Hello, I have a 2001 gen 1 Prius that contains a gen 2 catalytic converter that gives me a check engine light due to the “vacuole”, I’ve seen that you need to either weld it to get it to pass emissions, but I’m not sure where to start. the previous owner got it past emissions somehow. Any tips on whether I should get it welded to turn off the check engine light and fix the smell when the car idles, or should I just completely replace it with a gen 1 part? Another thing is the battery is also a gen 2 part that was put into the car in 2015, but I consistently get 38-45 mpg with no real issues, would it be better to swap it out?
I think you're referring to the vacuum-controlled valve in the exhaust line, that's part of the emissions control. If that's not working (rust) or missing, there's apparently a work-around using a Honda Gold Wing valve, IIRC; this has been discussed here, try searching the board. I replaced the entire exhaust line as a unit when the valve went out on my '02, but I'm not sure the parts are available anymore. I'm curious as to just how you can run a 2001 Prius using a gen. 2 HV battery, but if it's working OK, I'd leave it alone.There are several choices for gen. 1 HV batteries; I've got this one in my '02: https://greentecauto.com/hybrid-battery/toyota/prius-hybrid-batteries/toyota-prius-2001-2003/toyota-prius-gen-1-new-cell/
All you have to do is trick the ECU into thinking the VAV is still there by attaching the vacuum line into a similar vacuum reservoir, like that one on the Gold Wing. Easiest, of course, would have been to use the OEM reservoir off the original cat, but it probably got stolen. But any reservoir of the same approximate volume will work. You could literally glue/seal PVC plumbing pipe to create one, just have to get a nipple that fits the vacuum line, drill a hole in the PVC and glue it in. Your vacuum line might still be hanging under the car. It runs from a sensor located lower left of the throttle body across the passenger side of the engine compartment as the bottom hose on the two 4-hose brackets along the way. You could mount the replica reservoir under the car, but I just cut the hose in the engine compartment and lay my new reservoir on top of the engine or brake fluid reservoir. Both the Gold Wing and OEM reservoirs look like they belong there, no one would probably notice. Some others might look out of place, but who cares. You probably have a refurb battery that used Gen2 modules inside a Gen1 case. Perfectly fine, almost all you can get any more.
