2015 JKU P0420

Yes the downstream on bank 1.

Called the shop I used and he said his first thing would likely be to replace the cat. But I'm still thinking that would only be a band-aid since the jeep only had 75k miles on it.


If it was mine i'd just buy a O2 fooler for about $20-30 and save a bunch of money on more unnecessary parts and labor repairs. They do work I have them on my Jeep because of high flow Cats.

 
Yeah I guess my mind just wants to know why or what's causing the bank 1 side to misbehave when the bank 2 side is almost textbook.

Could be a bad O2, or maybe the Cat is going bad that's what it does is checks to see how the Cat is doing. But you said that they were both the same temp so I'd think the Cat was good.

I don't remember is both downstream the same PN? If so swap them and see if it follows the sensor.
 
It's weird, they are the same but they swap.

That's what I'm thinking of doing before I take it to the shop. If I move Bank 1 Sensor 2 to the bank 2 side then I know it's the sensor. But would they actually fail in the sense that they are reading voltage similar to the Sensor 1?

Worse case if it doesn't move and still misbehaves then I at least ruled out the sensor.
 
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Had the same deal going on with the PO430 code. Started reading graphs and driving myself crazy with it. At the same time the Jeep is running great. No loss of power, no missing, fuel mileage is excellent. Not gonna buy a cheap set of cats just to have them crap out in a year nor was I gonna dump a ton of money for an oem set as long as the Jeep is running great. Spent $15 bucks for a set of O2 spacers and they put the CEL light out and I’m back to enjoying my Rubi again. These Jeeps will drive you BAT SH$$ crazy if u let them 😎🍺🍺
 
Had all that stuff from a real bad tank of gas. Ran that tank out, filled up with good gas and took it out on the highway for an Italian tune up. Ran it up to speed to make the jump to Alderran and codes cleared the next day with no parts changed.
The manual makes a point about not all fuel being equal, and even makes recommendations about which brands to use. I've had similar experience though not in my Rubi. My 2005 4X4 Toyota PU was fussy about gas and would get noticeably better mileage and run more smoothly when filled with certain gas brands or, oddly, at specific stations of the same brand. I've even speculated that the age or quality of the storage tanks might influence things.