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P04FC Powertrain

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.

Affected components

  • Pcv valve
  • Oil separator
  • Oil filler cap

Common causes

  • High likelihood: PCV valve clogged or stuck
  • Medium likelihood: Oil separator clogged
  • Low likelihood: Excessive blow-by from worn piston rings

Diagnostic notes

  • The malfunction indicator lamp may illuminate
  • This code can affect emissions

Sources

Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.

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