Diagnostic procedure

DTC P0031 (L3) DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED BEEN RECORDED. Have FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor heater 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	INSPECT A/F SENSOR TERMINALS Turn the ignition switch off. Disconnect the A/F sensor 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 9.
3		No	Go to the next step.
4	INSPECT A/F SENSOR HEATER Inspect the A/F sensor heater. (See AIR FUEL RATIO (A/F) SENSOR INSPECTION [L3] .) Is the A/F sensor heater normal?	Yes	Go to the next step.
4		No	Replace the A/F sensor, then go to Step 9.
5	INSPECT POWER CIRCUIT OF A/F SENSOR HEATER FOR OPEN CIRCUIT Turn the ignition switch to the ON position. (Engine off). Measure voltage between A/F sensor terminal C (wiring-harness-side) and body ground. Is the voltage B+?	Yes	Go to the next step.
5		No	Repair or replace the wiring harness for open circuit, then go to Step 9.
6	INSPECT PCM TERMINAL Disconnect the PCM connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Is there any malfunction?	Yes	Repair the terminal, then go to Step 9.
6		No	Go to the next step.
7	INSPECT CONTROL CIRCUIT OF A/F SENSOR HEATER FOR SHORT TO GROUND Turn the ignition switch off. Inspect for continuity between A/F sensor terminal E (wiring-harness-side) and body ground. Is there continuity?	Yes	Repair or replace the wiring harness for short to ground, then go to Step 9.
7		No	Go to the next step.
8	INSPECT CONTROL CIRCUIT OF A/F SENSOR HEATER FOR OPEN CIRCUIT Remove the PCM with the PCM connector connected. Inspect for continuity between A/F sensor terminal E (wiring-harness-side) and PCM terminal 2A (wiring-harness-side). Is there continuity?	Yes	Go to the next step.
8		No	Repair or replace the wiring harness for open circuit, then, go to the next step.
9	VERIFY TROUBLESHOOTING OF DTC P0031 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the M-MDS. Perform the KOEO self-test with M-MDS, or A/F sensor heater, HO2S heater, A/F sensor, HO2S, and TWC Repair Verification Drive Mode. (See OBD-II DRIVE MODE [L3] .) Is the PENDING CODE for this DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [L3] .)
9		No	Go to the next step.
10	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE [L3] .) Are any DTC present?	Yes	Go to the applicable DTC troubleshooting. (See DTC TABLE [L3] .)
10		No	Troubleshooting completed.