it will start fine at times go get cofees or whatever u gota do shut it off somwhere while u shop, come back out to a no start condtition i know the problem is on this circut because removing the fuze and reinstaling it works to get it started again weird ehh! its the bcm/cluster fuze its so regular i had to wire a toggle switch to the circut to save time playing with fuzes evrytime i go somwere and look like an iddiot hanging out of the dooor in thhe fuzebox lol its almost narowed down to the class 2 data wires i beleive are purple somone on another fourm fixed it by sodering a wire acroos them before a join crimb maybe splice pack205? but never got back to me on it beeeeefore i start cuting wires i want to be sure apprently they all meaning the bcm.ecu all modules in car comunicate with eachother for a soh mesage to start the car and mine is mesing up somwere along that data causing the no start and dash cuting in and out radio as well, lol wen its not in locked mode!
i have exact same issue man did u get it figured out im going to pull my hair out on this problem soon it wont start then wen it does dont shut it off till u are done of everything u had to do that day lol or it will not start again if u shut it off u know its gona do it if u turn key and radio cuts out and dash cluster flashes of and on with a no crank condition
follow up: the bcm was burned out, found out this was common on a lot of these impala, 400 dollar repair and ready to go. new bcm then dealer had to program it, you can't program it yourself.. rest for garage labour