What causes the check engine light to come on a 2001 honda civic?

The check engine light on a 2001 Honda Civic can illuminate due to various issues, including a loose or damaged gas cap, faulty oxygen sensors, or issues with the catalytic converter. It may also indicate problems with the ignition system, such as bad spark plugs or ignition coils. Additionally, engine performance issues, like misfires or poor fuel efficiency, can trigger the light. To accurately diagnose the cause, it's best to use an OBD-II scanner to read the trouble codes stored in the vehicle's computer.