Hi, wise YT veterans -- thank you in advance for your analysis and recommendations on this ongoing mystery.

Since the summer, I've had a semi-constant CEL code P0420 for the catalytic converters below threshold, with 3 confirming diagnoses (1 at dealer; 2 at separate independent shops). Everybody claims to have exhausted all other explanations and possibilities, and that the cats are bad. Prior to that, last spring, I had to replace the Air/Fuel Sensor.

Not being willing or able to fork out $2500 to Toyota for these parts (a classic case of planned obsolescence and abuse of monopoly power), as the dealer prescribed, I've been intensively researching this issue for a solution.

In my initial inquiry to CA Air Resources Board, they told me that "Toyota did not certify a California 3.4L 4-runner in 2000, only in 2001 under test group 1TYXT03.4FFP." (WTF??)

After further research on the details of the engine family/test group for this for 2000 4Runner California - 3.4 Manual 5-spd 4WD, I get back to CARB and inform them that it's ENGINE FAMILY: YTYXT03.4FFR. Here is their helpful explanation and suggestion:

Thanks. The reason why there is no aftermarket catalytic converter for your vehicle is that converter manufacturers are not aware that there are Toyota 4Runners certified for 2000. They rely on our certification records which only show Tundra as the model under YTYXT03.4FFR (see certification records, click the last 3.4L Toyota truck on this website: http://www.arb.ca.gov/msprog/onroad/cert/pcldtmdv/2000/2000.php). We’ve contacted Toyota and they did say that your vehicle belong to the YTYXT03.4FFR test group, but was introduced later in the production model year; hence, it was not reflected in the original certification. With this information, we can say that the catalytic converters approved for the 2000 3.4L Tundra will fit your vehicle. However, to make it legal and recognized by Smog Check, the vehicle application list supplied by the converter manufacturer and posted in our website would have to include the 2000 3.4L 4Runner vehicle model. Converter manufacturers decide which vehicles would fit their products, thus the request to change the vehicle application list must come from them.

Here’s what you can do to speed up the process. Contact the converter manufacturer that you want to purchase your converter from. The list I provided you yesterday shows Airtek (Executive Order D-280-76) is selling p/n 712004 (two units) for the 3.4L Tundra while Miller (Executive Order D-353-42) is selling p/n 61212 (front converter) and p/n 45212 (rear converter). You can tell them to add the 2000 3.4L 4Runner on their list for these part numbers and send the revised list (which includes your 4Runner vehicle) to ARB. We can then post the revised list on the website without issuing a new Executive Order and you in turn can purchase and install these converters for your 4Runner vehicle.

My sincere questions, having come this far, are these:


[1] Should I give up on finding alternative explanations for this CEL P0420 for the catalytic converters below threshold, based on the 3 separate diagnoses, bite the bullet, and resign myself to replacing both cats?

[2] If so, take a gamble on one of these 3rd-party solutions, on assumption that their request to CARB for revised listing / approval goes through?

[3] Finally: your professional advice on which brand that CARB specifies above would be more reliable: Airtek-Catco vs. Miller??

Preliminary advice has been leaning away from Miller (i.e., towards Catco) -- but reliable info is hard to come by for me.

Thanks again in advance for helping out a noobish member who can't afford to throw away more $$ than necessary on this.

calguy248

 

did you install a new rear o2 sensor yet ? was one of the confirming diagnosis using a new sensor ? that has to be done

 

Yes, the one independent shop swapped it out for a known good rear O2 sensor during the test. He said conclusively that it showed that the cats were not functioning efficiently. The other shop's tests showed that the cats were only coming close to even borderline efficiency after an abnormally long time, due to being very slow to warm up.

I was able to squeak through Smog Check a month ago, during the few weeks that the CEL mysteriously went off -- but now it's back on permanently, even after resetting the designated fuse.

 

I have to change the color to read this

 

I vote for option #4 or #5

#4 move to another state
#5 cheat a little http://www.urdusa.com/index.php?cPat...hque62jcrfume5

BTW I've done both #4 and #5 no regrets.

 

HAAAaaaaa--good one. Cali makes it so hard to follow the rules....not to mention it is also one of the "welfare" states now......

BUT--I dont understand the Cat cert thing either, however, i am in texas and just grab a couple magna flow high flow cats (100$).....give that a try and put a skid on--maybe the tech wont look.

 

Hey Cal Guy,

I am in the exact boat as you right now. My CEL light has been coming for about a year off and on now with a P0420. If you looking to go OEM, try getting the parts from trdparts4u.com. Their prices are better than local deals so far. I just placed an order for my parts on Sunday, and the parts should be here tomorrow. This is including a new O2 sensor and A/F sensor. Dealer diagnosed it as the p0420, but that was right after it was smogged and the smog place told me that the emissions were extremely clean, so I am very hesitant to replace the cats. So new 02 and AF sensor for good measure and see if that cleans this up.

 

Thanks for some responses. Since I can't move out of CA, and while I ponder the unlikely prospects of sub-legal measures, I humbly ask again re. my original question:

Catco vs. Miller? Magnaflow-CarSound also says they’re in the final stages of the same approval process -- but their part wasn't included in CARB's official list (perhaps it's for 4R explicitly, r/t being included in the Tundra-labelled engine family).

Anybody? Thank you...

 

My Magnas has a CA on them and a carb number but they are not direct bolt-ins.

Its only illegal if they can tell the difference....

FWIW--i sold my stock Cats and asked the junker what the difference was between aftermarket and stock....he said they OEM use more Platinum on the cats versus aftermarket. But if your car is not running right with aftermarkets it will burn up.....