Powertrain, generic (extended)

P2122 Throttle/Pedal Position Sensor/Switch D Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2122 sets when pedal track D falls below its lower voltage limit, typically from a short to ground, a missing 5 V reference or a broken signal wire. Limits differ by maker: Ford uses 0.25 V and since 2020 lights both MIL and wrench lamp (in 2012 only the wrench lamp); GM's 2007 tables use 0.325 V with 19 of 39 counts at 12.5 ms (Type A), GM's 2023 table 23OBDG07 0.28 V for 0.2 s; the 2014 VW Passat flags anything under 0.61 V. GM bulletin 14636 extended coverage on 2009-2011 Impala and 2009 LaCrosse pedals with broken solder joints that set this and related codes. P2123 is the high counterpart, P2120 the general circuit code, P2127 the low fault on track E. The ECU limits power and pedal response.

Likely causes

Track D signal wire shorted to ground or chafed
Open or shorted 5 V reference feed to the pedal
Pedal sensor fault such as a cracked solder joint
Corroded terminals with high resistance

Symptoms

  • Engine warning lamp and reduced power message
  • Pedal feels dead or reacts only slowly
  • Cruise control may be unavailable

Repair estimate

DifficultyEasyDIY possible
Parts and labour€20–350
Time0.3–1.5 h

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

Parts involved

accelerator pedal position sensorpedal sensor wiringecm

Related codes

P2120P2121P2123P2124P2127P2138

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