C057F code meaning
Brake Booster Motor A Phase U-V-W Circuit/Open
Chassis system Generic code C05xx codes Check engine light
What C057F means
C057F covers an interrupted drive path in the three-phase motor of an electric brake booster: a winding, a phase lead or a power transistor that no longer carries current. GM documents it in several brake modules, always as Type A with MIL after one trip. Its 2016 and 2019 hybrid tables switch single bridge transistors while the motor is not being driven and set the code within 5 ms if the phase W voltage does not respond. The 2023 and 2025 EBCM tables measure coil resistance and trip above 0.20358 Ω (or below 0.01258 Ω) for 0.12 s, or when the voltage vector is off by more than 1.5 V. In GM's 2019 IBC unit C057F also covers phases that fail to rise above 3.46 V or sit near battery level before start-up. The brakes keep working, only without electric assist.
C057F at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C057F
- Hard brake pedal, noticeably more pedal force needed
- Brake system, ABS/traction and check engine lamps on
- Message about reduced brake assist
Common causes of C057F
- Most likelyBridge transistor in the brake module no longer switching (drive stage defect)
- PossibleBroken winding or failed internal phase connection in booster motor A
- PossibleCorroded or loose phase contact between control unit and motor, raising coil resistance
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake booster motor aMotor phase wiring
What each part of C057F means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 7F | The exact fault in that area. |
What to do next
- Note C057F 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 C057F
What does C057F mean?
C057F means "Brake Booster Motor A Phase U-V-W Circuit/Open". C057F covers an interrupted drive path in the three-phase motor of an electric brake booster: a winding, a phase lead or a power transistor that no longer carries current. It is a generic code, so it means the same on every make.
Is it safe to drive with C057F?
Drive gently and only to a workshop. With C057F the car can go into limp mode (reduced power) to protect itself.
Will C057F fail an emissions test?
C057F 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 C057F to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will C057F clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.