U0140: Lost Communication With Body Control Module
Another module has stopped receiving messages from the body control module.
Normal risk
Usually not a driving risk, but check that lights and wipers work.
Short answer · Can I keep driving with U0140?
Usually yes, if lights, wipers and locks work. Have it checked soon.
What does U0140 mean?
U0140 is stored when modules stop receiving messages from the body control module (BCM), which controls functions such as lights, locks and wipers.
What the car does when the code is set
Functions of the affected module may stop working or behave strangely, for example lights, locks, climate control, displays or the radio.
How the system works
Body functions such as lights, locks, displays, climate control and audio are handled by modules on the body network. A gateway often links this network to others. Missing messages from one module are stored as lost communication codes in the others.
Common symptoms
Possible causes
Listed without ranking. The cause on your car depends on make, engine and mileage — see the maker notes below.
- Power or ground fault at the moduleA blown fuse or poor ground.
- Network wiring faultDamaged or corroded wires and connectors.
- Low battery voltageCommon after the car has stood for a long time.
- Aftermarket equipmentAccessories connected to the body network can disturb it.
- Failed modulePossible, but check the basics first.
How it is diagnosed
- Check which functions do not workLights, locks, dashboard displays or climate control point to the module concerned.
- Check fuses and battery voltageUse the fuse diagram for the module.
- Look for water entryWet carpets, door seals and sunroof drains often explain corroded body modules.
- Scan all modulesA workshop checks whether the module responds and tests the network.
Questions about U0140
Can a BCM fault drain the battery?
A module that does not go to sleep can drain the battery.
Is a body network code dangerous?
Usually not for driving, unless lights, wipers or other safety functions stop working.