Diagnostic procedure

WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

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 WIRING HARNESS NOTE: Disconnect the HO2S wiring harness connector Only the suspect HO2S needs to be diagnosed. Switch the ignition to off. Disconnect the HO2S connector. Visually inspect the HO2S wiring harness. Check the connector (both halves) for contamination Make sure the connector pins are fully seated Is a concern present?	Yes	Repair if necessary. Go to Step 8.
3		No	Go to the next step.
4	INSPECT WHETHER HO2S SIGNAL LEVEL IS TOO HIGH Connect the HO2S connector Switch the ignition to ON (Engine running) Access and monitor the following HO2S signal PID. P0138:00. O2S12 P0158:00: O2S22 Is the voltage less than 1.1V?	Yes	Go to the next step.
4		No	Go to Step 6.
5	PERFORM THOROUGH WIGGLE TEST ON HO2S WIRING HARNESS Switch the ignition to off Switch the ignition to ON (Engine off) Access and monitor the HO2S signal PID on Step 4 Perform a thorough wiggle test on the HO2S wiring harness Does the voltage change during the wiggle test?	Yes	Repair if necessary. Go to Step 8.
5		No	Perform the "INTERMITTENT CONCERN TROUBLESHOOTING". Then go to the next step.
6	INSPECT HO2S SIGNAL FOR SHORT TO POWER SUPPLY INSIDE SENSOR Switch the ignition to off. Disconnect suspect HO2S connector. Start the engine and run it at idle. Access and monitor the HO2S signal PID at Step 4. Is the voltage less than 1.1V?	Yes	Replace suspect HO2S. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [MZI-3.7] .) Then go to Step 8.
6		No	Go to the next step.
7	INSPECT HO2S CIRCUIT FOR SHORT TO POWER SUPPLY IN WIRING HARNESS Switch the ignition to off. Disconnect the PCM connector. Switch the ignition ON (Engine off) Measure the voltage between HO2S terminal B and body ground. Is any voltage present?	Yes	Repair or replace suspected part, then go to the next step.
7		No	Go to the next step. (The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.)
8	VERIFY TROUBLESHOOTING OF DTC P0138:00, P0158:00 HAS BEEN COMPLETED Verify that all disconnected connectors are reconnected. Switch the ignition ON (Engine off) Clear the DTC from the PCM memory using the M-MDS. Perform the KOER self-test (See KOEO/KOER SELF TEST [MZI-3.7] ) Is the PENDING CODE for this DTC present?	Yes	Replace PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [MZI-3.7] .)
8		No	Go to the next step.
9	VERIFY AFTER REPAIR PROCEDURE Perform "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE [MZI-3.7] ) Are any DTC present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [MZI-3.7] )
9		No	Troubleshooting completed