Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.

DTC U0302 DIAGNOSTIC PROCEDURE

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 the FREEZE FRAME DATA on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY Check for related Service Bulletins and/or online repair information availability. Is any related repair information available?	Yes	Perform repair or diagnostic 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 TCM CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect the TCM connector. Check for poor connection (damaged, pulled-out pins, corrosion, etc.). Is there any malfunction?	Yes	Repair the terminal, then go to Step 8.
3		No	Go to the next step.
4	CHECK COMMUNICATION LINE FOR SHORT TO GROUND Check the continuity between the following terminals: TCM connector terminal AL and body ground TCM connector terminal O and body ground Is there continuity?	Yes	Repair or replace wiring harness, then go to Step 8.
4		No	Go to the next step.
5	CHECK COMMUNICATION LINE FOR SHORT TO POWER Measure the voltage between the following terminals: TCM connector terminal AL and body ground TCM connector terminal O and body ground Is voltage B+ ?	Yes	Repair or replace the wiring harness, then go to Step 8.
5		No	Go to the next step.
6	INSPECT PCM CONNECTOR FOR POOR CONNECTION Turn the ignition switch off. Disconnect the PCM connector. Check for poor connection (damaged, pulled-out pins, corrosion, etc.). Is there any malfunction?	Yes	Repair the terminal, then go to Step 8.
6		No	Go to the next step.
7	CHECK COMMUNICATION LINE FOR OPEN CIRCUIT Disconnect the PCM connector. Check the continuity between the following terminals: TCM connector terminal AL and PCM connector terminal 4AC TCM connector terminal O and PCM connector terminal 4Z Is there continuity?	Yes	Repair or replace the wiring harness, then go to the next step.
7		No	Go to the next step.
8	VERIFY TROUBLESHOOTING OF DTC U0302 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from PCM memory using the WDS or equivalent. Start the engine and warm it up completely. Is same PENDING code for this DTC present?	Yes	Replace PCM, then go to the next step.
8		No	Go to the next step.
9	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE ". (See AFTER REPAIR PROCEDURE .) Is there any DTC present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
9		No	Troubleshooting completed.