So, if you ever want to find out if all (and I do mean all) of your dash notification lights will light up while driving and while you're still half asleep, causing you to almost crap your pants, then I suggest you turn on a Tech2 while you're in the middle of rush hour traffic. It turns out all of your gauges will also bottom out and just chill there.

I was tired, I probably didn't think that one through. Anyway, got home later, decided to turn on the Tech2 the proper way and I magically had all the below DTC's. I presume they were all a function of doing something GM probably explicitly tells me not to do? None of them impacted the ability to drive the car. Just let them cycle themselves out or should I clear them with the Tech2?

P1626 - Theft Deterrent Fuel Enable Signal Lost
U1040 - Lost Comms With Electronic Brake Control Module (EBCM)
U1064 - Lost Comms with BCM/DIM
U1300 - CLass 2 Data Link Low

 

My guess is that something about the TechII interrupted the data stream between the modules (U1040 and U1064 really suggest that). It's probably because you activated the TechII at a time that the car was talking heavily between modules. I'd clear them and move on.