Powertrain, generic (extended)

P2129 Throttle/Pedal Position Sensor/Switch E Circuit Intermittent

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2129 is meant for short dropouts or spikes in signal circuit E that do not last long enough for a steady low or high fault. No manufacturer documents this code publicly. GM and Ford, which assign E to the second pedal sensor, catch such glitches inside their circuit codes instead: GM counts failures every 12.5 ms and flags the APP sensor 2 circuit after 19 of 39 counts (P2125/P2127/P2128), Ford uses 0.25/4.75 V limits. CARB requires circuit monitoring of input sensors; the code fits that duty. Check for loose pins and harness chafing with the pedal moved slowly. Effects range from a warning lamp to brief power cuts while driving.

Likely causes

Loose terminal or poor pin tension at the pedal connector
Chafed harness making intermittent contact
Worn spot or cracked joint inside the pedal sensor

Symptoms

  • Warning lamp that comes and goes
  • Brief hesitation or power loss while driving
  • Reduced power mode after repeated dropouts

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–350
Time0.5–2 h

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

Parts involved

accelerator pedal position sensorpedal sensor wiringecm

Related codes

P2125P2126P2127P2128P2138

References: law.cornell.edu, gsi.ext.gm.com, newtonnet.co.uk.