OBD-II · Engine and powertrain (P)
P0520
Engine oil pressure sensor/switch circuit
What it means
The ECU detects an electrical fault in the oil pressure sensor or switch circuit. This is a signal fault, not proof of low oil pressure, but the oil level and warning light should be checked first.
Symptoms
- engine warning light
- oil pressure warning may flicker or stay on
- possible wrong oil pressure reading
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | failed oil pressure sensor or switch |
| 02 | wiring or connector fault |
| 03 | oil leaking into the connector |
| 04 | ECU input fault |
What to check, step by step
- 01If the red oil pressure warning is on, stop the engine and check the oil level before driving further
- 02Check the oil level and that the correct oil grade is used
- 03Inspect the sensor or switch connector and wiring (oil leaking into the connector is common)
- 04Confirm the real oil pressure with a mechanical gauge in place of the sensor
- 05Replace the sensor or switch if the real pressure is correct