Fix the underlying issue that triggered the check engine light
Tighten or replace the gas cap if it is loose or damaged
Check the dashboard for any other warning lights or symptoms
Use an OBD-II scanner to read the trouble code
Repair or replace the faulty sensor, part, or wiring
Clear the code with an OBD-II scanner after repairs
Disconnect the vehicle battery for a short time if appropriate for your vehicle
Drive the vehicle to confirm the light stays off
Have a mechanic diagnose the problem if the light returns