Originally Posted by DenverX
What causes these cat's to fail? What symptoms should I expect to experience @ failure, and at what mileage?
Mine threw codes and turned on the CEL for low catalyst:
P0422 Catalyst System Low Efficiency Bank 1
P0432 Catalyst System Low Efficiency Bank 2
I also had a noticable noise in my exhaust from broken pieces of the cat sliding around under hard acceleration and braking. It sounded like a drill bit was sliding around in my exhaust during those times.
The CEL came on right around 1300 miles, but the sound was noticable when I picked the car up with just over 100 miles on it. Needless to say if they fail again, it's out of warranty, and I still have the car, I will NOT be buying them from Chrysler for $4,500.00. I do not know what the cause of the failure was.
I also agree that the cats probably aren't the same for N/A and SRT. Why don't you call your dealer in PA and have them look it up for you if you trust them more and have them call down to FL to set them straight?