GMC Complaints

On June 25, 2026 my 2023 GMC Yukon Denali with 53,456 miles was brought to an authorized GMC dealership after displaying a Service 4WD warning light and exhibiting a groaning noise when shifting into Drive and Reverse. The vehicle was diagnosed with the following brake system fault codes: P25A2, C0511, C0517, C1595 and C1596. These codes indicate brake control module failure and wheel speed sensor faults which are safety critical components. The dealership confirmed these findings but stated the repairs are not covered under the GMC powertrain warranty. Given that these are safety critical brake system failures on a nearly new vehicle with only 53,456 miles, we contacted GMC Customer Care on July 1, 2026 to request coverage under goodwill warranty as we believe these failures constitute a manufacturing defect. A case was opened however after 7 days no case advisor has been assigned and no decision has been made despite two promised timelines not being met. The brake system failures on a nearly new vehicle represent a serious safety concern as these systems directly affect the vehicle's ability to stop safely. The vehicle has been at the dealership since June 25, 2026 and remains unrepaired.

My 2026 GMC Sierra has an oil-canned roof from a touchless car wash because the sheet metal lacks structural rigidity. This caused the roof to buckle and caused a permanent fold in the roof of the truck. There is already documented issues for this exact problem on the newer GMC Canyons and Chevrolet Colorado mid-sized trucks. Bulletin for reference NHTSA Official TSB #23-NA-209 PDF. I leased the vehicle on 6/19/2026 and this happened on approximately 7/7/2026. The vehicle only has 1,480 miles on it as of this date.

The contact owns a 2022 GMC Sierra 1500. The contact stated that while merging onto the interstate at approximately 65 MPH, the rear wheels unexpectedly locked up without warning. The contact stated that the rear wheels remained locked for approximately half a second, causing a sudden reduction in speed and requiring the contact to pull over to the shoulder of the road. The vehicle was driven to a relative's residence and was then towed to a dealer. The dealer had not diagnosed the failure, and no repairs had been performed. The manufacturer was notified of the failure, and the contact was advised that there would be a follow-up. The failure mileage was approximately 32,000.

My car suffered a catastrophic engine failure, metal schards were found in the oil filter and was left out of the 2021 recall 25V274. The in service date of vehicle is March 13, 2021. The car was 83 days out of warranty when the engine failed. The truck has 47,000 miles on it. They are now trying to charge us, barter with us. They have gone from $2800 for repair, negotiated down to $100 to sign this off as a good will repair stripping us of lemon law rights and future recall remedies. Car is currently sitting at the dealership.

The contact owns a 2020 GMC Sierra 1500. The contact stated that while accelerating from a complete stop on several occasions, an abnormal clicking sound was heard from the engine compartment. The vehicle was taken to the dealer, where it was diagnosed with a failed fan belt pulley. The vehicle was not repaired. Additionally, while parked on one occasion, an abnormal clicking sound and a loud bang were heard from the engine compartment, and the vehicle stalled. The contact attempted to restart the vehicle, but it failed to turn over. The vehicle was taken to the dealer, where a failed valve spring was diagnosed. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 75,127.

As I was driving the automatic emergency brakes went off and stopped me so hard and fast that I feel like I got whiplash. The seatbelt yanked me backwards, smacking my head against the headrest, I have an instant headache from it and my neck and shoulder still hurt 20 minutes later. It scared me and my child half to death, my heart was pounding and I could have been rear ended. I was driving about 40mph and was in no way in any harm/needing to break (specially this hard) for anything when this happened. This is not the first time my car has unnecessarily automatically slowed down quickly but this is the first time it’s ever been this abrupt and severe. I will be taking my car to be inspected for this issue and if my neck and shoulder still hurt in the next day or two, I will also be going to the doctor about the incident.

The contact owns a 2026 GMC Sierra 3500. The contact stated that while driving at 35-40 MPH on the interstate and towing a loaded trailer, the vehicle experienced reduced braking performance. No warning lights illuminated. The local dealer was contacted and informed that the brakes performed differently. Additionally, the dealer stated that the transmission was not downshifting. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 500.

I am reporting a safety defect involving my 2025 GMC Hummer EV 3X (VIN: [XXX]). On XXX at approximately 18,880 miles, I first presented the vehicle for steering/alignment, suspension, and handling concerns. As of this complaint, the vehicle has approximately 26,840 miles. I have driven nearly 8,000 miles while repeatedly reporting unresolved safety concerns and transporting my two children (ages [XXX] and [XXX]) because I had no practical transportation alternative. Following warranty repairs, including rear control arm replacement, the vehicle developed a severe pull to the right that did not exist before repair. It requires constant steering correction to remain in its lane, and Super Cruise can no longer reliably maintain lane position. Premature and abnormal tire wear has continued throughout the unresolved alignment condition. The vehicle has undergone six warranty-related service events at two authorized GM dealerships. Despite repeated repair attempts and two direct escalations to General Motors requesting repurchase, the only resolution offered has been additional diagnostics and repair attempts. A courtesy loaner was not offered until the sixth service event, after months of unsuccessful repairs, thousands of miles of continued operation, lost wages, and repeated travel. The vehicle also continues to experience water intrusion despite warranty repairs. Rainwater enters the passenger compartment, leaving a persistent musty odor and raising concerns regarding mold, mildew, occupant health, and interior deterioration. I have filed a Georgia Lemon Law claim after exhausting GM’s internal process. I also documented my experience publicly. Posts received approximately 17,500, 48,900, 60,100, and 24,800 views. Many GM owners described similar repair experiences and unresolved INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

"Steering Assist Is Reduced – Drive With Care" warning appeared while the vehicle is in motion. This may require increased steering effort and could affect a driver's ability to respond to changing traffic conditions. Any steering-related warning that appears unexpectedly while driving deserves serious attention. P0128 code was shown. The cause was a faulty thermostat housing assembly and needed to be repaired. This is an extremely common issue in this vehicle across many years and needs to be investigated.

Catastrophic engine failure while traveling 40 mph. Dealership diagnosed as cylinder walls being scorched and rods blown through. No warning signs existed - just had a loud thud before the check engine light started flashing and grinding sound started coming from engine.