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 B13D3:51 (BCM) DIAGNOSTIC PROCEDURE

Step	Inspection	Results	Action
1	VERIFY BODY CONTROL MODULE (BCM) DTCs AGAIN Clear the DTC recorded in the memory. (See CLEARING DTC .) Perform the DTC inspection for the body control module (BCM). (See DTC INSPECTION .) Is the same Pending DTC present?	Yes	Go to the next step.
1		No	Go to repair completion verification 2.
2	VERIFY IF REMOTE TRANSMITTER BROUGHT INTO VEHICLE IS FOR THAT VEHICLE Does the remote transmitter belong to another vehicle?	Yes	Have the correct transmitter for the vehicle ready inside the vehicle and perform the repair completion verification.
2		No	Go to the next step.
3	PERFORM DTC INSPECTION AND DETERMINE WHICH KEY HAS MALFUNCTION Perform the following work for each of the programmed remote transmitters: Clear the DTC recorded in the memory. (See CLEARING DTC .) Perform the DTC inspection for the body control module (BCM). (See DTC INSPECTION .) Is the same Pending DTC present?	Yes	Replace the malfunctioning remote transmitter, then go to the next step. (See IMMOBILIZER SYSTEM-RELATED PARTS PROGRAMMING (US) .)
3		No	Go to repair completion verification 2.
4	INSPECT PUSH BUTTON START FOR MALFUNCTION Inspect the applicable part. (See PUSH BUTTON START INSPECTION .) Is the part normal?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See PUSH BUTTON START REMOVAL/INSTALLATION .)
5	INSPECT LF CONTROL UNIT FOR MALFUNCTION Inspect the applicable part. (See LF CONTROL UNIT INSPECTION (US) .) Is the part normal?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See LF CONTROL UNIT REMOVAL/INSTALLATION (US) .)
Repair completion verification 1	VERIFY THAT VEHICLE IS REPAIRED Install/connect the part removed/disconnected during the troubleshooting procedure. Clear the DTC recorded in the memory. (See CLEARING DTC .) Perform the DTC inspection for the body control module (BCM). (See DTC INSPECTION .) Is the same Pending DTC present?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW (US) .) If the CAN communication is normal, perform the diagnosis from Step 1. If the malfunction recurs, replace the body control module (BCM), then go to the next step. (See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION (US) .)
Repair completion verification 1		No	Go to the next step.
Repair completion verification 2	VERIFY IF OTHER DTC IS DISPLAYED Perform the DTC inspection. (See DTC INSPECTION .) Are any other DTCs displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting.
Repair completion verification 2		No	DTC troubleshooting completed.