U0140: Lost communication with the body control module (BCM)

What U0140 means

The body control module (BCM) looks after many cabin functions: lights, indicators, central locking, wipers, electric windows and sometimes the immobiliser. This code means it has stopped talking to the other control units over the data network. Because it does so much, the symptoms can vary widely.

Most common causes

• Low battery or loose terminals
• Blown power fuse for the body control module
• Loose, corroded or damp connector on the module (often from water leaking through the windscreen or blocked drains)
• Poor ground on the module
• Damaged network wiring
• Faulty body control module or a programming fault

Symptoms

• Lights, indicators or wipers failing or staying on
• Central locking or remote key not responding
• Various warnings on the dashboard
• Battery drain with the car parked
• On some cars, no start

Can you drive with U0140?

With care You can drive if lights, indicators and wipers work, but take care. Get it seen soon, as it can leave you without lights or unable to start.

How to check it

Before going to the garage, test lights, indicators, wipers and locking so you can tell them exactly what fails. Also look for damp carpets in the driver or passenger footwell, where this module often sits.

How to read and clear U0140 with Final OBD

Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see U0140 with this same explanation and whether it’s confirmed, pending or permanent.

With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.

Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.

Similar codes

• U0121 Lost communication with the ABS control module
• U0126 Lost communication with the steering angle sensor module
• U0128 Lost communication with the park brake control module
• U0131 Lost communication with the power steering control module
• U0141 Lost communication with body control module A
• U0146 Lost communication with gateway A
• U0151 Lost communication with the restraints control module
• U0155 Lost communication with the instrument cluster
• U0100 Lost communication with engine control module (ECM/PCM A)
• U0101 Lost communication with transmission control module (TCM)
• U0102 Lost communication with transfer case control module
• U0103 Lost communication with the gear shift module

U0140 is a generic code, so it means the same on any make, for example on BMW, Citroën, Ford, Mercedes-Benz, Renault, Volvo. See what Final OBD does on your car in makes and models.