P09A8Gate Select Position Circuit C Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- The module stores this code when the gate select signal on circuit C remains below its valid range for a calibrated time. Common triggers are a signal wire shorted to ground, a missing sensor supply or an internal sensor fault; depending on the sensor type, a broken signal wire can read low as well. No manufacturer documents this code publicly or explains what circuit C measures. Patents from Isuzu and Aisin AI show the select sensor as the feedback the module needs to line up the right gate. CARB requires out-of-range checks on such inputs. P09A9 is the high counterpart, P09A6 the general C fault, P0906 and P09A4 the low faults of A and B.
- What you may notice
- Check engine or transmission warning light on
- Gearbox holds one gear or drops to neutral
- Transmission warning message in the instrument cluster
- Likely causes
- LikelySignal wire of circuit C shorted to ground
- PossibleSensor supply for circuit C missing or pulled down
- PossibleInternal short in the sensor delivering signal C
- RareFaulty input stage in the transmission control module
- 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: €80 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.