I doubt you'll need a new ECM, It's pretty difficult to kill an LMM.
Disconnect AutoCal, turn off the vehicle, disconnect the batteries for 10 mins and try again.
DO NOT operate any vehicle feature that may communicate on the data bus. This includes opening or closing of hood, doors, windows, as well as changing settings on radio, HVAC, connecting/removing charging devices etc. Disconnect items that may interfere with the databus - phone chargers, GPS, etc.
If your still having problems, let me know.
Cheers
Cindy
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