Document No.:WP7 EUVI Engine information WEICHAI POWER CO., LTD.
Repair & Maintenance Information Requirements (OBD)
1. Component and diagnosis information ： Refer to Annex 1 "Component and diagnosis
information "
2. Diagnostic trouble codes：Refer to the file "Fault Code list and description "
3. Software calibration ID number applicable to a vehicle type：P_1434_EU6_EDC17
4. Information provided concerning proprietary tools and equipment
4.1 EOL
Manufacturer: LAUNCH、WEICHAI
Type：WP-EOL100、WEOL
Function: The tools used for ECU data calibration and diagnosis when the vehicles roll off the
production line.
Figure1 EOL made by LAUNCH
Figure2 EOL made by WEICHAI
4.2 Tester
Manufacturer: LAUNCH、WEICHAI
Type：WP-VDS100、"DIAGSMART"
Function: The tools used for reading fault information and maintenance on market service by
service stations.
Document No.:WP7 EUVI Engine information WEICHAI POWER CO., LTD.
Figure3 Tester made by LAUNCH
Figure4 Tester made by WEICHAI
5. Data record information and two directional monitoring and test data
4S stores need to record the data information and two directional monitoring and test data,
such as IUPR, the data tested by PMES and so on.
Document No.:WP7 EUVI Engine information WEICHAI POWER CO., LTD.
Vehicle OBD Information Requirements
1. The following information shall be made available to interested parties on a nondiscriminatory basis:
1.1 Type and number of preconditioning cycles used during type approval:
one hot WHTC
1.2 Description of the type of OBD demonstration cycle used for type approval:
cold WHTC & hot WHTC
1.3 Comprehensive document containing the following in a tabulated form:
i) Strategy for fault detection (fixed no. of cycles or statistical method)
ii) List of OBD output codes and format used
iii) Explanation of fault code data as requested in paragraph 2.3 for ISO 15765-4
and alternative protocols
Refer to the file " Fault Code list and description "
2. Information regarding the manufacture of diagnostic tools:
2.1 Communication protocol information as flow
2.1.1 Additional protocol information to allow complete diagnosis in addition to 4.7.3 of Annex
9B to UNECE Regulation 49：
WWWHOBD follows ISO27145 protocol, Referred spec 27145-3 and 27145-2
2.1.2 Methods of obtaining and interpreting fault codes not in accordance with the 4.7.3 of
Annex 9B to UNECE Regulation 49：
The DTCO format follows iso15031-6 protocol
2.1.3 List of all available functional tests
Current available function test :
Routine LiD
Engine Test Type
12
Detection of injector errors
14
High pressure test
15
Cylinder shut off test
16
Run up test
18
Compression test
22
SCR complete test(quantity measurement and emptying)
2.1.4 Details of how to obtain all component and status information, time stamps, pending
DTCs and freeze frames
The Read Data By Identifier service allows the client to request data record values from the
server identified by one or more data identifiers. regulate three mode.
Mode1:
This mode provide access to current emission relevant data value, inclanalog input ant outputs,
digital input and output, as also system status information, The request to information
acquires a DID that transfers the specific requested information to the on-board supply system.
referred spec 27145-3 and 27145-2.
The control units respond to this message by transferring the requested data value, which is
most recently determined by the system. All returned data values for sensor readings are
Document No.:WP7 EUVI Engine information WEICHAI POWER CO., LTD.
actual readings and not default or substitute values that are used by the system in case of an
error.
Mode6:
This mode permits the access to the result of the on-board diagnostic /monitoring tests for
specific components/systems.
Mode9:
This mode enable an external tester to query vehicle specific information like vehicle
identification number(VIN), the Calibration Verification Numbers(CVNS)and calibration
IDs(CALIDs).
2.1.5 Location of diagnostic connector and connector details
The diagnostic connector is up to the standard of SAE J1962. It is located under the instrument
panel at the driver’s left side, and is easily accessible from the driver’s seat.
3.Information on test and diagnosis of OBD-monitored components as follows:
3.1 Compression test :
The compression test is designed for the evaluation of both compression and expansion
behavior of each cylinder in an engine. For this purpose the engine is cranked while the
injections are switched off. During this cranking phase the durations for passing two freely
applicable angle segments are measured for each cylinder.
The calculation of the durations for each angle interval (in μs) is done in the ECU, the final
evaluation and display of the results is done in the service tester. By calculating the
difference of the two times per cylinder it is possible to judge the compression behavior
accurately for each single cylinder.
Test parameters:
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3.2 Run up test:
The run-up test (RunUpTst) is for the determination of the efficiency of single cylinders. The
test is structured into two stages. In stage one a cylinder will be switched off over the
diagnostic tester and the maximum speed will be measured, which is reached when
adjustable number of segments is given. This happens at given positions of the boostpressure actuator and the exhaust-gas recirculation and at given rail pressure and injection
rate for the pre injection and main injection of the remaining active cylinders. In stage two
all cylinders become switched off and the run down is controlled with an adjustable number
of segments. Over a comparison of these measured maximum speeds it’s possible to draw
conclusions on the efficiency of the single cylinders.
Test parameters:
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3.3 High pressure test:
In this test the set-point pressure is increased and relieved at four different engine speeds.
At each step the pressure build-up and drop-down times are measured whilst injections are
taking place normally. In a fifth step the engine speed from step four will be set again and
the pressure drop-down time with injections switched off is measured. The determination of
possibly faulty components is determined in a vehicle specific fault matrix via measured
pressure build-up/drop-down times. The High Pressure Test is a service function which has
no effect on normal driving. The test starts on demand by a diagnostic tester. All parameters
of the test are stored in the data set. Alternatively it is possible that the parameters are
handed over to the ECU by the tester. During the engine test the pressure characteristic is
considered in a pressure build-up and a pressure reduction phase at up to four different
engine speeds .The measuring point indicates the operating point that is active at the
moment.
