So I've been trying to flash my 2016 Duramax, I try doing a full flash and select ok, says please wait>ignition off now> then starts the 40 second count down. So I go ahead and try just a cal flash and sure enough it lets me license the ECU and flashes the truck. But now truck wont start, is there any reason why it wont let me do a full flash? What am I doing wrong?