P0420 booooooo

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JabroniBro

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Driving home today and my truck threw code P0420. It's a 2000 EB 4x4. 161k miles. New tranny, new cat, one new O2 sensor, new plugs and coils. Truck still drives strong and I don't notice anything amiss.

I just passed emissions a month prior so I don't have to worry about that. I know this is a generic code and there could be a variety of things causing it but since I have a bunch of new parts where would you start troubleshooting?
 

1955moose

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It's actually a catalytic converter code. Your guys that replaced the one, possibly missed another failing one. If your shop does a back pressure test on both sides, they'll find the culprit. Misfires left unattended are the biggest culprits of early cat failures.

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JabroniBro

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After I posted this I went to clean my TB and found both breather hoses disconnected! I dunno if this had anything to do with the code but I re-connected those, cleaned my MAF and IAT, and the light is still on but the truck runs a lot smoother. I passed emissions right before this code came on so I'm not worried about it as long as a cat isn't plugged - which it doesn't seem like it is.
 

1955moose

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As long as it's running ok, and you passed smog, why worry. Most muffler shops will check out your back pressure for free or low cost. They do it to sell you a cat or two.

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JabroniBro

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Yep, I'm not gonna worry about it. I'm just gonna put some electrical tape to hide the glow of the service engine light
 

1955moose

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Their was a rich lady in WW2 England, that did just that to a check oil light. She blew the engine, but Rolls Royce replaced it for her under warranty anyway. Privilege has it's perks. Why couldn't I have been born rich, instead of so good looking!

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nycnftm

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I just got P0141 one month before my smog test. :mad: A few years ago I got a code right after passing the test on my Accord and didn't fix it for 11 months
 

ManUpOrShutUp

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I just got P0141 one month before my smog test. :mad: A few years ago I got a code right after passing the test on my Accord and didn't fix it for 11 months

Thanks to this forum you now know the problem can be fixed with electrical tape.
 

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