GMC Sierra Complaints (2025)

179 consumer complaints on file.

#11682678August 24, 2025
ENGINE, UNKNOWN OR OTHER
I’m filing this safety complaint in addition to a previous complaint, 11678151. which occurred on August 1, 2025. On Friday, August 22, 2025, I experienced a 2nd Traction Control alert and engine failure lights on my 2026 Sierra Denali Ultimate truck which again caused the acceleration to drastically decline while driving home from work. Thank God my kids were not in the car with me this time. I am extremely appalled and confused as I've NEVER experienced this level of substandard operation from a new vehicle. I have informed the leadership team team at Cavender GMC West San Antonio, TX of the situation. The dealerships recommended (2) paths to exit the vehicle: GMC Customer Assistance and dealership trade-in.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11682108August 21, 2025
SERVICE BRAKES
We noticed that the brakes were really soft. We literally had to push on the brakes with excessive force. We took it to Lynch - West Bend, WI for a service call and was told that nothing was wrong with it. After leaving the dealership we did our own research (the hubby is a certified master technician himself). Come to find out through GM, contacts through TBM brakes and Duramax Forum.com "brake pedal effort" we found the issue and a solution and we fixed it ourselves. This truck is brand spanking new and the dealership threw their hands in the air with a safety issue and let us drive out of the parking lot. Imagine driving away after being told no issue to end up in an accident due to failed brakes. Who's to blame for that? Certainly not the customer. It was only when the new car sales manager took the truck for a drive, he agreed that there was a problem. - too late we took it home and fixed it ourselves. This problem needs to be looked into seeing its a known issue!
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11681244August 18, 2025
ENGINE
The contact owns a 2025 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle experienced a loss of automotive power. No warning light was illuminated. The vehicle was towed to a local independent mechanic, where it was diagnosed and determined that the engine had seized and needed to be replaced. The local dealer was contacted. The vehicle was not diagnosed or repaired. In addition, the contact related the failure to an unknown recall; however, the VIN was not under recall. The manufacturer was made aware of the failure. The failure mileage was approximately 75,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11679446August 8, 2025
UNKNOWN OR OTHER
Driving down interstate highway and sunroof “exploded”. Raising glass sunroof up about 2” above the body. Vehicle had 387 miles on it. This occurred at about 6:55 am and outside temperature was about 74 degrees. The rupture was loud and very startling and I exited the interstate pulling over to see what occurred. There was no damage whatsoever to any other body component and no “flying” debris was observed at anytime that could have struck the vehicle. I requested GMC dealer to look at onboard cameras and save video but they seemed dismissive. Had the interior sunroof shade not been closed I would have been showered in glass while driving.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11678658August 6, 2025
ELECTRICAL SYSTEM, VISIBILITY/WIPER, BACK OVER PREVENTION: REARVIEW SYSTEM BRAKING
The backup camera visibility at night is poor, making it very difficult to see behind the vehicle. This poses a potential safety hazard for pedestrians who may be in the path while reversing.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11678734August 6, 2025
ENGINE AND ENGINE COOLING
The contact owns a 2025 GMC Sierra 1500. The contact stated that while at a stop light waiting to make a left turn, the vehicle stalled. The vehicle failed to restart. No warning lights were illuminated prior to the failure. The contact stated that the failure was related to NHTSA Campaign Number 25V274000 (Engine and Engine Cooling). The vehicle was towed to the local dealer to be diagnosed, and the contact was informed that the engine had seized. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 21,100.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11678617August 5, 2025
UNKNOWN OR OTHER
The drivers side grab handle (a pillar trim piece) is cracked through completely at upper bolt mount location, causing the grab handle to be weakened and unable to safely support while using and could pull away from vehicle while in use potentially causing the driver to fall and become injured. I replaced the original with a genuine OEM replacement from the dealership and it cracked in the exact same place. I posted an inquiry to a Facebook group of fellow GMC owners and there were numerous reports of this having to them and having the dealership replace under warranty, only to have the issue occur again. This structural failure seems to happen with or without use of the grab bar.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11678151August 4, 2025
POWER TRAIN, VEHICLE SPEED CONTROL, UNKNOWN OR OTHER
I am writing to express my extreme disappointment and serious concern regarding a critical safety failure I experienced with my 2025 GMC Sierra 1500 Denali Unlimited (VIN: [XXX] ), which I purchased brand new in April 2025 from Cavender GMC, San Antonio, TX. On Friday, [XXX], with fewer than 9,000 miles on the vehicle, I was driving on the highway at about 65 MPH, with my minor son in the vehicle when the dash suddenly displayed a Traction Control (TRC) Fault message, followed immediately by "Acceleration is Limited." The truck experienced a severe and unexpected power loss, severely restricting my ability to accelerate or maintain safe highway speeds. I was forced to pull off the road abruptly to avoid a potentially dangerous situation. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11677947August 2, 2025
VISIBILITY/WIPER
