OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

P252F

Engine Oil Level Too High

The oil level monitor reports the engine oil level above the safe maximum after sensor checks pass. Overfilling raises foaming, blow-by and crankcase pressure — and on diesels with regen-by-injection, fuel dilution can drive the level up by itself. The ECM warns the driver and may flag for service.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / 2F

Possible causes

  • Overfilled at last service high
  • Fuel dilution from incomplete DPF regeneration medium
  • Coolant intrusion (head gasket / cooler) low

Inspection / repair

  • Difficulty: easy
  • DIY: possible
  • Estimated cost: 10–200 €
  • Estimated time: 0.2–1 h
  • Component: engine oil
  • MIL / check engine light

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication