P09A9Gate Select Position Circuit C 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
- Logged when the gate select signal on circuit C sits above its highest plausible value for longer than a calibrated time. Usual suspects are a short to the sensor supply or battery voltage, an interrupted sensor ground, or a sensor with an internal fault. No manufacturer publicly documents this code, and the physical meaning of circuit C is not published either. An Aisin AI patent describes the fallback once select feedback is lost: warning, stop request and a limp-home in first gear. CARB requires out-of-range checks on such inputs. P09A8 is the low counterpart, P09A6 the general C fault, P0907 and P09A5 the high faults of A and B. Shifting is usually curtailed.
- What you may notice
- Check engine or transmission warning light on
- Limp-home mode, often in a single low gear
- Gear changes refused while driving
- Likely causes
- LikelySignal wire of circuit C shorted to supply or battery voltage
- PossibleOpen or corroded sensor ground
- PossibleInternal fault of 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.