OBD-II code · Chassis
C0584 Brake Booster Motor B Phase U-V-W Circuit Low
Brake Booster Motor B Phase U-V-W Circuit Low: the signal voltage is below the expected range. The electric brake booster generates the braking assist; a motor or sensor fault can reduce or disable power-assisted braking. Safety-relevant.
Is it safe to drive with C0584?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyPhase shorted to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
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
- C0580Brake Booster Motor A Phase U-V-W Circuit Low
- C0581Park Brake Apply Performance
- C0582Brake Booster Motor A Phase U-V-W Circuit Range/Performance
- C0583Park Brake Release Performance
- C0585Brake Booster Motor B Phase U-V-W Circuit High
- C0586Brake Booster Motor B Phase U-V-W Circuit Range/Performance
- C0587Brake Booster Motor A Position Sensor Circuit/Open
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.