What might cause my 2001 Chevy Cavalier check engine light to come on?

The 2001 Chevy Cavalier check engine light (CEL) may come on for many different reasons such as a loose gas cap, faulty oxygen sensor, spark plug or coil issues, and catalytic converter problems. The most common cause is usually the o2 sensor which measures the level of oxygen in the exhaust and when it isn't working problem will illuminate the CEL. The first thing You should do is to check and see if the gas cap is on tight and is not damaged. The catalytic converter can become clogged over time from the pollutants and debris which will cause the check engine light to be on. The most efficient way to find out what the problem is would be using an OBD diagnostic tool to diagnose the problem. If You don't have a scanner You can get the inspection done by the dealership or an auto service shop.