OBD-II code · Chassis
C0543 Brake Pressure Sensor B Circuit High
Brake pressure sensor B signal voltage above expected range. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive with C0543?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelySignal wire open or short to power
- Less likelyConnector pins corroded - high contact resistance
- Less likelySupply wire pinched against B+ source
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–4 h
- Emissions test
- Usually unaffected
- Parts involved
- Brake Pressure Sensor B, Sensor Wiring
Related codes
- C053FBrake Pressure Sensor A Circuit High
- C0572Brake Pressure Sensor C Circuit High
- C0576Brake Pressure Sensor D Circuit High
- C05A0Brake Pressure Sensor E Circuit High
- C05C7Brake Pressure Sensor F Circuit High
- C0636Brake Pressure Sensor G Circuit High
- C063ABrake Pressure Sensor H Circuit High
- C063EBrake Pressure Sensor J Circuit High
- C0642Brake Pressure Sensor K Circuit High
- C0646Brake Pressure Sensor L Circuit High
- C064ABrake Pressure Sensor M Circuit High
- C064EBrake Pressure Sensor N Circuit High
- C0540Hill Hold Control Performance
- C0541Brake Pressure Sensor B Range/Performance
- C0542Brake Pressure Sensor B Circuit Low
- C0544Brake Pressure Sensor B Circuit/Open
- C0545VIN Not Programmed or Incompatible - BSCM
- C0546VIN Not Programmed or Incompatible
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.