Replacing a CARB-compliant catalytic outside of California

I'm seeking a second opinion or a possible workaround for a thorny repair issue.

I'm trying to replace the catalytic converter on a 2011 Prius with an Illinois title and registration.

However, the car was originally purchased from a Toyota dealership in California, and therefore has been configured for CARB-compliant operation. That is, it's configured to pass California smog checks. Or at least it was before the catalytic was stolen.

While I know that installing an aftermarket catalytic would probably cause a smog check failure in California, the important detail here is that the car is registered in Illinois. I only reside in Illinois, and have no plans to drive it to California.

My mechanic believes that the only repair option is to use an OEM Toyota catalytic. He says that due to the way the coolant system is configured in this CARB-compliant version of the 2011 Prius, the use of a cheaper, aftermarket catalytic may result in failure of the Illinois emissions test.

Yet it's proven seemingly impossible to source an OEM replacement catalytic any sooner than December or January. And the price tag for the OEM part is of course staggering.

I'd be grateful to hear about any possible workarounds here, bearing in mind that I don't need to pass the very stringent California emissions test - only the Illinois emissions test. I think someone here in another thread mentioned the use of a "coolant patch" in combination with an aftermarket catalytic. I don't know what that means but would love to find out.

 

Thank you for the input, everyone. It was helpful to read all of this before deciding.

Correct, and we do have an emissions test requirement in Illinois (although only in the two most urban regions, namely metro Chicago and right across the river from St. Louis) that it'd likely fail.

Plus, the cost of parts and labor (or time investment to figure out how do a temporary fix myself) are significant when piled on to the additional cost of eventually switching out the quick fix for a new OEM cat. If it wasn't for the unusually low mileage (59K), it might be more trouble than it's worth.

Luckily though...long story short, I remembered that an old friend had semi-recently opted to scrap her Gen 3 Prius after a hybrid battery failure way out in the middle of nowhere. I asked her about it, and it turns out that the local salvage yard had offered her only a small fraction of what she knew the scrap OEM cat to be worth, so she held on to the scrap OEM cat to wait for a better deal. Which I offered.

Mechanic says (after seeing photos of the scrap OEM cat) that, with the addition of a gasket, it should work. The cat does have 175K miles on it, but it's from a source I've known for years and trust to be legit (and thus grossly intact, rather than sliced off with a power tool!).

Anyway. Fingers crossed.