Downloaded from www.Manualslib.com manuals search engine •Continuity should exist.
• Check harness short to power supply circuit.
Is the check result normal?
Ye s>>Go to the next step.
No
>>Repair or replace the circuit for an open or short to power in harness or connectors.
5.CHECK O2SENSOR
• Connect O
2sensor connector.
• Connect ECM connector.
• If with the X-431, reference data stream value.
• If without the X-431, check as following:
Start engine and warm it up to normal operating temperature.
Turn ignition switch off.
Start engine and keep the engine speed between 3,500 and 4,000 RPM for at least 1 minute.
Let engine idle for 1 minute.
Set the digital multimeter probes between ECM terminal 4 and ground.
Check sensor output signal.
CHECKITEM CHECK CONTENT NORMAL
VALUE
Oxygensensor •
Warm-up
condition
• Become
lean while
decelerate Decelerate
from 4,000
RPM
suddenly Below
200 mV
• Warm-up
condition
• Become
rich while
accelerate Accelerate
suddenly 600 -
1,000 mV
• Warm-up
condition
• Check
with O
2sensor
signal Idle
100 -
900 mV
2500 RPM 600 -
1,000 mV
Is the check result normal?
Ye s>>Go to the next step.
No
>>Replace the O2sensor.
DIAGNOSIS & TESTING
03–11 6Chery Automobile Co., Ltd.
Downloaded from www.Manualslib.com manuals search engine Check reference values between ECM terminals and ground under the following conditions:
ECM TERMINAL NO.ITEMCONDITIONDATA (AVERAGE DC
VOLTAGE)
6 Injector 2
•Idle
• Engine is running
• Warm-up condition
• Accelerate suddenly Voltage: 11 - 14 V
7
Injector 3
27 Injector 1
47 Injector 4
ECM TERMINAL NO. ITEMCONDITIONDATA (AVERAGE DC
VOLTAGE)
17 Sensor (GND)•
Engine is running
• Warm-up condition:
78°C
• Idle: 795 RPM
• IAT: 36°C
• IAT signal voltage: 1.88
V 0V
33 Regulated sensor supply 1 5 V
37 Air flow sensor (1.8L)
Approximately 322 kg/h
Approximately 1.39 V
73 Regulated sensor supply 1 5 V
ECM TERMINAL NO.ITEMCONDITIONDATA (AVERAGE DC
VOLTAGE)
37 Manifold Absolute
Pressure (MAP) sensor (1.6L) •
Engine running: Idle
• Press accelerator pedal
slowly Approximately 1.3 V
• Engine running: 2000
RPM Approximately 1.5 V
• Press accelerator pedal
quickly Up to Approximately 4 V
(instantaneous)
On Board Diagnostic Logic
• Self-diagnosis detection logic.
DTC NO. DTC DEFINITION DTC DETECTION
CONDITION DTC SET
CONDITION POSSIBLE CAUSE
P0171 Fuel trim system too
lean Engine is running The amount of
mixture ratio
compensation is too large (The mixtureratio is too lean). •
Intake air leaks
• Air flow sensor
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel
pressure
• lack of fuel
• Incorrect PCV
hose connection
• Upstream O
2sensor
•ECM
DTC Confirmation Procedure:
Before performing the following procedure, confirm that battery voltage is more than 12 V.
• Turn ignition switch off.
• Connect the X-431 scan tool to the Data Link Connector (DLC) - use the most current software available.
• Turn ignition switch on.
DIAGNOSIS & TESTING
03–122Chery Automobile Co., Ltd.
Downloaded from www.Manualslib.com manuals search engine 4.CHECK O2SENSOR ELECTRICAL CONNECTOR
• Turn ignition switch off.
• Disconnect the O
2sensor (1) electrical connector
E-004.
• Inspect the electrical connector for damage.
Is the electrical connector OK?
Ye s>>Go to the next step.
No
>>Repair or replace the electrical connector
as necessary.
5.CHECK UPSTREAM O2SENSOR SIGNAL CIRCUIT
• Disconnect ECM harness connector.
• Check harness continuity between the following terminals.
COMPONENT TERMINAL ECM TERMINALO2SENSOR TERMINAL
TERMINAL 36
3
18 4
• Continuity should exist.
• Check harness for short to ground.
Is the check result normal?
Ye s>>Go to the next step.
No
>>Repair or replace circuit for an open or short to power in harness or connectors.
DIAGNOSIS & TESTING
BESM030017
03–124Chery Automobile Co., Ltd.
