Extended crank but no start issue

[billya]

I've been having this issue since when I first bought my 2021 Sierra. It's happened almost a dozen times- I've been in and out of the dealership with it. The most recent happened just last week while in the parking lot at my doctor's office. I usually have to sit for 15-20 mins then it starts normally again. I've had all the software updates (to date). Something I'm tracking for sure!

 

[gemarsh]

I've been having this issue since when I first bought my 2021 Sierra. It's happened almost a dozen times- I've been in and out of the dealership with it. The most recent happened just last week while in the parking lot at my doctor's office. I usually have to sit for 15-20 mins then it starts normally again. I've had all the software updates (to date). Something I'm tracking for sure!

Welcome.

 

[SneakAT4]

Glad I found this forum, I've been feeling like i'm taking crazy pills dealing with this issue.

I have a '21 GMC LM2, extremely intermittent ECNS issue (less than 10x since purchasing the truck new). I had a coolant flow control valve go bad recently and just got the truck back. According to the service invoice, they reflashed the ECM according to three separate bulletins. Previously, the truck would start almost instantly, maybe a .5 second crank. Now, the crank is significantly longer, which stresses me out and gives me flashbacks of getting ECNS in the pickup line at my kid's school. I called the dealer to ask about which bulletins they reflashed from, but the guy was clueless and said he wouldn't be able to say anything without bringing it in for a diagnostic. Extremely frustrating.

I've had the truck back for 2 days, and besides the longer crank, no discernible issues yet. Does anyone know the specific change in the reflash that extends the crank time, and is anyone else overly concerned so long as the ECNS is resolved? The truck has 22k miles on it, but it sounds like based on the feedback here, it's happening all across the board (even on LZ0 models).

This powerplant is easily my favorite of any truck I've owned. Hoping GM can get it together and resolve the issue.

 

[SneakAT4]

Glad I found this forum, I've been feeling like i'm taking crazy pills dealing with this issue.

I have a '21 GMC LM2, extremely intermittent ECNS issue (less than 10x since purchasing the truck new). I had a coolant flow control valve go bad recently and just got the truck back. According to the service invoice, they reflashed the ECM according to three separate bulletins. Previously, the truck would start almost instantly, maybe a .5 second crank. Now, the crank is significantly longer, which stresses me out and gives me flashbacks of getting ECNS in the pickup line at my kid's school. I called the dealer to ask about which bulletins they reflashed from, but the guy was clueless and said he wouldn't be able to say anything without bringing it in for a diagnostic. Extremely frustrating.

I've had the truck back for 2 days, and besides the longer crank, no discernible issues yet. Does anyone know the specific change in the reflash that extends the crank time, and is anyone else overly concerned so long as the ECNS is resolved? The truck has 22k miles on it, but it sounds like based on the feedback here, it's happening all across the board (even on LZ0 models).

This powerplant is easily my favorite of any truck I've owned. Hoping GM can get it together and resolve the issue.

One more thought to this. Besides the frustration of ECNS, has there been any long term effects of this noticed? I.e. Is the ECNS a precursor to something worse to come? So far I've read no instances of something worse happening, just an annoying intermittent issue.

 

[gemarsh]

Glad I found this forum, I've been feeling like i'm taking crazy pills dealing with this issue.

I have a '21 GMC LM2, extremely intermittent ECNS issue (less than 10x since purchasing the truck new). I had a coolant flow control valve go bad recently and just got the truck back. According to the service invoice, they reflashed the ECM according to three separate bulletins. Previously, the truck would start almost instantly, maybe a .5 second crank. Now, the crank is significantly longer, which stresses me out and gives me flashbacks of getting ECNS in the pickup line at my kid's school. I called the dealer to ask about which bulletins they reflashed from, but the guy was clueless and said he wouldn't be able to say anything without bringing it in for a diagnostic. Extremely frustrating.

I've had the truck back for 2 days, and besides the longer crank, no discernible issues yet. Does anyone know the specific change in the reflash that extends the crank time, and is anyone else overly concerned so long as the ECNS is resolved? The truck has 22k miles on it, but it sounds like based on the feedback here, it's happening all across the board (even on LZ0 models).

This powerplant is easily my favorite of any truck I've owned. Hoping GM can get it together and resolve the issue.

Welcome.