So any verdict yet? She all good??
Your theory of losing power at the ECM makes sense then. If the ECM is powered down, it would not be able to record faults. Have you done a full scan to see if there are any other no-comm codes? When you are logging with ED, do you give it a min to see if it loses communication or were you just looking at it right after it dies? If you ran a trace on a few engine parameters, do they freeze at a certain value to continue to read?It's just the engine I believe. I know I still have power steering because when it dies I can still easily turn the wheel.
I've had my Eurodyne logs running when it dies but I don't think it ever loses communication.
I have zero faults stored when I scan it after it dies.