U0140 Lost communication with body control module
What U0140 means
The body control module manages lights, locks, wipers, windows and often the immobiliser. U0140 means other modules on the vehicle network stopped receiving its messages. Depending on the car, many comfort and lighting functions can stop working, and in some cases the car may not start.
U0140 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.
At a glance
- Severity
- Medium
- Typical repair cost
- 100–1800 €
- Workshop time
- 1–6 h
- Repair difficulty
- Hard
- DIY possible
- No
- Check engine light
- Yes
- Affects emissions test
- No
Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.
Symptoms
- Several warning lights on
- Lights, wipers, central locking or windows not working
- Instrument cluster behaving oddly
- Possible no-start if the BCM handles the immobiliser
Common causes
- Blown fuse or failed power supply to the BCM
- Poor ground connection at the BCM
- Water ingress into the BCM or its connectors
- Damaged CAN bus wiring
- Failed body control module
Can I keep driving with U0140?
You can usually drive if the car starts, but have it diagnosed within one or two weeks. Check that headlights, indicators and wipers work before driving.
What to check first
- Check battery voltage and the fuses and relays that supply the BCM
- Try to communicate with the BCM directly using a scan tool
- Inspect the BCM and its connectors for water damage or corrosion, often under the dashboard or in the footwell
- Check the BCM ground and CAN wiring before replacing and programming a new module
Related codes
- U0127 Lost communication with tyre pressure monitor module
- U0126 Lost communication with steering angle sensor module
- U0121 Lost communication with ABS control module
- U0120 Lost communication with starter/generator control module
- U0109 Lost communication with fuel pump control module
- U0184 Lost communication with radio
- U0046 Vehicle communication bus C fault
- U0252 Lost communication with rear lighting control module B
Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
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