A blown fuse or poor power/ground connection at the body control module.; Corroded, pushed-back, or damaged terminals in the module connector or CAN bus splice.; Open or shorted CAN bus wiring between the body module and the module that set the code.; A failed body control module, often after water intrusion or a voltage spike.; Low battery voltage or a weak charging system causing modules to drop offline.; Aftermarket accessories tapped into the bus wiring and disturbing communication.

DTC codes / U01xx · Lost communication with a control module / U0143

U0143Lost Communication With Body Control Module 'C'

Q: What does code U0143 mean?

Lost Communication With Body Control Module 'C'. U0143 means the module that coordinates body functions, such as locks, lights, and wipers, has stopped reporting on the controller area network (CAN) bus. The computer that sets this code has tried to reach Body Control Module 'C' and received no valid response within the expected time window.

U0143 means the module that coordinates body functions, such as locks, lights, and wipers, has stopped reporting on the controller area network (CAN) bus. The computer that sets this code has tried to reach Body Control Module 'C' and received no valid response within the expected time window.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaLost communication with a control module

Symptoms you may notice

Often no symptoms besides the warning light, especially if the module only drops out intermittently.
Body accessories such as interior lights, power locks, or wipers may stop working or behave erratically.
The vehicle may fail to start or stall if the body module is involved in the immobilizer or power-mode handshake.
Multiple unrelated warning lights may illuminate because other modules lose shared body data.
Intermittent operation of accessories over bumps or in wet weather points to a wiring fault rather than a dead module.

Common causes, most likely first

A blown fuse or poor power/ground connection at the body control module.
Corroded, pushed-back, or damaged terminals in the module connector or CAN bus splice.
Open or shorted CAN bus wiring between the body module and the module that set the code.
A failed body control module, often after water intrusion or a voltage spike.
Low battery voltage or a weak charging system causing modules to drop offline.
Aftermarket accessories tapped into the bus wiring and disturbing communication.

How to diagnose and fix it

Verify battery voltage and charging system output, then clear the code and see if it returns.
Check all fuses feeding the body control module and inspect grounds for corrosion or looseness.
Inspect the module connector for bent pins, water intrusion, and tight terminal fit.
Measure CAN bus resistance and voltage at the diagnostic connector to confirm bus integrity.
Perform a wiggle test on harness sections while watching live data for the module to drop out.
If wiring and power are good, substitute a known-good module or perform a module communication test before replacement.
After repair, clear codes and verify the module stays online through a full drive cycle with accessories cycled.

Why U0143 is often a wiring fault

A body control module that is completely dead will usually set communication codes in several modules, not just one, so a single U0143 often points to a connector or splice rather than the module itself.
Water intrusion into a footwell or kick-panel area is a common hidden cause because the body module and its connectors are frequently mounted low in the cabin.
Aftermarket alarms, remote starters, and phone chargers plugged into the wrong circuit can back-feed the bus and cause intermittent loss of communication.
A module that wakes up only when a door is opened may test fine during a quick scan, so the fault can be missed unless the technician reproduces the exact conditions.
Replacing the body module without checking the CAN bus voltage can leave the new module offline as well, because a shorted bus wire will take down any module connected to it.

Can I keep driving with U0143?

The vehicle may be safe to drive if only accessories are affected, but avoid driving if the engine will not start reliably or if multiple warning lights suggest the bus is unstable. Have the fault diagnosed promptly, because a body module that drops offline can also affect safety-related lighting and locking functions.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.