Looking for some opinions on my latest issue.

Just recently repaired drivers side front o2 sensor wiring as it was all jacked up. Turns out the sensor itself was bad as well so replaced it with a good spare I had. Watching the sensor voltages on the app I use shows both front sensors working as they should, but the rears seem to be stuck in a high voltage state. Like 5-7v constantly and barely move, if at all. Fuel trims go to -10 or more, atleast at idle from what I've noticed.

Any ideas before I did deeper?

 

Is it throwing a code? The rears do not cycle like the fronts, they stay right at around .5v The purpose of the rears is to monitor cat efficiency. If they cycle then the cats are not doing anything.

 

No codes. Glad to hear they're not supposed to cycle like fronts because I honestly couldn't remember. Memory is wiped these days. I need to monitor them some more next time I drive it just in case, most likely tomorrow.

The fuel trims going that far negative is my next concern. Usually + or - 3 or so is about right, but going into -10 and staying there doesn't seem right to me. Noticed it last week after driving and idling in parking lot.