P04ECEVAP System Large Leak Detected - Fuel Tank Side
- 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
- Hybrids with a sealed fuel tank have a valve separating the tank from the charcoal canister and its vent side. CARB allows such sections to be leak-checked separately with their own codes; a Ford patent checks the tank side via tank pressure with the valve closed and the canister side with a leak check module. Conventional systems report the same leak as P0442, P0455 or P0456. P04EC reports a large leak in the tank section: it cannot be brought to test pressure or loses it at once – cap missing or open, line off. Stellantis documents it on the Jeep Wrangler 4xe plug-in hybrid only, whose conventional models report P0455; several bulletins name a cap not closed properly or a trapped tether, with a forced leak test via the scan tool.
- What you may notice
- Check engine light on
- Check fuel cap message, often right after refuelling
- Possibly fuel smell
- Likely causes
- LikelyFuel cap not closed properly or tether trapped
- PossibleCap or filler neck sealing surface poor
- PossibleRecirculation or vent line loose at the quick connector
- RareTank pressure sensor or valve faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €0 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.