P04ED
EVAP System Large Leak Detected Fresh Air Side
Same as P04EB on the fresh-air side, but with a leak large enough to prevent test build-up. The evaporative system captures fuel vapor from the tank and purges it into intake; leaks or stuck purge valves leak hydrocarbons and cause emissions failures.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: easy
Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
Common causes
Ordered by how often each turns out to be the cause.
- Vent valve stuck openCommon
- Hose pulled off or tornPossible
Parts involved
- EVAP Vent Valve
- EVAP Hose Fresh Air Side
P04ED is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.