Thats correct @glwood, i tried replacing both upstream and downstream O2 sensors and the codes came back.I didn't see an update...did the sensor swap keep the codes from returning?
Never mind...I see you replaced the pre-cats, and main cat converter. I guess a sensor swap alone wasn't the fix.
Here is a pic that shows why the o2 sensors were not the problem...
Its hard to see but i tried to shine a light into the good precat. There is some metallic material that u can barely see. That is the good bank 1 precat.
The bad precat, bank 2, has nothing, the reactive metal is completely gone, so i replaced everything and she runs line new, no codes!