U0143

Universal

Lost Communication With Body Control Module C

Definition source: General OBD-II reference catalog
Definition verification: Not independently verified for display.
Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium
Medium Severity

The vehicle’s network has detected that it cannot communicate with Body Control Module C. A body control module manages some vehicle body and convenience functions, but the functions assigned to this module vary by vehicle. Depending on what it controls, some features may stop working or a warning may appear. The code identifies a communication problem; it does not by itself prove that the module has failed.

Report an error with this code

⚠️ Before You Begin (Safety First)

If lighting, wipers, door operation, or another function needed for safe driving is unreliable, avoid driving until it is checked. Stop in a safe place if an essential function fails while driving. Do not probe network wiring or disconnect modules unless the vehicle-specific service procedure calls for it.

Common Symptoms

  • There may be no noticeable symptoms if the affected module controls functions that are not currently being used.
  • One or more body or convenience features may stop working if they depend on Body Control Module C.
  • A warning light or message may appear, or other modules may store communication codes.
  • Symptoms may come and go if a power, ground, connector, or network connection is intermittent.

Common Causes

  • A temporary loss of module communication, possibly associated with low or unstable vehicle power.
  • A loose, damaged, corroded, or wet connector or wiring connection.
  • A fault in a network circuit or connection that prevents messages from reaching the module.
  • An interruption in power or ground to Body Control Module C.
  • A fault within the module, which should be considered only after its power, grounds, and network connections are checked.
  • Recent electrical work or added equipment that disturbed wiring or affected vehicle network communication.

Diagnostic Steps

  1. Note which features are not working and whether the problem is constant or intermittent; this can help narrow down which systems may be affected.
  2. Check the owner’s manual for the meaning of any displayed warning and whether the affected features are needed for safe driving.
  3. With the vehicle safely parked, visually check for obvious battery-terminal looseness or corrosion. Do not short the terminals or disconnect the battery without checking the vehicle-specific guidance.
  4. If the owner’s manual identifies a relevant fuse, inspect it using the manual’s instructions. Do not repeatedly replace a fuse that blows again.
  5. Look for visible damage, moisture, or loose connections in wiring that is readily accessible without removing trim or disturbing safety-system components.
  6. Record this and any other stored diagnostic codes before clearing anything. If the code returns or safe-driving functions are affected, arrange diagnosis by a qualified technician.

When to Call a Professional

A technician can scan all modules to see whether other communication codes are present and confirm whether Body Control Module C is expected on this vehicle. Using the correct wiring information, check its power and grounds, inspect network connections, and test network communication before deciding whether a module needs repair or replacement. Exact tests depend on the model, year, and engine.

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Commonly Asked Questions

Does U0143 prove that Body Control Module C needs replacement?

No. It reports lost communication, not the cause. Power, ground, wiring, connectors, and network communication should be checked before condemning the module.

Can this code appear if the vehicle seems to work normally?

Yes. The communication loss may be intermittent, or the affected module may control functions that are not noticeable under current conditions.

Why are there other communication codes with U0143?

Several modules may report a communication problem when a shared network connection or vehicle power is disrupted. A full-module scan can help distinguish a broader network issue from a problem limited to one module.

Can I identify what Body Control Module C controls from this code alone?

No. The module’s role and exact diagnostic procedure depend on the vehicle’s model, year, and engine. Vehicle-specific service information is needed.

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