Page 409 of 1903
Downloaded from www.Manualslib.com manuals search engine 6.CHECK MAF SENSOR
• For 1.8L engine, check air flow in data stream.
ECM TERMINAL NO. ITEMCONDITIONDATA (AVERAGE DC
VOLTAGE)
37 Sensor signal•
Engine is running
• ECT: 78°C
• Idle: 795 RPM
• IAT: 36°C
• IAT signal voltage:
1.88 V Approximately 322 kg/h
Approximately 1.39 V
• For 1.6L engine, check MAP sensor signal voltage.
TERMINAL
NO. ITEM
CONDITION DATA (DC
VOLTAGE)
4 MAP
sensor Engine:
Running •
Engine
running: Idle
• Press
accelerator
pedal slowly Approximately
1.3 V
• Press
accelerator
pedal quickly Up to
Approximately 4V
(instantaneous)
Is the check result normal?
Ye s>>Go to the next step.
No
>>Check connectors for rusted terminals or loose connectors in the air flow sensor circuit or ground.
DIAGNOSIS & TESTING
03
03–125Chery Automobile Co., Ltd.
Page 412 of 1903
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.
Page 419 of 1903
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.
Page 420 of 1903
Downloaded from www.Manualslib.com manuals search engine •Start engine and warm it to normal operating temperature, then select view DTC and data stream.
• If the DTC is detected, the DTC condition is current. Go to Diagnostic Procedure - Step 1.
• If the DTC is not detected, the DTC condition is intermittent (See Diagnostic Help and Intermittent DTC Trou-
bleshooting in Section 03 Electronic Engine Controls for more information.
NOTE :
While performing electrical diagnosis & testing, always refer to the electrical schematics for specific circuit
and component information.
Diagnostic Procedure
1.CHECK EXHAUST GAS LEAK
• Start engine and run it at idle.
• Listen for exhaust leak before three way catalyst.
Is the check result normal?
Ye s>>Go to the next step.
No
>>Repair or replace.
2.CHECK ECM CONTROL SIGNAL IN DATA STREAM
• With the X-431, select view data stream.
MONITOR ITEM CONDITION DATA
Injector pulse •
Engine: Warm up
• Shift: P or N
• Air condition: Off
• No load Idle
Approximately 2.5 ms
Is the check result normal?
Ye s>>Go to next 5.
No
>>Go to the next step.
3.CHECK O2SENSOR ELECTRICAL CONNECTOR
• Disconnect upstream O
2sensor (1) harness con-
nector.
• 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.
DIAGNOSIS & TESTING
BESM030017
03–136Chery Automobile Co., Ltd.
Page 421 of 1903
Downloaded from www.Manualslib.com manuals search engine 4.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 power.
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.
5.CHECK THE FUEL PRESSURE
• Release fuel pressure to zero.
• Install fuel pressure gauge (2) and check fuel
pressure.
• Observe the following fuel pressures when testing (See Fuel Pressure Test in Section 04 Fuel Delivery).
FUEL PRESSURES
Key On 400 kPa (4.0 bar)
Key Off 380 kPa (3.8 bar) in 10 minutes
Engine: Idle 400 - 420 kPa (4.0 - 4.2 bar)
DIAGNOSIS & TESTING
BESM030020
03
03–137Chery Automobile Co., Ltd.
Page 422 of 1903
Downloaded from www.Manualslib.com manuals search engine Is the check result normal?
Ye s>>Go to step 7.
No
>>Go to the next step.
6.DETECT MALFUNCTIONING PART
• Check the following:
Fuel pump and circuit
Fuel pressure regulator
Is the check result normal?
Ye s>>Go to the next step.
No
>>Repair or replace.
7.CHECK MAF/MAP SENSOR
• Turn ignition switch off.
• Install all removed parts.
• For 1.8L engine, check MAF signal in data stream.
TERMINAL NO. ITEMCONDITIONDATA (AVERAGE DC
VOLTAGE)
37 MAF sensor•
Engine is running
• ECT: 78°C
• Idle: 795 RPM
• IAT: 36°C
• IAT signal: 1.88 V 322 kg/h
1.39 V
• For 1.6L engine, check MAP sensor signal voltage.
TERMINAL
NO. ITEM
CONDITION DATA (DC
VOLTAGE)
4 MAP
sensor Engine:
Running •
Engine
running: Idle
• Press
accelerator
pedal slowly. Approximately
1.3 V
• Press
accelerator
pedal quickly. Up to
approximately 4V
(Instantaneous)
Is the check result normal?
Ye s>>If with the X-431, go to the next step.
If without the X-431, go to step 9.
No
>>Check connectors for damaged or air flow signal circuit for short to power.
DIAGNOSIS & TESTING
03–138Chery Automobile Co., Ltd.
Page 430 of 1903
Downloaded from www.Manualslib.com manuals search engine 6.CHECK INJECTOR POWER SUPPLY CIRCUIT FOR OPEN
• Turn ignition switch on.
• Check injector supply voltage between sensor ter-
minal and ground in the electrical connector.
• Battery voltage should exist.
Is the check result normal?
Ye s>>Go to step 8.
No
>>Go to the next step.
7.DETECT MALFUNCTIONING PART
• Check the following:
Front fuse and relay box F3, A13, G5
Fuse 12, fuse 24, fuse 27
Without EOBD (1.6L)
Front fuse and relay box F3, G2, G5
Fuse 12, fuse 23, fuse 24
harness between injector and fuse
Is the check result normal?
Ye s>>With the X-431, check the system, If OK, go to the next step.
No
>>Repair or replace malfunctioning parts.
8.CHECK INJECTOR CONTROL CIRCUITS FOR AN OPEN
• Check injector control circuit voltage.
• 3.6 V should exist.
Is the check result normal?
Ye s>>Go to step 10.
No
>>Go to the next step.
DIAGNOSIS & TESTING
LTSMD030024
03–146Chery Automobile Co., Ltd.
Page 431 of 1903
Downloaded from www.Manualslib.com manuals search engine 9.DETECT MALFUNCTIONING PART
• 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.
Is the check result normal?
Ye s>>Go to the next step.
No
>>Repair circuit for an open in harness or connectors.
10.CHECK INJECTOR RESISTANCE
• Check fuel injector resistance between the following terminals.
INJECTOR
NO. INJECTOR
TERMINAL RESISTANCE
(APPROXIMATELY) (20°C)
11&2
12
21&2
31&2
41&2
• Check sensor signal output.
• Connect ECM connector.
• Connect injector connector.
• Check fuel injector voltage between the following terminals and ground.
TERMINAL NO. ITEMCONDITIONDATA (AVERAGE DC
VOLTAGE)
6
Injector•
Engine is running
• Warm-up condition
• Idle
• Accelerate suddenly Voltage: 11 - 14 V
7
27
47
DIAGNOSIS & TESTING
03
03–147Chery Automobile Co., Ltd.
