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OBD-II · Network and communication (U)

U0140

Lost communication with body control module (BCM)

What it means

Another module has stopped receiving messages from the body control module, which runs lights, locks, wipers and similar functions.

Symptoms

  • Lights, central locking, wipers or windows not working
  • Immobiliser may stop the engine starting
  • Several warning messages on the dash

Likely causes, most likely first

Likely causes, most likely first
No.Cause
01weak 12V battery or recent battery disconnection
02blown BCM fuse
03water ingress into the BCM (often under the dashboard or in a footwell after a blocked drain or leaking windscreen seal)
04corroded BCM connectors
05failed BCM

What to check, step by step

  1. 01Check 12V battery and fuses
  2. 02Check whether the BCM answers a scan tool
  3. 03Look for water in the footwells and around the BCM; check scuttle drains and windscreen seal
  4. 04Inspect BCM connectors for corrosion
  5. 05Test power, ground and CAN at the BCM