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 U0100:87 (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	PERFORM IMMOBILIZER SYSTEM-RELATED PART PROGRAMMING Perform the procedure for immobilizer system-related parts programming. (See IMMOBILIZER SYSTEM-RELATED PARTS PROGRAMMING (US) .) 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.
2		No	Go to repair completion verification.
3	INSPECT BODY CONTROL MODULE (BCM) FOR MALFUNCTION DEPENDING ON REPEATABILITY 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, replace the body control module (BCM) and perform the repair completion verification. (See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION (US) .)
3		No	Go to repair completion verification.
4	INSPECT PCM FOR MALFUNCTION DEPENDING ON REPEATABILITY 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, replace PCM and perform the repair completion verification. (See PCM REMOVAL/INSTALLATION (VIN M) .) (See PCM REMOVAL/INSTALLATION (VIN L) .)
4		No	Go to the next step.
Repair completion verification	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		No	DTC troubleshooting completed.