2006 Tacoma which catalytic converter is bad?

My 06 Tacoma pre runner v6 has 205k miles on it and the CEL is on and error code is P0420. Took it to dealer and they said I need to replace both cats. It's this common to have both go out at the same time? They quoted $2800 for 2. I'm in California so no aftermarket cats for me. How can I test them to see which one is bad or if they are both bad?

Thanks!

 

I'm not exactly sure about California's laws, but I would check out an independent shop. Could save you some money.

 

I tried, but there are no california legal aftermarket cats available for my truck (v6). shop told me to go to the dealer. I pretty much have no options here. I need the factory cat to pass smog in CA.

 

With 205K miles you are best off replacing both. That's qyite a bit of mileage on originals and typically I have seen converters go no more than about 250K and they were BARELY passing emissions. If they were passing emissions the CEL light was on which automatically made it fail anyways. Replace them both. Get some fresh ones, wash your hands and walk away with the bloody nose you received from it.

If you want to be insanely anal about it, a quick test is temperature differential.

Take an IR gun and measure the temp coming from the engine side of the cat, write the reading then take the temp from the exiting side of the cat. If you are at 100* or more difference, it's likely bad.

 

Thank you! Yeah I think I have to just suck it up

 

Isn't there a CA approved cat that u can install yourself?

 

Nope, not for the 4L V6 Prerunner. They have them for the 2.7L though

 

If you take the exhaust off at the cat/header (theyre built together if you didnt know) you can see inside and check if the cat is still there. Or poke something in there and see if you hit catylitic converter. If not then it's blown out.

The real question here, though, is why it's blown out. Could be the miles, but also likely, your head gasket could be going out. I had a cat blown out on the left bank and it just so happens that my head gasket was bad on that side too... the burnt coolant blew out the cat. You might wanna have them do a coolant pressure check to see if you need a head gasket job also... And if that's the case just look for a donor engine that has the headers with it.. itll be cheaper that way.

 

P0420 and P0430 are the messages thrown when the primary Cat (closet to the head) isn't making enough or making too much oxygen.(usually the first case) .
Depending on the failure mode you may need to replace the rear cat too. In Calif (at least in SoCal) you can't get used cats from a junk yard even with an engine.

I would suggest you look for discount dealer and buy the Cats carry out (you may need to pay for cores) and then take them to you local exhaust shop for install.

Ranger098 also has good advice, while the cats will fail due to miles most of the time, they're easily damaged by oil or antifreeze contamination. Make sure you don't have any mechanical issues.

(i had this message on my previous truck from 200K miles to the day I traded it in 300 K and tried everything short of replacing the cats)

 

I have a set of cats for sale.

 

I just made a post here with my scan tool readings. What do you guys think?
https://www.tacomaworld.com/threads/my-scan-tool-o2-sensor-readings-normal.392720/

 

are they good working OEM cats for 06 tacoma v6?

 

Sorry they just sold yesterday

 

Was the CEL on when you traded it in? and they took the truck as a trade in with that error? did they take a ton off the trade in price because of it?