C05C2 code meaning
Brake Booster Motor A Over Temperature
Chassis system Generic code C05xx codes Check engine light
What C05C2 means
The electric booster or integrated brake unit has found its drive motor A, or the power stage feeding it, too hot. GM uses the code in several EBCM tables, all Type A with MIL: one design trips above 154 °C estimated motor temperature or on a bridge driver over-temperature shutdown, the Cadillac XT4 unit above 120 °C and 142 °C rotor/ECU temperature, 23OBDG07 and 25OBDG03B also when torque limiting stops the plunger refill, and 25OBDG04B above 140/160 °C magnet or 210/240 °C winding temperature. Mitsubishi lists C05C2 for Outlander PHEV code C18E1-4B with MIL after two trips, although that page describes a missing supply to the stroke sensor. Expect reduced boost after long or repeated hard braking. C0594 covers motor performance.
C05C2 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C05C2
- Malfunction indicator lamp and brake warning on GM models
- Reduced brake assist, pedal feels harder
- Regenerative braking temporarily disabled
Common causes of C05C2
- Most likelyLong downhill braking or repeated hard stops overheating the motor
- PossibleHydraulic fault making the motor run longer than normal
- PossiblePower stage or bridge driver reporting false or real over-temperature
- Less likelyLow supply voltage forcing current limitation
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake booster motor aElectric brake boosterBrake system control module
What each part of C05C2 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| C2 | The exact fault in that area. |
What to do next
- Note C05C2 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 C05C2
What does C05C2 mean?
C05C2 means "Brake Booster Motor A Over Temperature". The electric booster or integrated brake unit has found its drive motor A, or the power stage feeding it, too hot. It is a generic code, so it means the same on every make.
Is it safe to drive with C05C2?
Drive gently and only to a workshop. With C05C2 the car can go into limp mode (reduced power) to protect itself.
Will C05C2 fail an emissions test?
C05C2 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 C05C2 to fix?
Difficulty: hard. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will C05C2 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.