C064ABrake Pressure Sensor M Circuit High
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- C064A: the voltage from sensor M exceeds what any valid pressure would give. On WABCO's Trailer EBS D the brake pressure sensor of an extra EBS relay valve, for example on a drawbar trailer's front axle, draws its supply from the trailer modulator and returns its actual value as an analog signal; all active sensors share supply outputs that are protected against short circuits. A short from that supply to the signal pin therefore drives the reading to the top. Kelsey-Hayes adds the opposite path: an open circuit lets a bridge output rise to supply level, so a high code does not exclude a broken wire. No passenger-car maker documents C064A. With the channel discarded, the system falls back to reduced functions.
- What you may notice
- Brake or ABS warning lamp on
- Load-dependent or electronic pressure control disabled
- Likely causes
- LikelySignal pin shorted to the sensor supply or battery voltage
- PossibleOpen sensor ground or signal line letting the input float high
- RareSensor output stuck at its upper limit
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €1,600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.