C054EVacuum Sensor B Range/Performance
- Generic OBD-II code · Chassis
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- Sensor B reports a plausible-looking voltage, but the vacuum it represents contradicts the expected value. With two vacuum sensors a module can also compare them with each other; publicly, the comparison methods come from patents on booster sensors: Ford treats booster pressure lying clearly above manifold pressure as sensor degradation, since a working check valve prevents that state, and checks whether booster pressure moves after brake applications; GM tracks booster vacuum against MAP-based engine vacuum with the throttle closed. A real leak or a weak pump can look identical, so the vacuum system is tested before replacing the sensor. No maker documents C054E publicly, and the meaning of B is maker-specific. C054A is the counterpart on sensor A.
- What you may notice
- Brake assist or brake system warning
- Pedal feels firmer after several brake applications
- Likely causes
- LikelySensor B drifting or fouled
- PossibleLeak, faulty check valve or weak vacuum pump
- RareWrong sensor type fitted after repair
- Repair
- Medium · Often possible to do yourself.Typical cost: €30 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.