LSUMatt1514

I've been throwing this code for about a year and a half and it is getting more and more frequent. I don't believe that I have any problems with my cats because I've noticed no performance degradation (Alabama has no emissions testing so no tests and/or failed tests). Up to this point, everytime I get the CEL, I pull out my code reader and just erase the P0420 code....for the time being. However like I mentioned earlier, it's now popping very frequnently (almost once a week depending on how much I drive).

The dealer has even told me that he could put two new cats on there ($1,500) and I could have the CEL come on in a week and throw the same code. Others here have recommended replacing the fuel/air sensor before the first cat and the O2 sensor after the second cat. This will cost about $200 and may or may not solve the problem. Still others have installed the URD simulator, but I don't want to get into any legal trouble when I go to sell my truck private party and it has an illegal after market part on it, particularly with something as delicate as emissions and emissions testing.

Has anyone come up with a definitive solution to fix this? It's pretty bad when even the dealer can't guarantee a fix for you that would net them $1,500 and quite frankly can't offer any solutions. The local service manager told me point blank he wouldn't worry with it. However, I may be selling my truck in the next 6 months and don't want to have to come off the price $1,500 because of this code. God forbid the CEL came on while someone was test driving it!

Someone please help!!!! Any input will be greatly appreciated. I know there are several of you on here that have had or are having this issue. Thanks.

Matt

MTL_4runner

Matt, there's no smog testing in Alabama that I am aware of, so as long as your vehicle will pass inspection, then I would just use the URD O2 simulator and be done with it. Replacing the front/rear O2 sensors are not likely to buy you anything towards a fix and replacing the cats is uber expensive. Your call though.

Nismo Convert

It could be an exhaust leak before the cat, I had this issue before, fixed the leak fixed the code, the front O2 sensor will also clear the code, but not for ever. Check for a leak first, I hear it's common.

LSUMatt1514

Never thought about an exhaust leak. I'll try to go by an exhaust shop (maybe like a Meineke) on Friday and have them check for any exhaust leaks and also see if they can run a test on the cats. I just dropped well over $700 today on preventative maintenance (timing belt, V belts, water pump, transmission service, coolant, etc.) so I'm not exactly jumping up and down to go out and spend $1,500 on cats. I worry about the O2 simulator because what if Alabama adopts emissions testing down the road or what if the car ends up somehow in an emissions testing state. I know the Atlanta area has stringent emissions testing.

Talked to the guy at the dealership (sales rep) and he's turning back flips wanting to buy my 4Runner for his son. I doubt that the two of us will be able to come to a common ground on cost because he doesn't realize just how much money I've got tied up in mods on this truck. I did a list today and it's somewhere around $6,000 (when the stuff was new...or course there's depreciation). I'm not giving this thing away despite the fact it has 180k miles. It still looks and runs great but.....

Those new Tundras are AWESOME (and ridiculously expensive I might add...nice to not have a car payment).

Thanks guys. Keep the input coming.

Matt

Nismo Convert

I've blown 6 pre/post cat donut gaskets in 3 weeks, they weren't sealing right so with a proper amount of RTV ( have resorting to it) it has been fixed, no leaks no P0420.

MTL_4runner

This is correct, a pre cat exhaust leak can cause this code too, but Matt I thought you had already looked at exhaust leaks many moons ago when you first posted this thread for fixing your P0420 code and you said there were none?

By all means if there are any, get them fixed before doing anything else.

Original thread.....
https://www.yotatech.com/forums/f2/c...acement-89187/

LSUMatt1514

MTL,
I have checked for exhaust leaks in the past and didn't see any. At one time I had one right at my muffler, but the muffler was replaced under warranty. As far as exhaust leaks up by the cats....I've never seen anything but I will be sure to double check. I doubt that's it but definitely worth a look.

Matt

kenwoodrunner

if it ends up being your cats why don't you try an Quality aftermarket cat maker. if it is certified you should be good? just make sure the cat they sell you will turn your light off! mike

LSUMatt1514

I bought a replacement rear cat once and ended up sending it back. The opening didn't even have a flange for the O2 sensor (and is was supposed to be a direct replacement for my stock cat) and the build quality was not impressive. I sent it back. I didn't want to drop the stock cat off the truck and then the crappy aftermarket one not fit or clear the CEL. Very skeptical of the aftermarket cats I've seen on the internet.

kenwoodrunner

i would be skeptical also because there is alot of crap out there. but there has to be an aftermarket fix out there for alot less than 1500! just trying to brainstorm! mike