P09A3Gate Select Position Circuit B Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Plausibility fault of gate select circuit B: the signal is electrically valid but does not match what the module expects. That could be the reading of circuit A, the learned gate positions, or the target gate the module has commanded, as in the Aisin AI select control that compares actual and target gate. Which comparison applies depends on whether B is a redundant track or a separate sensor, and no manufacturer publishes that or uses this code in citable material. CARB requires rationality checks on such inputs. P09A2, P09A4 and P09A5 are electrical faults of B, P0905 and P09A7 the same check on circuits A and C. A fallback mode with limited shifting is likely.
- What you may notice
- Check engine or transmission warning light on
- Wrong gate selected or gears refused
- Slow, jerky shifting in fallback mode
- Likely causes
- LikelyWorn or drifting select sensor, signal B no longer agrees with the reference
- PossibleGate positions not relearned after actuator, clutch or module replacement
- PossibleContact resistance at connector pins distorting signal B
- RareSluggish or worn select mechanism so the measured gate lags the commanded one
- 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.