2020 RST Z71 starting and then dying

[bradleymichael]

Brand new 2020 RST Silverado, 5.3L, z71....   I barely have 1600 miles on it and the other day I remote started it... heard it start but when I got up to it, it wasn't running...  did the push button start and it started up and then sputtered and died... did that several times...   I waited maybe 5 to 10 minutes then it finally started and stayed running.   I took it to the dealer and they said it was some sensor that they reset.. code was P00C6....   ran great for a few days...  same thing happened again..  this time it was code P12A6, and they told me it needed a new fuel pump control module...   they ordered it and installed it...  got it home and a few hours later...  same thing.    The dealer currently has the truck and said it had the same code P12A6...   anybody else having this issue?  If so, what did they fix on it to remedy it?

[hyperlite986]

Very similar issue.  I can't remember what codes I had but they had to replace ECU. So far so good.

[Beermister]

I have a new 2021 6.2 RST Z71 4400 miles on it and it did the same thing to me last Saturday let it sit for 1 hour then it finally started. Took it to the dealership exactly the same codes and they had to run a new upgrade software on the ECM. Hope that fixes the problem. There is a GM service bulletin out about the problem dated February 9 or so 2021. Running a new upgraded software program on the ECM is supposed to be the fix.