What P2138 means
Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation
How to diagnose
- Read freeze frame data. When P2138 set, your ECU snapshotted every sensor at that moment. This tells you what the car was doing when the fault triggered — RPM, load, coolant temp, throttle position, fuel trims. Almost always enough info to figure out the cause without further testing.
- Check for related codes. If you have P2138 plus other codes, fix the earliest one in the chain first — a single root cause often triggers multiple codes.
- Cheap fixes first. For most codes, the order is: inspect connectors + wiring (free), check for vacuum leaks (cheap), replace sensor (moderate), replace mechanical part (expensive). Follow that ladder before dropping money on parts.
Manufacturer-specific descriptions
Different manufacturers use P2138 for slightly different failure modes:
| AUDI | Accelerator Pedal Position (APP) assembly failure, Powertrain Control Module (PCM) failure, Throttle Position Sensor (TPS) failure, Wiring issue |
| BMW | Throttle/Pedal Position Sensor/Switch "D" / "E" Voltage Correlation |
| GM | Accelerator Pedal Position (APP) Sensors 1-2 Not Plausible |
| HONDA | Accelerator Pedal Position (APP) Sensor 1/2 (Throttle Position Sensor D/E) Incorrect Voltage Correlation |
| MITSUBISHI | APS(main/sub) correlation |
Read P2138 on your own car
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