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Home >> Mazda >> 2021 >> CX-30 Turbo >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Communication Devices >> On-Board Diagnostic - Body Control Module (BCM) (2 Of 2) >> DTC U0300-57: Body Control Module (BCM) Internal Malfunction [Body Control Module (BCM)] >> Diagnostic Procedure
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Diagnostic Procedure

DTC U0300:57 (BODY CONTROL MODULE) DIAGNOSTIC PROCEDURE

Step Inspection Results Action
1 VERIFY BODY CONTROL MODULE (BCM) REPLACEMENT RECORD
  • Verify if the body control module (BCM) has been replaced before performing this troubleshooting procedure.
  • Has the body control module (BCM) been replaced?
 Yes After performing the procedure required for the body control module (BCM) replacement again, perform the repair completion verification according to the [BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION].
(See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION (US) .)
No Go to the next step.
2 INSPECT BODY CONTROL MODULE (BCM) FOR MALFUNCTION
  • 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 body control module (BCM) and perform the repair completion verification.
(See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION (US) .)
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.
No DTC troubleshooting completed.
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