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.

   DTC	+			-	Voltage
   	A/F sensor 1
   	Bank	Connector	Terminal
   P0131	1	F72	1	Ground	Battery voltage
   P0151	2	F73	1

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.

   DTC	IPDM E/R		A/F sensor 1		Continuity
   	Connector	Terminal	Connector	Terminal
   P0131	F19	53	F72	1	Existed
   P0151			F73	1

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.

   DTC	A/F sensor 1			ECM		Continuity
   	Bank	Connector	Terminal	Connector	Terminal
   P0131	1	F72	3	F79	102	Existed
   			4		101
   P0151	2	F73	3		111
   			4		107

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

   DTC	A/F sensor 1			--	Continuity
   	Bank	Connector	Terminal
   P0131	1	F72	3	Ground	Not existed
   			4
   P0151	2	F73	3
   			4

   DTC	ECM			--	Continuity
   	Bank	Connector	Terminal
   P0131	1	F79	102	Ground	Not existed
   			101
   P0151	2		111
   			107

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 EXHAUST MANIFOLD AND THREE WAY CATALYST .

NO

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