Help me use my scangauge to diagnose P0420 code

I have a P0420 code (catalyst inefficiency code, bank one). I cleared it once and it came back. Truck runs perfect. No other concerns.

I went on Scanguage's website and found XGauge codes to read air/fuel ratio and O2 sensors. I tried all the codes, and not all of them work. If I understand correctly, the ones I have programmed and working now are A/F ratio for bank 1, A/F ratio for bank 2, number 2 sensor for bank 1, number 2 sensor for bank 2. As far as I can tell, sensor 2 is the downstream sensor after the cat.

Comparing bank 1 and bank 2 readings, I see no differences in behavior between the two banks.

The truck has 64K miles on it. Seems pretty lame to have a CAT die on me. Hoping it's a sensor issue, but sounds like that doesn't happen too often from reading on here.

Still have about 9 months and 16K left on the catalytic converter warranty. Its temping to go down to the dealer and drop it off, but I know nothing about the quality of the staff down there, and I fear being told that I have a CAT bad and need to replace the sensors too because they are damaged, etc, etc. I would rather be educated on what sensor readings would indicate what first. I want to replace only what is needed.

Thanks for any help that you can offer.

Anybody switched O2 sensors side to side and see if the code moves to the other bank?

Which side is bank 1?

 

Yeah, I should take it in there and see what they say. Just trying to avoid the add on of two O2 sensors that I do not need, just to get the CAT warrantied.