P091AGear Shift Position Circuit B
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Circuit B is a second channel reporting the shift position of an automated manual gearbox, for instance a redundant sensor track or a separate sensor on another shift rail. This general circuit code sets on an electrical fault on that signal that matches none of the more specific B variants. No manufacturer documents the code publicly, and which physical sensor carries the letter B depends on the design. Patents from Aisin AI and Nissan/Aichi describe shift stroke sensors as the feedback for gear engagement, an Aisin AI patent also covers the fallback when a stroke sensor fails. CARB requires circuit checks on such inputs. P091B to P091D are the B siblings, P0914 and P095A the same signal on circuits A and C. Shifting may be restricted.
- What you may notice
- Transmission or engine warning light on
- Slower or restricted gear changes in fallback mode
- Gearbox may hold a gear or stay in neutral
- Likely causes
- LikelyLoose or corroded connector at the shift position sensor
- PossibleDamaged signal, supply or ground wire of sensor circuit B
- PossibleFaulty shift position sensor B
- RareFaulty sensor input 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: €100 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.