I have done all the battery tested good. I checked every positive and negative connection I can find. It did it again last night. You can hook a jumper to it and everything and it will not do anything. After letting it sit and waiting something resets and it starts. I scanned it after I got it started and I had 4 can bus codes in bcm, radio, dash and I don’t remember the other module. Out of all the gm vehicle I have owned over the last 20 years this one has been a pos.