What 73 owners told NHTSA about the 2020 GMC Sierra 2500 Hd

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.

NHTSA ODI 11499881

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

NHTSA ODI 11457481

While driving Truck was setting Cruise Control at approx 100km/hr. The cruise would set but at approx 70km/hr. Tried to set multiple time throughout the trip but no change. Recorded video and sent to dealer. They brought truck in to check it out, but said that since they can't duplicate the problem they cannot diagnose it. This has happened multiple times and have recorded video each time. Again dealer said they can't do anything unless they see it themselves.

NHTSA ODI 11444126