Diagnostic Procedure

DTC P0031:00 DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA (MODE 2)/SNAPSHOT DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED Have the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor heater, HO2S heater related) been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA (Mode 2)/snapshot 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 CONNECTOR CONDITION Switch the ignition to 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 connector and/or terminals, 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 .) Is there any malfunction?	Yes	Replace the A/F sensor, then go to Step 9. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION .)
4		No	Go to the next step.
5	INSPECT A/F SENSOR HEATER POWER SUPPLY CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT Verify that the A/F sensor connector is disconnected. Switch the ignition to ON (engine off). Measure the voltage at the A/F sensor terminal 2B (wiring harness-side). Is the voltage B+?	Yes	Go to the next step.
5		No	Inspect the ENG BAR 15 A fuse. If the fuse is blown: Repair or replace the wiring harness for a possible short to ground. Replace the fuse. If the fuse is deteriorated: Replace the fuse. If the fuse is normal: Repair or replace the wiring harness for a possible open circuit. Go to Step 9.
6	INSPECT A/F SENSOR HEATER CONTROL CIRCUIT FOR SHORT TO GROUND Verify that the A/F sensor connector is disconnected. Switch the ignition to off. Inspect for continuity between A/F sensor terminal 2D (wiring harness-side) and body ground. Is there continuity?	Yes	If the short to ground circuit could be detected: Repair or replace the wiring harness for a possible short to ground. If the short to ground circuit could not be detected: Replace the PCM (short to ground in the PCM internal circuit). (See PCM REMOVAL/INSTALLATION .) Go to Step 9.
6		No	Go to the next step.
7	INSPECT PCM CONNECTOR CONDITION Disconnect the PCM connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Is there any malfunction?	Yes	Repair or replace the connector and/or terminals, then go to Step 9.
7		No	Go to the next step.
8	INSPECT A/F SENSOR HEATER CONTROL CIRCUIT FOR OPEN CIRCUIT Verify that the A/F sensor and PCM connecters are disconnected. Inspect for continuity between A/F sensor terminal 2D (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 a possible open circuit, then go to the next step.
9	VERIFY DTC TROUBLESHOOTING COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the M-MDS. (See AFTER REPAIR PROCEDURE .) Perform the KOEO or KOER self test. (See KOEO/KOER SELF TEST .) Is the PENDING CODE for this DTC present?	Yes	Repeat the inspection from Step 1. If the malfunction recurs, replace the PCM. (See PCM REMOVAL/INSTALLATION .) Go to the next step.
9		No	Go to the next step.
10	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 .)
10		No	DTC troubleshooting completed.