C055F code meaning
BSCM/EBBC Hydraulic Unit Performance
Chassis system Generic code C05xx codes Check engine light
What C055F means
The brake system control module (BSCM) or electronic brake boost controller (EBBC) has found that its hydraulic unit – master cylinder, pedal simulator, separation valves or boost plunger – does not perform as calculated. GM's 2019 tables test it during shutdown: a simulator leak sets C055F if secondary pressure drops under 15 bar; in 2025 a master cylinder leakage above 200 mm³/s also counts, Type A with MIL. On 2026 Silverado/Sierra 1500 GM replaces the master cylinder (PIT6450A); on 2022–26 trucks and SUVs the code appeared below −23 °C from low battery voltage (PIT6476). Jeep logs it as ABS Hydraulic Unit Performance on the 2021 Wrangler 4xe with MIL and fixes stored cases by ABS software (08-032-22). Expect a hard or changed pedal.
C055F at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.3 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C055F
- Service Brake System message, ABS and stability lamps
- Hard pedal or changed brake pedal effort
- Check-engine lamp on some models
Common causes of C055F
- Most likelyInternal leak or failure of the master cylinder or pedal simulator
- PossibleLow battery voltage, especially in severe cold, during the self-test
- PossibleBrake module software flagging the unit too readily (update available)
- Less likelyPoor power or ground terminals at the brake module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Bscm hydraulic unitBrake system control module
What each part of C055F means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 5F | The exact fault in that area. |
What to do next
- Note C055F 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 C055F
What does C055F mean?
C055F means "BSCM/EBBC Hydraulic Unit Performance". The brake system control module (BSCM) or electronic brake boost controller (EBBC) has found that its hydraulic unit – master cylinder, pedal simulator, separation valves or boost plunger – does not perform as calculated. It is a generic code, so it means the same on every make.
Is it safe to drive with C055F?
Drive gently and only to a workshop. With C055F the car can go into limp mode (reduced power) to protect itself.
Will C055F fail an emissions test?
C055F 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 C055F to fix?
Difficulty: workshop only. A typical repair takes 0.3 to 4 hours of work. This is a job for a workshop.
Will C055F clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.