ML2021

UPDATE: Took the truck to the dealer yesterday and they uploaded the new software for the ECM. I noticed that the starter cranks a bit longer now which is a bit irritating but if it fixes the no start issue, who cares. I'll post an update if it happens again. Thanks again for the heads up with this issue.

Thanks for the update and advice. I just got home from a 2 week trip with the truck and it happened 4 times now. I will definitely let them know.

I'll start digging through the threads to see if I can find it. Thanks for the warning. Looks like I'll be visiting the dealer when I get back from this trip.

Yes it's the 3.0L diesel.

I have a 2021 GMC Sierra with 14000 miles on it. Over the past 3 weeks, my starter has hung up 3 times now. Each time it engaged for approximately 20 seconds with no start. Once the starter stopped, I tried it again with no problem. The engine started without hesitation. First time it was cold outside, parked on a hill, and I used my key fob. The second time it was cool outside, truck was level and used the push button to start. Third time it was warm outside, truck was level and used the push button. Is there a known issue with the ignition system on the new Sierra trucks?