What P2122 means
Your gas pedal has two or more position sensors so the computer can cross-check them. One of them, sensor D, is sending a voltage that's too low, as if its wire were cut or shorted to ground. A worn sensor inside the pedal assembly is the most common cause, followed by a damaged wire or corroded connector.
How the engine computer detects it
Throttle/Pedal Position Sensor "D" Circuit Low: the signal voltage is below the expected range. Often a short to ground or high resistance in the wiring.
Written from public technical sources and not yet checked by a mechanic. How we write these pages
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
Common causes
- Pedal sensor track worn Most likely
- Signal wire shorted to ground Possible
- Connector pins corroded - high contact resistance Less likely
How to diagnose P2122
- Check for P2127 or P2138 as well. Several pedal sensor codes together point to the shared wiring or a failed pedal assembly.
- With the ignition off, unplug the connector at the gas pedal and look for corrosion, spread pins or moisture, for example from a wet floor or a spilled drink.
- Follow the wiring from the pedal for pinched or chafed spots, especially where it moves or rubs.
- With a scanner, watch sensor D while you slowly press the pedal. It should rise smoothly; a dropout at one spot points to a worn sensor track.
- Replace the pedal assembly if the sensor is worn, since the sensors are built into it. Some cars need a pedal relearn with a scanner afterwards.
Vehicles that report P2122 most
| Vehicle | Years | Reports | Share | Median miles |
|---|---|---|---|---|
| Chevrolet Impala | 2009–2012 | 8 | 48k | |
| Chevrolet Malibu | 2016–2017 | 4 | — | |
| Jeep Renegade | 2017–2020 | 3 | — |
Counts of owner complaints to the NHTSA that mention P2122 (34 in total), not failure rates: popular models get more complaints simply because more of them are on the road. Models with fewer than 3 complaints are left out.
Reading the code
- P
- Powertrain
- 2
- Generic (SAE) code
- 122
- Specific fault
Questions drivers ask
Can I drive with code P2122?
Drive only to a shop or somewhere safe. With one pedal sensor out of range, the computer relies on the other and usually cuts power, so expect slow acceleration when merging or turning across traffic. Have it towed if the pedal does little or nothing.
Will my car pass an emissions inspection with P2122?
Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.
Often reported together
Codes that owners mention in the same NHTSA complaints as P2122. They can point to a shared cause, so it's worth checking them together.
This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.