Lost Communication With Body Control Module
The U0140 code means the vehicle's onboard diagnostic system has detected: Lost Communication With Body Control Module. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $200 - $1000 (parts and labor)
Common Misconceptions / Fact Check
-
Commonly claimedU0140 means the Body Control Module (BCM) has failed and needs replacing.
VerifiedInternal BCM failure is comparatively rare. U0140 means a module stopped communicating on the network -- the common causes are CAN wiring faults and loss of power/ground. Check power, ground, and connectors first; replace the module only after those pass.
Network codes mean modules are not communicating. You need a scanner that reads all systems to find the problem.
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Common Symptoms
- Multiple warning lights on dashboard
- Interior lights malfunction
- Power windows or locks inoperative
- Wipers or turn signals not working
- Key fob does not work
Probable Causes (Ranked by Likelihood)
- CAN bus wiring fault to BCM (open/short, chafed harness) High
- BCM power supply or ground loss (blown fuse, corroded ground, low battery voltage) High
- BCM connector water damage / corrosion Moderate
- Failed body control module (BCM) -- internal hardware failure or software needing update Moderate
Step-by-Step Diagnostic Procedure
-
Check BCM power and ground circuits
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Inspect BCM connector for water damage -- BCM is often near the windshield cowl where water leaks occur
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Verify CAN bus wiring to BCM
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Check for water leak into the BCM area
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Replace BCM if communication lost -- requires programming and configuration
Common Fixes by Vehicle
What techs usually find when diagnosing U0140 on specific vehicles — tap your vehicle for the fix and the exact part:
2007-2018 Chevrolet Silverado/GMC Sierra moderate DIY
Lost communication with BCM (Body Control Module). The BCM on GM trucks is behind the glove box. Water intrusion from a clogged A/C evaporator drain is the number one cause of BCM failure on these trucks. Check for water stains or corrosion on the BCM connector. Clear the evaporator drain (a compressed air blast through the drain hose works), dry the BCM, and clear codes.
Labor: 30 min - 2 hours2008-2020 Ford F-150/Escape/Explorer moderate DIY
Ford BCM communication loss often accompanies multiple other U-codes because the BCM is a gateway for many subsystems. Check the BCM fuse and power supply first. On F-150, the BCM is behind the driver kick panel. If the connector is dry and undamaged, the CAN bus wiring between the BCM and the gateway module may be damaged. Use a multimeter to check continuity on the CAN-H and CAN-L wires.
Labor: 1-3 hours2008-2020 Chrysler/Dodge/Jeep (various) moderate DIY
On Chrysler vehicles, the BCM and TIPM work together. U0140 often appears after jump-starting or battery replacement because the BCM loses its configuration. Perform a BCM reset by disconnecting the battery, waiting 10 minutes, then reconnecting. If the code persists, the BCM needs to be re-flashed with the latest software using wiTECH. Some aftermarket scanners (Autel MaxiSys) can also perform BCM resets on Chrysler.
Labor: 30 min - 2 hoursFrequently Asked Questions
Can I drive with code U0140?
Drive short distances only. Lost communication codes indicate a module has stopped communicating on the vehicle network. The affected system may not function correctly.
What causes U0140?
The most common causes are CAN bus wiring faults and power/ground loss to the module -- check power, ground, and connectors first. Internal BCM failure does happen but is comparatively rare, so replace the module only after the wiring and power/ground checks pass.
Is U0140 expensive to fix?
Repair costs range from $200 - $1000 (parts and labor). Wiring repairs are on the lower end, while module replacement is on the higher end. The module may also need to be programmed after replacement.
Sources
This page is built from documented references. Verify against your own service info before repair work.
U0140 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
See All Codes & Fixes for Your Vehicle
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