Downloaded from www.Manualslib.com manuals search engine 11 .CHECK INJECTOR POWER SUPPLY CIRCUIT AND CONTROL CIRCUIT
• Turn ignition switch off.
• Disconnect injector harness connector (1).
• Turn ignition switch on.
• Check injector supply voltage between sensor ter-
minal and ground in the electrical connector.
• Battery voltage should exist.
• Turn ignition switch off.
• Disconnect ECM harness connector.
• Check harness continuity between following terminals.
INJECTOR NO. ECM
TERMINAL INJECTOR
TERMINAL
12 72
262
372
44 72
• Continuity should exist.
• Check harness for short to power.
Is the check result normal?
Ye s>>Go to step next step.
No
>>Repair or replace circuit for an open or short to power or short to ground in harness or connectors.
DIAGNOSIS & TESTING
BESM040006
LTSMD030024
03–128Chery Automobile Co., Ltd.
Downloaded from www.Manualslib.com manuals search engine 12.CHECK INJECTOR RESISTANCE
• Disconnect injector harness connectors (See Fuel Pressure Test in Section 04 - Fuel Delivery).
• Check the resistance of the injectors.
INJECTOR
NO. INJECTOR
TERMINAL RESISTANCE
(APPROXIMATELY) (20°C)
11&2
16
21&2
31&2
41&2
Is the check result normal?
Ye s>>Go to the next step.
No
>>Replace injector.
Go to step 14.
13.CHECK INJECTOR
WARNING!
Confirm that the engine is cooled down and there are no fire hazards near the vehicle.
• Remove fuel delivery rail with injectors (See Fuel Injector Rail Removal & Installation 1.6L & 1.8L & 2.0L in
Section 04 Fuel Delivery).
NOTE :
Be careful not to drop the fuel injectors when removing the fuel delivery rail.
• Keep fuel hose and all injectors connected to injector rail.
• Disconnect all ignition coil harness connectors.
• Prepare pans or saucers under each injector.
• Observe the fuel injectors and crank engine for about 3 seconds.
• Fuel should be sprayed evenly by each injector.
Is the check result normal?
Ye s>>Go to next step.
No
>>Clean any injector that sprays unevenly or replace any injector that does not spray fuel.
DIAGNOSIS & TESTING
03
03–129Chery Automobile Co., Ltd.
Downloaded from www.Manualslib.com manuals search engine Check reference values between ECM terminals and ground under the following conditions:
ECM TERMINAL NO.ITEMCONDITIONDATA (AVERAGE DC
VOLTAGE)
6 Injector 2
•Engine is running
• Warm-up condition
• Idle
• Accelerate suddenly Voltage: 11 - 14 V
7
Injector 3
27 Injector 1
47 Injector 4
ECM TERMINAL NO. ITEMCONDITIONDATA (AVERAGE DC
VOLTAGE)
17 Sensor (GND)
•Engine is running
• Warm-up condition:
78°C
• Idle: 795 RPM
• IAT: 36°C
• IAT signal: 1.88 V 0V
33 Regulated sensor supply 1 5 V
37 Air flow sensor (1.8L) 322 kg/h
1.39 V
73 Regulated sensor supply 1 5 V
ECM TERMINAL NO.ITEMCONDITIONDATA (AVERAGE DC
VOLTAGE)
37 Manifold Absolute
Pressure (MAP) sensor (1.6L) •
Engine running: Idle
• Press accelerator pedal
slowly Approximately 1.3 V
• Engine running: 2000
RPM Approximately 1.5 V
• Press accelerator pedal
quickly Up to approximately 4 V
(instantaneous)
On Board Diagnostic Logic
• Self-diagnosis detection logic.
DTC NO. DTC DEFINITION DTC DETECTION
CONDITION DTC SET
CONDITION POSSIBLE CAUSE
P0172 Fuel trim system too
rich Engine is running The amount of
mixture ratio
compensation is too
large (The mixture
ratio is too rich) •
Air flow sensor
• Manifold Absolute
Pressure (MAP)
sensor
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel
pressure
• Upstream O
2sensor
•ECM
DTC Confirmation Procedure:
Before performing the following procedure, confirm that battery voltage is more than 12 V.
• Turn ignition switch off.
• Connect the X-431 scan tool to the Data Link Connector (DLC) - use the most current software available.
• Turn ignition switch on.
• With the scan tool, record and erase stored DTCs in the ECM.
DIAGNOSIS & TESTING
03
03–135Chery Automobile Co., Ltd.