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	INSPECT FOR POWER SUPPLY IN WIRING HARNESS Switch the ignition to off. Disconnect the A/F sensor connector Switch the ignition to ON (Engine off). Measure the voltage between suspect A/F sensor wiring harness-side connector terminal 2 and ground. Is the voltage greater than 10 V?	Yes	Switch the ignition to off. Go to the next step.
3		No	Inspect the ENGINE fuse If there is fuse deterioration, replace the fuse. If the fuse has melted, repair for a short to ground and replace the fuse. If the fuse is normal, repair an open circuit. Go to Step 9.
4	INSPECT A/F SENSOR HEATER CIRCUIT FOR OPEN CIRCUIT IN WIRING HARNESS Disconnect the A/F sensor connector. Disconnect PCM connector For DTC P0135:00 Measure the resistance between A/F sensor (RH) wiring harness-side connector terminal 4 and PCM wiring harness-side connector terminal 2J For DTC P0155:00. Measure the resistance between A/F sensor (LH) wiring harness-side connector terminal 4 and PCM wiring harness-side connector terminal 2E Is the resistance less than 5 ohm?	Yes	Go to the next step.
4		No	Repair an open circuit, then go to Step 9.
5	INSPECT A/F SENSOR HEATER CIRCUIT FOR SHORT CIRCUIT TO GROUND Measure the resistance between A/F sensor wiring harness-side connector terminal 4 and ground Is the resistance greater than 10 kilohms?	Yes	Go to the next step.
5		No	Repair for a short to ground circuit, then go to Step 9.
6	INSPECT A/F SENSOR HEATER CIRCUIT FOR SHORT CIRCUIT IN WIRING HARNESS Measure the resistance between A/F sensor wiring harness-side connector terminal 4 and the following terminals A/F sensor wiring harness-side connector terminal 1 A/F sensor wiring harness-side connector terminal 2 A/F sensor wiring harness-side connector terminal 3 A/F sensor wiring harness-side connector terminal 5 A/F sensor wiring harness-side connector terminal 6 Is the resistance greater than 10 kilohms?	Yes	Go to the next step.
6		No	Repair for a short circuit, then go to Step 9.
7	INSPECT A/F SENSOR INTERNAL RESISTANCE OF A/F SENSOR HEATER Measure the resistance between A/F sensor connector terminal 2 and 4 on the component side Is the resistance between 1-10 ohms?	Yes	Go to the next step.
7		No	Replace the suspect A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [MZI-3.7] .) Go to Step 9.
8	INSPECT A/F SENSOR HEATER CIRCUIT FOR INTERNAL SHORT CIRCUIT TO GROUND Measure the resistance between A/F sensor component side connector terminal 4 and ground. Is the resistance greater than 10 kilohms?	Yes	Go to the next step. (The system is operating normally at this time. The concern may have been caused by a loose or corroded connector.)
8		No	Replace the suspect A/F sensor (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [MZI-3.7] .) Go to the next step.
9	VERIFY TROUBLESHOOTING OF DTCs P0135:00, P0155:00 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 KOER self-test (See KOEO/KOER SELF TEST [MZI-3.7] .) Is the pending code for this DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [MZI-3.7] .)
9		No	Go to the next step.
10	VERIFY AFTER REPAIR PROCEDURE Perform "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE [MZI-3.7] ) Are any DTC displayed?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [MZI-3.7] .)
10		No	Troubleshooting completed.