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U0140 — Lost Communication with Body Control Module
SeriousNetwork/CANPower derate likely — plan to stop soon
Seen on: Heavy Truck
Lost Communication with Body Control Module. Common causes: BCM not responding.
Don't risk it — get a diesel tech on the truck.
Your code rides along, so nearby mechanics see the fault before they quote you.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- BCM not responding
- BCM power/ground
- CAN fault
First moves (roadside)
- Check BCM power
- ground
- and CAN bus connections
FAQ
What does U0140 mean?
Lost Communication with Body Control Module. Common causes: BCM not responding.
How serious is U0140?
Serious — Power derate likely — plan to stop soon.
What's the most likely cause of U0140?
The most common cause is: BCM not responding. Other possibilities include BCM power/ground; CAN fault.
Can I keep driving with U0140?
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Throwing this code right now?
Find a mechanic or related guides
General diagnostic guidance for diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.