ISC CM2250 Idle Surge, no active codes, zero accellerator/ throttle response

[Btech]

Good chance there are some blocked faults that pertain to this issue that you cant see. Turbo parameters going to default values should have some type of fault code to accompany that.
Just from what you describe though makes me wonder if there isn't a engine datalink wiring issue somewhere causing all your issues. I would check and go over that first.