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Network fault code

U0140: Lost Communication With Body Control Module

Fix soon

Effects range from a warning light to systems not working. Have it checked soon.

What U0140 means

Two of the car's computers have stopped talking to each other over the in-car network.

Common causes

  • Weak battery or poor earth connections
  • Damaged network wiring or connector
  • A module that has failed or lost power

What to check first

  1. Check the battery and earth connections first.
  2. Check the fuse for the module named in the code.

Get U0140 explained for your car: $2.99

  • U0140 explained in full for your make and model: meaning, how urgent, likely causes and what to check, in order.
  • A short personal note from us within 24 hours, or your money back.
  • Your own private report page you can save as a PDF or show your mechanic.

Read your car's codes yourself, free

Plug a cheap ELM327 OBD-II adapter into the port under the dashboard and open the scan tool: Chrome or Edge on a computer with a USB adapter, or Chrome on Android with a Bluetooth LE adapter. It reads and clears codes and shows emissions readiness. It does not work on iPhone.

Open the free scan tool

Need help with U0140?

Tell us your car and what it is doing with U0140. We reply by email with what to check first, in plain words. Free.

Related codes

U0001U0100U0101U0121U0155

General guidance only, not a diagnosis. A qualified mechanic should confirm the cause before you replace parts.