Test pipe and a O2 bung. You could go with a Walker replacement or even better a aftermarket which might be even cheaper.
2011 GMC Terrain Needs new catalytic converter. Go OEM or Aftermarket?
- Thread starter Matt1980
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Personally, Walker aftermarket is so different than the OE part - the bends and wash coat, as well as the construction will be different. I’d look at Catco/Eastern, Magnaflow or MillerCat, or even Chinese(TWG makes a lot of the eBay and Ultra-Power units).
Be aware, unless it’s an OE or CARB cat, the CEL will be paying a visit for a P0420 when the 2/25 EPA mandated warranty is up.
Be aware, unless it’s an OE or CARB cat, the CEL will be paying a visit for a P0420 when the 2/25 EPA mandated warranty is up.
I think you just sealed it for me, THANKS! Yes I do have 2.4 Ecotec garbage engine. I had a cracked exhaust manifold at 80,000 when they did the warranty work and replaced it. I would not be the least bit surprised if it is broke again since this is a common problem on the 2.4 Ecotec. I am taking it to the dealer Saturday and they are going to do a full diagnostic to make 100% sure it is the CAT and not some other part. If the manifold is cracked I will replace that too. Of course when I did it the first time the manifold was $90, now it is over $200 SMH. You mentioned you have replaced these CATS. I am looking online and this seems to be the newest part number and does look correct, but does this look like the ones you've replaced?
That looks about right, but it's been a while now that many of that gen have been scrapped or are too beat up to be worth this particular repair.
Do you have any data logging available to you? Such as a scanner that can show live data? No need to take it to the dealer, all one needs to watch is the output voltage of the post-cat O2 to condemn a cat. Ok, ok, to be specific one should also verify that the fuel trims while at warm cruise are within the +/- 10% range generally accepted in the field. Assuming those numbers check out, and given you've replaced both O2 sensors, just replace the cat on faith.
Edit to clarify my pick based on fitment: to be more specific, I've found there to be one of two (or both) design issues with the aftermarket units. The first: the cat to manifold flange is almost always clocked just a bit off on the aftermarket units. Second: the mounting tab for the support bracket to the block never lines up. Not even close. Not that they fit well from the factory, but the aftermarket parts are downright unusable.
I have a dealer credit so its only going to cost me $40 to have them do a full diagnostic. Yeah I have a $50 scan tool that can do some live data, but If I am going to shell out north of $1000 I want to be 100% sure it is the cat and not something like a cracked exhaust manifold (doubtful). That being said I may hook up the scanner tomorrow and get some live data info from the 02 sensor. Thanks again.
Isn’t there TWO cats? Front & rear? Hopefully only one is bad.I think you just sealed it for me, THANKS! Yes I do have 2.4 Ecotec garbage engine. I had a cracked exhaust manifold at 80,000 when they did the warranty work and replaced it. I would not be the least bit surprised if it is broke again since this is a common problem on the 2.4 Ecotec. I am taking it to the dealer Saturday and they are going to do a full diagnostic to make 100% sure it is the CAT and not some other part. If the manifold is cracked I will replace that too. Of course when I did it the first time the manifold was $90, now it is over $200 SMH. You mentioned you have replaced these CATS. I am looking online and this seems to be the newest part number and does look correct, but does this look like the ones you've replaced?
I think there might be, but according to the Special Coverage 15810 it is the cat I posted above that generally goes bad.
Even $40 is a waste in this case. If you had a cracked manifold backed by a functioning cat, you wouldn't be seeing a P0420. If anything, a cracked manifold would mask a failing cat.
I don't mean to downplay the relevance of proper diagnostics, but in this case I'm confident that your cat is the issue. The PCM logic is fairly simple when it comes to assessing cat function: while cruising at a steady load, warmed fully, assuming all other parameters are within limits, if the primary and secondary oxygen sensor output signals more or less match then you've found your issue.
I will run the live data tomorrow and report back. Thanks again sir.
Ok here is some live data from the O2 sensors, thanks
Took it to the dealer today and they did a full diagnosis for me and for free which suprised me, but I am not complaining. It is the catalytic converter and their quote is $1750. That is high but not aggregiously expensive like I thought it would be. However I will probably do it myself, after checking the all-data-diy instructions and watching a decent youtube video this is not a hard job.
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