P2138: Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation
Dual redundant potentiometers or Hall tracks in the Accelerator Pedal Position (APP) sensor disagree by more than the safety threshold.
| Trouble Code (DTC) | P2138 |
|---|---|
| Official SAE Definition | Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation |
| Vehicle Subsystem | powertrain |
| Driving Severity | HIGH |
Observable Symptoms
- Reduced Engine Power / EPC warning light
- Throttle unresponsive or limited to 1,500–2,000 RPM
Most Probable Root Causes
- Worn tracks inside accelerator pedal assembly
- Water intrusion or fret corrosion in pedal or bulkhead connector
Step-by-Step Diagnostic Procedure
- Graph APP Sensor D and E voltages smoothly from 0% to 100% pedal travel with ignition on, engine off
- Inspect pedal harness connector and replace APP assembly if tracks drop out