general problems of the 2021 GMC Yukon - part 2

The vehicle had a total failure of its rear safety package which includes blind spot monitoring, rear cross traffic alert, rear parking sensors and rear safety alert. The warning illuminated on the dash that all of these functions were offline and service was needed. We took the Yukon to a gm dealer and they replaced a computer and had a hard time getting it to program. This failure also affected the hvac system in the car, with the fan staying on high. After 23 days of service, the dealer thought they fixed it. After two weeks of having the vehicle back the same alert came on 5-6 times in the same day, with another safety package failure. Now the alert doesn’t come on but none of those safety features work, they are all offline. It is bad enough driving a 20’ long vehicle without the safety package working, but now it is worse in that the car doesn’t alert you to the fact it isn’t working and you might not remember that it is defective. This could cause a collision on the highway or result in the driver backing into something or someone, relying on this technology.

I was driving 30 mph when the car went into neutral and rolled to a stop. When I put on the brakes the engine shut off and it went into park. It would not restart or shift out of park . I was stuck in an active busy road. The car was towed to the dealer. They said it was a problem with the bcm. GMC had put out a bullletin which was to reprogram the bcm. My concern is that if this had happened on a busy interstate in traffic at highway speeds the results could have been fatal.

This new 2021 GMC Yukon denali we purchased on June 2, 2021 has a very sophisticated controls system that includes a feature, entitled "brake assist," that is designed to detect "rapid brake pedal applications due to emergency braking situations and provides additional braking to activate the antilock brake system (abs) if the brake pedal is not pushed hard enough to activate abs normally. " "brake assist disengages when the brake pedal is released. " after I left the dealership (June 2nd), I noticed that the "service brake assist" light had illuminated on the driver information center (dic). I pulled off the road to check the owner's manual, and then continued home trusting that no immediate hazard existed. I subsequently set up an appointment with the dealership for a checkup. A week later, the dealership downloaded a new software package from GMC. The brake assist light did not appear when the engine started, so I left for home (50-minute drive at moderate speeds). Enroute to my home, I stopped at a store and turned the engine off. Started home a few minutes later. While accelerating past 45 mph, the brake system independently engaged, which threw me against the steering wheel and into the windshield. As the SUV decelerated through 20 mph, the brakes automatically released. I was not hurt, nor did I lose angular control of the vehicle. I completed my drive home and parked the Yukon normally. Did not drive it again until returning to the dealership a few days later. This second visit did not bear fruit. After significant explorative work, the lead mechanic drove the vehicle several miles under a multitude of conditions, but could not duplicate the problem or get the light on the dic to extinguish. At my request, the dealership returned possession to me with the light still illuminated. I have driven the vehicle several miles since then with the "service brake assist" light still illuminated. I suspect this is a GMC software problem.

Travelling down the highway 69 mph with my wife and three small children when the dash flashed multiple error codes, engine speed limited to 62 mph, and brakes essentially went out. Was able to get safely stopped. Contacted dealership and they advised shutting it off for 20 min and it would "reset". It did not reset and we refused to drive it in such unsafe circumstances without adequate brake function etc. GMC roadside assistance came and towed it away. Could have resulted in much worse outcomes and we are thankful no one was injured. Very nervous to drive it again after we get it back, not knowing if it will malfunction again.

The contact owns a 2021 GMC Yukon. The contact stated while driving at various speeds, the message “safety restraint unavailable” was displayed. The vehicle was taken to a dealer where it was diagnosed that the battery voltage was low. The battery was replaced; however, the failure reoccurred. The vehicle was taken to the dealer on two other occasions, where the system was reset, but the failure reoccurred approximately two months later. The manufacturer was notified of the failure. The failure mileage was approximately 16,000.

Driving approx. 62 mph on a highway, went to slow down and unable to brake, upon pushing down on the break there was resistance, after pumping the breaks multiple times I was eventually able to slow down with a lot of force. Messages on dashboard read "brake system failure" "62 max speed esc, service esc, service trailer break system, and forward collision system unavailable. " abs, esc and check engine light all illuminated on dash screen.

We were coming back from a trip with my children and this vehicle was barely 2 weeks old with 0 miles and we were on a highway when all the emergency lights on the dash went off. It was flagging the electrical system, the engine, the brakes. Honestly all the lights possible went off. The vehicle was lagging and it felt force when we pushed on the gas. Our hands were gripping the steering wheel to keep it in lane till we could get off.