C0642Brake Pressure Sensor K Circuit High
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- C0642 means the output of sensor K exceeds its upper limit. Electro-hydraulic brakes like Mercedes' Sensotronic Brake Control work with a high-pressure accumulator and a pedal value sensor with two Hall elements; during a pre-drive check the unit pressurises the calipers to test, among other things, its pressure sensors. A high fault on any such sensor would make the module believe the brakes are applied. Saab's 9-5 sets its sensor code above 4.75 V for 0.1 s; GM's 2019 EBCM uses 95.24 % of supply on the main channel and 94.50 % on the reference channel. No maker says which sensor would be K, so the letter cannot be linked to a location. Typical: short to 5 V or battery, lost sensor ground, internal fault.
- What you may notice
- Brake system and ESC warning lamps on
- Brake lights or hold functions may be requested wrongly on some systems
- Likely causes
- PossibleSignal shorted to 5 V or battery voltage
- PossibleLost sensor ground
- PossibleInternal fault of sensor K signalled at the upper rail
- 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.