Catalytic Converters

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DWTahoe

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I was just checking to see if anyone else has had to replace the cats in their Tahoe's or Yukons, etc?

My 2015 Tahoe LT with 88k miles just got the oil changed and put in a software update for the brake module. Afterwards I got a CEL, took it back in and they said it's P0420 and P0430 which is both banks on the catalytic converters. We reset the light and within a few miles it was back on.

I'm just wondering if anybody has experience with this. They didn't mention anything else that could cause the fault but replacing the cats are $1700, they come as a set and they replace them all. Any chance this is a faulty sensor somewhere? and if not, this seems early for the cats to be a problem.

Thanks.
 

wjburken

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I was just checking to see if anyone else has had to replace the cats in their Tahoe's or Yukons, etc?

My 2015 Tahoe LT with 88k miles just got the oil changed and put in a software update for the brake module. Afterwards I got a CEL, took it back in and they said it's P0420 and P0430 which is both banks on the catalytic converters. We reset the light and within a few miles it was back on.

I'm just wondering if anybody has experience with this. They didn't mention anything else that could cause the fault but replacing the cats are $1700, they come as a set and they replace them all. Any chance this is a faulty sensor somewhere? and if not, this seems early for the cats to be a problem.

Thanks.

I would have someone check your 02 sensors before they replace your Cats.
 

Doubeleive

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I was just checking to see if anyone else has had to replace the cats in their Tahoe's or Yukons, etc?

My 2015 Tahoe LT with 88k miles just got the oil changed and put in a software update for the brake module. Afterwards I got a CEL, took it back in and they said it's P0420 and P0430 which is both banks on the catalytic converters. We reset the light and within a few miles it was back on.

I'm just wondering if anybody has experience with this. They didn't mention anything else that could cause the fault but replacing the cats are $1700, they come as a set and they replace them all. Any chance this is a faulty sensor somewhere? and if not, this seems early for the cats to be a problem.

Thanks.
even if they are bad unless there doing it under warranty 2 aftermarket cat's are less than half of that cost, a magnaflow should be just under $300
 
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DWTahoe

DWTahoe

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Thanks for the info guys. They didn't do an official quote (they just ball parked what they had charged before), so I'm not sure how much of that was labor and how much was parts. I tried to get under there and check it out. Is this something that I could do or is it pretty much required that the shop does it? I can bolt on but don't have any way to weld anything if needed.

It looks like individual cats are fairly cheap but it gets pretty expensive if you buy a bolt on replacement.
 
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ChrisYukon

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even if they are bad unless there doing it under warranty 2 aftermarket cat's are less than half of that cost, a magnaflow should be just under $300

I was going to say this - don’t ever buy OEM cat converters. Bolt-in isn’t a big deal - welding pipes is easy for muffler shops.
 

gat0r

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quality stainless headers & high flow cats are cheaper than that...
just sayin ;) lol


avg life is typically 100k miles
they can go out early. worth inquiring about warranty for it. thought i read that warranty for cats is either 80k, 100k or 150k, but that also depends on state laws & such

if engine isnt running right or dumping too much fuel... that will lead to premature failure
 
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DWTahoe

DWTahoe

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quality stainless headers & high flow cats are cheaper than that...
just sayin ;) lol


avg life is typically 100k miles
they can go out early. worth inquiring about warranty for it. thought i read that warranty for cats is either 80k, 100k or 150k, but that also depends on state laws & such

if engine isnt running right or dumping too much fuel... that will lead to premature failure


I did see something in the manual about emissions stuff but I thought it said 70k miles, but I may be wrong. I assumed the dealer would know about warranty since they get paid either way, by me or by GM if they are required to warranty it.

I was wondering if the engine not running right would cause premature wear. However, I take great care of it, I don't have any other codes and I haven't had any other issues with it. It seems like if the engine wasn't running right I would have noticed something (missing, unusual mpg, weird acceleration, etc.), I'm pretty OCD when it comes to vehicles, but it's been running fine.
 

poblack

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Watch the type of gas you put in it. I had the same issues before and actually failed an emissions test. I think the problem carbon deposits were clogging the engine, injectors, etc. they are much more sensitive in the current model. Before I was buying cheap gas at Kroger. Now I only buy Chevron or other top tier gas.

Before replacing the CAT, do a flush. I can’t remember what the dealer called it, but it invoked spraying the internal engine compartments to remove the deposits. Cost $150
 
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DWTahoe

DWTahoe

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Thanks for the info everyone. Update: It's been about 140 miles since they reset the CEL and it turned back on immediately. This weekend the CEL was off again and has not come back on. I guess I will keep an eye on it and see if it stays off, no other errors or weird driving issues for now *knock on wood*.

I did end up doing some other work on it and happened to check the temps on the inlet and outlet of all 3 cats, all seemed to read what was expected, I believe. About 100 to 150 degrees hotter on the outlet than on the inlet side. My research indicated the cats should be burning off the bad gasses and should be hotter on the outlet side. Thanks.
 

John H

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Check into the warranty. I received the same exact codes a few months ago on my 2015 Tahoe LT and the same problem with the cats was diagnosed. I had 81200 miles and just could not believe the warranty was only to 80K. My dealership went back to GM with it and in about 4 days, I was told that GM would replace the entire catalytic converters assembly under warranty. Don't know the details but the my only out of pocket was $100.00
 

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