C0585 code meaning
Brake Booster Motor B Phase U-V-W Circuit High
What C0585 means
C0585 stands for a phase of booster motor B reading too high, for instance a lead shorted to battery positive or an upper transistor stuck on. The number had another use on older GM-platform cars: on the 2011 Saab 9-5 it identified the left rear damper actuator of the adaptive suspension. In its booster meaning no manufacturer publishes it. The checks required mirror those for C0581 on side A – offline short-to-supply tests and drain-source voltage monitoring as in TI's DRV3245Q-Q1. Redundant drives then isolate the faulty side: Kollmorgen's early patent on redundant windings already shared the torque among the healthy winding sets, and in the Hyundai Mobis design the remaining power module takes over the whole current command.
C0585 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0585
- Brake system warning lamp
- Reduced or switched-off electric assist
Common causes of C0585
- PossiblePhase lead of side B shorted to battery voltage
- PossibleUpper transistor of power module B shorted or stuck on
- Less likelyCode read on an older GM-platform vehicle where C0585 belongs to a damper actuator
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake booster motor bMotor phase wiring
What each part of C0585 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 85 | The exact fault in that area. |
What to do next
- Note C0585 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about C0585
What does C0585 mean?
C0585 means "Brake Booster Motor B Phase U-V-W Circuit High". C0585 stands for a phase of booster motor B reading too high, for instance a lead shorted to battery positive or an upper transistor stuck on. It is a generic code, so it means the same on every make.
Is it safe to drive with C0585?
Drive gently and only to a workshop. With C0585 the car can go into limp mode (reduced power) to protect itself.
Will C0585 fail an emissions test?
C0585 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C0585 to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will C0585 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.