Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)
The EVAP system detected a large leak that strongly correlates with a missing or improperly closed fuel filler cap. After re-tightening the cap, the code clears once the readiness monitor completes.
Affected components
- Fuel filler cap
- Evap lines
Common causes
- High likelihood: Fuel cap loose, missing, or worn seal
- Low likelihood: Filler neck damaged
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
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.