P012FEngine Coolant Temperature / Engine Oil Temperature Correlation
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P012F compares the coolant temperature sensor with the engine oil temperature sensor. The documented user is Ford's Power Stroke diesel. After a calibration update for the 6.0 litre engine, Ford uses it to monitor oil cooler efficiency: if the oil gets much hotter than the coolant at certain speed and load, the oil-to-coolant heat exchanger is probably clogged, and P012F sets together with the wrench lamp. On the 6.7 litre (2015–2018) several bulletins treat P012F as a false setting – partly below 5 °C ambient – cured by reprogramming the engine module. Ford's 2023 diesels run the cold-start comparison of coolant against oil temperature (35 °C limit after 6 h) under P0196 instead. GM does not use the code, and the code does not say which sensor or which system is at fault.
- What you may notice
- Check engine light and/or wrench lamp (Ford)
- Raised oil temperature with a clogged oil cooler
- Often no driving symptoms when software is the cause
- Likely causes
- LikelyOil cooler (oil-to-coolant heat exchanger) clogged – oil much hotter than coolant
- PossibleEngine module software (false setting, especially in cold weather)
- PossibleCoolant or oil temperature sensor inaccurate, or its wiring faulty
- RareThermostat stuck open or low coolant
- RareBlock heater in use (only coolant preheated)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.