HELP! I'm Having Similar Electrical Problem w/ my 2016!
Didn't drive the car for a couple weeks. Went to start it up and it was dead. I just got the car from a family member. So I jumped it and it started up, no problem. I drove it around for awhile to charge up the battery which was the original GM battery. I parked my car for a couple days and went to start it up again. Other than feeling just a little weak, it still started up on the first attempt. But since I'd observed that it was a 5 year old battery, I drove down to O'Reilly's to have it tested.
The service employee brought out a battery tester and told me that the battery was bad, and advised me that although it may start up again (after turning it off for him to test) his advice was to get a new battery ASAP. They had a SuperStart Platinum (SSB 94RPLT) in stock so I bought it for $240. I swapped out the battery in the O'Reilly's parking lot and all the guages came to life, but the car would not turn over. It just made one clicking sound. The yellow engine light was illuminated.
I noticed that the vehicle info display on the driver dash was instructing me to "lower the driver side window, and then to raise it back up again... so I did that. it gave no indication that I had completed the task however... so I tried to start it again. still nothing... and still the "raise/lower driver window' instruction. which I did again. then tried to start again. still nothing... the yellow engine light was still on. All other vehicle electrical seemed fine. radio, telephone, on-star, headlights, Onstar, etc...
At this point I decided to use my Onstar service on the vehicle. they sent a tow truck out. while I waited I plugged in my BLUE DRIVER computer scanner to see what codes the vehicle might be reading or need to be cleared... but NOTHING came up. NO Codes.
Tow truck driver came and couldn't tow vehicle that night because dealer didn't have overnight drop off... going to try again today...