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	VERIFY FUEL AND ENGINE OIL CONDITIONS NOTE: An engine that consumes oil at a high rate deposits high levels of phosphorus on the catalyst and reduces the catalyst efficiency. Make sure the customer has not: Refueled the vehicle with leaded gasoline. Noticed a high vehicle oil consumption. Does the vehicle exhibit one of the above conditions?	Yes	Replace the fuel and/or engine oil. Go to the next step.
3		No	Go to the next step.
4	VERIFY RELATED PENDING CODE OR STORED DTCs Switch the ignition to off, then to the ON (Engine off). Verify related pending code or stored DTCs. Is other DTCs present?	Yes	Go to the appropriate DTC troubleshooting. (See DTC TABLE [MZI-3.7] .)
4		No	Go to the next step.
5	INSPECT THE ELECTRONIC ENGINE CONTROL (EEC) WIRING HARNESS NOTE: Inspect the A/F sensor and HO2S electrical connectors to make sure the correct A/F sensor and HO2S are connected to the correct electrical connector. The electrical connectors are color coded to make sure the correct connection is made. If the electrical connection of the A/F sensor and HO2S are interchanged/crossed, the catalyst efficiency monitor test fails. Visually inspect for following: HO2S wiring harness connectors for any indication of crossed wiring. Wiring harness for exposed wiring, corrosion and correct routing. PCM connectors for damaged or pushed out pins, corrosion and loose wires Are there any concerns with the wiring or the PCM connection?	Yes	Repair or replace malfunctioning part. Then go to Step 10.
5		No	Go to the next step.
6	CHECK THE FUEL PRESSURE NOTE: Fuel pressure above the specification can produce an abnormally rich air/fuel mixture. This rich air/fuel mixture can cause higher than normal catalyst operating temperatures. Connect the fuel pressure gauge. (See FUEL LINE PRESSURE INSPECTION [MZI-3.7] .) Start the engine and record the fuel pressure. Switch the ignition to off. Is the fuel pressure within the specification?	Yes	Go to the next step.
6		No	Repair or replace malfunctioning part according to the inspection results. Then go to Step 10.
7	INSPECT GAS LEAKAGE OF EXHAUST SYSTEM Visually inspect for exhaust gas leakage in exhaust system. Are there gas leakage?	Yes	Repair or replace malfunctioning exhaust parts, then go to Step 10.
7		No	Go to the next step.
8	INSPECT INSTALLATION OF A/F SENSOR AND HO2S Inspect for looseness of A/F sensor and HO2Ss Are they it normal?	Yes	Go to the next step.
8		No	Retighten sensor, then go to Step 10
9	INSPECT TWC Clear the DTC using the M-MDS Cycle the ignition switch off then back to the ON position Inspect the TWC. Is it normal?	Yes	Go to the next step
9		No	Replace the TWC, then go to the next step.
10	VERIFY TROUBLESHOOTING OF DTC P0420:00, P0430:00 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. Start the engine and run it at idle Retrieve DTCs using the M-MDS 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] .)
10		No	Go to the next step.
11	VERIFY AFTER REPAIR PROCEDURE Perform the "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] )
11		No	Troubleshooting completed.