Possible O2 sensor issue? P2415

[filtercoffee]

out of the blue my Z4 M threw an SES.
P2415: O2 Sensor Exhaust Sample Error Bank 2 Sensor 1
P2197: O2 Sensor Signal Stuck Lean Bank 2 Sensor 1

These are the wideband sensors upstream of the cats.
I logged some O2 sensor values using a bluetooth obdii scanner:
https://photos.app.goo.gl/akqv1sFWCyiT7qL48

Since the O2 readings are so different, I think the likely cause is bank 2 sensor 1 needs replacing?
I plan to try replacing it over the weekend, but I thought I'd show you folks the graphs so you can save me some time if I'm wrong.

[filtercoffee]

Anyone? Updated with pics of the o2 sensor readings and LTFT

Also I have decided to fire the parts cannon since the car is coming up on 66k miles and could use the maintenance anyway.
1. O2 sensor replacement this weekend. ($250)
2. MAF sensor replacement this weekend. ($105)
3. Spark plugs and ignition coils in a couple of weeks. ($210)

Unrelated it's getting an engine oil change ($70) and diff oil change ($40) this weekend.
Doing it all myself for the first time. Very excited.
So thankful that it's easy on the Z4M. Another thing that makes this car so great.

[RobMCoupe]

Live data is needed. You want to monitor the sensor voltage. It sounds like bad sensor is providing same voltage regardless of fuel trim. That is what I do before spending money on sensor.

[86Zed]

You have been doing a lot of exhaust component swapping recently, any concerns with the O2 sensor handling during that?

[filtercoffee]

Update - I replaced both pre-cat O2 sensors with new ones (thank you RockAuto!) and problem is solved.
Bank 2 sensor was black, coated with carbon deposit. I hope it's just black from running rich. Pic attached.
Check engine light is gone, and bank 1 and 2 sensor readings are matching very closely now.

PS - it was a real pain to access the bank 2 sensor, since it's all the way at the bottom of the headers (video). I went from top of the engine bay instead of going from under the car, to avoid removing the front reinforcement plate. Stuck my arm deep in there and had to stretch to put an o2 sensor socket on it. I bought 3 different o2 sensor sockets and only 1 of them worked for that location - the compact o2 sensor socket. Then to access it with a ratchet, I had ratchet -> extension -> u-joint -> extension -> u-joint -> o2 sensor socket.

[filtercoffee]

Originally Posted by RobMCoupe

Live data is needed. You want to monitor the sensor voltage. It sounds like bad sensor is providing same voltage regardless of fuel trim. That is what I do before spending money on sensor.

I did, I posted some data in the first post. I couldn't tell if it looked normal or not but it was definitely concerning that the two o2 sensors had seemingly different bias voltages.

Originally Posted by 86Zed

You have been doing a lot of exhaust component swapping recently, any concerns with the O2 sensor handling during that?

No, I did headers several months ago and the one sensor only just failed. i think it's just time. Recently swapped mufflers but I'm not sure how that would've caused an o2 sensor to fail.

[RobMCoupe]

Nice to have problem solved.