I found two extra O2 sensors for pre cat.
Tried swapping, but nothing changes.
The same shadow errors remain
https://i.ibb.co/WkfxLzH/20211007-160316.jpg
"Short signal to negative"
Not sure if it means anything...
Even if I disconnect the O2 sensor, the error remains.
Maybe it clears itself after however many cycles, I'm not sure.

It's saying that the signal wire is shorting to ground.

Can you chart the output from O2 real-time?

I can see, I think both INPA and bmwscanner have live data.
Not sure about charting.
I know it's saying signal wire is shorting to the ground, but is it really possible 3 wires have a short?

I checked resistance between pin 1 (red and white wire) and pin 3 (black) ground wire. Resistance is 2.090 on my multimeter

If the signal wire is shorting to the ground, it would be Pin 4, yellow wire, which is signal. I'll check resistance between yellow and black

Resistance between ground and signal wires is 043.3 on all 4 connectors
https://i.ibb.co/8Xd6LSw/20211007-170411.jpg https://i.ibb.co/F4dpMRR/20211007-170259.jpg

I think if it was a short, it would be 0

Maybe also worth noting that the pre cat connectors are male, and O2 sensors are female.
While the opposite is true for post cat. Car connectors are female, and O2 sensor connectors are male.

That seems very odd they all read the same. I'm sure you would get an immediate error if it was a dead short. A weak (say 43k Ω) path to ground may give you a shadow error to look into.

You said all four; do you mean feed and signal on both pre-cat? Or signal on post and pre?

This is resistance between pin 3 and 4 on all 4 O2 connectors. So between singal wire and ground.
I would doubt that they are all equally screwed...
Maybe someone can take a measurement on a car without errors?
Or maybe I should go back and measure resistance between pins connector X6002 and each wire at O2 connector, to see if there are any shorts?
I guess all 4 wires should not be making any connections unless connected to the DME. So it wires are different, resistance should be infinite?

Ignore the shadow codes, they are there to indicate that there "has been" a problem and will eventually go away

Still have yet to get my shadow codes to go away. Even if I clear them or whichever, they still remain. I can find two BOSCH O2 sensors for about $70. Thinking I might pull the trigger and order them.

The top two are the same ones I get no matter what.