Test parameters:
Rail_tiUpHpTst[%], [%]=[0,...,3]
Rail_stUpHpTst[%], [%]=[0,...,3]
Rail_tiDwnHpTst[%] [%]=[0,...,6]
Rail_stDwnHpTst[%] [%]=[0,...,4]
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Annex 1 Component and diagnosis information
1.1 List and Purpose of All Components Monitored by the OBD System
The following chapter is designed to give an overview of the components monitored by the
EOBD system. Its components and their functions within the whole system are described
shortly.
Fuel System
 High Pressure Pump
The High Pressure Pump is used to provide the high fuel pressure needed for direct diesel
injection. The installed pump is a CPN2.2+ -type pump that always delivers maximum fuel
quantity. It is fed by a gear Supply Pump with low pressure fuel.
 Rail Pressure Sensor
The Rail Pressure Sensor is used to determine the actual rail pressure. That value is needed for
high pressure control, engine protection and injection control. The sensor is mounted to the
rail.
 Solenoid Valve Injectors
The Solenoid Valve Injectors are used to inject the desired fuel mass into the combustion
chamber. They are mounted to the cylinder head centered above the combustion chamber.
Comprehensive Components

Boost Pressure and Temperature Sensor
The Boost Pressure and Temperature Sensor are used to measure the air pressure and
temperature after turbocharger and charge air cooler. The location of this measurement is
on the intake manifold. These values are used to calculate the air fuel ratio by the ECU and
the appropriate amount of fuel is calculated and injected to avoid extra black smoke occurs.

Air Pressure Sensor
The Air Pressure Sensor is used to determine the atmospheric air pressure. This value is
needed when calculating the EGR set point, injection control. The sensor is located inside the
ECU.

Camshaft Sensor
The Camshaft Sensor is used to determine the top dead centre of the first cylinder. It is
mounted to the gear box.

Coolant Temperature Sensor
The Coolant Temperature Sensor is used to measure the temperature of the engine coolant.
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This value is used for EGR control, and injection control. It is mounted to the thermostat.

Engine Speed Sensor
The Engine Speed Sensor is used to measure the engine speed. Moreover the measured signal
is needed to synchronize the engine together with the Camshaft Speed Sensor. The sensor is
installed at the crankcase.
 EGR Cooler Downstream Temperature Sensor
The EGR Cooler Downstream Temperature Sensor is used to measure the temperature of
EGR cooler downstream. This value is used monitor the efficiency of the cooler.
 Charged Air Cooler Downstream Temperature Sensor
The Charged Air Cooler Downstream Temperature Sensor is used to measure the
temperature of Charged Air cooler downstream. This value is used for calculating the cooler
efficiency.
 EGR Valve Position Sensor
The EGR Valve Position Sensor is used to measure the position of EGR Valve.
 Throttle Valve Position Sensor
The Throttle Valve Position Sensor is used to measure the position of Throttle Valve.
 HFM Sensor
The HFM Sensor is used to measure the amount of the air mass flows into the engine. This
signal is used for closed−loop control on the EGR valve.
DeNOx System
 SCR Catalyst Upstream Temperature Sensor
SCR catalyst upstream temperature sensor is installed in exhaust pipe before catalyst. It is used
to provide dew point detection of NOx sensor, control and correction of urea injection.
 Urea Heating Valve
Urea heating valve is installed in heating pipe of coolant water. It is used to control heating of
urea pipe from coolant water.
 NOx Sensor
There are two NOx sensors used in the DeNOx system. One NOx sensor is installed in exhaust
pipe after the turbocharger and before the HCI dosing unit. The other one is installed after
catalyst. It is used to measure NOx concentration of exhaust.
 Urea Tank Temperature and Level Sensor
Urea tank temperature and level sensor is installed in urea tank. It is used to provide
temperature and level of urea tank.
 Urea pump Temperature Sensor
Urea pump temperature sensor is installed in urea supply module. It is used to measure the
temperature of urea supply module.
 Urea Pressure Sensor
Urea pressure sensor is installed in supply module. It is used to measure pressure of urea.
 Pump Speed Sensor
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Pump speed sensor is installed in supply module. It is used to measure the rotating speed of
the urea pump.
 Pump Actuator
Pump actuator is installed in supply module. It is used to control the pressure of urea.
 Urea Dosing Valve
Urea dosing valve is installed in exhaust pipe. It is used to inject urea to exhaust pipe.
 Environment Temperature Sensor
Environment temperature sensor is installed exposed in the air. It is used to measure
environmental temperature.
DPM system
 DOC upstream Temperature Sensor
DOC upstream temperature sensor is installed in exhaust pipe before the DOC. It is used to
provide the exhaust temperature before DOC, and activation of HC injection.
 DPF upstream Temperature Sensor
DPF upstream temperature sensor is installed in exhaust pipe after the DOC and before the
DPF. It is used to provide the exhaust temperature, and control for appropriate amount of
diesel fuel injection when it is undergoing regeneration.
 DPF differential Pressure Sensor
The DPF differential pressure sensor is installed in exhaust pipe before and after DPF. It is used
to provide the exhaust pressure difference across the DPF. The measurement is used to
estimate the soot load inside the DPF with a soot load model.
 DPM Upstream Temperature/pressure Sensor
The sensor is integrated and installed in the metering unit before HC metering Valve. It is
used to provide the fuel temperature and pressure.
