P2120Throttle/Pedal Position Sensor/Switch D Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2120 is the general circuit check for signal D, which GM, Ford and VW all use for the first accelerator pedal track. GM's 2007 tables call it APP Sensor 1 Circuit: the ECM watches sensor 1 for steady or intermittent opens and shorts within its 0.325-4.75 V window and counts failures every 12.5 ms, setting the code at 19 of 39 counts. GM PIP3783D lists P2120 among the pedal codes on 2007-2014 full-size trucks and SUVs and blames weak pin grip in the inline connectors C109 and C205. Ford's 2024 summary uses P2120 as the base code whose failure types 16 and 17 replace P2122 and P2123. Range/Performance is P2121, low and high voltage P2122/P2123, dropouts P2124. With one track lost, the ECU cuts power.
- What you may notice
- Engine warning lamp and reduced power message
- Sluggish or capped acceleration
- Fault often intermittent and hard to reproduce
- Likely causes
- LikelyPoor terminal tension or corrosion at pedal, inline or ECM connectors
- PossibleOpen or short in the sensor 1 signal, reference or ground wire
- PossibleInternal fault in the pedal sensor, such as a cracked solder joint
- RareECM input fault
- 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.