Open or high-resistance signal circuit between the accelerator pedal sensor E and the engine control module, often from a chafed or broken wire; Corroded, loose, or water-intruded connector pins at the pedal assembly or the engine control module; Failed accelerator pedal position sensor E inside the pedal assembly, typically an internal potentiometer or hall-effect element that has gone open; Short to voltage on the sensor E signal circuit, which can be caused by harness damage near the pedal or along the firewall; Poor sensor ground or reference voltage supply shared with the pedal sensors, which skews the E signal high; Engine control module internal fault on the sensor input circuit, which is rare but does occur

DTC codes / P21xx · Fuel and air metering / P2128

P2128Accelerator Pedal Position Sensor E Circuit High

Q: What does code P2128 mean?

Accelerator Pedal Position Sensor E Circuit High. P2128 means the engine computer has detected an abnormally high voltage on the signal circuit for accelerator pedal position sensor E, which is one of the redundant pedal position sensors used to cross-check driver demand. The computer compares this sensor's output against the other pedal sensors and the expected range, and it sets the code when the E circuit voltage stays above the calibrated threshold for longer than the fault timer allows.

P2128 means the engine computer has detected an abnormally high voltage on the signal circuit for accelerator pedal position sensor E, which is one of the redundant pedal position sensors used to cross-check driver demand. The computer compares this sensor's output against the other pedal sensors and the expected range, and it sets the code when the E circuit voltage stays above the calibrated threshold for longer than the fault timer allows.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illuminated check engine light or electronic throttle control warning lamp
Reduced engine power or limp-home mode with a limited throttle opening
A dead or unresponsive accelerator pedal, or a pedal that feels normal but produces no engine response
Hesitation, stumble, or surging during light throttle application
Often no symptoms besides the warning light, especially if the fault is intermittent
Transmission may hold a gear or shift harshly because torque management is affected

Common causes, most likely first

Open or high-resistance signal circuit between the accelerator pedal sensor E and the engine control module, often from a chafed or broken wire
Corroded, loose, or water-intruded connector pins at the pedal assembly or the engine control module
Failed accelerator pedal position sensor E inside the pedal assembly, typically an internal potentiometer or hall-effect element that has gone open
Short to voltage on the sensor E signal circuit, which can be caused by harness damage near the pedal or along the firewall
Poor sensor ground or reference voltage supply shared with the pedal sensors, which skews the E signal high
Engine control module internal fault on the sensor input circuit, which is rare but does occur

How to diagnose and fix it

Scan all modules for stored and pending codes and record freeze-frame data for P2128 before clearing anything
Inspect the accelerator pedal connector and the engine control module connector for corrosion, pushed pins, or water intrusion
Back-probe the sensor E signal circuit and compare its voltage against the other pedal sensor signals through a smooth sweep of the pedal
Check the sensor reference voltage and ground at the pedal connector under load with a meter or oscilloscope
Perform a wiggle test on the harness while watching live pedal position data to expose an intermittent open or short
Repair or replace the damaged section of harness, then clear codes and verify the pedal position readings track correctly
If wiring and connectors are sound, replace the accelerator pedal assembly and relearn the pedal position if the manufacturer requires it

What the pedal sensor E code hides

Sensor E is one of several redundant pedal tracks, so a high signal on E alone often means the other tracks still read correctly and the driver notices little beyond the warning light.
A common misdiagnosis is replacing the pedal assembly when the real fault is a rubbed signal wire behind the pedal bracket or at a bulkhead pass-through.
Water intrusion into the pedal connector after a windshield leak or floor flooding can set this code without any visible damage to the pedal itself.
A failing sensor ground shared with the pedal tracks can push the E signal high and mimic a bad sensor, so always load-test the ground before condemning parts.
Clearing the code without checking freeze-frame data can erase the pedal angle and engine speed at the moment of failure, which are the best clues for an intermittent fault.

Can I keep driving with P2128?

The vehicle may enter reduced power mode with limited throttle response, so avoid highway merging and heavy traffic until it is repaired. If the pedal has gone unresponsive or the engine idles only, stop driving and arrange a tow rather than risk a stall in motion.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.