Powertrain, generic (extended)

P2120 Throttle/Pedal Position Sensor/Switch D Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

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.

Likely causes

Poor terminal tension or corrosion at pedal, inline or ECM connectors
Open or short in the sensor 1 signal, reference or ground wire
Internal fault in the pedal sensor, such as a cracked solder joint
ECM input fault

Symptoms

  • Engine warning lamp and reduced power message
  • Sluggish or capped acceleration
  • Fault often intermittent and hard to reproduce

Repair estimate

DifficultyEasyDIY possible
Parts and labour€20–350
Time0.3–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

accelerator pedal position sensorpedal sensor wiringecm

Related codes

P2121P2122P2123P2124P2125P2138

References: gsi.ext.gm.com, static.nhtsa.gov, fordservicecontent.com, static.nhtsa.gov.