C064CBrake Pressure Sensor M 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 M stays inside its electrical window, but the pressure it reports is not believable. Trailer EBS shows an active test: when the control pressure exceeds 0.3 bar, WABCO's modulator switches its redundancy valve to reservoir pressure and starts EBS braking; during the stop it briefly switches back and uses its internal actual-pressure sensors to confirm that pneumatic pressure is present, otherwise it changes to purely pneumatic braking. Kelsey-Hayes lists in-range checks for hydraulic sensors: high pressure lasting unusually long, or high pressure while the brakes are not applied. No carmaker documents C064C or says which sensor is M. Possible causes: drift, a sticking valve, a leak, contamination in the sensor port.
- What you may notice
- Warning lamp on after a brake application
- Braking switched to a backup mode with less precise pressure control
- Likely causes
- LikelySensor reading drifted from the true pressure
- PossibleValve in the measured circuit not switching as commanded
- RareContamination or air at the sensor port
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €2,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.