Diagnostic Procedure

WARNING: This page is about a different car, the 2020 Mazda CX-30. However, it is still accessible from the selected car via links, so may be relevant.

DTC U0401:00 (TCM, ET6A-EL, ET6AX-EL, US) DIAGNOSTIC PROCEDURE

Step	Inspection	Results	Action
1	RECORD VEHICLE STATUS WHEN DTC WAS DETECTED TO UTILIZE WITH REPEATABILITY VERIFICATION Record the freeze frame data/snapshot data. NOTE: Recording can be facilitated using the screen capture of the PC function.	-	Go to the next step.
2	VERIFY RELATED REPAIR INFORMATION OR SERVICE INFORMATION AVAILABILITY Verify related Service Bulletins, online repair information, or Service Information availability. Is any related information available?	Yes	Perform repair or diagnosis according to the available information. If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VERIFY PCM DTC Perform the PCM DTC inspection using the M-MDS. (See DTC INSPECTION .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [PCM (SKYACTIV-G (US))] .)
3		No	Go to the next step.
Repair completion verification	VERIFY DTC TROUBLESHOOTING COMPLETED Clear the DTC using the M-MDS. (See CLEARING DTC .) Perform the following procedure to ensure that the DTC has been resolved: Start the engine and warm it up completely. Drive the vehicle for a while under the following conditions: Selector lever position: D position Perform the DTC inspection using the M-MDS. (See DTC INSPECTION .) Are any DTCs present?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See ON-BOARD DIAGNOSTIC SYSTEM DTC TABLE (TCM) (US) .)
Repair completion verification		No	DTC troubleshooting completed.