The passenger side outside rear view mirror does not provide for a clear view on the passenger side of the vehicle. The adjustments on the mirror cannot be set to reduce or eliminate a blind spot on the vehicle. The mirror is not like a normal mirror from other vehicles. I have almost hit several vehicles due to the lack of clear view with the mirror. To give an idea of the blind spot, a vehicle can be seen in the rear view mirror but not seen in the side view mirror or it gives a false distance of where the vehicle is on side mirror. There is no verbiage on the side view mirror of objects appear closer like other mirrors do.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11676005July 24, 2025
FUEL/PROPULSION SYSTEM, POWER TRAIN, ELECTRICAL SYSTEM
This is the second time in 2 days!! While driving ~35MPH the truck experienced a harsh transmission shift followed by a sudden loss of acceleration and entered shutdown mode to protect the engine. The steering became stiff, all dashboard warning lights illuminated, and a message appeared on the driver display indicating a transmission issue and advising to drive with caution. This created an extremely hazardous condition for me while driving on s busy stretch of road. I pulled onto the side of the road, came to a complete stop, shifted into park, and turned off the engine. Upon restarting the vehicle, the Check Engine Light remained on, and the transmission continued to shift abnormally at low speeds, including some noticeable shuddering. My GMC application recorded the issue and reminded me to schedule service.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11676015July 24, 2025
SERVICE BRAKES, ENGINE, FUEL/PROPULSION SYSTEM
While in the parking lot of a local grocery store, I shifted the vehicle into reverse, at which point all dashboard warning lights immediately illuminated and the braking response became significantly weakened and nearly unresponsive. I placed the vehicle back into park, paused, and then attempted to shift into reverse again, but the dashboard alerts and brake issue persisted. This created a very unsafe driving situation because the brake system was very unresponsive. Despite the unsafe condition, I cautiously drove to my home 2miles away at a speed of under 20 MPH, requiring excessive brake pressure to bring the vehicle to a stop. I parked the vehicle in my driveway and left it there overnight. The next morning, I tested the brakes, and they seemed to return to normal so I drove 5 miles to my local GMC service center. Service Tech confirmed Check Engine Light On and reported code P0700 and P00FF in the report.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11674120July 16, 2025
POWER TRAIN, ELECTRICAL SYSTEM, FUEL/PROPULSION SYSTEM
While driving on the highway at 70 MPH, the truck experienced a harsh transmission shift followed by a sudden loss of acceleration and entered shutdown mode to protect the engine. The steering became stiff, all dashboard warning lights illuminated, and a message appeared on the driver display indicating a transmission issue and advising to drive with caution. The RPMs surged and the truck struggled to maintain a speed of 45 MPH while the remaining at 4000 RPM. This created an extremely hazardous situation for both me and my passenger. I safely pulled into the breakdown lane, came to a complete stop, shifted into park, and turned off the engine. Upon restarting the vehicle, the Check Engine Light remained on, and the transmission continued to shift abnormally at low speeds, including noticeable shuddering.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11670638July 1, 2025
SERVICE BRAKES, STEERING, BACK OVER PREVENTION: WARNINGS
My 2025 GMC Denali EV has experienced repeated safety-critical issues, including severe torque pull under acceleration, making it difficult to maintain safe lane position and compromising steering control. This behavior persists even after inspection and is documented on video. The vehicle has also had repeated service brake assist faults, including one critical failure at under 6,000 miles and additional incidents that resulted in me being stranded out of state. Additionally, I have experienced ghost braking while reversing, where the vehicle unexpectedly applies brake force even when parking assist features are manually disabled. I have performed comparative testing with an identical Denali EV loaner (same year and build), as well as three dealership test units, all of which exhibited proper steering stability and regenerative braking behavior. My vehicle’s issues are therefore not “normal operation” but clear, reproducible defects that affect both safety and expected vehicle performance. These issues raise major concerns for real-world safety scenarios requiring immediate acceleration (e.g., merging onto highways or avoiding fast-approaching vehicles). My documented comparative evidence and repeated attempts to have the defects addressed have not resulted in a safe resolution.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11670408June 30, 2025
STRUCTURE:BODY, UNKNOWN OR OTHER
Tailgate switch Tailgate opened on its own with trailer attached while driving damaging the top of my tailgate. No notification inside cab. No console / fob / tailgate buttons were pushed. Discovered tailgate was down after I arrived home and had done a wide u-turn in my back yard. So far dealership has done very little diagnostic wise. Two trips to dealership so far with little to no results. Now I’m scared to use my trailer or utilize the bed of the truck to haul anything due to tailgate might open on its own at 75 mph on a major interstate/ 2 lane road hurting or killing the people in the vehicles behind me. Totally unacceptable from GMC / dealer for a 70k truck.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11669746June 27, 2025
POWER TRAIN
Truck was in "Park" idling for 20 minutes when it went from Park to "Reverse" on its own. A person sitting in a dump truck saw the backup lights on my truck come on and the truck started backing towards his truck. My truck hit his truck causing damage to my left rear bumper.
