Ok guys I took off the stock exhaust and busted out the inside filters. (Not the cat) and now my check engine light is on. What did or didn't I do ? Note it's my first Cummins so take it easy on me please. Lol

 

Firing squad comes to mind..... J K! Im gonna assume you didn't research your intention(s) before "doing the deed?" Well, you either have to go with a complete delete kit, or replace what you destroyed. Both will be a bit pricey.