2020 GMC SIERRA 2500 Complaints

The contact owns a 2020 GMC Sierra 2500 equipped with Goodyear Tires, Tire Line: Wrangler Trail Runner, Tire Size: LT275/65/R20, DOT Number: PJ0TJB1V 2319. The contact stated that within a three-day period while hauling a camper on a road trip, all four tires experienced a failure. The contact indicated that the first failure occurred while driving approximately 60 MPH; the rear driver’s side tire experienced a blowout. During the failure, the driver’s side rear quarter panel was severely damaged. The contact stated that later on while driving at an undisclosed speed, the rear passenger’s side tire experienced a similar blowout causing damage to the passenger’s side rear quarter panel. Additionally, on another occasion while driving approximately 50 MPH on the same road trip, the front passenger’s side tire experienced tread separation. While at the service center the mechanic discovered that the front driver’s side tire had also experienced partial tread separation. The cause of the failure was not determined. The manufacturer and local dealer were notified of the failure. The failure mileage was 25,400.

I took my vehicle into the local dealership two weeks ago for the DPF emissions voluntary recall. Prior to the service I was getting 16.6 mpg for the 42000 miles on my truck. After the service, for the ~200 miles driven on same route and conditions commuting to and from work I have only been able to achieve ~13 mpg. There has been no other changes to my vehicle or operating conditions. When I took the vehicle in the advisor mentioned that it may take awhile for the service because “we have to download the update wirelessly.” While researching this issue the recall document specifically warns against wireless download of the update. I am not sure if this may be the result of not following the correct process or not and I am headed back to the dealer today. I also found several others posting on the diesel forums about similar significant loss of mpg after the update. Losing almost 25% fuel efficiency after the update is unacceptable and reflects the my previous experience of efficiency loss during an actual regeneration cycle prior to the update. The vehicle is acting as if it is running in a constant regeneration cycle. Unsure if this may lead to dangerous driving condition due to excessive stress and wear on the affected parts and engine.

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

DEF tank system failure. Vehicle is under warranty, 18 months old, (purchased 08/20) with 20,000 miles. 6 WEEKS AGO I took to dealer who informed me that there are no DEF tanks available and don't know when they will be available. This is a hazard: if I am on a trip and the system shuts off I could be stranded anywhere with the reduced speed that the DEF system creates. If this system is designed to shut off (with warning) there should be ample supplies at all GMC dealers for repair. If there aren't ample supplies the system should NOT shut the truck down. THIS IS A SAFETY HAZARD THAT IS PREVENTABLE!

DEF Emission system failure. Total component breakdown requiring replacement. Parts unavailable.

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.

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.

Was driving truck down driveway at about 5km per hour and the parking brake automatically engage bringing the vehicle to a sudden and unexpected hard stop. Brought to dealership, then said they cannot duplicate the problem and therefore there is no action to be taken.

While driving my 2020 GMC 2500 Denali with the Duramax Diesel engine, the power assist for the steering and brakes failed without any warning. This made the truck nearly impossible to steer and stop. Luckily, I was able to avoid a collision and get the truck stopped in a safe location. The truck is currently being towed to Rivard GMC in Tampa, Fl. Doing an internet search, I found this problem has happened to others as well. Please ask GM to rectify this extremely dangerous defect.

TL* THE CONTACT OWNS A 2020 GMC SIERRA 2500. THE CONTACT STATED THAT UPON DRIVING OVER A HILL AT 45 MPH, A VEHICLE WAS STOPPED IN THE MIDDLE OF THE ROAD. IN AN EFFORT TO AVOID HITTING THE VEHICLE, THE CONTACT DROVE THE VEHICLE OFF THE ROAD AND INTO A CONCRETE CULVERT AT THE END OF THE RAVINE. THE AIR BAGS DID NOT DEPLOY UPON IMPACT. THE AUTHORITIES WERE CALLED TO THE SCENE AND THE CONTACT WAS RUSHED TO A LOCAL HOSPITAL VIA AMBULANCE. THE CONTACT WAS DIAGNOSED WITH FRACTURED VERTEBRAE THAT MAY REQUIRE POSSIBLE SURGERY. A POLICE REPORT WAS FILED AT THE SCENE. DUE TO THE ACCIDENT, THE VEHICLE WAS TOWED TO AN INDEPENDENT MECHANIC WHERE THE VEHICLE WAS REPAIRED. THE DEALER NOR THE MANUFACTURER HAVE YET TO BE NOTIFIED OF THE FAILURE. THE VEHICLE WAS REPAIRED AND SOLD. THE FAILURE MILEAGE WAS APPROXIMATELY 15,500.