P0658Actuator Supply Voltage A Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- Actuator supply A is a high-side switch feeding several actuators together; its use differs by maker (Ford transmission solenoids, GM shared high-side driver, GM Europe 2.0 CDTI internal 5 V supply). P0658 means the supply output is too low with the driver on – a short to ground (0.5 Ω or less). GM's engine module checks its shared high-side driver in 20 of 25 samples; the lamp rating changed from none (2016) via two trips (2017–18) to the first trip (2025). GM's transmission modules include an open circuit here, set it in the first trip and block the solenoid diagnostics, so the gearbox goes into limp mode. On GM Europe's 2.0 CDTI it means the internal 5 V supply is too low – no MIL, and if it recurs, the engine module is replaced.
- What you may notice
- Transmission limp mode or fixed gear
- Several actuators not working
- Check engine light (GM from 2017)
- Codes for individual solenoids
- Likely causes
- LikelyActuator supply wire shorted to ground
- PossibleActuator (solenoid) shorted internally
- PossibleTransmission harness or connector (also open, in transmission modules)
- PossibleModule internal (main cause on the Saab diesel)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €150 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.