Dreaded P0420 code!

[kh02sport]

For the last few months I've been going round for round with this dang 420 code. I've since replaced both O2 sensors, MAF, spark plugs and wires. The best luck I've had of it not popping back up was running pure gas. I have an ultra-gauge so I'm able to check and clear the CEL when it comes on. I'm just tired of driving and waiting for it to pop up again. I've researched it to death and seems all I have left to replace is the cats (which isn't happening) way to much money. I've been toying with the idea of high flows and an O2 simulator. But I want that to stay as a last resort. I know there is loads of threads on here about this code mostly because I've already read most of them which has got me to where I am now. I don't know what else to try. Any help would be greatly appreciated

2002 T4R Sport Edition 4WD 167k miles

 

[SweetWaterSurprise]

This was an interesting idea.

http://www.toyota-4runner.org/3rd-gen-t4rs/175242-how-make-your-own-rear-o2-simulator-$5.html

 

[AZ4Running]

Whats the big deal just replace the cat.

 

[kh02sport]

Whats the big deal just replace the cat.

Those cost way to much. And the after markets are crap

 

[deverlow]

With the amount of money you're going to throw at a multitude of variables to make the code disappear, you might as well just replace the cat with an aftermarket. I replaced mine with an aftermarket in November 2012 from a trusted local muffler shop and have put almost 40K on it, never had an issue. Unfortunately I can't remember what brand it is. To make a blanket statement that all aftermarkets are crap is a falsehood.

 

[kh02sport]

With the amount of money you're going to throw at a multitude of variables to make the code disappear, you might as well just replace the cat with an aftermarket. I replaced mine with an aftermarket in November 2012 from a trusted local muffler shop and have put almost 40K on it, never had an issue. Unfortunately I can't remember what brand it is. To make a blanket statement that all aftermarkets are crap is a falsehood.

I've just read so many posts about the aftermarket cats none of which had good things to say so I was wanting to stay away from it. Finding that trusted muffler shop will be a shot in the dark also. It's not a complete no though. I've thought on it a lot and a buddy of mine has an 02 tacoma with no cats and no CEL so I know it's possible. In the end it's looking like a high flow cat magnaflow muffler and an O2 sim if I need it. Unless someone can suggest an easier route. Or has had luck with a certain aftermarket brand

 

[kh02sport]

Also it has 2 cats. Doesn't that mean it's one of the California emissions vehicles. Or did all of the 2002 models have 2 cats?

 

[Scramble]

With the amount of money you're going to throw at a multitude of variables to make the code disappear, you might as well just replace the cat with an aftermarket. I replaced mine with an aftermarket in November 2012 from a trusted local muffler shop and have put almost 40K on it, never had an issue. Unfortunately I can't remember what brand it is. To make a blanket statement that all aftermarkets are crap is a falsehood.

Agreed, Cats are cheap now. When my original cat went bad back in 2004 (only 5years old) Toyota wanted $1500. LOL yea right! I found a rebuilder online for $350 & sent back the core. It's still in there to this day & has out lasted the OEM by (10-11 years).

 

[my92t4r]

You could try seafoam to see if it helps. It did on my M20

 

[AZ4Running]

Cats are not that expensive and if you can wield or know someone that can its pretty cheap. Get Magnaflow ctpats they flow well and last unlike cheap cats. Look on ebay or amozon. You might also find someone parting out a 4runner that will sell you the cats.

 

[kh02sport]

You could try seafoam to see if it helps. It did on my M20

Tried seafoam and cataclean. No luck.

 

[kh02sport]

Agreed, Cats are cheap now. When my original cat went bad back in 2004 (only 5years old) Toyota wanted $1500. LOL yea right! I found a rebuilder online for $350 & sent back the core. It's still in there to this day & has out lasted the OEM by (10-11 years).

Do you remember where you got the rebuilt one from? That sounds like the direction I'm wanting to go.

 

[Scramble]

Do you remember where you got the rebuilt one from? That sounds like the direction I'm wanting to go.

LOL, that was 10 years ago. Google is your friend.

 

[kh02sport]

This was an interesting idea.

http://www.toyota-4runner.org/3rd-gen-t4rs/175242-how-make-your-own-rear-o2-simulator-$5.html

Just finished up with your suggestion. No more pending codes are showing on my gauge. I guess only time will tell but thanks for the help!

 

[SweetWaterSurprise]

Good luck, worth a shot

 

[animator]

Also it has 2 cats. Doesn't that mean it's one of the California emissions vehicles. Or did all of the 2002 models have 2 cats?

