[j911brick]

I've been doing some research and i know this issue has been beat to death. but I'm kinda at my wits end. This is about my wifes car (09 v6) and its not a short story.

it started a year or so ago with a couple cat codes and maybe fuel trim on bank one. we replaced the bank 2 cat first with a Flowmaster and that solved the problem for a while. then the cel came on again and we replaced all the 02 sensors with genuine GM. Then the cel came back and we replaced the bank 1 cat with a new Flowmaster. cel came on again with a bank one fuel trim code. the dealership basically it was a known timing chain issue and we decided to get a new motor and transmission.

now just a couple weeks later cel is on again with a p0420 code. I'm not happy. after writing the dealer a $16k check they say we need new cats because the previous engine condition caused the bank one cat to go bad.

Sounds like BS to me and they don't know any more than i do. they told me to take the cat off and look at it. look at what exactly?

 

[j911brick]

nobody?

 

[Joshua1983]

nobody?

Couldn’t they just use a high temp thermometer? Check the inlet and outlet temps around 50mm before and after the CAT. Outlet temp should be atleast 40 degrees Celsius hotter than the inlet temp?

 

[Overboost]

Aftermarket cats are nowhere near as good as the factory ones but much cheaper to purchase
Wife's Enclave had the same issues so I made pigtails with a capacitor and a resistor to keep the ECU seeing "within threshold"
If the cat falls below 99.7% it will trigger that code. Added the pig tails and problem "went away". A quick Google search you can find the design and parts needed to make a couple.
Cost me $8 in total

 

[OneOfAKind.6.0]

Aftermarket cats are nowhere near as good as the factory ones but much cheaper to purchase
Wife's Enclave had the same issues so I made pigtails with a capacitor and a resistor to keep the ECU seeing "within threshold"
If the cat falls below 99.7% it will trigger that code. Added the pig tails and problem "went away". A quick Google search you can find the design and parts needed to make a couple.
Cost me $8 in total

Can you please explain how specifically you did these “pigtails” I’m having the same problem and my tags expire in a few weeks. I haven’t been able to figure out what’s causing my problem either.