U0143 — Lost Communication With Body Control Module "C"
vehicle network
Is it safe to drive?
Drive with caution Depends on what is affected. A single dead convenience module is fine to drive with; loss of communication with engine, braking or steering modules is not. If multiple critical systems drop out, do not drive.
How to diagnose with an OBD scanner
- Read the code and freeze frame Connect an OBD2 scanner, confirm U0143 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
- Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many U0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
- Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the vehicle network (CAN bus) communication for damage, corrosion, chafing or poor contact.
- Subsystem check Measure resistance between CAN-High and CAN-Low at the OBD port with power off — about 60 Ω is healthy.
- Subsystem check Scan all modules: the one that does not respond is either the culprit or downstream of the break.
- Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm U0143 does not return.
Approximate repair cost
Repair cost depends on which component actually failed. Typical scenarios for U0143 (parts and labor, USD, independent shop rates): Remove interfering aftermarket device: $0–$150; Replace the faulty control module: $300–$1,500; Repair CAN wiring or connectors: $100–$400. Overall, fixing U0143 usually costs between $0 and $1,500. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.
Common questions
Will U0143 clear itself?
Sometimes U0143 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.
Is it safe to drive with U0143?
Depends on what is affected. A single dead convenience module is fine to drive with; loss of communication with engine, braking or steering modules is not. If multiple critical systems drop out, do not drive.
How do I diagnose U0143 myself?
Start with a scan: confirm U0143, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the vehicle network (CAN bus) communication, and verify the suspect component against live data before buying parts.
How much does it cost to fix U0143?
Remove interfering aftermarket device — $0–$150; Replace the faulty control module — $300–$1,500; Repair CAN wiring or connectors — $100–$400. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.
What is the most common cause of U0143?
The most common causes are: damaged CAN bus wiring or short to power/ground, poor grounds or low battery voltage, corroded connectors, especially in wet areas.
What does U0143 mean?
Seeing U0143 on your scanner? The control unit has caught the vehicle network (CAN bus) communication operating outside its calibrated window. The formal description is “Lost Communication With Body Control Module "C"”, and the code is grouped under vehicle network faults.
To set U0143, the control module compares live readings of the vehicle network (CAN bus) communication against calibrated limits, usually over several drive cycles. Alongside the code it stores a freeze frame — a snapshot of rpm, load, coolant temperature and vehicle speed at the moment of failure. Reading that snapshot first saves diagnostic time.
Common symptoms of U0143
- intermittent loss of functions (gauges, windows, steering assist)
- modules intermittently not communicating with the scanner
- random, hard-to-reproduce electrical glitches
- no-start or intermittent starting in some cases
- multiple warning lights on at once
What causes U0143?
- corroded connectors, especially in wet areas
- poor grounds or low battery voltage
- water ingress in harness junctions
- damaged CAN bus wiring or short to power/ground
- a faulty module pulling the bus down
- aftermarket equipment interfering with the bus
How to diagnose U0143
- Connect an OBD2 scanner, confirm U0143 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
- Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many U0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
- Visually inspect the wiring harness and connectors related to the vehicle network (CAN bus) communication for damage, corrosion, chafing or poor contact.
- Measure resistance between CAN-High and CAN-Low at the OBD port with power off — about 60 Ω is healthy.
- Scan all modules: the one that does not respond is either the culprit or downstream of the break.
- Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm U0143 does not return.
How to fix U0143
Start with the cheapest and most common causes before replacing expensive parts:
- Remove interfering aftermarket device — $0–$150
- Replace the faulty control module — $300–$1,500
- Repair CAN wiring or connectors — $100–$400
How much does it cost to fix U0143?
Repair cost depends on which component actually failed. Typical scenarios for U0143 (parts and labor, USD, independent shop rates):
- Remove interfering aftermarket device: $0–$150
- Replace the faulty control module: $300–$1,500
- Repair CAN wiring or connectors: $100–$400
Overall, fixing U0143 usually costs between $0 and $1,500. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.
Can you drive with U0143?
Depends on what is affected. A single dead convenience module is fine to drive with; loss of communication with engine, braking or steering modules is not. If multiple critical systems drop out, do not drive.