The Engine Light Stays on on 2000 Chevrolet Silverado 1500

The engine light is constantly on in the dashboard panel. It runs OK and the oil has been changed. What could cause this?

2 answers
go to any parts house like autozone or something they can hook it up to the computer for free and tell you what the code is then get on line a research the code
Here is some helpful info about your check engine light, and what to do: http://repairpal.com/check-engine-light