P2121Throttle/Pedal Position Sensor/Switch D Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2121 means pedal signal D is electrically intact but implausible. Ford's 2012 OBD summary sets it only on second-generation ETC systems, whose pedals carry three tracks D, E and F: if sensor D disagrees with the others by more than 1.1 degrees, the PCM stores P2121 without MIL but with the wrench lamp, and pedal response becomes rate-limited using the healthy tracks. Mitsubishi lists P2121 for the accelerator pedal sensor on the 2022 Outlander as a one-trip code that turns the MIL on. Newer Ford and GM systems with two tracks report such disagreement as P2138 instead. Circuit faults on D are P2120 and P2122-P2124; P2126 is the same check for track E. The car stays drivable but reacts softly to the pedal.
- What you may notice
- Wrench or engine warning lamp on
- Softened, delayed acceleration
- Idle may rise when the brake is not pressed
- Likely causes
- LikelyWorn or dirty track D giving an offset reading
- PossibleContact resistance at the pedal connector
- RareShared reference or ground line shifting one signal
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €20 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.