Throttle/Pedal Position Sensor/Switch "E" Circuit High
The PCM detected an abnormally high voltage signal from Sensor/Switch E (typically the pedal position sensor or throttle position sensor), indicating a circuit malfunction. The vehicle will enter limp mode with severely restricted acceleration or complete loss of throttle response, making safe driving impossible.
What You Might Notice
- Severe acceleration limitation or complete loss of throttle response
- Engine stalling at idle or during deceleration
- Stuck throttle position at any RPM
- Hesitation when attempting to accelerate
- Limp mode engagement with reduced power output
Most Common Causes
- 1
Open or shorted wiring circuit
Damaged, exposed, or pinched wiring between the pedal/throttle position sensor and PCM can cause abnormally high voltage readings. This is the most common cause of P2128.
- 2
Defective throttle or pedal position sensor
A failing sensor with internal resistance breakdown or contact degradation will produce incorrect high voltage signals and trigger the code.
- 3
Corroded or loose electrical connectors
Corrosion, water intrusion, or poor connections at the sensor connector or PCM harness can create high-resistance faults that register as high voltage.
- 4
Faulty drive-by-wire actuator motor or circuit
A malfunctioning electronic throttle body or its control circuit may cause the PCM to detect and report high sensor voltage as a protective measure.
How to Diagnose It
- 1
Check Open or shorted wiring circuit — Damaged, exposed, or pinched wiring between the pedal/throttle position sensor and PCM can cause abnormally high voltage readings. This is the most common cause of P2128.
- 2
Check Defective throttle or pedal position sensor — A failing sensor with internal resistance breakdown or contact degradation will produce incorrect high voltage signals and trigger the code.
- 3
Check Corroded or loose electrical connectors — Corrosion, water intrusion, or poor connections at the sensor connector or PCM harness can create high-resistance faults that register as high voltage.
- 4
Check Faulty drive-by-wire actuator motor or circuit — A malfunctioning electronic throttle body or its control circuit may cause the PCM to detect and report high sensor voltage as a protective measure.
How to Fix It
- 1
Inspect and repair wiring harness
Visually inspect all wiring between the pedal/throttle position sensor and PCM for damage, corrosion, pinching, or exposed conductors. Repair or replace damaged sections and ensure proper routing away from heat sources.
- 2
Test and replace throttle position sensor
Use a multimeter to measure voltage at the sensor connector while operating the throttle/pedal. If voltage remains abnormally high (typically above 4.5V at rest), replace the sensor with a manufacturer-spec unit.
- 3
Clean or replace electrical connectors
Disconnect the sensor and PCM connectors, inspect for corrosion or debris, and clean contacts with electrical contact cleaner. If pins are heavily corroded or damaged, replace the connector assembly.
- 4
Diagnose and repair electronic throttle body
If other fixes fail, use a scanner to monitor live throttle body commands versus actual position. A faulty drive-by-wire motor or control circuit may require throttle body replacement and recalibration.
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