Diagnostic procedure

DTC P0031 [L3] DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA (MODE 2) Is DTC P0031 on FREEZE FRAME DATA (Mode 2)?	Yes	Go to the next step.
1		No	Go to troubleshooting for DTC on FREEZE FRAME DATA (Mode 2). (See DTC TABLE .)
2	VERIFY FREEZE FRAME DATA (MODE 12) AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED BEEN RECORDED Have FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor heater related) been recorded?	Yes	Go to the next step.
2		No	Record the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
3	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.
3		No	Go to the next step.
4	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 10.
4		No	Go to the next step.
5	INSPECT A/F SENSOR HEATER Inspect the A/F sensor heater. (See AIR FUEL RATIO (A/F) SENSOR INSPECTION .) Is the A/F sensor heater normal?	Yes	Go to the next step.
5		No	Replace the A/F sensor, then go to Step 10.
6	INSPECT POWER CIRCUIT OF A/F SENSOR HEATER FOR OPEN CIRCUIT OR SHORT TO GROUND A/F sensor connector is disconnected. Turn the ignition switch to the ON position. (Engine off). Measure voltage between A/F sensor terminal A (wiring-harness-side) and body ground. Is the voltage B+?	Yes	Go to the next step.
6		No	If the A/F sensor heater related fuse. If the fuse is melt: Repair or replace the wiring harness for a possible short to ground. Replace the fuse. If the fuse is deterioration: Replace the fuse. If the fuse is normal: Repair or replace for a possible open circuit. Then go to Step 10.
7	INSPECT CONTROL CIRCUIT OF A/F SENSOR HEATER FOR SHORT TO GROUND A/F sensor connector is disconnected. Turn the ignition switch off. Inspect for continuity between A/F sensor terminal E (wiring-harness-side) and body ground. Is there continuity?	Yes	If the short to ground circuit could be detected: Repair or replace for a possible short to ground. If the short to ground circuit could not be detected: Replace the PCM (short to ground in PCM internal circuit). (See PCM REMOVAL/INSTALLATION .) Then go to Step 10.
7		No	Go to the next step.
8	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 10.
8		No	Go to the next step.
9	INSPECT CONTROL CIRCUIT OF A/F SENSOR HEATER FOR OPEN CIRCUIT A/F sensor and PCM connectors are disconnected. 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.
9		No	Repair or replace the wiring harness for open circuit, then go to the next step.
10	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 .) 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 DTC present?	Yes	Go to the applicable DTC troubleshooting. (See DTC TABLE .)
11		No	Troubleshooting completed.