P091C code meaning
Gear Shift Position Circuit B Low
Powertrain system Generic code P09xx codes Check engine light
What P091C means
Set when the shift position signal on circuit B of an automated manual gearbox stays below its lowest valid value for longer than a calibrated time. Usually the signal line is shorted to ground, the sensor supply is missing, or the sensor has failed internally. No manufacturer documents this code publicly. Patents from Aisin AI and Nissan/Aichi present the shift stroke or shift position sensor as the feedback that confirms an engaged gear; with a reading below the valid band that confirmation is lost on this channel. CARB requires out-of-range checks on such inputs. P091D is the opposite high fault, P0916 and P095C are the low faults of circuits A and C, P091B the plausibility fault of circuit B. The gearbox may run in fallback mode.
P091C 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 P091C
- Transmission or engine warning light on
- Restricted gear changes or a held gear
- Engine start may be blocked if neutral cannot be confirmed
Common causes of P091C
- Most likelySignal wire of circuit B shorted to ground
- PossibleOpen or shorted sensor supply line
- PossibleFaulty shift position sensor B
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 P091C 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. |
| 1C | The exact fault in that area. |
What to do next
- Note P091C 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 P091C
What does P091C mean?
P091C means "Gear Shift Position Circuit B Low". Set when the shift position signal on circuit B of an automated manual gearbox stays below its lowest valid value for longer than a calibrated time. It is a generic code, so it means the same on every make.
Is it safe to drive with P091C?
Drive gently and only to a workshop. With P091C the car can go into limp mode (reduced power) to protect itself.
Will P091C fail an emissions test?
Yes, it can. P091C 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 P091C to fix?
Difficulty: hard. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will P091C clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.