OBD-II · Engine and powertrain (P)
P0198
Engine oil temperature sensor circuit high
What it means
The oil temperature signal voltage is above its valid range, usually an open circuit or unplugged sensor.
Symptoms
- engine warning light
- wrong or missing oil temperature reading
- often no noticeable change in driving
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | unplugged or corroded connector |
| 02 | open circuit in the wiring |
| 03 | failed sensor |
| 04 | poor sensor ground |
What to check, step by step
- 01Check the oil level (on many European cars the oil temperature sensor is combined with the oil level sensor in the sump)
- 02Compare the oil temperature with coolant temperature after an overnight cold soak: they should be close
- 03Inspect the sensor connector and wiring, especially under the sump where it is exposed to water and salt
- 04Replace the sensor if the wiring is good