P0659Actuator Supply Voltage A Circuit High
- 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). P0659 means a short to voltage on the supply output, checked with the driver off – the output should then be dead (GM: 0.5 Ω or less to the supply, 20 of 25 samples; lamp after two trips in 2017–18, none in 2016). The driver can then no longer switch the actuators off; GM's transmission modules block their solenoid diagnostics while P0658/P0659 are active, and limp mode follows. On GM Europe's 2.0 CDTI it means the internal 5 V supply is too high, without MIL – the engine module is replaced.
- What you may notice
- Check engine light (GM from 2017)
- Transmission or actuator limp mode
- Actuators cannot be switched off
- Follow-up codes
- Likely causes
- LikelyActuator supply wire shorted to battery or ignition voltage
- PossibleHarness chafed against a 12 V line
- PossibleModule (driver shorted; internal on the Saab diesel)
- RareExternal voltage fed back through a faulty actuator
- 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.