I don't think the two events are related. Those data busses are designed to be tolerant of mis-connected systems. So if the dealer connected the wrong computer the worse you should get is a "can't communicate" error.

Since the CEL came back on again, you should ask the dealer to tell you what diagnostic trouble code(s) were logged. Once you get them, post them here. There are enough engine management system geeks on this board that you will know in a minute if the dealer is feeding you a line.


Just my $.02