Are tundras catalytic converters the same 2000-2006?

I’ve got a 2003 tundra and have some catalytic converter codes and now my cat has started making some nasty rattle noises so I think it’s time for a replacement. Are the catalytic converters compatible throughout the years could I put one that’s says it’s for 2005-2006 on my 2003 or would there be fitment issues?

 

What are the codes? People often get P0420 and P0430 but it has absolutely nothing to do with the cats. Read why HERE.

 

Im getting Po420, Po430, and Po442
And I can see small holes rusted in my exhaust but the main issue is the loud rattling that’s coming from my cat.

 

Are you sure it's not the heat shield? They are notorious for rattling.

 

I’m sure it doesn’t even have the heat shield on the cat and the one on the truck is tight and if I give it a wack you can hear the rattle in it

 

Exhaust leaks will also cause cat inefficiency codes, leaks at flanges, etc.

Do you have any way to do realtime monitoring of the O2 sensors, upstream and downstream, to see if the voltage is staying pretty stable?

 

Not sure but I’m more worried about the noise than the codes and I figured if I replaced it then I can fix both.

 

No offense intended, but that's a naive approach. Mainly because these trucks have a serious problem with aftermarket cats, and OEM is prohibilively expensive to buy. Much more expensive than $50-100 in gaskets and hardware to ensure you've got no leaks You should do everything you can to avoid replacing the cats, in reality. Seriously.

As long as you didn't do something stupid, like ignore upstream O2 codes or rich running for extended periods, it's difficult to kill an OEM cat. More likely you're leaking somewhere, at a flange or manifold, or someone installed aftermarket O2 sensors, or someone cut/spliced the wiring for the O2 sensors at some point, or you have a bad upstream or downstream sensor.

I'd probably start by inspecting your O2 sensor wiring, you have one sensor pre-cat, one post-cat on each side if V8.
I'd probably inspect the cats to see if someone else already replaced the cats at some point, and if so, I bet that's your problem, again, these trucks don't play nicely w/aftermarket cats despite what any exhaust shop will tell you otherwise, we know better.
I'd inspect your flanges where the manifold meets the cat, and every flange after to make sure the bolts are intact, no holes in the pipes, gaskets OK if present.

While I know it can be tempting to just say, "FUCK IT! Replacing everything with NEW!" this is one of those cases where "new" is not "better". Especially if the "new" is aftermarket. I can tag about half a dozen members off the top of my head who installed quality aftermarket cats on their 1st Gen Tundra and continue to struggle with popping cat efficiency codes. The only brands of cats people have found to work most of the time are Walker, Magnaflow, and Summit Racing's products.

If you do replace any sensors, always:

• Use the part finder at www.densoautoparts.com to get the upstream "a/f ratio" sensor part number and downstream part number specifically the "Exact Fit" part for your specific truck (Denso is the OEM manufacturer of this part)
• It's recommended to replace in pairs, upstream/downstream sensors on each bank.
• Never buy electronics like this from scAmazon or fleaBay, counterfeits are rampant, Summit Racing and RockAuto are better options.

On the P0442, it could be something as stupid simple as a bad/old gas cap or a cracked EVAP hose. However, the '03-'04 did have a TSB because the fuel filler neck cracked. Read that TSB and check if your VIN is affected by looking here: https://www.tundras.com/posts/2973696

Don't get me wrong, the "rattling around" in the cats isn't exactly promising. But if you live in a rusty area, or the truck lives in a rusty area, and the exhaust is eaten up, you gotta expect that'll happen. As long as there's no hole in the body of the cat, it's the very last thing I'd replace.

 

The rattle went away but my registration just expired and I’m not gonna be able to register my truck until I figure this out.

 

If cats got stolen off an '03 but I had a totalled '05, would they swap over without issue?

Original question never got answered :
> Are the catalytic converters compatible throughout the years could I put one that’s says it’s for 2005-2006 on my 2003 or would there be fitment issues?

 

The answer to your question is: WHAT CAB TYPES, YEARS AND ENGINES ARE WE TALKING ABOUT?

Your response would enable others to actually answer your question factually, otherwise we're punching in the dark over here. If you have a V6 truck donor for your V8 truck, no not compatible, obviously. But ...

If you want internet strangers to randomly plug at possible answers ... It looks like, based on the exploded diagrams in Toyota's EPC, my 2006 access cab V8 and a 2003 regular cab V8 are different (at least on passenger side). So, depending on what you tell us, or what VINs are on both the trucks, you yourself could go look up the answer to that question using the "Look up your part numbers" sticky thread available to everyone here.

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