OBD-II code · Chassis
C05D4 Brake Master Cylinder Piston Position Sensor Calibration Not Learned
Master cylinder piston position sensor calibration not learned.
Is it safe to drive with C05D4?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyCalibration not performed
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.3–1.5 h
- Emissions test
- Usually unaffected
- Parts involved
- Master Cylinder Pos Sensors
Related codes
- C05D1Brake Master Cylinder Piston Position Sensor Supply Circuit
- C05D2Master Cylinder Piston Position Higher Than Expected
- C05D3Driver Applied Pressure Higher Than Expected
- C05D5Brake Master Cylinder Cut Off Valve
- C05D6Power Steering Control Module Processor Performance
- C05D7Brake Transmission Shift Interlock (BTSI) Control Circuit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.