P091A code meaning
Gear Shift Position Circuit B
Powertrain system Generic code P09xx codes Check engine light
What P091A means
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.
P091A at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P091A
- Transmission or engine warning light on
- Slower or restricted gear changes in fallback mode
- Gearbox may hold a gear or stay in neutral
Common causes of P091A
- Most likelyLoose or corroded connector at the shift position sensor
- PossibleDamaged signal, supply or ground wire of sensor circuit B
- PossibleFaulty shift position sensor B
- Less likelyFaulty sensor input in the transmission control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Gear shift position sensor bWiring harnessTCM
What each part of P091A means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 9 | Area: transmission. |
| 1A | The exact fault in that area. |
What to do next
- Note P091A and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P091A
What does P091A mean?
P091A means "Gear Shift Position Circuit B". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P091A?
Drive gently and only to a workshop. With P091A the car can go into limp mode (reduced power) to protect itself.
Will P091A fail an emissions test?
Yes, it can. P091A is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P091A to fix?
Difficulty: hard. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will P091A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.