (APP) Sensor
Fuel Level Sensor
Fuel Tank Pressure (FTP) Sensor
Radiator Coolant Temperature (RCT) Sensor
Powertrain Interface Module (PIM)
Transmission Control Module (TCM)
66
ECM Outputs
Inputs
Outputs
•
•
•
Crankshaft Position (CKP) Sensor
Camshaft Position (CMP) Sensor
Engine Coolant Temperature (ECT) Sensor
•
•
•
•
•
Manifold Absolute Pressure (MAP) Sensor
Mass Air Flow (MAF) Sensor
•
•
•
•
•
•
•
•
•
Intake Air Temperature (IAT) Sensor
Throttle Position (TP) Sensor
4 Heated Oxygen Sensors (HO2S)
Accelerator Pedal Position (APP) Sensor
Fuel Level Sensor
Fuel Tank Pressure (FTP) Sensor
Radiator Coolant Temperature (RCT)
Sensor
Powertrain Interface Module (PIM)
Transmission Control Module (TCM)
•
•
•
•
•
•
•
8 Fuel Injectors
8 Ignition Coil/Driver Modules
Throttle Actuator Control (TAC)
System
Camshaft Position Actuator Solenoid
Enhanced EVAP Emissions Vacuum
Purge Solenoid
Transmission Functions
A/C Compressor Clutch
Fuel Pump Relay
ISO 15765 (SERIAL DATA)
Malfunction Indicator Lamp (MIL)
ECM Outputs
The ECM controls the systems that affect vehicle performance and emissions. The systems that the ECM
controls include:
•
•
•
•
•
•
•
•
•
•
•
8 Fuel Injectors
8 Ignition Coil/Driver Modules
Throttle Actuator Control (TAC) System
Camshaft Position (CMP) Actuator Solenoid
Enhanced EVAP Emissions Vacuum Purge Solenoid
Enhanced EVAP Emissions Vent Solenoid
Transmission Functions
A/C Compressor Clutch
Fuel Pump Relay
ISO 15765 (SERIAL DATA)
Malfunction Indicator Lamp (MIL)
The ECM performs the diagnostic function of these systems as well. It recognizes operational problems, alerts
the driver through the Malfunction Indicator Light (MIL) and stores Diagnostic Trouble Codes (DTCs). The
ECM can detect up to 175 DTCs, making driveability diagnosis more efficient.
67
ECM Programming
ECM Programming
ECM Programming should be performed when replacing the ECM or when directed by a service procedure.
Do NOT program the ECM unless directed by a service procedure or service bulletin.
Before programming the ECM:
•
It is essential that the IDSS is equipped with the latest software. Check for the latest revision. If
updates are required, QUIT IDSS and perform IDSS updates as required.
•
Battery voltage must be greater than 12 volts but less than 16 volts. Prior to programming, connect a
factory recommended battery charger at its lowest 12 volt setting. Any fluctuation, spiking, over
voltage or loss of voltage will interrupt the programming.
•
Programming can take up to 20 minutes to complete. A stable battery voltage is critical. Turn off or
disable any systems that put a load on the vehicle battery, such as the air conditioning (HVAC), radio,
interior or exterior lights.
68
ECM Programming
ECM Programming (cont’d)
Make certain all scan tool connections are secure.
DO NOT disturb scan tool harnesses while programming. If an interruption occurs, programming failure or
control module damage may occur.
IDSS will provide step by step instructions to complete ECM programming.
After successfully programming the control module, ensure that all post programming procedures are
performed. DTCs may set during programming. Clear DTCs after programming is complete.
69
Notes
70
Notes
71
Notes
72
Notes
73