 DPM Downstream pressure Sensor
The sensor is integrated and installed in the metering unit after HC metering Valve. It is used
to provide the fuel pressure downstream of HC dosing valve.
 HC metering Valve
The HC metering Valve is installed in the HC metering unit. It is used to measure the amount
of fuel for HC injection.

HC Shut-off Valve
It is used to control the on and off of the fuel flow to the dosing unit.

HC dosing unit
It is used to inject the fuel to the exhaust stream before DOC.
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1.2 Description of OBD test principles and basic monitoring parameters
1.2.1 Description of error handling for the diesel engine
Fault diagnosis system is responsible for monitoring the engine control-related components
and control functions. Diagnosis system monitors electrical connection failures of the system
components, signals credibility and components measured value drift fault.
1.2.1.1 Fault storage
When fault diagnosis system has tested a component failure, the component is placed firstly
at "preliminary fault status."If the fault has been existed for a certain time (each component
has a time-to-defect), then it is placed at "confirmed defect status." If the fault disappears at
the time-to-defect, then the timer stops timing and reset to zero, if the fault occurs again, the
timer re-starts timing (figure 1). Fault recovery process and the fault test process is similar
(figure 2).
5.1 Fault test
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5.2 Fault recovery
Entry state management
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5.3 Entry state management
In order to operate vehicles safely and protect the engine and its components, some
measures to deal with the fault at "confirmed defect status" must be taken:
Measures to deal with the faults:
• The use of alternative values for certain variables
• Disable some functions
• Limit the range of variables
• Engine shutdown
Fault handling measures have been playing roles before the faults restore.
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For different fault parts and fault type, fault information related to environment variables may
be set immediately or after setting driving cycles into the fault memory. General diagnosis
device can read out memory failure information and the environment variable information
from the fault memory. If the fault stored in the memory disappears at set warm-up cycle, it
will be deleted.
Because of limited memory size, memory can store limited fault information. When the fault
memory is full, and there are new fault storing request, the lowest priority fault information
will be replaced by the new one. If there are a lot of the lowest priority faults, the fault
information stored longest will be renewed.
1.2.1.2 Fault classification and Warning system
MIL activation modes
5.4 MIL activation modes
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5.5 MI activation modes before engine start-1
MI activation modes before engine start
5.5 MI activation modes before engine start-2
MI activation modes after engine start
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5.6 MI activation modes after engine start
MI Counters
1) Continuous MI on time (last activation)
Count while when MI is in mode “continuous”
Reset:
(1) Fault reoccurs after having been healed for 3 or more operation cycles
(2) Fault is erased via self deletion (40 Warm up cycles or 200h)or fault memory clear via
tester
2) Cumulative continuous MI on time (lifetime)
Count while: MI is in mode “continuous”
Reset: no reset
3) Class B1 fault counter *: Class B1 fault in state “confirmed and active”
Count while: Class B1 fault in state “confirmed and active” (MI switches on)
Reset:3 operation sequences without B1 fault (no reset via Tester)
Initialization: when B1 counter >= 200h AND no B1 fault in “confirmed and active” OR reset
via tester
Initialization Action: set B1 counter to 190h
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Interaction when B1 counter >= 200h:
MI behavior (engine on)
Activate MI (according activation mode):
(1) Fault is in state “confirmed and active”
(2) Malfunction emission control strategy (MECS) activated
Activation state changes *:
(1) B1 fault counter >=200h:
Transition: “short” to “continuous”
(2) Single positive test result (Class A and B1):
Transition: “continuous” to “short”
Deactivate MI: 3 successive operation sequences without fault
(* Engine on: visible in “discriminatory” display strategy only)Fault memory state
5.7Fault memory state
Part2 Degrade system
Degrade system include torque limit and vehicle limit.
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5.8 inducement control overview
5.9inducement array
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5.10 inducement state
5.11 inducement level bit
Activation conditions:
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5.12 inducement level1
Level 2: “Severe inducement”
vehicle creep mode (“disable vehicle”):
limit vehicle speed to 20 km/h
Reasons for activation:
- Same as for Stage1 but additionally
- Non heated SCR systems: no delivery due to frozen reagent (after 70 min)
Activation conditions
Options (use at least one), wait for:
- Engine restart (key off -> on) OR
- Fuelling (fuel tank level increase by measureable amount) OR
- Parking (stationary vehicle for > 1h)
and(mandatory):
- Disable on time limit (stationary after 8h engine operation)
5.12 inducement level1
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1.2.2 Description of monitoring strategy for NOx emission monitoring and control system
OBD regulations requires that, any abnormal running of the engine related to NOx emission
control system should be monitored by the NOx sensor placed in the exhaust pipe. When NOx
emission is over 1.5g/kWh, the fault indicator is activated. When the fault time is over 10
hours , torque limiter start to work. When the fault time is over 20 hours , Vehicle speed limiter
start to work.
In cold WHTC cycle, hot WHTC cycle and the regeneration state, simulate the faults with the
total emission of 1.5g/kWh by using the deteriorated reactant, calculate separately
conversion efficiency limits at the corresponding conditions based on NOx concentration
measured.
At relatively stable conditions, the current average conversion efficiency limit is calculated
according to the NOx conversion efficiency limits at the corresponding conditions of total
1.5g/kWh emissions.
Average conversion efficiency limit=1-∫((1 minus conversion efficiency limit) NOx mass flow
upstream the catalyst)/∫NOx mass flow upstream the catalyst.
Actual average NOx conversion efficiency at present is calculated according to the actual
conditions and measured NOx concentration.
Actual average conversion efficiency =1-∫actual NOx mass flow downstream the catalyst
measured by the sensor/∫NOx mass flow upstream the catalyst.
