'97 2.5TL - Check engine light

Hi:

I have a 2.5TL that has had the check engine light on for about 2 weeks. I wanted to ask if anyone knows of the various causes for this light to come on and if I could get away without taking it initially to the shop if it was something I could diagnose and fix.

Any suggestions on the common engine problems that trigger this light?

Regards

Joel