P04FCCrankcase Ventilation System Performance
- 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
- The crankcase ventilation routes blow-by gas into the intake, and CARB requires it to be monitored. P04FC is a general function check: pressure or flow in the system deviates from the model. FCA uses it on the 2.0-litre turbo in the Wrangler and Cherokee (2018–19) and the 3.6 Pentastar in the Challenger (2020), with known false triggers fixed by engine module software; the strategy is not published, a FCA patent evaluates a pressure sensor in the fresh-air line.
- What you may notice
- Check engine light on
- Possibly oil consumption or oil in the intake
- Whistling from false air
- Likely causes
- LikelyModule software (FCA false trigger)
- PossiblePCV valve or oil separator blocked or sticking
- PossibleVentilation or fresh-air hose leaking or loose, oil filler cap leaking
- RareIncreased blow-by (piston rings)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.