OBD-II · Engine and powertrain (P)
P2135
Throttle/pedal position sensor A/B voltage correlation
What it means
The two position signals that should always agree (usually the two sensors in the electronic throttle body) disagree with each other.
Symptoms
- reduced power or limp mode (EPC light on VW group cars)
- poor or no response to the accelerator
- raised or unstable idle
- engine warning light
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | worn sensor tracks in the throttle body |
| 02 | corroded or loose throttle body connector |
| 03 | wiring fault on one of the signal or reference wires |
| 04 | water or oil in the connector |
| 05 | low battery voltage |
What to check, step by step
- 01Check the battery and charging voltage
- 02Inspect the throttle body connector and wiring for corrosion, oil and loose pins
- 03Watch both signals in live data through the full throttle travel: look for a dropout or step on one of them
- 04Check the 5 V reference and ground shared by both sensors
- 05Replace the throttle body if the wiring is good, then run the throttle adaptation