OBD-II code · Network
U0053 Vehicle Communication Bus C (-) High
Bus C low-side line voltage above expected range. 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 with U0053?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyWire shorted to battery
- Less likelyGateway module routing CAN messages incorrectly
- Less likelyCAN terminating resistor (120 Ω) drifted out of spec
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
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–6 h
- Emissions test
- Usually unaffected
- Parts involved
- Bus C Wiring
Related codes
- U0035Vehicle Communication Bus A (-) High
- U0044Vehicle Communication Bus B (-) High
- U0062Vehicle Communication Bus D (-) High
- U0090Vehicle Communication Bus G (-) High
- U0099Vehicle Communication Bus H (-) High
- U0050Vehicle Communication Bus E (+) Open
- U0051Vehicle Communication Bus C (-) Open
- U0052Vehicle Communication Bus C (-) Low
- U0054Vehicle Communication Bus C (-) shorted to Bus C (+)
- U0055Vehicle Communication Bus D
- U0056Vehicle Communication Bus D Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.