If the actual average NOx conversion efficiency is lower than the average conversion efficiency
limit corresponding to the total 1.5g/kWh of NOx emissions, the system makes a judgment
that the actual NOx emissions exceeding emission limit of 1.5g/kWh.
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Description of monitoring strategy for NOx emission monitoring and control system.
Start
Catalyst
temperature within
the normal
No
Y
NOx density calculated
No
upstream the catalyst
Yes
Exhaust gas flow
calculated within the
normal range?
N
Yes
Integrated NOx conversion
efficiency limit and actual
Reset pre-
Stable
Ye
Integrated above result and
calculated average NOx
conversion efficiency and two
average conversion efficiency
Actual
average
conversion
lower
the
NOx
efficiency
No fault
N
Actual
Ye
Faultdetecte
MI activated
average
conversion
lower
average
Fault
N
the
NOx
efficiency
average
Ye
MI on and torque limiter
End
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1.2.3 Diagnosis of fuel control unit
OBD system tests continuously and circularly the electrical connection faults of the fuel
control unit drive circuit. Faults include the short circuit to power supply, short circuit to
ground, open circuit and overheating fault.
Error test is conducted inside the drive circuit module. Diagnostic functions assess the results
of error test and handle the error.
Test the battery short-circuit fault when the drive circuit is switched on: Monitoring the actual
output current of the drive circuit, if it exceeds the maximum limit, then short-circuit to
battery fault is detected; after that, the error is handled by the system diagnostic function.
Test the ground short-circuit fault when the drive circuit is switched off: Monitoring the actual
output current of the drive circuit, if it exceeds the minimum limit, then short-circuit to ground
fault is detected; after that, the error is handled by the system diagnostic function.
Test the open circuit fault when the drive circuit is switched off: Monitoring the actual output
current of the drive circuit, if it is within the preset range, then open circuit fault is detected;
after that, the error is handled by the system diagnostic function.
Test the overheating fault when the drive circuit is switched on: Monitoring the temperature
of the drive circuit parts, if it exceeds the temperature limit, then the error within the module
of the drive circuit is detected; after that, the error is handled by the system diagnostic
function.
Diagnosis flowchart for fuel control unit (drive circuit electrical fault)
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Start
Drive circuit
No
switched
Yes
Short circuit
to power
Yes
Yes
Fault detected
Fault detected
No
Yes
Fault detected
Fault detected
No
End
Open
No
No fault detected
No fault
to ground?
No
Yes
Temperatur
short circuit
Fault handled and MI on
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1.2.4 Diagnosis of common rail pressure sensor
OBD system monitors continuously and circularly the output signal of common rail
pressure sensor: When the sensor output voltage signal exceeds the upper rated limit, short
circuit to power supply or open circuit is detected; When the signal is lower than the lower
limit, short circuit to ground fault is detected.
1.2.5 Diagnosis of pressure limit valve
OBD system monitors the open status of the pressure limit valve, the valve will be
opened compulsively when the following conditions occur:
When the rail pressure is higher than the upper limit, but valve has not been opened; or rail
pressure sensor goes wrong. In addition, the valve would be opened when it is blocked. If the
system detects an open valve, then the fault is of the max. type error; if system detects a
pressure lower than the lower limit, the fault is the min error; if the pressure limit valve is not
opened when the rail pressure is higher than the upper limit, the fault signal error is detected.
OBD system also monitors the wear of the pressure limit valve. Once the pressure limit valve
is opened, the system will activate the timer and counter. Timer is used to cumulate open
time of the pressure limit valve, while counter is used for open times of the valves .Once the
timer exceeds the upper limit, then the min, type of error is detected. Once the counter
exceeds the upper limit, then the max, type of error is detected; If the timer and counter are
beyond the upper limits, then the signal type error is detected. The fault can’t be self repaired,
it can only be removed by the diagnostic device integrated with KWP2000 3B protocol (reset
timer and counter).
1.2.6 Diagnosis of water temperature sensor
OBD system monitors continuously and circularly the output signal of the cooling water
temperature sensor: When the sensor output voltage signal exceeds the upper limit, the
short circuit to power supply or open circuit fault is detected; When the signal is lower than
the lower limit, the short circuit to ground fault is detected.
1.2.7 Diagnosis of injector
Each cylinder injector and the drive circuit is detected once every working cycle. Electronic
injector control system controls the voltage on two ends of injector, charge and discharge
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current solenoid valve with the help of the high and low side transistors.
Four injectors are controlled by a "column" module, the injector is controlled by a specialized
drive chip. The drive chip monitors the voltage at the both channels of the high and low sides,
charge and discharge current. If a deviation occurs compared with expected voltage/current,
then the fault is detected and transmitted to the micro-controller.
A mode recognition system is used to determine the fault more accurately (either for a specific
cylinder, specific module, or for the chip itself).In this mode recognition system, the energizing
time, the voltage, the current and the drive chip of each injector are all took as a mode,
compare this mode with the pre-defined error mode matrix, if more than a certain number of
cases conforming with pre-defined error pattern are detected, then the fault corresponding
to the error pattern is detected.
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Injector diagnosis flowchart:
Start
Injector drive
Yes
chip fault
Fault detected
No.
Injector
Yes
connection
Fault detected
No.
There is failure
for injector
Yes
Fault detected
No.
No fault detected
No fault
Fault handled and MI on
End
1.2.8 Diagnosis of atmospheric pressure sensor
OBD system tests the signal range of output voltage of the atmospheric pressure sensor.
If the output voltage signal of the sensor exceeds the upper limit, it indicates that the sensor
short circuit or open circuit to battery; if the sensor output signal is lower the lower limit, then
the sensor short circuit to ground.
