C0590Brake Booster Motor A Phase U-V-W Current High
- Generic OBD-II code · Chassis
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- C0590 means the current measured in the drive of booster motor A is too high, mostly checked while the bridge is idle and almost nothing should flow. GM uses it in several units, always Type A with MIL: its 2016/2019 hybrid booster trips on leakage current above 20 A for 5 ms, the XT4 module on an idle offset above 36.1 A or a phase current above 200 A, and the 2023/2025 EBCM tables on a shunt offset above 38 A for 0.2 s. In GM's 2019 IBC unit it also flags a bridge driver whose overcurrent detection fails its power-up self-test. Mitsubishi maps C18E1-19 of the Outlander PHEV brake unit to C0590 with MIL after one trip; booster assist, regeneration and automatic braking stop. On the 2011 Saab 9-5 the number was a damper actuator code.
- What you may notice
- Brake assist warning, much higher pedal effort
- Check engine, ABS or brake warning lamps on
- Regenerative braking and automatic brake functions unavailable
- Likely causes
- LikelyLeaking or partly conducting MOSFET in the booster motor bridge
- PossibleShunt or measuring amplifier offset drifted upward
- PossibleWinding short in booster motor A drawing excess current
- RareBridge driver chip failing its overcurrent self-test
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €200 – €3,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.