PR25DD engine
- RETIGHTEN A/F SENSOR 1
Loosen and retighten the A/F sensor 1. Refer to CATALYST : Exploded View .
GO TO 2.
- CHECK EXHAUST GAS LEAK
- Start engine and run it at idle.
- Listen for an exhaust gas leak before three way catalyst (manifold).
Is exhaust gas leak detected?
YES
Repair or replace.
NO
GO TO 3.
- CHECK FOR INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
Is intake air leak detected?
YES
Repair or replace.
NO
GO TO 4.
- CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE
- Clear the mixture ratio self-learning value. Refer to Work Procedure .
- Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171 or P172 detected? Is it difficult to start engine?
YES
Perform trouble diagnosis for DTC P0171 or P0172. Refer to DTC Diagnosis Procedure or DTC Diagnosis Procedure
NO
GO TO 5.
- CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
- Disconnect A/F sensor 1 harness connector.
- Turn ignition switch ON.
- Check the voltage between A/F sensor 1 harness connector and ground.
+
-
Voltage
A/F sensor 1
Connector
Terminal
F44
4
Ground
Battery voltage
Is the inspection result normal?
YES
GO TO 6.
NO
Repair or replace error-detected parts.
- CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT
- Turn ignition switch OFF.
- Disconnect ECM harness connector.
- Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
+
-
Continuity
A/F sensor 1
ECM
Connector
Terminal
Connector
Terminal
F44
1
F90
86
Existed
2
88
- Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector and ground.
+
-
Continuity
A/F sensor 1
Connector
Terminal
F44
1
Ground
Not existed
2
+
-
Continuity
ECM
Connector
Terminal
F90
86
Ground
Not existed
88
- Also check harness for short to power.
Is the inspection result normal?
YES
GO TO 7.
NO
Repair or replace error-detected parts.
- CHECK AIR FUEL RATIO (A/F) SENSOR 1 HEATER
Refer to Component Inspection .
Is the inspection result normal?
YES
GO TO 8.
NO
GO TO 11.
- CHECK MASS AIR FLOW SENSOR
Refer to Component Inspection .
Is the inspection result normal?
YES
GO TO 9.
NO
Replace mass air flow sensor. Refer to AIR CLEANER AND AIR DUCT : Exploded View .
- CHECK PCV VALVE
Refer to POSITIVE CRANKCASE VENTILATION : Periodic Maintenance .
Is the inspection result normal?
YES
GO TO 10.
NO
Repair or replace PCV valve. Refer to Component Location .
- CHECK INTERMITTENT INCIDENT
Perform Refer to Inspection .
Is the inspection result normal?
YES
GO TO 11.
NO
Repair or replace.
- REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace air fuel ratio (A/F) sensor 1. Refer to CATALYST : Exploded View .
INSPECTION END