C0584 code meaning
Brake Booster Motor B Phase U-V-W Circuit Low
What C0584 means
C0584 means a phase of booster motor B is held too low – shorted to ground, a lower transistor that will not switch off, or a driver whose gate supply has collapsed. No manufacturer publishes the code in its booster meaning; it shows up only in GM's older keyword list (PIP5094), where the number belonged to another system. Gate drivers such as TI's DRV8343-Q1 test every phase for a short to ground while the bridge is disabled, and the DRV8305-Q1 reports when its charge pump falls too far below the motor supply. With two independent winding systems, as in the Hyundai Mobis patent, a fault in one system must not pull down the other, so the module isolates side B and, where the design allows, keeps braking assist going on side A.
C0584 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 C0584
- Brake system warning and possibly reduced assist
- Driver assistance braking functions may be limited
Common causes of C0584
- PossiblePhase lead of side B shorted to ground or housing
- PossibleLower transistor of power module B shorted
- PossibleGate-driver supply of channel B too low
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 C0584 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 84 | The exact fault in that area. |
What to do next
- Note C0584 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 C0584
What does C0584 mean?
C0584 means "Brake Booster Motor B Phase U-V-W Circuit Low". C0584 means a phase of booster motor B is held too low – shorted to ground, a lower transistor that will not switch off, or a driver whose gate supply has collapsed. It is a generic code, so it means the same on every make.
Is it safe to drive with C0584?
Drive gently and only to a workshop. With C0584 the car can go into limp mode (reduced power) to protect itself.
Will C0584 fail an emissions test?
C0584 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 C0584 to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will C0584 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.