Code result
U0091
CAN Communication Bus \"C\" Off
High severity
What it means
Bus C (third CAN bus, often used for chassis or infotainment) has entered the bus-off state. All modules on Bus C lose communication.
Is it safe to drive?
No — stop driving
This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly.
Most likely causes
Bus C shorted to supply or ground
highOne of the most commonly reported causes for this code — check this first.
Bus C terminating resistor failed
mediumA plausible cause — test and verify before replacing parts.
Gateway module routing CAN messages incorrectly
lowLess common, but worth ruling out after the more likely causes.
Related help
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