P0420 and P0430 at the same time do i need 2 cats or all 4

2008 V6 4.0 195 ODO Running down the free way in SoCal today. I get the P0420 and P0430 on my scam gauge. Are my catalytic converter done? truck runs good power is good.

 

Yup both cats are done, always start by checking for exhaust leaks but you will likely need both cats.

Assume you live in Cali, you'll need them for emission testing correct?

 

I changed my dirty PCV valve and that made a difference for me. I had P0420 that would come and go. It came back the last time i filled the tank. My 02 sensor is seized so i haven't gotten to try the fouler cheat. I did the PCV valve for $8 OEM and the light went out on it's own. It's only been a hundred mile but the truck starts and runs better. I thought i started and ran fine before I did the PCV but there was a noticeable improvement after I did it. My truck has 208K.

 

Yes, also have to be carb tested cats

 

so i need cats , Do i need just the lower cats 17410-op020 and 17450-0p020 or do i need all 4 of them with the manifold 17150-op100 and 17140-09100

 

I would spend $50 first on the downstream O2 sensors. I could see two going bad at once, though not that likely. Getting two cats to fail simultaneously is pretty long odds even at that mileage. Two simultaneous leaks is also unlikely unless you ran over something.

contaminated fuel is a very real possibility, give the sudden dual onset. Can’t help but wonder is something else is driving an over rich mixture and this is just the first code to fire. Get a buddies scanner and look for pending codes and fuel trims.

 

I got a 06 prerunner in California and was getting both codes too. I did the anti-fouler trick* on both o2 sensors and I passed smog. I'm at 315k miles and still going strong.

*note that it does get rid of the CEL light but, it's not a permanent fix, you'll probably need to replace the cats. I'm trying not to.

here's the how-to
https://www.tacomaworld.com/threads/0430-and-0420-code-hell-d-fixed.406596/

 

You just need the upper ones with the manifolds. There are no sensor after the cats in the y-pipe, so those can’t throw codes and rarely go bad anyway (being that far from the exhaust valves). Still got to keep them to pass the visual pet of the inspection.

 

If it doesn’t get rid of the CEL then what is the point?? That would be the ONLY reason to space the O2 sensors with spark plug antifoulers. And this trick might still fail you if you draw a really anal inspector

 

I'm looking in to getting AZ or NV tags. I did a full trans rebuild in april of this year. I only drive the Truck to Glamis and may be on sunday 5 to 6k a year. most of the time it is parked inside. I have a daily car. I got a parts list to do everything almost 7k in parts. I just wont the light off now, and i will drive it till there clogged.

 

So here’s some numbers I’m getting from my scan gauge three

The first photo is going 65 miles an hour at 2500 RPMs locked up in fourth gear

The second photo is me sitting at a light in drive.

 

Please read again.

*note that it does get rid of the CEL light but, it's not a permanent fix, you'll probably need to replace the cats. I'm trying not to.

 

The antifouler trick got rid of the 420/430 codes for me, worked like a charm. It started getting them once or twice a year about 4 yrs ago and eventually went to once a day over that period. It took about 30min to do both inc drilling out the fouler to fit the O2 sens. Hasn't thrown the code since. I can watch my OBD values from the head unit and indecently the AFR has always sat right around 14.6 (+/- .1) and still is. Truck has consistently gotten decent mileage and runs great.

 

I can vouch for this. My truck runs great and it passed smog. Thousands of miles later I am still not planning on installing new converters.
Ridefreak, I am happy to see similar experiences.

Here's a picture of the 06 with my 21 OR LB and my dad's 16 OR SB in the back.


Shot on an iPhone 7.

 

I drilled some at work today. I'm going to try to get them some time this weekend. Did you do both down stream O2's

 

Yes, both.

 

ditto

 

Oops, I was obviously out to lunch; read does as doesn’t…

 

Same issue. The antifoulers worked great for me

 

Never seen o2 reported as a percentage. Guessing 45% is same as .45 volts, but don’t know. A properly running system should have bxs2 as .45 volts at most times other than heavy acceleration. Failing cats will show lower numbers. System checks all the time, so need longer term observation of s2 readings to determine cat health. LT FT is a bit high in cruise. Could be a slight vacuum leak, but would expect to see it also at idle and didn’t.

possibility that the system gets upset occasionally and goes too rich due to an intermittent sensor issue. Cat can’t handle it due to age and reads low. Ecu catches it and throws 420/430 codes.