OBD-II · Engine and powertrain (P)
P02E1
Diesel intake air flow control (throttle) performance
What it means
Diesels have an electronic intake throttle that controls air flow for EGR and DPF regeneration and closes at switch-off to stop the engine shuddering. The throttle does not reach the commanded position, usually because it is sticking with soot.
Symptoms
- engine warning light
- possibly reduced power (limp mode)
- engine may shake when switched off
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | soot and oil build-up on the throttle plate (EGR gas enters nearby) |
| 02 | worn throttle motor or gears |
| 03 | position sensor fault |
| 04 | wiring resistance |
What to check, step by step
- 01Compare commanded and actual throttle position in live data.
- 02Remove and inspect the throttle for soot; clean it carefully.
- 03Check movement using the approved actuator test. Do not force an electronic throttle plate by hand; manual movement or cleaning must follow the manufacturer's procedure with the unit safely isolated.
- 04Replace the throttle unit if it still does not follow commands; run an adaptation.