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1.2.9 Diagnosis of boosting pressure sensor
OBD system tests the signal range of output voltage of the boosting pressure sensor.
If the output voltage signal of the sensor exceeds the upper limit, it indicates that the sensor
short circuit or open circuit to battery; if the sensor output signal is lower than the lower
limit, then the sensor short circuit to ground.
1.2.10 Diagnosis of ECU modulus conversion module
OBD system tests the signal of ECU modulus conversion module. When the converter
reference voltage is higher than the upper limit calibrated, the largest type of fault is tested.
And when the converter reference voltage is lower than the lower limit calibrated, the
smallest type of fault is tested. When the converter test pulse voltage exceeds the upper
limit calibrated, signal type fault is tested; and when the converter signal is not converted
completely at certain time window, unauthentic type of fault is tested.
1.2.11 Diagnosis of ECU power supply module
OBD tests the voltage signal of ECU power supply module. When the voltage of the power
supply module is higher than the upper limit, the largest type of fault is tested. And when
the voltage is lower than the lower limit, the smallest type of fault is tested.
1.2.12 Diagnosis of fuel supply system
When the rail pressure controller operates at the state of closed loop controlling, the OBD
system tests the fault of fuel supply system by monitoring the controller deviation, the min.
rail pressure and the max. rail pressure.
The controller deviation includes plus deviation and minus deviation.
OBD can test two controller plus deviation faults. For the first deviation test, it makes a
comparison between the measured rail pressure deviation and the calculated limit according
to the engine speed. If the actual value is larger than the calculated value, then a fault is
tested.
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For the second deviation test, two conditions must be met. First of all, the above described
first plus deviation fault must have been tested. Secondly, the fuel supply of fuel control unit
must be greater than one of the calibrated limits. When the above two conditions are met,
compare the deviation of rail pressure controller and one calibrated limit. If the deviation is
larger than the limit, then a fault is tested.
For test of controller minus deviation, the following conditions must be met: the fuel supply
of the control unit is lower than a calibrated limit, fuel temperature is higher than a
calibrated limit and injection quantity exceeds a calibrated limit. At this time, when the
deviation of rail pressure controller is lower than the calculated limit based on the engine
speed, then a minus deviation fault is tested.
When the rail pressure is lower than the calculated limit based on the engine speed, the
minimum rail pressure fault is tested.
When the rail pressure exceeds the calibrated limit, the maximum rail pressure fault is
tested.
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Detecting flowchart for common rail pressure controller plus deviation (1):
Start
No
Meeting all
monitoring
conditions?
Yes
No
Yes
Controller
deviation over
upper limit?
Fault detected
No fault detected
Fault handled and MI on
No fault
End
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Detecting flowchart for rail pressure controller plus deviation (2):
Start
N
Meeting
all
Ye
N
Controlle
r plus
Yes
N
Fuel
delivery
Yes
Controller
deviation
Yes
Fault
N
No fault
No fault
End
Fault handled and
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Detecting flowchart for common rail pressure controller minus deviation:
Start
N
Meeting
all
Yes
Fuel flow
N
less than
Yes
Controller
deviation
Yes
Fault detected
N
No fault
No fault
End
Fault handled and MI
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Detecting flowchart for rail pressure min/max limit:
Start
Common rail
pressure less than
the min. value?
Yes
Fault detected
No
Common rail
pressure over the
max. value?
Yes
Fault detected
No
。
No fault detected
No fault
Fault handled and MI on
1.2.13 Diagnosis of crankshaft sensor
The OBD system tests the output signal of crankshaft sensor for “no signal” or “unauthentic
signal”.
End
The crankshaft sensor is composed of a signal wheel and a Hall sensor. If the phase sensor
signal is effective, but there is no crankshaft sensor signal, then no crankshaft sensor signal
fault is tested.
The credibility of the signal is determined by testing the dynamic change of crankshaft signal.
When the dynamic change exceeds the stated engine speed limit, unauthentic signal fault is
tested.
The monitoring function is continually performed in engine operation.
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1.2.14 Diagnosis of camshaft sensor
The OBD system tests the output signal of camshaft sensor for “no signal” or “unauthentic
signal”.
If the camshaft sensor signal is effective, but there is no camshaft sensor signal is tested, then
no camshaft sensor signal fault is tested.
If the camshaft sensor signal and the phase sensor signal failed synchronically, or there is an
improper angle deviation between the crankshaft sensor signal and the camshaft sensor signal
in engine operation, then unauthentic phase sensor signal is tested.
The monitoring function is continually performed in engine operation.
1.2.15 Diagnosis of EGR valve position sensor
OBD system monitors continuously and circularly the output signal of EGR valve position
sensor: When the sensor output voltage signal exceeds the upper rated limit, short circuit to
power supply or open circuit is detected; When the signal is lower than the lower limit, short
circuit to ground fault is detected.
1.2.16 Diagnosis of Throttle Valve position sensor
OBD system monitors continuously and circularly the output signal of throttle valve position
sensor: When the sensor output voltage signal exceeds the upper rated limit, short circuit to
power supply or open circuit is detected; When the signal is lower than the lower limit, short
circuit to ground fault is detected.
1.2.17 Diagnosis of EGR Cooler Downstream Temperature Sensor
OBD system monitors continuously and circularly the output signal of EGR Cooler Downstream
Temperature Sensor: When the sensor output voltage signal exceeds the upper rated limit,
short circuit to power supply or open circuit is detected; When the signal is lower than the
lower limit, short circuit to ground fault is detected.
