Powertrain, generic (extended)

P2128 Throttle/Pedal Position Sensor/Switch E Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2128 sets when pedal track E reads above its upper limit, typically from an open sensor ground, a short to 5 V or a broken track. Where E is a half-scale signal the limit lies far below the supply: GM's 2006 tables flag sensor 2 above 2.295 V and the 2014 VW Passat above 2.43 V. Pedals with two full-scale tracks use about 4.75 V (Ford, GM 2007, 19 of 39 counts) or 4.824 V for 0.2 s (GM's Bosch-based 2012 ECM). Since both tracks often share one ground, an open ground can set P2128 together with P2123. With E rejected the ECU steers on track D only and limits output; Ford's 2020-2023 summary lights MIL and wrench lamp. P2127 is the low fault on E, P2123 the high fault on D, P2138 the D/E comparison.

Likely causes

Open or high-resistance ground of the pedal sensor
Track E signal shorted to the 5 V reference
Broken track or solder joint inside the pedal sensor

Symptoms

  • Engine warning lamp and reduced power message
  • Weak acceleration even with the pedal fully pressed
  • Often stored together with P2123 if the ground is open

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

P2125P2126P2127P2129P2123P2138

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