Page 417 of 1903
Downloaded from www.Manualslib.com manuals search engine DIAGNOSIS & TESTING
LTSMW030048T
03
03–133Chery Automobile Co., Ltd.
Page 418 of 1903
Downloaded from www.Manualslib.com manuals search engine DIAGNOSIS & TESTING
LTSMW030049T
03–134Chery 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 423 of 1903
Downloaded from www.Manualslib.com manuals search engine 8.PERFORM ACTIVE TEST FUNCTION
• Start engine.
• Select ACTIVE TEST menu.
• Perform injector active test.
• Make sure that each test produces a momentary engine speed drop.
Is the check result normal?
Ye s>>Go to step 11.
No
>>Go to the next step.
9.CHECK FUNCTION OF INJECTOR
• Listen to each injector operating sound.
• Operating sound should exist.
Is the check result normal?
Ye s>>Go to step 11.
No
>>Go to the next step.
10.CHECK INJECTOR CONTROL CIRCUIT
• Turn ignition switch off.
• Disconnect injector harness connector (1).
• Disconnect ECM harness connector.
• Check harness for a short to ground between the following terminals.
INJECTOR NO. ECM
TERMINAL INJECTOR
TERMINAL
12 72
262
372
44 72
DIAGNOSIS & TESTING
BESM040006
03
03–139Chery Automobile Co., Ltd.
Page 424 of 1903
Downloaded from www.Manualslib.com manuals search engine •Continuity should not exist.
Is the check result normal?
Ye s>>Go to the next step.
No
>>Repair or replace circuit for short to ground in harness or connectors.
11 .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 13.
12.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 injector harness connectors.
• Disconnect all ignition coil harness connectors.
• Prepare pans or saucers under each injector.
• Crank engine for about 3 seconds.
• Make sure fuel does not drip from injector.
Is the check result normal?
Ye s>>Go to next step.
No
>>Replace the injectors from which fuel is dripping. Always replace O-ring with new one.
DIAGNOSIS & TESTING
03–140Chery Automobile Co., Ltd.
