OBD2 code U0031: Vehicle Communication Bus C (+) Open
The plus line of vehicle bus C is open.
Detected Root Component
Network Component
Observed Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Possible Causes
- Bus-C high wire broken
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
Tools Required
Interactive Diagnostic
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Parts likely to be the cause (Moteur (général))
Moteur (général)
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Frequently asked questions about code U0031
What does code U0031 mean? ▾
OBD2 code U0031: Vehicle Communication Bus C (+) Open. The plus line of vehicle bus C is open.
What are the symptoms of code U0031? ▾
Code U0031 may cause: Multiple warning lights may illuminate, Affected modules may go into limp mode or shut down, Specific functions inoperative depending on module, Diagnostic tools may show communication faults. The intensity of these symptoms varies depending on the vehicle and driving conditions.
What causes code U0031? ▾
The most common causes of code U0031 are: Bus-C high wire broken, Gateway module routing CAN messages incorrectly, CAN terminating resistor (120 Ω) drifted out of spec. A proper OBD2 diagnostic will pinpoint the exact cause.
Is it serious to drive with code U0031? ▾
Yes, code U0031 is critical (Critical). Avoid driving and consult a professional promptly to prevent major damage.
How do I fix code U0031? ▾
Start by reading the code with an OBD2 scanner, then follow the interactive decision tree on this page. Priority causes to check: Bus-C high wire broken, Gateway module routing CAN messages incorrectly, CAN terminating resistor (120 Ω) drifted out of spec. Difficulty: Medium · Estimated time: 30-60min.