p0420 and p0430 codes

I recently bought a 2002 Tundra (Saturday) and driving home today (Monday) the check engine light came on after reading it the P0430 And P0420 codes popped up, looking deeper into the truck I found that not only does it have a newer TRD exhaust but aftermarket headers as well! Would this send bad readings to the O2 sensors and cause the check engine light, or is it more then likely that I need to replace the sensors or cats?

 

Read this thread: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

It covers the common causes of cat inefficiency codes, and also covers the bases for all the stuff you'll need to worry about on your truck beyond those codes. This truck is new to you, and I honestly wish you'd have seen it prior to purchase, b/c there's a lot of ways to get fucked buying a 1st gen. Especially from shady sellers ... which ...

The fact it popped the codes on the way home is sketch. Chances are, the seller cleared the codes knowing goddamn well they'd pop on you. Makes me question what else they're hiding.

First thing to check is whether all four air-fuel/O2 sensors are intact with un-cut/un-spliced wiring. If they are, let's chat this one through. But first, read that thread I linked, and pay attention when you get to the P0430/P0420 snippet, because it'll explain what those codes mean and how people often get boned into spending unnecessary money on making them go away.

 

Ok thank you i'll definitely take a look at them and the linked thread, I am also taking it to a mechanic tomorrow morning to get the timing belt changed (Yes I have the Asin Kit) would it be a good idea to let them take a crack at the codes as well?

 

These trucks don’t like aftermarket cats, check if they are oem or not.

 

I mean, everything we can collectively tell you is in that thread. I don't know if the mechanic can actually do anything, and here's why in tl;dr format:

• ECU thinks both of your cats are failing to filter out enough emissions.
• It thinks that for a number of reasons:
  • One or both of your upstream or downstream a-f/O2 sensors are failed and/or have had their wiring spliced in a way that they're sending bad readings to your ECU
  • Previous owner installed aftermarket cats and these trucks only like OEM, Magnaflow, and some Walker products, and throw codes on about every other brand members have tried
  • Previous owner installed aftermarket a-f/O2 sensors and these trucks only seem to work worth a shit with the "exact fit" Denso (OEM) brand part, too many found that out the hard way
  • Previous owner removed the cats (straight pipe) or deleted the cat's guts to get more flow, thus they're not filtering out shit
• Your mechanic can spend time trying to figure it out, but is it worth your $$ if they're not doing diagnostics for free? Doubt it.
• There's more technical info in that thread I linked to really break down what's happening to generate those codes.

There are ways to hack your way around this if all four O2 sensors are intact and working. Things like O2 spacers for the rears. But likely not emissions legal.

 

Also be sure the o2 sensors are Denso with OEM connectors. Our trucks are allergic to Chinesium parts

 

And as much as your mechanic or others may tell you, "awwww, that's bullshit!", we can tell you, from experience ... anyone that's been on this website more than a couple years will swear by it, because we've seen it over and over and over again. Aftermarket parts being DOA or dying within weeks. Throwing codes after days or weeks using aftermarket. Catastrophic failure (like, lose the truck level) from aftermarket parts. To the point we had to create a unique thread with wins/losses for various aftermarket parts, a hall of fame/shame if you will.

It's nuts. There's a gaggle of knowledge in this forum that your average mechanic won't have access to. And a lot of it was [probably poorly] condensed into that one thread, which I happened to post, but it's not my voice there. It was a collaborative effort, and it's constantly being updated.

 

Perfect, Thanks for the advice! After looking at the truck and doing some research ( thanks for the threads) I think my best bet is to just bypass the sensors altogether as, in my county the vehicle does not have to pass an emissions test for state inspection. I'll have to do it after I get it back with the new timing belt put in and keep you guys updated.

 

I mean, those upstream sensors are pretty critical for your ECU to calibrate the proper air/fuel ratio, to avoid misfires. You really need to keep the upstream functional. If anything, use foulers/spacers on the rear sensors, play around until you get things just right so it's not throwing codes.