Chery Tiggo. Manual — part 156
DIAGNOSIS & TESTING
LTSMW030029T
03
DIAGNOSIS & TESTING
LTSMW030030T
Check reference values between ECM terminals and ground under the following conditions:
ECM TERMINAL NO.
ITEM
CONDITION
DATA (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.
ITEM
CONDITION
DATA
17
Sensor (GND)
• Engine is running
• ECT: 78°C
• Idle: 795 RPM
• IAT: 36°C
• IAT signal: 1.88 V
0 V
33
Regulated sensor supply 1
5 V
37
Air flow sensor
322 kg/h
1.39 V
On Board Diagnostic Logic
• Self-diagnosis detection logic.
DTC NUMBER
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).
• MAF sensor
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel
pressure
• Upstream O
2
sensor
• 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.
• 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.
DIAGNOSIS & TESTING
03
Diagnostic Procedure
1.
CHECK EXHAUST GAS LEAK
• Start engine and run it at idle.
• Listen exhaust gas leak before three way catalyst.
Is the check result normal?
Yes
>>
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.
REFERENCE DATA
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?
Yes
>>
Go to step 5.
No
>>
Go to the next step.
3.
CHECK UPSTREAM O
2
SENSOR ELECTRICAL CONNECTOR
• Turn ignition switch off.
• Disconnect the upstream O
2
sensor (1) electrical
connector.
• Inspect the electrical connector for damage.
Is the electrical connector OK?
Yes
>>
Go to the next step.
No
>>
Repair or replace the electrical connector
as necessary.
4.
CHECK UPSTREAM O
2
SENSOR SIGNAL CIRCUIT
• Disconnect ECM harness connector.
• Check harness continuity between the following terminals.
UPSTREAM O
2
SENSOR
ECM TERMINAL
O
2
SENSOR TERMINAL
O
2
sensor 1
36
3
18
4
DIAGNOSIS & TESTING
BESM030017
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