It has California emissions, but that does not necessarily mean you need a cali-spec convertor (unless you live in Cali). If you look at the sticker under the hood, it should specify if it is Cali or not.


I have the exact same truck, with almost the exact same miles. 160-ish was when my 420 code showed up, and I too, tried most of the recommendations found on the internet, including pulling the cats off and soaking them in cleaner for a weekend. Based on temp readings, my front cat is done.


I have not tried to replace the front cat, mostly due to cost, and as a hold-over for now, I am using an O2 simulator. It works. And it's cheap.


If you want to properly diagnose your cats, get an infrared thermometer, and take your cats temp readings when hot with the engine running. That will tell you if they are working or not. Youtube videos show how to do this.

 

[kh02sport]

It has California emissions, but that does not necessarily mean you need a cali-spec convertor (unless you live in Cali). If you look at the sticker under the hood, it should specify if it is Cali or not.


I have the exact same truck, with almost the exact same miles. 160-ish was when my 420 code showed up, and I too, tried most of the recommendations found on the internet, including pulling the cats off and soaking them in cleaner for a weekend. Based on temp readings, my front cat is done.


I have not tried to replace the front cat, mostly due to cost, and as a hold-over for now, I am using an O2 simulator. It works. And it's cheap.


If you want to properly diagnose your cats, get an infrared thermometer, and take your cats temp readings when hot with the engine running. That will tell you if they are working or not. Youtube videos show how to do this.

I have a gauge that can monitor the sensor output and I diagnosed it with that. I found through more days of google that all the 01-02 have the cali type 2 cat emission set up. I think im just going to have them both cut off and replace with 1 magnaflow high flow. Everyone seems to have had good experiences with those and just continue to run my o2 sim. There's no emissions here so that's not an issue. Now I just have to figure out if I can run just 1 cat or if i need to put 2 on there. If anyone knows then that would be helpful and save me the exta $100 on the second cat

What's your gas mileage like? I feel like my cats are killing mine. I get 15 city 16 hwy. Seems like everyone i read about is getting 20-21

I'm also really tempted to go ahead and replace the factory muffler with a Borla XR1 during the cat replacement but that will depend on if I need 2 cats or 1. I don't want to be $500 deep into exhaust

 

[BamaDrewski]

I have also been CAT shopping and found a pretty good deal on a MagnaFlow High Flow CAT. Some website called "Planet Magnaflow" (Authorized MagnaFlow dealer) has a deal on the Model 27301 which is a direct fit for the 3.4 3rd Gen. (This means no welding!) Also, this is a 49 state legal CAT - not the CaliCrapCAT.

If you enter your email address when the pop-up shows up, it gives you a $44 discount and free shipping. That brought my cost down to $251 DELIVERED!

Just a suggestion. Throwing CataClean, Seafoam and all sorts of stuff might be a temporary fix but with all the miles on our Runners, I think after 15 years, it's worth it to change my CAT. Just a suggestion.....

 

[kh02sport]

I have also been CAT shopping and found a pretty good deal on a MagnaFlow High Flow CAT. Some website called "Planet Magnaflow" (Authorized MagnaFlow dealer) has a deal on the Model 27301 which is a direct fit for the 3.4 3rd Gen. (This means no welding!) Also, this is a 49 state legal CAT - not the CaliCrapCAT.

If you enter your email address when the pop-up shows up, it gives you a $44 discount and free shipping. That brought my cost down to $251 DELIVERED!

Just a suggestion. Throwing CataClean, Seafoam and all sorts of stuff might be a temporary fix but with all the miles on our Runners, I think after 15 years, it's worth it to change my CAT. Just a suggestion.....

Were you actually able to bolt it on? I've noticed a lot of the bolt on exhaust parts still require cutting and welding.

 

[Robb235]

Just finished up with your suggestion. No more pending codes are showing on my gauge. I guess only time will tell but thanks for the help!

Glad it worked for you.

Were you actually able to bolt it on? I've noticed a lot of the bolt on exhaust parts still require cutting and welding.

I unbolted my cat, but I also had to drill the studs out. Not fun. Originally I soaked the studs and nuts in PB Blaster, and then tried to remove the nuts with a 6 point socket. No luck, the socket and breaker bar rounded off the nuts. I cut the nuts off with a Drimmel, and then drilled out the studs with some extra long bits from either Home Depot or Lowes. It took hours to do, metal shavings everywhere. I used grade 8 nuts, bolts, washers, and lock washers (forget what size) to bolt it back in place.