Fault code B1346 – a step-by-step guide to diagnosing and fixing it

Error code B1346 is displayed and the check engine light is on - what does this mean?

The DTC B1346 is a body control module (BCM) fault code that is detected by the OBD/EOBD system and indicates a problem with the electrical circuitry or sensors in the body area. This trouble code typically relates to communication between different control units or defective components in the comfort system. Depending on the vehicle manufacturer, the exact definition of fault code B1346 can vary, but usually refers to problems with the central locking system, power windows or other electrical body functions.

What causes can this fault code have?

• Defective body control module (BCM)
• Damaged cable connections to the control unit
• Corroded or loose plug connections
• Defective sensors in the door area
• Faulty central locking components
• Blown fuses in the BCM circuit
• Faults in the CAN bus communication
• Water damage to electrical components
• Defective power window motors or switches

What symptoms occur in parallel with fault code B1346?

• Central locking problems: The doors cannot be locked or unlocked centrally
• Power window failures: Individual or all power windows do not work
• Interior lighting: Irregular behavior of the interior lighting
• Comfort functions: Failure of seat heating, air conditioning or other electrical systems
• Warning lights: Various indicator lights in the dashboard come on
• Starting problems: In rare cases, the vehicle may fail to start

How to fix the problem of error code B1346?

• Repairing EOBD error code B1346 requires a systematic diagnosis of the affected electrical systems.
• Perform a BCM reset: Disconnect the battery for 15 minutes to reset the body control module and fix temporary software errors
• Check plug connections: Clean all connections to the BCM, check for corrosion and tighten firmly
• Check fuses: Identify and replace defective fuses in the BCM circuit
• Inspect wiring harness: Repair or replace damaged wiring between BCM and affected components
• Test sensors: Check defective door or window sensors with a multimeter and replace if necessary
• Update BCM software: Have the specialist dealer install the latest firmware for the body control module
• Replace the entire BCM: In the event of irreparable damage, replace the entire control unit with a new or reconditioned module