List of issues thus far...2019 Denali Ultimate

[Ziggo]

10/29/2018 - took delivery of my 2019 Denali Ultimate

 

11/10/2018 - Wife drove truck from Brownsville, TN to Jackson, TN and back. On the way back, the digital instrument cluster and heads up display went black. Came back about 8 to 10 seconds later. Later that evening, I get into the truck to drive to the end of the driveway to get the pizza from the delivery guy (yeah, call me lazy, but we do have a long driveway) - upon starting the truck, the brake, stabilitrack, ABS, check engine lights come on along with "Service PCM", "Check Brakes" and "Speed Limited to 62mph" messages on the digital instrument console. Called OnStar and they confirmed and sent an email. 

 

11/11/2018 - Took the truck to local dealership. There were DTC codes and they pulled them. Dealership stated they contacted GM Engineering and were awaiting a response. I also mentioned the high pitch whine issue when at steady throttle. They were able to recreate the whine and were unsure of where it was coming from. They said they thought it might be the sound system. That didn't seem consistent with me as it is always when the truck is at steady stated load as if it were a hydraulic whine from the drive train. 

 

11/12/2018 - As if by happenstance, there was a software update available this morning. I let it install. Afterward, when I get into the truck and the "GMC" logo displays on the digital instrument console, it blinks on and off sporadically. Sometimes it shows nothing at all. Other times, it just shows a horizontal line across the display. 

 

1/27/2019 - Today I was driving from my home in Brownsville, TN to Southaven, MS with my family to attend a cheer competition for my two daughters. Driving at around 70mph, the typical instrument cluster/heads up display going dark issue happened, but this time the entire truck violently jerked as if the engine shut off but the drive train, considering everything was still locked into gear, pushed the engine over until the power came back on a split second later. The radio was muted when this happened and it magically unmuted itself (as if the power blinked). That was the first incident. Three other times after that, the instrument cluster and heads up display went dark and came back on as if power was removed and it rebooted (individual objects on the display coming back on as the data from the CAN bus was received). 

 

- Anytime the temperature drops below what seems to be around 35F, lane keeping and parking assist becomes unavailable. 

- Anytime I connect my 8x16 trailer, the blind spot monitoring system for both the driver and passenger side goes nuts until eventually the system says it shuts it off on the console, but the mirror lights keep going ape shit...

- This has only happened twice, but I have had the "ghost" trailer issue as well. The display on the center console acts as if a trailer is connected, but the digital instrument console shows the message "Trailer Disconnected" warning. How can a trailer be detected and disconnected at the same time? 

 

Are there any official GMC reps on here that can assist?

 

Anyone else care to comment?

 

Thanks in advance,

Steve

[Ziggo]

Speaking of which, anyone on here have a list of TSBs that should apply to the 2019 Sierra? It would be greatly appreciated...

 

Z

[CamaroGuy]

Sounds like you may have a main ground issue. Also, there are software updates that have to be done at the dealer for the DIC going blank. That could be part of your issue if it hasn't been done already. 

[Rduatctt]

The whine is a fuel vent hose. Had the same problem. They replaced with a new part and took care of the problem. Don’t have the part number but can get it. It’s on this forum somewhere, that’s how I got it. In fact, I was the one that located the noise, told them what it was and the part needed to fix it