OBD-II code · Chassis
C05D5 Brake Master Cylinder Cut Off Valve
Fault on master cylinder cut-off valve — used in brake-by-wire systems to isolate the master cylinder during normal electric boost.
Is it safe to drive with C05D5?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyValve stuck or coil failed
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 2–6 h
- Emissions test
- Usually unaffected
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Master Cylinder Cutoff Valve
Related codes
- C05D2Master Cylinder Piston Position Higher Than Expected
- C05D3Driver Applied Pressure Higher Than Expected
- C05D4Brake Master Cylinder Piston Position Sensor Calibration Not Learned
- C05D6Power Steering Control Module Processor Performance
- C05D7Brake Transmission Shift Interlock (BTSI) Control Circuit
- C05D84WD/AWD Clutch A Actuator Control Circuit/Open
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.