California has done it to me again. new smog is visual only 2001 up Dummy says the cat is wrong one. funny thing hes smogged the jeep twice before never said anything. I don't know how to tell to check this. Cat is a bolt in and dosent look like its ever been changed. it turns out they say its the two small precats on the manifold. I didn't know they could be replaced on the manifold.

 

2001 Cat system should look like this (below) with a down stream, unmonitored Cat. Is this what you have?

 

The precats are not part of the manifolds. The stock setup is a twin downpipe that bolts to the bottom of the manifolds, right up there where it's next to impossible to reach. There are direct bolt-on replacements available from Walker/Dynomax (stock performance) and Magnaflow (high flow), and both have a CARB compliant version. You can alternately have the cats cut out and new ones welded in, but I don't the rules for that for you poor subjects of California.

If you still have the original cats, I can't see how you're out of compliance, since California emissions was the only thing offered in 2001. If your cats have been replaced, it's possible someone went with the cheaper non-CARB replacements. There's about a $220 difference between the Walker 81850 (CARB) and 52304 (non-CARB) on Amazon.

Did the guy give you any indication why he thinks the cats have been replaced? Post some pics so we can see what you have.