I have to get my 2008 SS smogged and the rear O2 sensor and evap shows not ready. In California the evap does not have to be ready. I have a new ZZ crate motor. Previous owner put in a 3" Down pipe. I have tried many drive cycles, I called the previous owner to ask if he disabled the Rear O2 in HP tunes. He can't recall. I looked up the tune and I didn't see it disabled. Here are my choices as I see it , but any advice will be welcomed.
1--replace rear O2
2--Put stock tune back in temporarily
3--Make the O2 "invisible" in HP Tunes ( no idea how to to do this)

If anyone has had this problem your input would truly be appreciated.

 

You do know that the catalytic converter is part of the downpipe? California is very strict about catalytic converters.

Have you visually inspected the system? Is there a properly labelled converter? Is there a #2 O2 sensor?

 

Yes on the car and O2

 

Cat

 

If it will run with the stock tune, that seems like the easiest.

I think the O2 sensor monitors runs continuously or twice a drive, so I don't know how it could "be not ready".

I suppose you could try a battery disconnect lobotomy.