DTC Diagnosis Procedure

1. Turn ignition switch OFF.
2. Check ground connection E9. Refer to Ground Inspection in Circuit Inspection .

Is the inspection result normal?

YES

GO TO 2.

NO

Repair or replace ground connection.

1. Disconnect A/F sensor 1 harness connector.
2. Turn ignition switch ON.
3. Check the voltage between A/F sensor 1 harness connector and ground.

   A/F sensor 1		Ground	Voltage
   Connector	Terminal
   F65	1	Ground	Battery voltage

Is the inspection result normal?

YES

GO TO 4.

NO

GO TO 3.

1. Turn ignition switch OFF.
2. Disconnect IPDM E/R harness connector.
3. Check the continuity between IPDM E/R harness connector and A/F sensor 1 harness connector.

   +		-		Continuity
   IPDM E/R		A/F sensor 1
   Connector	Terminal	Connector	Terminal
   E119	8	F65	1	Existed

4. Also check harness for short to ground.

Is the inspection result normal?

YES

Perform the trouble diagnosis for power supply circuit.

NO

Repair or replace error-detected parts.

1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.

   A/F sensor 1		ECM		Continuity
   Connector	Terminal	Connector	Terminal
   F65	3	F77	66	Existed
   	4		67

4. Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector and ground.

   A/F sensor 1		Ground	Continuity
   Connector	Terminal
   F65	3	Ground	Not existed
   	4

   ECM		Ground	Continuity
   Connector	Terminal
   F77	66	Ground	Not existed
   	67

5. Also check harness for short to power.

Is the inspection result normal?

YES

Replace malfunctioning air fuel ratio (A/F) sensor 1. Refer to Removal and Installation (Three Way Catalyst) .

NO

Repair open circuit, short to ground or short to power in harness or connectors.