Code result
U0031
Vehicle Communication Bus C (+) Open
Moderate severity
What it means
The plus line of vehicle bus C is open. Modules sharing this segment drop offline. A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Bus-C high wire broken
highOne of the most commonly reported causes for this code — check this first.
Gateway module routing CAN messages incorrectly
lowLess common, but worth ruling out after the more likely causes.
CAN terminating resistor (120 Ω) drifted out of spec
lowLess common, but worth ruling out after the more likely causes.
Related help
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