O2 sensor voltage

[FrontierTails]

CEL P0420 code
100k miles

Replaced the downstream passenger side sensor, no change.

Looked at the live data and it makes me wonder if I replaced a bad sensor with another bad sensor?

I didn’t look at live data with the old sensor, so I don’t know for sure.

Oem cat on the way if it turns out to be that.

 

[Cimmerian]

It's probably the cat, mine crapped out at 120k miles. Instead of replacing, I just put on two extenders and the codes went away. Jeep still drives perfect with no MPG loss.