Evaporative Emission System Leak Detected (Very Small Leak)
A very small leak (typically equivalent to a 0.020 inch / 0.5 mm orifice) has been detected. Smaller threshold than P0442; intermittent and often weather-dependent. Modern OBD-II requires this monitor on most vehicles since model year 2000.
Affected components
- Fuel filler cap
- Evap canister
- Evap purge valve
- Evap vent valve
Common causes
- High likelihood: Fuel cap seal hardened or worn
- Medium likelihood: Purge or vent valve leaking slightly
- Medium likelihood: Hairline crack in EVAP hose
Possible symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Related codes
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.