check engine light stays on

[rgloston]

Originally Posted by MT-2500

Code 420\430 does not always mean the cat is bad.
Ckeck the link below on info and test for code 420/430
MT-2500
http://www.troublecodes.net/articles/catfailure/

If you decide to, have GM perform the tests mentioned above by MT-2500. This can be done in about half-an-hour. Chalk up the $50+ bucks when you do.

Keep in mind the 80K warranty. Am told that GM techs replace them more than people know. Better to have knowledge from all angles. Good post, MT.