It's often triggered by:
* Loose gas cap: The simplest explanation. Make sure your gas cap is tightly secured. Try tightening it and see if the light goes off after driving a short while. If the light stays on after a few driving cycles it means more work is needed.
* Faulty gas cap: The gas cap itself might be damaged or worn out, preventing a proper seal. Replacing the gas cap is inexpensive and a good first step if tightening doesn't work.
* Problem in the EVAP system: This system prevents fuel vapors from escaping into the atmosphere. A leak in any part of the system (hoses, canister, sensor, etc.) can trigger the light. This requires a more thorough diagnostic check by a mechanic.
If tightening the gas cap doesn't resolve the issue, you should have a mechanic diagnose the problem to pinpoint the source of the leak within the EVAP system. Ignoring it could lead to further issues and potential emission failure during inspection.
