Woke up one morning and the entire back seat, entire truck flooring was soaking wet. Got it to Gerber collision in El Reno, Oklahoma. They said that the back window had a crack in it. My insurance said it is a mechanical issue on the sliding back glass and they do not cover such issue. Also want to turn in that the transmission in this truck had to be replaced two week prior to this incident. The truck only had 118,000 miles on it. Safe to say that this 10 point GMC diesel truck is a nightmare and the entire truck is a hazard. They need to take these truck off the market.

- Petal, MS, USA

Power Steering works sometimes and then stops Trailer Break system issues

- Pittsford, NY, USA

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving on a main road at 40 MPH, the vehicle lost automotive power, causing the vehicle to shut off. There was no warning light illuminated. The vehicle was towed to a local dealer where the vehicle was diagnosed, and the contact was informed that the engine wiring harness was faulty and needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 80,000.

- Prairieville, LA, USA

Loss of power steering. Loss of engine propulsion at high rates of speed. Engine would not start.

- Keswick, MT, USA

Hi I have always taken good care of my 2020 gmc Sierra 1500 at4 6.2 Kept up with its regular and recommended maintenance. I had no warning signs on the dash. So it surprised me that while on my way to work early one morning I was getting off the highway exit and the truck lost power, my steering wheel hardened and it posed a great threat to my life and others on the road, as it suddenly decelerated in a area where people are driving at accelerated speeds. The whole truck was loosing power and shaking hard as I attempted to steer it to a safe location on the side of the road. Had a mechanic inspect it and they determined The truck ended up with a seized engine. I have since not been able to use my truck for 8 months and still currently paying monthly payments of 1000 to pay it off.

- Alamo, TX, USA

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving 60 MPH, the horn failed to function as intended. There were no warning lights illuminated. The contact stated that on a separate occasion, the right lane sensor stopped working as intended. There were no warning lights illuminated. The contact stated that on a separate occasion, while driving 60 MPH in the rain or on rough asphalt, the rear suspension caused the vehicle to fishtail to the right. The contact turned to the left to control the vehicle. The contact stated that the vehicle returned to normal functionality after the failure. The low transmission fluid warning light was illuminated. The vehicle was taken to an independent mechanic, who diagnosed the vehicle with an electrical systems failure. The independent mechanic informed the contact that there was adequate transmission fluid inside the transmission, and it was unclear why the warning light was illuminated. The contact was informed that weights were added to the wheels to balance each wheel. The vehicle was not yet repaired for the other failures. The contact stated that the transmission was replaced a year prior to the failure, and the horn had failed to function soon after the transmission replacement. The manufacturer was made aware of the failure. The failure mileage was approximately 68,000.

- Indianola, MS, USA

Engine Light came on, performance rough at various speeds / conditions, and smelled like burning and strong urea smell. GM Maintenance identified a failed DEF injector / replaced

- Brighton, MI, USA

Engine light would come on for a few days and than turn itself off. this occurred for about 8/9 months; however, instructed by the GM Maintenance department that if the vehicle came in and the light turned off before they got to it i would be charged for the diagnosis and no work would be performed. Engine light came on and i was able to park the vehicle / they picked it up and read it prior to putting in their lot until a tech became available. GM Maintenance was able to diagnosis that there was an issue with the EGR sensor and NOx catalytic converter without filter failed / both items replaced

- Brighton, MI, USA

Engine light came on and real bad urine smell / burning coming from the vehicle / rough performance. This issue occurred at various speeds / trips / drive types with the only variation being speed from 25MPH to 75MPH. Vehicle went in to discover that the reductant control module software (RCM) out of date, and two NOx sensor failures

- Brighton, MI, USA

After repair got a few miles down the road and noticed the volt meter jumping back and forth between the white lines. Line would slowly go up to max line and then slowly drop back down to lower limit and continue to go back and forth. This was very concerning to myself and i was waiting for something to fail while driving. Got about 10 miles away and was to concerned / returned the vehicle Informed by GM Maintenance tech that this is what / how the vehicle is designed and that it is the operating within its parameters. I expressed that only time i noticed something like this was prior to an engine light / electrical failure; however, maintenance team expressed GMs stance that it is operating within tolerance.

- Brighton, MI, USA

While driving my vehicle it began down shifting harder than normal (at various speeds and road (highway, city and dirt road)); along with a noticeable burning smell after every trip. GM Maintenance personnel discovered that the wire was chafed and arching / catching on fire underneath passenger side resulting in the burning smell and the wiring issue aligned to the transmission. Personnel took a video and provided to me as evidence of the fire / smell; however, that was on their official GM app so i was unable to download

- Brighton, MI, USA

Vehicle Stuck in gear. Dealership was delivering the car back to myself when about a mile out from my house when the vehicles made a sudden downshift and was stuck back in gear. Driver called and notified me that it was on its way back to the shop for further work

- Brighton, MI, USA

I was driving about 45 mph when the vehicle started to brake on its own. Message center said "Brake Failure max speed 62 mph". I had to move the vehicle, so I continued forward. It was still trying to self-brake, i decided to stop and turn ignition off so computers could re-set but I had no brakes. I had to stand on brake pedal to get it stopped. Turned ignition off and restarted. The problem was gone, but it happened again 2 weeks later. Took to dealership where purchased and they said it needed a computed recalibration. Something I didn't know about. They charged me $200 to recalibrate the computer. My issue is the danger of not having brakes, not the $200. How many similar vehicles could this happen to?

