GMC Complaints

The contact owns a 2021 GMC Yukon XL. The contact stated that while driving 55 MPH, several unknown warning lights illuminated, and the check engine warning light started blinking. The contact pulled over and became aware that the vehicle was shaking. The vehicle was turned off and restarted; however, the failure persisted, with smoke coming from the vehicle. The vehicle was repaired under NHTSA Campaign Number: 25V274000 (ENGINE AND ENGINE COOLING); but the repair failed to fix the vehicle. The vehicle was taken to the dealer, where it was diagnosed, and it was determined that the camshaft needed to be replaced and that cylinder #8 was damaged and had detached. The manufacturer was notified of the failure. The failure mileage was 116,204.

The contact owns a 2019 GMC Yukon XL. The contact stated that while driving and while the vehicle was parked on several occasions, there was a tapping sound coming from the engine compartment. The vehicle was taken to a dealer where it was diagnosed that the lifters were inoperable, and the lifters and or the engine needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 158,000.

While driving vehicle the engine lost power and shut off in traffic. There were no warning signs of issues at that time. The dashboard went blank and then reappeared and the truck was in park. after that the truck would not shift gears. The truck was towed to the dealership and found to have had catastrophic engine failure.

The contact owns a 2021 GMC Yukon. The contact stated that while driving at an undisclosed speed, the vehicle made an abnormal sound and failed to accelerate above 25 MPH. No warning light was illuminated. The vehicle was taken to an independent mechanic, who determined that there was metal in the engine and that the engine needed to be replaced. The vehicle was then taken to the dealer, where it remained for eight months before the engine was replaced. The manufacturer was made aware of the failure. The failure mileage was approximately 127,000.

Leaking transmission fluid at 7,000 miles. Technicians noticed during routine oil change at dealership.

When trying to put car in park a "shift to park" notice appears on dashboard not allowing the car to be turned off. It takes multiple attemps be able to get the car into park and turn OFF. This has been an ongoing problem for several years and reported to the dealer. To date the dealer tells me there is nothing wrong with the car. Battery has been changed multiple times.

My family drove from [XXX] to [XXX]. Upon arrival check engine light came on, we proceeded to a local shop, by the time we arrive check engine light was flashing and engine was knocking and was clearly malfunctioning. Shop owner recommended we transport the vehicle back home as service shops in the area were experiencing high volume and parts shortages. We had vehicle towed to a local shop in [XXX]. The engine is giving diagnostic codes P0300, P050D, [XXX] with internal knocking and tapping. Vehicle has been kept current on all oil changes and has no external leaks. GMC wants at least $12,000 to replace the engine. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

[Symptom & Safety Hazard] While driving my 2020 GMC Acadia 3.6L V6, the Driver Information Center displayed the warning: "Steering Assist Reduced, Drive With Care" (SARDWC). Steering effort increased abruptly, the engine temperature gauge dropped to cold/zero, and the HVAC system lost air-conditioning function. The warning and reduction in steering assist presented a safety hazard and increased the risk of a crash. [Diagnostic Findings] Vehicle diagnostics identified DTC P0128 - Engine Coolant Temperature Below Thermostat Regulating Temperature. A GMC Certified Dealer technician diagnosed a failed engine coolant thermostat housing assembly. [Manufacturer Information] GM documentation links DTC P0128 and invalid engine coolant temperature signals to the "SARDWC" condition. GM Bulletin 17-NA-158 states the “SARDWC” condition is caused by an invalid coolant temperature signal and the steering module relies on coolant temperature information for steering-assist compensation. GM bulletin PIT5967 directs technicians to diagnose and repair DTC P0128 when the warning message is present. In Oct 2025, GM issued N252508350 for 2021 Acadia vehicles equipped with the 3.6L LGX engine due to an engine coolant thermostat condition. My 2020 Acadia is part of the same generation vehicle platform and is equipped with the same 3.6L LGX engine. It experienced the same thermostat-related failure symptoms, including DTC P0128 and the "SARDWC” warning. [Reason for Complaint] I am filing this complaint because a thermostat-related cooling-system failure resulted in a steering-assist warning and reduction in steering assist while the vehicle was being driven. Moreover, GM issued N252508350 for 2021 Acadia vehicles equipped with the 3.6L LGX engine due to the same engine coolant thermostat condition, yet similarly affected 2020 Acadia vehicles are not included. NHTSA should investigate whether additional 2020 vehicles are experiencing the same failure sequence and resulting safety risk.

Vacuum pump failure caused my brakes to lock up and almost caused me to wreck into another vehicle

Transmission causes problems in can be on interstate and be switching lanes and it loses power and wont go takes forever to shift out. It will cut out and you can barely get pulled off side of rd in time. Electrical the battery voltage goes crazy up and down causing vehicle to power surge bad or at night time lights will go out for no reason while driving every now and then you can smell something melting or burning also the engine gets so hot but it's right temperature cooling fan runs constantly even when car is cool.since all the problem with Transmission the suspension is off some how. Its like it's not stable