Diagnostic Procedure

DTC P0131 DIAGNOSTIC PROCEDURE TABLE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED. Have FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS (HO2S related) been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY Verify related Service Bulletins and/or on-line repair information availability. Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VERIFY RELATED PENDING OR STORED DTC Turn the ignition switch off, then to the ON position (Engine off). Verify the pending code or stored DTCs using the WDS or equivalent. Is other DTC present?	Yes	Go to the appropriate DTC troubleshooting procedures. (See DTC TABLE .)
3		No	Go to the next step.
4	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA Is DTC P0131 on FREEZE FRAME DATA?	Yes	Go to the next step.
4		No	Go to troubleshooting procedures for DTC on OBD-II FREEZE FRAME DATA . (See DTC TABLE .)
5	INSPECT FRONT HO2S CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect the front HO2S connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 10.
5		No	Go to the next step.
6	INSPECT FRONT HO2S CIRCUIT FOR SHORT TO GROUND Turn the ignition switch off. Inspect for continuity between the following terminals and body ground: Front HO2S terminal A (wiring harness-side) and body ground Front HO2S terminal B (wiring harness-side) and body ground Is there continuity?	Yes	Repair or replace the wiring harness for a possible short to ground, then go to Step 10.
6		No	Go to the next step.
7	INSPECT FRONT HO2S Inspect the front HO2S. (See FRONT HEATED OXYGEN SENSOR (HO2S) INSPECTION .) Is there any malfunction?	Yes	Replace the front HO2S, then go to Step 10. (See FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION .)
7		No	Go to the next step.
8	INSPECT PCM CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect the PCM connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 10.
8		No	Go to the next step.
9	INSPECT FRONT HO2S CIRCUIT FOR OPEN CIRCUIT Turn the ignition switch off. Inspect for continuity between the following circuits: Front HO2S terminal A (wiring harness-side) and PCM terminal 2AD (wiring harness-side) Front HO2S terminal B (wiring harness-side) and PCM terminal 2Z (wiring harness-side) Is there continuity?	Yes	Go to the next step.
9		No	Repair or replace the wiring harness for a possible open circuit, then go to the next step.
10	VERIFY TROUBLESHOOTING OF DTC P0131 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the WDS or equivalent. Perform the KOEO self-test (using WDS or equivalent) or the HO2S heater, HO2S, and TWC Repair Verification Drive Mode (not using WDS or equivalent). (See KOEO/KOER SELF TEST .) (See OBD-II DRIVE MODE .) Is the PENDING CODE for this DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION .)
10		No	Go to the next step.
11	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
11		No	DTC troubleshooting completed.