OBD-II code · Chassis
C0585 Brake Booster Motor B Phase U-V-W Circuit High
Brake booster motor B phase voltage above expected range. Boost control tracks commanded vs. actual manifold pressure; persistent deviation means wastegate, vanes, hose or actuator are not delivering the requested pressure.
Is it safe to drive with C0585?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyPhase shorted to power
- Less likelyConnector pins corroded - high contact resistance
- Less likelySupply wire pinched against B+ source
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
- Parts involved
- Brake Booster Motor B, Motor Phase Wiring
Related codes
- C0582Brake Booster Motor A Phase U-V-W Circuit Range/Performance
- C0583Park Brake Release Performance
- C0584Brake Booster Motor B Phase U-V-W Circuit Low
- C0586Brake Booster Motor B Phase U-V-W Circuit Range/Performance
- C0587Brake Booster Motor A Position Sensor Circuit/Open
- C0588Brake Booster Motor A Position Sensor Circuit Low
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.