OBD-II · Engine and powertrain (P)
P2018
Intake runner (swirl) flap position sensor circuit intermittent bank 1
What it means
Intake manifold runner flaps - called swirl flaps on diesels - change how air enters the cylinders at low rpm. The position sensor signal drops out or jumps.
Symptoms
- engine warning light
- often no noticeable change
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | loose or corroded connector |
| 02 | chafed wiring |
| 03 | failing position sensor |
What to check, step by step
- 01Wiggle-test the harness while watching live data.
- 02Inspect the position sensor connector and wiring.
- 03Check the 5 V reference, ground and signal.
- 04Check the linkage between actuator and flap shaft is intact.
- 05Replace the sensor/actuator or manifold as required.