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 B13D3:94 (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 BODY CONTROL MODULE (BCM) DTCs Clear the DTC recorded in the memory. (See CLEARING DTC .) Perform the DTC inspection for the body control module (BCM). (See DTC INSPECTION .) Is a DTC related to a keyless receiver displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE (BCM) (US) .)
2		No	Go to the next step.
3	VERIFY BODY CONTROL MODULE (BCM) DTCs Clear the DTC recorded in the memory. (See CLEARING DTC .) Perform the DTC inspection for the body control module (BCM). (See DTC INSPECTION .) Is a DTC related to a keyless antenna displayed?	Yes	Repair the malfunctioning location according to the applicable DTC troubleshooting. (See DTC TABLE (BCM) (US) .)
3		No	Go to the next step.
4	VERIFY DTCs WITH REMOTE TRANSMITTER IN DIFFERENT LOCATIONS Perform the following procedure 3 times with the remote transmitter inside the cabin with certainty. Switch the ignition off. Switch the ignition ON (engine off or on). Perform the DTC inspection for the body control module (BCM). (See DTC INSPECTION .) Move the remote transmitter to a different location. Is the same Pending DTC present?	Yes	Go to the next step.
4		No	Go to repair completion verification 2.
5	INSPECT PUSH BUTTON START CONNECTOR FOR MALFUNCTION Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION .) Is the connector and terminal normal?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning location and perform the repair completion verification.
6	INSPECT LF CONTROL UNIT CONNECTOR FOR MALFUNCTION Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION .) Are the connector and terminal normal?	Yes	Go to the next step.
6		No	Repair or replace the malfunctioning location and perform the repair completion verification.
7	INSPECT REMOTE TRANSMITTER FOR MALFUNCTION DEPENDING ON REPEATABILITY Install/connect the part removed/disconnected during the troubleshooting procedure. Clear the DTC recorded in the memory. (See CLEARING DTC .) Re-program key ID number of the remote transmitter. (See IMMOBILIZER SYSTEM-RELATED PARTS PROGRAMMING (US) .) 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, replace the remote transmitter, then go to the next step. (See IMMOBILIZER SYSTEM-RELATED PARTS PROGRAMMING (US) .)
7		No	Go to repair completion verification 2.
8	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.
8		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.