V8Chevy

Man, sorry to hear that. It's ridiculous for them to make you wait. Unless it is a widespread problem, it seems like they could pull you an ECM from the factory production line since a portion of the production units aren't necessarily sold vehicles and are just going to sit on a dealer's lot for some duration. Taking care of your issue should be top priority, since you are a paid customer. There's no excuse for you to have to wait for a back ordered item.

Great question and sorry for the slow reply. I haven't visited this thread in a while. I've been holding off because I wanted to make sure that the ECM flash does the trick. I have no desire to have to keep visiting the dealership to get every iteration of the ECM flash every time they think they have a new fix in place. Hell it kind of sounds like the there's still some uncertainty on whether or not the latest and greatest ECM flash fixes things. With that said, mine has been starting fine for a really long stretch, but within the last month it has happened twice, but has always started on the 2nd try and I'm grateful that it hasn't left me stranded. Reading through this thread, it sounds like there are really two different issues out there: (1) the long crank/no start but starts on the 2nd attempt and (2) the long crank/no start with multiple tries/stranded scenario Part of me is concerned that if they do the ECM reprogramming that I end up moving from a moderately bad (issue #1) scenario to a really bad (issue #2) scenario and I don't want to push my luck until the dust has settled and we have confirmation that there truly is a fix for this. I will continue to periodically monitor this situation as I'm sure that it will be officially corrected. The question is just when? And to be honest, I hope that they are putting more time and resources into resolving issue #2 as I really feel for those guys and am not going to b!tch about mine knowing that some have it far worse.

Interestingly, it has been many months and several thousands of miles since mine has done the no start crank event. I've not done anything to it nor taken it to the dealer for the ECM update unless it was done over the air, but I thought I read that they can't do an ECM update over the air. Perhaps it's a warm weather issue as it seems like it hasn't done it since summer. Only time will tell. Still loving the hell out of this truck and 3.0 Duramax.

Most of my commute to work and back is on the highway so I just leave my start stop function turned on. I do get caught at several stop lights on my way to the highway from time to time and have not had any issues with the truck starting when I let off the brake. My no start issues have only happened after the truck has sat for a few hours at a time. It has always started on my 2nd try. As long as it continues to start on the 2nd try and at the low frequency that I'm currently experiencing, there's no way in hell I'll be trading it in on any other pickup offering out there currently as I'm really digging this little 3.0 straight six.

Mine did it again today @ 2630 miles. This time it was with the remote start. As soon as I caught that it was continuing to crank without starting, I pushed and held the start button on the remote again and it immediately stopped cranking. It started right up on the second try. The first time it did this was when I was starting it with the dash's start button, but it seemed to keep cranking no matter what I did to the start button, so I liked that the remote stopped it immediately rather than letting it keep cranking. Just wanted to pass this along as I don't recall reading that the remote would stop it immediately like it did for me today. Other than this, the truck has been great!

I experienced this for the 1st time last week. 2021 Sierra Denali with ~2,000 miles. Mine started fine early in the morning ~6:00 AM and ran fine on my drive to work. It sat at work all day and did it to me when I was leaving work around 4:00 PM. Perhaps I missed it, but has anyone actually experienced it during a start stop event? Trying to brainstorm this a bit, but it seems like the issue would have to be tied to the ECM not giving the OK to feed fuel to the cylinders. I say this because the engine is getting air (no clogged air filter) and it doesn't have an ignition system (no spark plugs) to worry about so it really points to a lack of fuel to start the engine. A sensor or condition must be telling the ECM to not distribute fuel to the injectors for some reason. For example, on my GM gas cars, the engine will not start if I mash the gas pedal to full throttle while trying to start the engine as I do this intentionally to prime my oil pump on the first start after changing the oil and filter. My 3.0 no start issue seemed very similar except that I did not have my foot touching the throttle pedal. It's probably something simple causing it...