Crash:
Yes
Fire:
No
Injuries:
0
Deaths:
0
#11668227June 20, 2025
SERVICE BRAKES
While towing my fifth wheel trailer, the truck intermittently disconnects the trailer brakes while in motion. This results in a sudden loss of roughly 75% of my braking capability, creating an extremely dangerous situation. I have a professional driving background, which has helped me avoid an accident so far, but this issue could easily result in a collision, especially under emergency braking or downhill conditions Service Attempt: On June 17, 2025, I brought the vehicle to Madras Chevrolet in Oregon. The dealership acknowledged the issue but stated the truck is “within GM parameters,” so no repairs were made. They claimed the problem might be with the trailer, but I’ve confirmed the trailer works properly with other tow vehicles. This appears to be a systemic electrical or control issue with the truck. Safety Concern: No vehicle should be allowed to disable trailer brakes while moving. This is a clear design or control system fault. I am concerned that other GMC or GM truck owners may be at similar risk and urge the NHTSA to investigate this problem before it results in serious injury or death. PS. On social media most owners say this is happening to them
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11667918June 19, 2025
SUSPENSION
The passenger side rear wheel went into a pothole while making a right turn on a city street. This resulted in the right rear leaf spring breaking at the forward mounting point. This caused thr rear axle to swivel impacting the rear of the wheel well. The ESC malfunction indicator and impact sensor malfunction llights illuminated appropriately 2-3 miles later after I was in a highway. This is a significant safety concern as I was at an increased speed in heavy traffic by the time the lights illuminated. This not only puts the vehicle occupants at risk, this is potentially a significant risk to other motorist. There were no noticeable indications of damage besides pulling until I was at appropriately 55mph on the highway. The vehicle is currently at a dealership for repair.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11666790June 13, 2025
ENGINE, POWER TRAIN, VEHICLE SPEED CONTROL
The contact owns a 2025 GMC Sierra 1500. The contact stated while driving approximately 4 MPH and turning left into a parking spot, the vehicle independently accelerated. The contact stated that the brake pedal was depressed. The contact stated there was no warning light illuminated. The contact stated that the failure was intermittent, but the failure occurred while slowing down under 5 MPH and turning to the left. The contact had taken the vehicle to a local dealer; however, the failure was not duplicated. The vehicle was not repaired. The manufacturer was informed of the failure. The failure mileage was approximately 17,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11666150June 10, 2025
STEERING
The contact owns a 2025 GMC Sierra 2500. The contact stated that while driving at an undisclosed speed, after driving over a small pothole on the road, the alignment was dramatically altered, causing the vehicle to slightly veer out of the intended lane even though the steering wheel was centered. No warning lights were illuminated. The vehicle was not taken to the dealer or an independent mechanic. The vehicle was not repaired. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the NHTSA Hotline for assistance. The contact stated that he previously owned another vehicle of the same year, make, and model that had experienced the same failure and a case was filed with the manufacturer for the vehicle, resulting in a buyback. The failure mileage was 2,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11664839June 4, 2025
FUEL/PROPULSION SYSTEM, ENGINE
The vehicle was purchased for the express purpose of towing a 6,600 lbs Travel Trailer. This truck is equipt with the 3 liter Diesel engine. While towing the truck computer counts down milage available based on Def level. The count down is not mile for mile it is an exponential count down. This factor triggers a series of warnings concerning vehicle operation and impending speed restrictions. 1000 mile DEF range warning is first up. Followed shortly there after with a 300 mile DEF range warning (700 miles had never been reached to trigger the warning). The next warning is "DEF Low (red warning) speed restricted soon". Shortly there after a 500 mile count down starts for the first impending speed reduction to 65 MPH max. This is followed by other speed restrictions that will put the vehicle eventually into a 5 MPH speed restricted mode. When adding DEF to the tank the level has never been below 60% full. Its not empty as the gauge and computer indicate. With each filling of the DEF tank the range you can drive is less and less until the truck is driven without the trailer hooked up. GM has a service bulletin for this situation that has been in place since September 23, 2024 and no permanent repair of solution has been prescribed. During the 500 mile count down to the first speed restriction the instrument cluster is locked out to only display "DEF Empty" and alternately the DEF range counting down. No other safety features are visible such as engine temp or transmission temp important to know while towing. I Purchased this vehicle March 17, 2025 stating my intentions to tow a travel trailer. The dealership no GMC ever made me aware of the Service bulletin of the DEF restrictions. Had they done so I would have purchased a different vehicle with out the associated travel issues. Please reference GM Service Bulletin #24-NA-196 Document ID 6736285. This document was given to me after my 4 visit to a GMC dealership to have the issue addressed.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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