C05C2Brake Booster Motor A Over Temperature
- Generic OBD-II code · Chassis
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- 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.
- What you may notice
- Malfunction indicator lamp and brake warning on GM models
- Reduced brake assist, pedal feels harder
- Regenerative braking temporarily disabled
- Likely causes
- 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
- RareLow supply voltage forcing current limitation
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.