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?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $50 - $600 (fuses, grounds, or wiring most often; module replacement only after the circuit tests good)
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
- Check Engine or related warning light on
- The Body Control Module's functions may be degraded or offline
- Often stored alongside other U-codes when a whole bus segment drops
- Symptoms can be intermittent - connector and wiring faults come and go with heat and vibration
Probable Causes (Ranked by Likelihood)
- The Body Control Module has lost power or ground (check its fuses first) High
- CAN bus wiring damage - chafed harness, corroded connector, water intrusion High
- Failed Body Control Module no longer transmitting Moderate
- Another faulted module loading down the bus Low
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
What does U0140 mean?
U0140 means other modules stopped receiving messages from the Body Control Module on the vehicle network. It is a communication fault - the module may be fine but unreachable.
Can I keep driving with U0140?
Usually yes for a short period. The affected function may be degraded, and intermittent wiring faults tend to worsen - diagnose soon.
Should I replace the module for U0140?
Not first. Most communication codes are power, ground, fuse, or wiring problems. Replace the module only after those test good - modules are expensive and often require programming.
Mechanics Guide Step-by-step diagnosis, and what most sources get wrong
Step-by-Step Diagnostic Procedure
-
Scan ALL modules - the pattern of which modules report lost communication localizes the break.
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Check the fuses and grounds feeding the Body Control Module before suspecting the module itself.
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If many modules are unreachable, test the CAN bus: about 60 ohms across CAN High/Low (two 120-ohm terminators) with the battery disconnected.
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Wiggle-test connectors along the affected harness while watching for the module to drop on and off.
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Only after power, ground, and bus test good should the Body Control Module be suspected.
Common Misconceptions / Fact Check
-
Commonly claimedU0140 means the Body Control Module (BCM) has failed and needs replacing.
VerifiedU0140 records that a module stopped communicating on the network. The common causes are CAN wiring faults and loss of power or ground; internal BCM failure is comparatively rare. Verify power, ground, and connectors before replacing the module.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
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:
Commonly Affected Vehicles
- All OBD-II vehicles - network (U) codes are standardized across makes
Related Codes
See All Codes & Fixes for Your Vehicle
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