OBD system monitors continuously and circularly the output physical signal of EGR Cooler
Downstream Temperature Sensor: When the sensor output physical signal exceeds the upper
rated limit, physical range check high error is detected; When the physical signal is lower than
the lower limit, a physical range check low error is detected.
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1.2.18 Diagnosis of HFM Sensor
OBD system monitors the output signal of HFM Sensor: When the sensor output time signal
exceeds the upper rated limit, a "maximum value exceeded" is detected; When the signal is
lower than the lower limit, a "minimum raw value fallen short of" is detected.
The supply voltage BattU_u is continuously monitored to check whether it is in the permissible
limit defined by the application parameters. If the supply voltage exceeds these thresholds,
an error of supply voltage is detected.
1.2.19 Diagnosis of Charge Air Cooler Efficiency Monitoring
The temperature upstream of the Charge air cooler is calculated via an air system model. The
temperature downstream of the coolant temperature are measured via sensors. If the
efficiency calculated from these temperatures is less than a given threshold value, the Charge
Air cooler is detected as defective.
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Start
N
Meeting
all
N
Yes
defective
cooler ?
Yes
Fault
N
No fault
No fault
Fault handled and
End
1.2.20 Diagnosis of EGR Cooler Efficiency Monitoring
The temperature upstream of the EGR cooler is calculated via an on−board air system model.
The temperature downstream of the coolant temperature are measured via sensors. If the
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efficiency calculated from these temperatures is less than a given threshold value, the EGR
cooler is detected as defective.
1.2.21 Diagnosis of urea tank temperature sensor
This diagnostic function tests the voltage signal range of urea tank temperature sensor.
When the voltage signal of the sensor is higher than the calibrated upper limit, sensor short
circuit to power is tested. When the signal is lower than the lower limit, sensor to ground
short circuit is tested.
1.2.22 Urea level sensor and remaining urea test
Diagnostic function monitors circularly the range of the output voltage signal of the urea
level sensor.
When the sensor output voltage signal exceeds the upper limit, short circuit to power supply
is detected; when the signal is lower than the lower limit, short circuit to ground is detected.
According to the OBD regulations, the remaining urea in the urea tank should be tested.
The remaining urea test is divided into 3 level. If remaining urea is lower than the first level,
then storage is error, but MI is not activated and urea injecting continuously. If remaining urea
is lower than the second level, MI is activated and urea injection is stopped, but the urea is
cooled continuously. If the remaining urea is lower than the third level, that is urea tank is
empty, then MI is immediately activated, at the same time the urea injection and cooling is
stopped.
Diagnosis flowchart for urea level sensor:
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Start
No
Urea volume
sensor
Yes
Sensor volt
Yes
signal over
Fault detected
No
Sensor volt
signal less
Yes
Fault
No
No fault detected
No fault
End
Fault handled and MI on
Document No.:WP7 EUVI Engine information WEICHAI POWER CO., LTD.
Urea volume detecting flowchart:
Start
Remaining up to
3rd grade: tank
emptied?
Yes
Fault detected
No
Remaining up to
2nd grade:
Yes
Fault detected
No
Remaining up to1st
Yes
grade: urea adding?
Fault detected
detected
No
No
fault
detecte
No fault
Fault handled and MI on
d
detecte
d
End
1.2.23 Diagnosis for temperature sensor of urea supply module
The diagnosis function performs the range check of voltage signal sent from
temperature sensor of the urea supply module.
The short circuit to power supply would be detected when the voltage signals from
sensor got above the rated upper limit; the short circuit to ground would be detected when
the voltage signals got below the rated lower limit.
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Whereas the urea solution will freeze when the temperature is below -11℃, the system
has urea solution heating function. If the urea temperature measured by the urea supply
module is less than the rated lower limit or more than the rated upper limit during urea
solution heating, the signal is not plausible.
1.2.24 Diagnosis for sensor power supply control module of after-treatment control unit
The sensor power is supplied by power supply control module. One power supply
control module can supply power for four sensors.
The power supply control module chip CY310 has self-diagnosis function. At the time of
fault handling, the error report self-diagnosed from power supply control module chip is
sent to after-treatment control unit, the final reaction corresponds with related sensor error
path.
1.2.25 Diagnosis for urea pressure pump
In the DeNOx system, the urea pump of supply module is used to increase the pressure
of urea solution. The pump adopts closed loop mode to control urea pressure in supply
module.
The pump speed can be calculated by measuring the operation of pump transmission
shaft with three Hall sensors. According to the measured values from three Hall sensors, the
faults of the pump can be detected, such as pump motor blocked, over speed for pump, Hall
sensor failure.
1.2.26 Diagnosis for urea injection valve
The urea injection valve adopts PWM wave control and is used to control the injection of
urea. The faults of urea control valve include short circuit to ground, short circuit to power
supply, open circuit, injector blocked.
The short circuit to ground and to power supply can be detected by the feedback
values of urea injection valve pins. The system inspects the feedback values of pins several
times, if the times of relevant feedback value setting is more than rated times, the system
reports the related faults. Under the condition of urea valve with its power on, if the PWM
wave controlled by injection valve is over the rated value, namely there is a request for
injecting urea; but the feedback voltage of the injection valve is less than the working limit,
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namely there’s no action of the injection valve, the open fault then can be detected.
The plausibility of urea injection quantity and pump speed would be confirmed every
time in the course of system starting. The system evaluates the pump speed in accordance
with urea injection. If the urea injection quantity has a large change, but the pump speed
has a small change, then the fault of injector blocked should be detected.
