Bound to happen. I finally got my first P0420 code!

This link has some great advice to clear up many of these problems.:

http://www.tacomaworld.com/forum/pe...ary-air-filter-diy-another-way-1gr-fe-v6.html

 

Yes, there are several threads that cover it. I simply started this thread as it pertained specifically to my truck.

 

First was the downstream 02 sensor, replaced....code gone. Then the upstream 02, replaced....code gone. Then 40 miles later P0446 . Evap ...DAMN IT!!

 

I would look to see that no fuses are blown, and that you didn't cause a wire to accidentally contact the hot exhaust during or after the repairs. Then inspect and/or replace your gas cap.

 

Did the new gas cap already. Checked all of the fuses under dash and under hood. Everything checks out. I just replaced the purge solenoid under the hood. tested the old one with the battery...no clicky. Charcoal canister assembly is next if this doesn't work.

 

I forgot I had started this thread a while back. I don't have the P0420 code setting anymore because I was able to aquire a parts truck with a good cat in it. I simply swapped them out and no more code!

 

Ok ...so here is my update. I replaced the purge valve under the hood. The one on the drivers side fender to no avail. Code came right back after 35 miles. So i bit the bullet and bought the charcoal canister. Ebay $265. I put it in, not really a big deal if you are mechanically inclined at all. Just racked up 400 miles with no code. I have a feeling that the problem was not so much the canister itself but that other small purge valve that comes with the assembly. Oh well, if it lasts me another 12 years it was worth the money. If this helps anyone out, or I can help with any advice, please sent me a message.

 

I'm trying to figure out my p0420 code. What kind of range should I see out of the af sensor? I was watching it on my way to work this morning and it ranged from 3.23v-3.29v.

I checked my cats with a temp gun. And the upstream seemed to be working correctly. Cooler temp at the inlet hotter at the outlet but the downstream cat was basically the same temp in and out. The downstream cat is just over a year old with 20000 miles on it. It's a MagnaFlow cat.

 

Anyone?

Here's my graph doing 55 for about a mile and a half. The spike is where I let off the throttle for a second. To me it looks like my a/f sensor doesn't look as it should. It is a brand new denso.

 

The California VINs require different configurations of the exhaust system If you hollow out one of the CATs you will still pass emissions in other states but you will have the stupid check engine light on. Make sure you reset the light by disconnecting the battery before going to get the test done. I was hoping someone would post a solution on how to adjusting the catalyst settings in the computer that initiate the check engine light.

 

On my 3rz I deleted the 1st cat and didn't throw a cel. I don't have to deal with any sort of emissions so I'm not sure if it would still pass. The turbo definitely would not in CA.

If you disconnect the battery you'll have to go through a few drive cycles to pass. At least I did when I lived in a place that it was required.

You can't tune the ecu. There are some 01-04 ecus that are supposedly tunable but it's still in the works by OvTune.

You might be able to trick the ecu into receiving a different signal by adding a resistor. This would likely mess with the fuel map if the ecu thinks it's seeing stoic but in reality it's not.

 

Thanks for the reply. I did some research about the resistor and believe it would be worth a try, but opted to order the Under Dog O2 simulator for $119. This seemed more certain to work without collateral issues and multiple attempts (easy to install). Not sure if it matters on a first gen, but this way the ecu will get better feedback and not make unnecessary mixture adjustments.