6.2L (2020) starts then dies immediately

[GMCustomerService]

On 10/11/2022 at 3:51 PM, whistleblower said:

Model year 2020, manufactured in late 2019, 6.2L with ~70k miles, ~1,900 hours.  

 

Engine suddenly won't run.  It fires up, idles rough for one-two seconds, then dies.  Runs no longer than 2-3 seconds.  This has all transpired in the last hour.  

 

I returned home from a short errand, shut engine off and went inside, walked back outside to start the vehicle but have not been able to get it to run ever since.  Engine was shut off for ~10 minutes between running normally and suddenly dead.  

 

No lights on dash, no 'check engine'

 

Any ideas?  Perplexed.  

 

Feels fuel related (pump? pressure?) or maybe a sensor is erroneously shutting down the motor.  These are just guesses, I'm somewhat at a loss given the motor gave no warning of issue and has been running pretty much flawlessly.

 

Any tips or hints are appreciated.  

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[rlcole321]

Just a note, to clear PCM memory, the Batt needs to be disconnected for a minimum of 3 hours (OBD2). It also helps, before reconnecting the Batt, to turn the key on, pump the brakes a couple of times, this should clear any capacitance.

[20L8TSierra24]

My brand new 6.2 did this at the dealer on day 1. I signed the papers, jumped in and while I was adjusting the radio settings, it died. They updated the throttle body or something and it's been fine for the 1000 miles I have on it now.

[johnnyquick]

On 10/17/2022 at 2:29 PM, rlcole321 said:

Just a note, to clear PCM memory, the Batt needs to be disconnected for a minimum of 3 hours (OBD2). It also helps, before reconnecting the Batt, to turn the key on, pump the brakes a couple of times, this should clear any capacitance.

No key to turn in the 2020 plus RST

But of course my truck is running perfectly now so I cannot wait until this happens when I am in the middle of nowhere or my wife is driving it.

Putting it for sale after this trip.

[richard wysong]

There is a TSB for the 21s for that problem. They  reprogram the fuel control module. Well discussed in a past post

[JerD]

Hello there, I'm new here. I currently drive a 2020 yukon xl denali 6.2L with 38K kilometers on it. My engine just started doing this on Saturday. Fired up no problem but immediately stalled at idle. I tried again and it fired right up again, I noticed a little puff of black smoke on the initial fire but it again stalled at idle. It did this 6 more times. No check engine light or warnings of any kind. The my gmc app says no issues,good to go.

I gave up and called onstar and they sent a tow truck. It is currently at the dealership waiting for service. Has anyone figured this issue out yet? 

 

Thanks, 

Jeremy