If you were to remove the pre-cats on a 2002 and have it connected directly to a y-pipe, the check engine light would come on due to the O2 sensors. Correct?

So my question is will any O2 Simm work, or do you have to a specific one for your car?

Thanks

 

you can modify the b-pipe and stick both downstream O2 sensors behind the main cat and have no CEL