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

P04FC

Crankcase Ventilation System Performance

A general performance fault of the crankcase ventilation system - PCV pressure or flow does not match the engine model. Possible causes are a clogged PCV valve, blocked separator, oil-filler cap with a damaged seal, or excessive blow-by from worn rings.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / FC

Possible causes

  • PCV valve clogged or stuck high
  • Oil separator clogged medium
  • Excessive blow-by from worn piston rings low

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 80–800 €
  • Estimated time: 0.6–3 h
  • Component: pcv valve
  • Component: oil separator
  • Component: oil filler cap
  • 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