U0140Network Communication

Lost Communication With Body Control Module

U0140 means a module has lost communication with the body control module over the CAN bus. The BCM manages lighting, locks, and many accessories. It usually points to a wiring, power, ground, or connector fault.

🚗 Not recommended. The body control module manages many systems, so losing it can cause widespread faults.

HIGH

severity

🎯 Top Causes, Ranked by Likelihood

#1Wiring, connector, or CAN bus fault$50-$500

45%

Damaged or corroded wiring to the BCM.

#2Power or ground fault$50-$400

30%

Blown fuse or poor ground at the BCM.

#3Failed body control module$300-$1200

15%

The BCM itself has failed.

🩺 Common Symptoms

Multiple electrical faults
Lights, locks, or wipers not working
Warning lights
Erratic gauges
Other U-codes stored

💰 Repair Cost: DIY vs Shop

DIY Cost

$50-$400

Shop Cost

$150-$1000

📋 Free OBD2 Code Cheat Sheet

The 50 most common codes with likely cause and DIY fix cost. Sent once, no spam.

🔧 How to Diagnose U0140

1Check BCM fuses, power, and grounds first

2Inspect CAN wiring and connectors at the BCM

3Scan all modules for lost-communication patterns

4Back-probe the CAN bus for correct resistance and signal

❓ Frequently Asked Questions

Can I drive with U0140?

Not safely. The BCM controls many systems and its loss can cause unpredictable electrical faults. Diagnose it first.

What causes U0140?

Wiring, connector, or power/ground faults at the BCM, far more often than a failed module.

Why do so many things stop working with U0140?

The body control module manages lights, locks, wipers, and more. When it drops off the bus, all of those can fail.

🔗 Related Codes

U0100U0146U0155U0164