Diagnosis flow chart for urea injection valve (short circuit to ground and to power supply)
Start
Has injection valve
Y
pin P3.3 been set or
SCG fault detected
reached the count
detected
N
Has injection valve
pin P3.6 been set or
reached the count
Y
SCB fault detected
detected
N
No fault detected
No fault
End
Diagnosis flow chart for open circuit
Fault handled or MI on
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Start
N
the injection
valve operate
in
Y
Duty
N
cycle
more than the
limit value？
Y
injection valve
voltage less
Y
Fault detected
than
N
No fault detected
No fault
End
Fault handled or MI on
Document No.:WP7 EUVI Engine information WEICHAI POWER CO., LTD.
Diagnosis flow chart for injector blocked
Start
the change of urea
N
injection quantity
more than rated value
Y
the change of pump
N
speed more than
rated value in a certain
Y
No fault detected
Fault detected
No fault
End
Fault handled or MI on
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1.22 Diagnosis for urea pressure sensor and its plausibility
The diagnosis function performs the range check of voltage signal sent from urea
pressure sensor circularly.
The short circuit to power supply would be detected when the voltage signals from
sensor got above the rated upper limit; the short circuit to ground would be detected when
the voltage signals got below the rated lower limit.
The plausibility of urea pressure sensor should be inspected before urea pressure
increased in the course of system starting. The system compares the urea pressure with the
atmospheric pressure, if the difference is too large, then the fault can be detected.
1.2.27 Diagnosis for CAN and CAN communication
The system inspects the short circuit for CAN 1 and 2, CAN system hardware will report
related error when short circuit on High Side to Low Side of CAN 1 or 2 occurs.
The system inspects the message AMB and EEC1 for CAN, when the frame is detected
for time-out, effective message is overridden and J1939 message range stands in error, the
system can report error.
1.2.28 Diagnosis for urea heater valve
In winter, the system heats urea tank through introducing engine cooling water. The
cooling water is controlled with urea tank heater valve. Once the temperature reaches a
certain level, the urea tank heater valve will turn off. If the valve blocked, the urea tank
temperature would be too high due to the cooling water heating the urea tank continuously.
1.2.29 Diagnosis for NOx sensor
NOx sensor is in communication with after-treatment control unit through CAN, the
communication is as follows: the heating signal transferred from after-treatment control
unit to NOx sensor, or NOx value transferred from NOx sensor to after-treatment system.
The system determines the connecting faults of NOx sensor by the messages from CAN.
The faults include short circuit, open circuit, unreasonable supply voltage for sensor, NOx
signal above the Max. credible value of NOx.
The system determines the NOx heater signal faults by the messages from CAN. The
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faults include shirt circuit and open circuit.
The NOx sensor operates around 800℃. The NOx heater starts heating the NOx sensor
after dew-point inspection. The system would inspect the sensor plausibility during NOx
sensor heating. If Max. heating time was over the time limit and no temperature signal came
from NOx sensor, the system would detect plausibility of heating.
Plausibility inspection for NOx sensor:
The inspections for NOx sensor plausibility include peak value inspection and
unreasonable signal change-range inspection. In this way, the plausibility NOx sensor signal
can be detected, as well as avoid using fake NOx sensor.
When the NOx flow rises from one steady-state to another before catalyst, NOx density
measured by NOx sensor should appear a wave peak after a certain period.
Wave peak inspection:
When the NOx flow rises from one steady-state to another before catalyst, the system
records the NOx density before changing. A min. change limit can be calculated by recorded
NOx density adding a theoretic change-value (calculated from catalyst temperature). After a
certain time delay, compare the min. change limit with the current NOx density measured by
NOx sensor, when measured density is less than min. change limit, NOx sensor signal peak
error can be detected.
Unreasonable signal change-range inspection:
When the NOx flow rises from one steady-state to another before catalyst, the system
records the NOx density before changing. After a certain time delay, compare the current
NOx density measured by NOx sensor with the former recorded value, when absolute value
of the difference is less than a certain value, the system determines that the signal of NOx
sensor is not plausible.
Diagnosis flow chart for connection fault of NOx sensor
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Start
CAN message
N
transmission
Y
NOx sensor
Y
short circuit
N
sensor supply
N
voltage
Y
downstream signal more
than the max. probable
value of NOx？
Y
N
No fault detected
Fault detected
No fault
End
Fault handled and MI on
Document No.:WP7 EUVI Engine information WEICHAI POWER CO., LTD.
Diagnosis flow chart for signal fault of NOx heater
Start
CAN message
N
transmission
Y
NOx heater
Y
short circuit
N
Start heating and
timing after dew-point
Receive the temp.
signal from NOx
sensor after
heating time over
Y
No fault detected
N
Fault detected
No fault
End
Fault handled or MI on
Document No.:WP7 EUVI Engine information WEICHAI POWER CO., LTD.
Diagnosis flow chart for peak value fault of NOx sensor
Start
NOx flow rises from
one stead-state to
another before
catalyst?
N
Y
Delay timing and record
NOx density measured
measure current NOx density
and calculate min. change limit
after a certain time delay
Current
N
NOx
density
No fault detected
Y
Fault
No fault
Fault handled or
MI on
End
Document No.:WP7 EUVI Engine information WEICHAI POWER CO., LTD.
Diagnosis flow chart for unreasonable signal range of NOx sensor
Start
NOx flow rises from one
stead-state
to
N
another
Y
Delay timing and record NOx density
measured by NOx sensor
Current NOx density measured and
min. change limit calculated after a
certain time delay
Absolute value of
N
the difference
more than a
No fault
Fault
Y
No fault
detected
Fault handled and MI on
End
1.2.30 Diagnosis of SCR upstream temperature sensor
This diagnostic function tests the voltage signal range of SCR upstream temperature sensor.
