Diagnostic Procedure

WARNING: This page is about a different variant/trim than selected.

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA HAS BEEN RECORDED Has FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
1		No	Record FREEZE FRAME DATA 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 Service Bulletins available?	Yes	Perform repair or diagnosis according to the available Service Bulletins. If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VISUALLY INSPECT HO2S HARNESS Switch the ignition to off. Disconnect the suspect HO2S connector. Visually inspect suspect HO2S for: Pinched, shorted, and corroded wiring and pins Oil or water contamination Crossed sensor wires Damaged HO2S Is a concern present?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 11.
3		No	Go to the next step.
4	CHECK FOR UNMETERED AIR LEAKS NOTE: Fuel calculations can be affected by unmetered air leaks. Carefully inspect the following areas for potential air leaks: Hoses connecting to the MAF sensor assembly Hoses connecting to the throttle body Intake manifold gasket leaks PCV system Vacuum lines are disconnected Improperly seated engine oil dipstick, tube or oil fill cap Is a concern present?	Yes	Repair the source of the air leak. Go to Step 11.
4		No	Go to the next step.
5	INSPECT FOR SOURCE OF POTENTIAL HO2S CONTAMINATION Investigate the following items as potential sources of HO2S contamination: Use of unapproved silicon sealers Fuel contaminated by silicon additives Excessive oil consumption Glycol leaking internally in the engine Lead-contaminated fuel Short drive cycles in cold weather Use of unapproved cleaning agents Is a concern present?	Yes	Repair the source of the contamination. Change the engine oil and oil filter. Go to Step 11.
5		No	Go to the next step.
6	INSPECT EXHAUST SYSTEM AND FUEL SELECTION CONCERNS Inspect the suspect exhaust system for the following: Leaks, cracks, or punctures at flanges and gaskets Aftermarket accessories and performance modifications Exhaust leaks at the HO2S Verify with the customer that flex fuel is not being used on a non-flex fuel vehicle. Is a concern present?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 11.
6		No	Go to the next step.
7	CHECK HO2S CIRCUIT(S) FOR OPEN IN HARNESS NOTE: Diagnose the suspect sensor indicated by the DTC. Verify the harness pins are in the correct location. Suspect HO2S connector is disconnected. Switch the ignition to off. Disconnect the PCM connector. Check the connector (both halves) for any water contamination and replace if necessary. Measure the resistance between the following terminals (wiring harness-side): P2A01:00: HO2S (RH) terminal B-PCM terminal 3Z HO2S (RH) terminal D-PCM terminal 2G P2A04:00: HO2S (LH) terminal B-PCM terminal 3AB HO2S (LH) terminal D-PCM terminal 2G Is the resistance less than 5 ohm?	Yes	Go to the next step.
7		No	Repair for open circuit, then go to Step 11.
8	CHECK HO2S CIRCUIT FOR SHORT TO GROUND Suspect HO2S and PCM connectors are disconnected. Measure the resistance between the following suspect HO2S terminals: P2A01:00: HO2S (RH) terminals B and D (wiring harness-side) HO2S (RH) terminal B (wiring harness-side) and body ground P2A04:00: HO2S (LH) terminals B and D (wiring harness-side) HO2S (LH) terminal B (wiring harness-side) and body ground Is the resistance greater than 10 kilohms?	Yes	Go to the next step.
8		No	Repair for short circuit, then go to Step 11.
9	CHECK HO2S CIRCUIT FOR SHORT TO VOLTAGE Suspect HO2S and PCM connectors are disconnected. Switch the ignition to ON (engine off). Measure the voltage between the following suspect HO2S terminals (wiring harness-side) and body ground: HO2S (RH) terminal B (P2A01:00) HO2S (LH) terminal B (P2A04:00) Is there any voltage?	Yes	Repair for short circuit, then go to Step 11.
9		No	Go to the next step.
10	CHECK HO2S CIRCUIT CONTINUITY NOTE: HO2S is displayed as O2S on the scan tool. Suspect HO2S and PCM connectors are disconnected. Switch the ignition to off. Reconnect the PCM connector. Connect a 5 A fused jumper wire between suspect HO2S terminal (wiring harness-side) B and D Start the engine and run it at idle. Access the PCM and monitor the suspect HO2S signal PID. (See ON-BOARD DIAGNOSTIC TEST .) O2S11 (VOLT) PID (P2A01:00) O2S21 (VOLT) PID (P2A04:00) Is the voltage greater than 1 V?	Yes	Replace the HO2S, then go to the next step. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION .)
10		No	Go to the next step. (The system is operating normal at this time. The concern may have been caused by a loose or corroded connector.)
11	VERIFY TROUBLESHOOTING OF DTC P2A01:00, P2A04:00 HAS BEEN COMPLETED Verify that all disconnected connectors are reconnected. Switch the ignition to ON (Engine off). Clear the DTC from the PCM memory using the M-MDS. 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.
11		No	Go to the next step.
12	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 .)
12		No	Troubleshooting completed.