What 147 owners told NHTSA about the 2024 GMC Yukon Denali Xl 1500

The contact owns a 2024 GMC Yukon. The contact stated that there was a strong mildew odor coming from the vehicle while entering the vehicle, and there was moisture around the trunk near the wiring harness. The vehicle was taken to Modern Auto Company (6224 MO-100, Washington, MO 63090), but the cause of the failure was not found. O'Fallon Buick GMC (2150 Technology Dr, O'Fallon, MO 63368) diagnosed the vehicle with a failure of the wiring harness and stated that there was moisture entering the vehicle through the wiring harness. However, after the contact inquired about the odor inside the vehicle, the dealer refused to continue working with the contact. The manufacturer was notified of the failure, and a claim was filed, and an appointment was scheduled for service at Dave Sinclair Buick GMC (5655 S Lindbergh Blvd, St. Louis, MO 63123). The dealer informed the contact that the wiring harness appeared to have already been replaced. The dealer found no leaks inside the vehicle and informed the contact that the vehicle would be returned. The contact hired a mold expert to inspect the vehicle while the vehicle was at the dealer. The mold expert discovered several cases of toxic mold inside the vehicle and deemed the vehicle unsafe to drive. The contact stated that her daughter had severe respiratory issues and was transported in the vehicle. The daughter had several doctor’s visits, was put on several medications, and missed 40 days from school due to her illness. The contact associated the failure with her daughter's illness and stated that her daughter’s health improved once she was no longer transported in the vehicle. Since the failure, the contact had to pay out-of-pocket for a rental vehicle. A field investigator had been hired by the manufacturer to inspect the vehicle, and the contact was awaiting the results. The vehicle remained with the dealer unrepaired. The failure mileage was approximately 27,000.

NHTSA ODI 11751904

Start transmission was replaced by dealer at 75 miles. 2nd transmission was replaced at 175 miles transmission was humming and slipped at around 30 to35 mph this was around April of 2024 August 1 2025 while driving at 45 dash board lit up went flashing and suv slowed dramatically down to 30 mph Got to dealership and they kept the vehicle for about a week and returned it with it being supposedly fixed. About mid October while driving at 60 mph it shut down again almost causing a wreck went to 30 miles per hour again. Hurt my wife’s neck when it reduced speed so quickly. Took back to dealership and I told them this car is dangerous this was with about 20 k miles Been in shop was told it is scanning with 22 repair codes we have not had the car for 5 weeks and are trying to work with gm and dealer to get us out of it. But as of this report no progress. On interstate in city traffic this car will hurt or kill many people. I’m refusing to let my family or myself drive it. There is no warning when it will flash lights in dash and reduce speed. Also the front crash sensors went out and are currently not working we have all service records and paperwork that has been done including maintenance records We were given vehicle back with no warnings. I went to Nita’s and ran vin and it still shows issues. We are still making payments but driving a loaner car. The car is dangerous. I advised the dealer the first time it happened. I didn’t want it back. My wife went and got it and it sis it the second time and now she agrees it is dangerous contacted GM and they want to fix it but dealer implies they can’t ?..

NHTSA ODI 11700720