When the voltage signal of the sensor is higher than the calibrated upper limit, sensor short
circuit to power is tested. When the signal is lower than the lower limit, sensor to ground
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short circuit is tested.
1.2.31 Diagnosis of DPF upstream temperature sensor
This diagnostic function tests the voltage signal range of DPF upstream temperature sensor.
When the voltage signal of the sensor is higher than the calibrated upper limit, sensor short
circuit to power is tested. When the signal is lower than the lower limit, sensor to ground
short circuit is tested.
1.2.32 Diagnosis of DOC upstream temperature sensor
This diagnostic function tests the voltage signal range of DOC upstream temperature sensor.
When the voltage signal of the sensor is higher than the calibrated upper limit, sensor short
circuit to power is tested. When the signal is lower than the lower limit, sensor to ground
short circuit is tested.
1.2.33 Diagnosis of DPM upstream temperature sensor
This diagnostic function tests the voltage signal range of DPM upstream temperature sensor.
When the voltage signal of the sensor is higher than the calibrated upper limit, sensor short
circuit to power is tested. When the signal is lower than the lower limit, sensor to ground
short circuit is tested.
1.2.34 Diagnosis of DPM upstream pressure sensor
This diagnostic function tests the voltage signal range of DPM upstream pressure sensor.
When the voltage signal of the sensor is higher than the calibrated upper limit, sensor short
circuit to power is tested. When the signal is lower than the lower limit, sensor to ground
short circuit is tested.
1.2.35 Diagnosis of DPM downstream pressure sensor
This diagnostic function tests the voltage signal range of DPM downstream pressure sensor.
When the voltage signal of the sensor is higher than the calibrated upper limit, sensor short
circuit to power is tested. When the signal is lower than the lower limit, sensor to ground
short circuit is tested.
1.2.36 Diagnosis of DPF pressure difference sensor
This diagnostic function tests the voltage signal range of DPF pressure difference sensor.
When the voltage signal of the sensor is higher than the calibrated upper limit, sensor short
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circuit to power is tested. When the signal is lower than the lower limit, sensor to ground
short circuit is tested.
1.2.37 Diagnosis for HC dosing valve
The HC dosing valve adopts PWM wave control and is used to control the injection of HC.
The faults of HC dosing valve include short circuit to ground, short circuit to power supply,
open circuit, valve blocked.
The short circuit to ground and to power supply can be detected by the feedback
values of HC dosing valve pins. The system inspects the feedback values of pins several
times, if the times of relevant feedback value setting is more than rated times, the system
reports the related faults. Under the condition of HC dosing with its power on, if the PWM
wave controlled by HC dosing valve is over the rated value, namely there is a request for HC
injection; but the feedback voltage of the injection valve is less than the working limit,
namely there’s no action of the dosing valve, the open fault then can be detected.
The plausibility of HC dosing valve would be confirmed every time in the course of
system starting. The system evaluates the HC pressure. If the value has a large difference
from the calibrated threshold，then the fault of dosing valve blocked should be detected.
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Diagnosis flow chart for HC dosing valve (short circuit to ground and to power supply)
Start
Has the valve pin been set or
Y
reached the count value?
SCG fault detected
detected
N
Has the valve pin been set or
reached the count value?
Y
SCB fault detected
detected
N
No fault detected
No fault
End
Fault handled or MI on
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Diagnosis flow chart for open circuit
Start
the
N
valve operated in working state?
Y
the
N
feedback signal larger than the limit
value?
Y
the
feedback signal smaller than the limit
value?
No fault detected
Y
Fault detected
N
No fault
End
Fault handled or MI on
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Diagnosis flow chart for valve blocked
Start
Is there a system test for
N
the HCI system？
Y
Is the fuel pressure in the
N
calibrated threshold？
Y
No fault detected
Fault detected
No fault
Fault handled or MI on
End
1.2.38 Diagnosis for HC shut-off valve
The HC shut-off valve adopts PWM wave control and is used to control the injection of HC.
The faults of HC shut-off valve include short circuit to ground, short circuit to power supply,
open circuit, valve blocked. The logic of the valve faults detected is similar to HC dosing
valve.
1.2.39 Diagnosis for HC injection valve
The HC injection valve is a mechanical valve. The fault of HC injection valve is blocked. The
Document No.:WP7 EUVI Engine information WEICHAI POWER CO., LTD.
logic of the valve blocked detected is similar to HC dosing valve.
1.2.40 Urea quality monitoring
OBD system monitors the Urea quality. When the urea quality is detected to have problem,
when NOx emission is over 0.9g/kWh, the fault indicator is activated. When the fault time is
over 10 hours , torque limiter start to work. When the fault time is over 20 hours , Vehicle
speed limiter start to work.
In hot WHTC cycle，simulate the faults with the emission of 0.9g/kWh by adding water to urea,
calculate the conversion efficiency limits at the corresponding conditions based on NOx
concentration measured.
At relatively stable conditions, the current average conversion efficiency limit is calculated
according to the NOx conversion efficiency limits at the corresponding conditions of 0.9
g/kWh emissions.
Average conversion efficiency limit=1-∫((1 minus conversion efficiency limit) NOx mass flow
upstream the catalyst)/∫NOx mass flow upstream the catalyst.
Actual average NOx conversion efficiency at present is calculated according to the actual
conditions and measured NOx concentration.
Actual average conversion efficiency =1-∫actual NOx mass flow downstream the catalyst
measured by the sensor/∫NOx mass flow upstream the catalyst.
If the actual average NOx conversion efficiency is lower than the average conversion efficiency
limit corresponding to the total 0.9 g/kWh of NOx emissions, the system makes a judgment
that the actual NOx emissions exceeding emission limit of 0.9 g/kWh.