Diagnosis Procedure
- CHECK DTC PRIORITY
If DTC P0139 or P0159 is detected with DTC P0137, P0138, P0157 or P0158, perform trouble diagnosis for DTC P0137, P0138, P0157 or P0158.
Is applicable DTC detected?
YES
Perform diagnosis of applicable. Refer to DTC Index .
NO
GO TO 2.
- CLEAR MIXTURE RATIO SELF-LEARNING VALUE
- Clear the mixture ratio self-learning value. Refer to Description .
- Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected? Is it difficult to start engine?
YES
Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to DTC Description , DTC Description or DTC Description , DTC Description .
NO
GO TO 3.
- CHECK HO2S2 GROUND CIRCUIT
- Turn ignition switch OFF.
- Disconnect heated oxygen sensor 2 harness connector.
- Disconnect ECM harness connector.
- Check the continuity between heated oxygen sensor 2 (HO2S2) harness connector and ECM harness connector.
DTC
HO2S2
ECM
Continuity
Bank
Connector
Terminal
Connector
Terminal
P0139
1
F62
4
F13
35
Existed
P0159
2
F56
4
- Also check harness for short to ground and short to power.
Is the inspection result normal?
YES
GO TO 4.
NO
Repair open circuit, short to ground or short to power in harness or connectors.
- CHECK HO2S2 INPUT SIGNAL CIRCUIT
- Check the continuity between HO2S2 harness connector and ECM harness connector.
DTC
HO2S2
ECM
Continuity
Bank
Connector
Terminal
Connector
Terminal
P0139
1
F62
3
F13
41
Existed
P0159
2
F56
3
32
- Check the continuity between HO2S2 harness connector and ground, or ECM harness connector and ground.
DTC
HO2S2
Ground
Continuity
Bank
Connector
Terminal
P0139
1
F62
3
Ground
Not existed
P0159
2
F56
3
DTC
ECM
Ground
Continuity
Connector
Terminal
P0139
F13
41
Ground
Not existed
P0159
32
- Also check harness for short to power.
Is the inspection result normal?
YES
GO TO 5.
NO
Repair open circuit, short to ground or short to power in harness or connectors.
- Check the continuity between HO2S2 harness connector and ECM harness connector.
- CHECK HEATED OXYGEN SENSOR 2
Check heated oxygen sensor 2. Refer to Component Inspection .
Is the inspection result normal?
YES
INSPECTION END
NO
Replace malfunctioning heated oxygen sensor 2. Refer to Removal and Installation (bank 2) , Removal and Installation (bank 1) .