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

P051F

PCV Filter Restriction

The pressure or flow sensor in the PCV path detects increased restriction across the oil-mist filter element. Once saturated with oil mist, the filter no longer passes blow-by gas, raising crankcase pressure and pushing oil past seals.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number5 / 1F

Possible causes

  • PCV filter saturated with oil mist high

Inspection / repair

  • Difficulty: easy
  • DIY: possible
  • Estimated cost: 40–200 €
  • Estimated time: 0.3–1 h
  • Component: pcv filter
  • Component: crankcase pressure sensor a
  • MIL / check engine light
  • emissions-relevant

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