P0923Gear Shift Forward Actuator Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Set when the drive circuit of the forward shift actuator of an automated manual gearbox shows a voltage that is too high for the current switching state. Typical reasons are a valve or motor line shorted to battery voltage, or a driver stage in the module that no longer switches off; depending on circuit design an open load can also read high. No manufacturer documents this code publicly. A ZF patent describes double-acting shift cylinders whose chambers each have a 3/2 solenoid valve, and an Isuzu patent drives a shift motor forward or reverse by shift direction. CARB requires circuit checks on outputs. P0922 is the opposite low fault, P0920 the open circuit, P0927 the reverse direction. An actuator that stays energised can hold or force a gear, so shifting is usually locked.
- What you may notice
- Transmission warning light on
- Gearbox locks in one gear or refuses to shift
- Possible grinding when a gear is pushed unintentionally
- Likely causes
- LikelyDrive wire shorted to battery voltage
- PossibleDriver stage in the control module stuck on
- RareOpen coil or winding read as high on some circuit designs
- 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: €100 – €2,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.