Powertrain, generic (extended)

P2127 Throttle/Pedal Position Sensor/Switch E Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2127 reports that pedal track E reads below its lower limit. Because many pedals run the second track at roughly half the voltage of the first, the limit for E can sit lower than for D: GM's 2006 tables flag sensor 2 under 0.1625 V and the 2014 VW Passat under 0.27 V, against 0.61 V for track D. Full-scale designs use similar limits on both tracks: Ford 0.25 V, GM's 2023 table 0.28 V for 0.2 s, GM's Bosch-based 2012 ECM 0.625 V. Typical causes are a short to ground on the E signal wire, an open reference feed, or a worn spot at the closed end of the track. With E gone the ECU relies on track D alone and holds back torque. P2128 is the high fault on E, P2122 the low fault on D, P2125 the general E circuit code.

Likely causes

Track E signal wire shorted to ground
Open 5 V reference feed for the second track
Worn track E at the closed-pedal end
Corroded or loose pedal connector

Symptoms

  • Engine warning lamp, on newer Fords together with the wrench lamp
  • Reduced power and slower pedal response
  • Traction control may be switched off

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

P2125P2126P2128P2129P2122P2138

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