There is an issue that is causing the batteries to die. This in return causes the Vehicle to go into Limp home mode with no warning. The "issue" was supposed to be resolved by the Dealer in March 2022. The resolution was that one battery was bad. The vehicle is equipped with two batteries. Each of which is sufficient to run the vehicle. A single battery failure should not have caused the truck to have a power limitation. Furthermore the issue was not resolved and General Motors and the Local dealership refuse to continue to work on the issue. This is even after filling complaints with BBB. As of November 2022 the issue has cause both batteries to go bad. The dealer has refused to work on the vehicle and it has been out of service for more than 30 days. Secondary issue. The dealer has refused to work on the vehicle but computer is locked by GM so that only GM equipment can see full scope of codes. This means I can not have third parties work on the vehicle. This is can get the vehicle stuck in areas where there is not GM facilities and GM will not provide any assistance as it is not under warranty. This has also prevented me from finding the actual resolution to the problem.

- Plymouth, NH, USA

DEF system failed. Wire harness burned out. Tank failure. Truck went into limp mode. I personally know 3 others with the same issue.

- Middletown , NY, USA

Service Trailer Brake System Alert constantly going off

- Mandeville, LA, USA

Truck has had multiple issues related to the electrical system and truck modules. It is my opinion that these are all related to voltage issues or module problems. i have had multiple infotainment issues with delays loading, freezing up etc. dealer has ran updates and checks with nothing found. In October around $35k miles the truck Radio would not work if i used the push button start. if i shut the truck off opened the door and let everything reset i could push the start button in the truck and the radio would work majority of the time. The next day i went out to a completely dead truck. I talked to my service department at the local dealer and they said i would need to bring it in but suggested i disconnect the batteries and recharge the batteries. after doing so everything started working correctly. it fixed my radio problem and never went dead again. since then i have experienced popping noises through the speakers when playing music occasionally. over the last few weeks i noticed the engine does not attempt to increase cold idle speed until i press the brake to put it in gear. January 22nd i hit the autostart button and it did not work. i started the truck and it had CEL, Traction control, park brake and wrench, lights on with service emissions, and power reduced messages displayed. Truck is running odd. codes present are (ENGINE GMLAN)P0118 - engine coolant temp circuit high voltage, (BRAKES GMLAN_ABS) U0401- invalid data from engine control module, P0562- system voltage low, (HVAC CONTROLS GMLAN_HVAC) B1325 -. control module power circuit. Truck is starting and charging fine. No connection issues at batteries. There are many TSB's and many complaints regarding similar issues. common brake and emissions faults with minor differences. Module failures, communication faults, and or electrical faults are likely causing all of these similar issues. they need to be categorized as the same failure group which will show GM has a bigger issue.

- Shawnee, KS, USA

Went out to my vehicle that has been sitting in my driveway for 24 hours and attempted to unlock it with the key fob. Nothing. Tried the other fob. Nothing. Used the key to unlock the door and get in to push button start and nothing. I plugged both batteries into chargers and they would start to charge, then discharge after the batteries got up to about 20% I called GMC roadside assistance and they sent someone out. The service guy showed up about 45 min later and hooked up a jump box to each battery. Still no luck in getting it started. He said it must have some major electrical issues. Since we could not get it to shift to neutral, he could not tow it and I am now waiting for a tow in the morning. This truck has less than 10,000 miles on it. I'm dealing with this less than 5 months into ownership and this comes after I had to take it into service the second day of owning the vehicle because I had a def sensor crystallize and go bad. So, I owned the truck for less than 24 hrs and had to put it in the shop for a week. Now, it goes back. This is ridiculous for a $81,000 truck that has less than 10K miles.

- Fort Pierce, FL, USA

As I was driving home my check engine light came on and all of my lights went out. I had no tail lights and the radio started saying no signal detected. The dash screen was saying service keyless entry system. And I had no running lights but my headlights. Pretty scary thinking no one could see me as they were driving behind me at a high rate of speed. My truck only has 200 miles on it so this is really scary to be having issues so early in the ownership of this truck. I've always had Ford but this truck caught my eye and I stepped out of my comfort zone and now wishing I would have stayed in in.

- Washington, MI, USA

2020 GMC Sierra denali duramax 3000 miles tried turning on truck this morning to go to work and would not even crank it is a push start option have no clue on how im going to take it to the dealership if I cant get it of park into neutral for a tow truck at least ! truck does not crank it throws me a ton of messages stability trak dsc ABS power reduced 4WD check trailer lights. Bunch of messages I took video of it and so truck doesn't even try to start. I took a video or the problem

- Avondale, AZ, USA