OBD-II code · Chassis
C05B3 Brake Booster Temperature Sensor C Circuit Low
Brake booster temperature sensor C signal voltage below expected range. Boost control tracks commanded vs. actual manifold pressure; persistent deviation means wastegate, vanes, hose or actuator are not delivering the requested pressure.
Is it safe to drive with C05B3?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal wire shorted to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
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 Booster Temp Sensor C
Related codes
- C0579Brake Booster Temperature Sensor B Circuit Low
- P25C6Brake Booster Temperature Sensor A Circuit Low
- C05B0Brake Hydraulic Circuit C Leak
- C05B1Brake Hydraulic Circuit D Leak
- C05B2Steering Wheel Angle Sensor Signal - Yaw Rate Sensor Signal Correlation
- C05B4Brake Booster Temperature Sensor C Circuit High
- C05B5Brake Booster Temperature Sensor C Circuit/Open
- C05B6Brake Booster Temperature Sensor C Circuit Range/Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.