Downloaded from www.Manualslib.com manuals search engine Diagnostic Procedure
1.CHECK GROUND CONNECTIONS
• Turn ignition switch off.
• Loosen and retighten ground screws on the body (See Ground Inspection in Section 03 Electronic Engine Con-
trols).
• Inspect ground connections E-207 and E-208 mounting position (See Vehicle Wiring Harness Layout - Engine
Room Harness (With 1.6L/1.8L Engine) in Section 16 Wiring).
Are the ground connections OK?
Ye s>>Go to the next step.
No
>>Repair or replace ground connections.
2.CHECK O2SENSOR ELECTRICAL CONNECTOR
• 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.
3.CHECK O2SENSOR GROUND CIRCUIT
• Disconnect ECM harness connector.
• Check harness continuity between ECM terminal 18 and O
2sensor terminal 4.
• Continuity should exist.
• Check harness open and 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.
4.CHECK O2SENSOR INPUT SIGNAL CIRCUIT FOR AN OPEN AND SHORT
• Check harness continuity between ECM terminal and O
2sensor terminal as follows.
O2SENSOR ECM TERMINAL O2SENSOR TERMINAL
Upstream O
2sensor 18 4
DIAGNOSIS & TESTING
BESM030017
03
03–11 5Chery Automobile Co., Ltd.
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 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.