- Blanchard, OK, USA

I have taken my vehicle to 3 seperate mechanics (GMC, AAMCO and Independent). They all agree that my valve body inside the transmission must be replaced. The problem is that valve bodies are on a national back order and cannot be fullfilled for months, putting my transmission at risk for further failure. Reading online forums, there are many GMC owners facing this same issue. The mechanics at GMC are requesting that I change out my entire transmission, since that will be a quicker solution than waiting months for that valve body. Now, I am being told that they are having difficulty locating an original manufactured transmission. This puts me in a serious bind because my truck is my only vehicle and there are no valve bodies or transmissions to fix this issue. My truck is only a 2020 and I just surpassed 100k miles. There were no dashboard warning lights that indicated my trucks problem. Only the fact that my truck is shuddering when shifting gears and that a diagnostic tool had to find the source of the problem. This problem started about 5 months ago and has progressivly gotten worse.

- El Paso, TX, USA

I was about 45 miles or so from home on [XXX]. As I left a business my truck went about 100 feet and the engine stopped working. No warning. Truck was towed to a GM dealer in Wilmington Il. It was determined the cause was due to the wiring from the engine ECM that was run over the top of a very sharp plastic mounting bracket for the ECM. The wire had been cut because of the way this was done at the factory. In addition the fuel pump also needed to be replaced. At the time of this, the truck had 39,140 miles on it. I had no warning this was about to happen. No check engine light went on, etc. Most of my route home is on the highway. Had this not happened on a side street, I would have been involved in an accident. I ended up paying $865.42 plus towing for this repair I should not be paying for. The people at the GM dealer told me this has been happening on numerous GM pick up trucks. This is NOT a maintenance issue or an isolated case. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Braidwood, IL, USA

Dear NHTSA, I am filing a complaint against General Motors, LLC (GM) for failing to follow through on a legally binding lemon law settlement and leaving me with an inoperable, unsafe vehicle. Vehicle Information: -??Vehicle: 2020 GMC Sierra 1500 -??VIN: [XXX] -??Date of Purchase: [XXX] -??Dealership: Diamond Chevrolet Buick GMC Nature of the Complaint: 1.Vehicle Declared a Lemon: -??GM acknowledged that my vehicle was defective and offered a CCP ? 998 settlement on April 18, 2024, for $97,000 plus pre-judgment interest. -??Despite accepting the offer, GM has failed to facilitate the buyback or repurchase of the vehicle. 2.Ongoing Safety Hazard: -??The vehicle is non-operational and poses a safety hazard due to repeated transmission failures, loss of engine power, steering/braking issues, and limp mode activation. -??GM-??s delay in replacing the vehicle leaves me exposed to ongoing safety concerns. Request for Action: I request that the NHTSA: -??Investigate GM-??s failure to address and rectify the vehicle-??s safety issues. -??Document GM-??s negligence in resolving safety defects under a recognized Lemon Law claim. -??Initiate necessary action to protect consumers from ongoing safety hazards caused by GM-??s failure to act. Please contact me for additional information or supporting documentation. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Wildomar , CA, USA

Had GMC (Leominster, MA), perform the safety recall for the transmission on my Sierra. This is the one for the rear wheel lockup that requires a software update. My battery was completely dead after the vehicle sat for a week. No accessori s plugged in, and it's a 6 month old battery Battery tested fine and is charging now, but it appears the CPU never fully powered down after the software update, resulting in needing multiple jump starts and 3+ hours of run time to charge the battery enough to turn over on its own. I can see this being a safety issue in relation to the Auto-start, because when it is being used, the battery is needed to restart the engine. This could result in a stall at an intersection, and if drivers are not alert, may collide with a stalled vehicle.

- Brookline, NH, USA

While driving on interstate transmission would -??lock up-?? momentarily creating drastic drop in speed and unable to shift gears and accelerate. -??D-?? would start flashing in dash board. Dealership said this is unrelated to current recall about rear wheels locking up from valve body failure and instead this is an electrical issue. Dealership also stated this is the 2nd truck in a week they have had come in with this issue. Almost caused accident on interstate with my family and I as a result of sudden drop in speed and unable to accelerate with multiple cars behind us.

- Roscoe , IL, USA

Driving down highway at 60 mph and truck shut off. had to try to get it over to the shoulder to off the travel lane. Dealer found wire harness chaffed at front left shock tower ECM bracket. Several wires damaged, repaired and cleared codes. This could have been much worse had I been in heavy traffic and needed to cross additional lanes of traffic to park in a safe area. I had no power steering and limited space to park the truck. I called to police to have a car dispatched to park behind me so the truck could be loaded on a tow vehicle to bring it to the dealer. This could have been worse had my wife been driving.

- Marquette, MI, USA

On [XXX], I was driving my truck on [XXX] through Phoenix, AZ. It was 5 days after I had purchased the vehicle and only had 250 miles on the odometer. I was in the left lane was traveling at approximately 75mph. Within the span of about 20 seconds, several lights on the dash annunciated and several messages including a message about a brake failure and steering assist failure and then the engine suddenly turned off. The steering seemed heavy and the brakes seemed less responsive. I was able to coast to a stop on the side of the road thanks to the help of a couple truckers who blocked traffic across multiple lanes. The truck was towed to the dealer and they told me the entire engine needed to be replaced. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- North Pole, AK, USA