What Does U0140 Mean?
The diagnostic network has lost communication with the Body Control Module (BCM). This module typically manages interior/exterior lighting, door locks, wipers, and other body functions.
Common Causes
35%
Failed or corrupted Body Control Module
25%
Corroded or loose connector at BCM
20%
Open or short in CAN bus wiring to BCM
15%
Low battery voltage or BCM power supply circuit fault
5%
Software version mismatch after module replacement or programming
Diagnostic Steps
1
Step 1: Locate BCM and inspect all connectors for corrosion, damage, or loose connection
2
Step 2: Check BCM power and ground circuits with multimeter, verify fuses are intact
3
Step 3: Measure CAN bus voltage at BCM connector (should see ~2.5V on each line at rest, toggling between 2-3V when active)
4
Step 4: Check for BCM internal fault by attempting to access module functions with scan tool
5
Step 5: Verify CAN bus termination resistance and check for shorts to ground or power in wiring
Estimated Repair Cost
$150 - $1,200
Parts + labor, varies by vehicle and location
The diagnostic network has lost communication with the Body Control Module (BCM). This module typically manages interior/exterior lighting, door locks, wipers, and other body functions.
The most common cause of U0140 (Lost Communication With Body Control Module) is: Failed or corrupted Body Control Module
Typical repair costs for U0140 range from $150 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
May affect exterior lighting, instrument cluster warnings, and door lock operation. Ensure all lights function properly before driving at night.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0140 to identify the root cause.
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Quick Info
Category
Network
System
Body Control Network
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
