Exit DIAGS on a PW.
You can create the missing XML file by running the first diag in the main diags menu. Then you can disable diags in the exit menu. Also, your battery will continuously discharge while in diags mode, so you should keep it plugged into a charger until you get around to exiting diags properly.
Then chose “D) Exit, Reboot or Disable Diags” then “D) Disable Diagnostics” and “Q) To continue”
Slapped together from threads
I have never done it...