U0140 Code: Lost Communication with BCM — Causes & Fix
U0140 means lost communication with the body control module (BCM) — the module that manages lights, locks, and many body electrics.
- Applies to
- All OBD-II vehicles (any make or model)
- Est. repair cost
- $50 – $800
- Time to fix
- 1–4 hours
What it means
Causes include BCM power/ground loss, CAN wiring faults, or a failed BCM. U0140 is a generic OBD-II network/communication ("U") code defined in the SAE J2012 standard, so it applies to virtually any modern OBD-II vehicle regardless of make. These faults usually point to the vehicle's data bus (often CAN) or a module that has dropped off the network. Fix the wiring/module fault, then clear the code with a scan tool.
Symptoms
- Multiple body-electrical features not working
- Warning lights
- Lights/locks/wipers acting up
How to fix it
- 1
Check BCM power and grounds
1. Verify BCM power and grounds. 2. Inspect the CAN wiring to the BCM.
- 2
Diagnose the BCM
1. Scan whether the BCM responds. 2. Repair wiring or address the module, then clear the code.
Frequently asked questions
Why did lots of features stop with U0140?
The body control module runs many electrics. If the network loses it, those features stop working together. Check BCM power, grounds, and wiring.
Last updated July 19, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.