P2109 code meaning
Throttle/Pedal Position Sensor A Minimum Stop Performance
Powertrain system Generic code P21xx codes Check engine light
What P2109 means
P2109 flags an implausible rest reading on position signal A: with the throttle or pedal resting on its lower mechanical stop, the minimum learned at key-on falls outside the window the calibration accepts. Ford names its first throttle body sensor TP A, so on such layouts the code concerns the throttle. Subaru documents P2109: bulletin 09-102-23 traces it on the 2022 WRX to a throttle plate that has frozen shut and supplies new ECM software, and 09-97-22 adds improved detection logic for 2020-2022 Legacy and Outback. A Delphi patent describes several learn attempts before an obstruction is reported. Circuit faults on A have their own codes (P0120-P0123); P2113-P2117 run the same check for letters B to F. Expect a warning lamp and possibly limp mode.
P2109 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2109
- Engine warning lamp, often after a cold or wet night
- Raised or unsteady idle
- Reduced power until the fault clears
Common causes of P2109
- Most likelyIce or carbon holding the throttle plate off its rest stop
- PossibleECM software with oversensitive detection (update available)
- PossibleRest position not relearned after cleaning or replacing the throttle body
- Less likelySensor A worn or drifted at the closed end of its track
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Throttle position sensorThrottle bodyECM
What each part of P2109 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 1 | Area: fuel and air metering. |
| 09 | The exact fault in that area. |
What to do next
- Note P2109 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 P2109
What does P2109 mean?
P2109 means "Throttle/Pedal Position Sensor A Minimum Stop Performance". P2109 flags an implausible rest reading on position signal A: with the throttle or pedal resting on its lower mechanical stop, the minimum learned at key-on falls outside the window the calibration accepts. It is a generic code, so it means the same on every make.
Is it safe to drive with P2109?
Drive gently and only to a workshop. With P2109 the car can go into limp mode (reduced power) to protect itself.
Will P2109 fail an emissions test?
Yes, it can. P2109 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 P2109 to fix?
Difficulty: medium. A typical repair takes 0.3 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2109 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.