C05D0
Brake Master Cylinder Piston Position Sensor A/B Correlation
Master cylinder piston position sensors A and B disagree beyond plausible deviation.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Common causes
Ordered by how often each turns out to be the cause.
- One sensor driftedCommon
Parts involved
- Master Cylinder Pos Sensor A
- Master Cylinder Pos Sensor B
C05D0 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.