P0131

P0131, P0151 A/F SENSOR 1

DTC Logic


DTC DETECTION LOGIC

To judge the malfunction, the diagnosis checks that the A/F signal computed by ECM from the A/F sensor 1
signal is not inordinately low.






DTC CONFIRMATION PROCEDURE


1. PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next test.
1.Turn ignition switch OFF and wait at least 10 seconds.
2.Turn ignition switch ON.
3.Turn ignition switch OFF and wait at least 10 seconds.

TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10.5 V at idle.
- GO TO 2.

2. CHECK A/F SENSOR 1 FUNCTION

With CONSULT
1.Start engine and warm it up to normal operating temperature.
2.Select "A/F SEN1 (B1)" or "A/F SEN1 (B2)" in "DATA MONITOR" mode with CONSULT.
3.Check "A/F SEN1 (B1)" or "A/F SEN1 (B2)" indication.
With GST
Follow the procedure "With CONSULT" above.
Is the indication constantly approx. 0 V?
YES- Proceed to "Diagnosis Procedure" .
NO- GO TO 3.

3. PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT
1.Turn ignition switch OFF, wait at least 10 seconds.
2.Turn ignition switch ON.
3.Turn ignition switch OFF, wait at least 10 seconds and then restart engine.
4.Drive and accelerate vehicle to more than 40 km/h (25 MPH) within 20 seconds after restarting engine.

CAUTION:
Always drive vehicle at a safe speed.
5.Maintain the following conditions for approximately 20 consecutive seconds.





NOTE:
-Keep the accelerator pedal as steady as possible during cruising.
-If this procedure is not completed within 1 minute after restarting engine at step 1, return to step
1.
6.Check 1st trip DTC.
With GST
Follow the procedure "With CONSULT" above.
Is 1st trip DTC detected?
YES- Proceed to "Diagnosis Procedure" .
NO- INSPECTION END


Diagnosis Procedure


1. CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY

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.





Is the inspection result normal?
YES- GO TO 3.
NO- GO TO 2.

2. CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT

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





Is the inspection result normal?
YES- Perform the trouble diagnosis for power supply circuit.
NO- Repair or replace error-detected parts.

3. CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT

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.





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










5.Also check harness for 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.

4. CHECK INTERMITTENT INCIDENT

Check intermittent incident. Refer to "Intermittent Incident" Intermittent Incident.
Is the inspection result normal?
YES- Replace malfunctioning air fuel ratio (A/F) sensor 1. Refer to "Removal and Installation (LH)" Removal And Installation (LH) or "Removal and Installation (RH)" Removal And Installation (RH).
NO- Repair or replace error-detected parts.