I will start by saying that I have had this issue since I had the truck (2020), less than 10k miles. I mentioned to the dealer multiple times. I was told that they can't figure it out since it has to be doing it while it is at the dealership to figure it out. I am finally fed up with that answer. The issue is with trailering. It will randomly lose trailer brakes while driving down the road. Sometimes the brakes will come back right away, sometimes they will not. Other times other lights that should be working will randomly stop working as well such as turn signals. This has happened multiple times and I only tow a few times a year when I pull my travel trailer. I have a video of it doing it as I am driving down the road. For the additional details with approximate date that this incident occurred, I will put the last date that this was found.

- Grandville, MI, USA

I was driving my 2020 GMC Sierra 1500 on a local street when the dashboard suddenly displayed a -??Brake Failure-?? warning. I immediately realized I had no braking power and had to safely roll into an uphill parking space to stop the vehicle. While waiting for the tow truck, I researched the issue and discovered there is a known recall related to the brake calipers on some 2020 Sierra 1500 models. However, when I entered my VIN, it showed no open recalls. I also contacted GMC directly, and they confirmed that there are no active recalls associated with my vehicle. Additionally, the vehicle's onboard information system indicated that the front brakes were at 65% and the rear brakes at 80%, suggesting that brake wear was not a contributing factor.

- Thornwood, NY, 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

Brake monitor repair keeps illuminating since 2/1/2025! Replaced all brakes and rotors, yesterday 4/27/2025. now don't drive over 43 mph illuminates, emergency brake illuminates says push brake peddle to disengage parking brake yet parking brake has never been engaged

- Garden City, MI, USA

recently when starting truck brake message alert comes across on dash reading brake error, and not to drive above 45 miles per hour and brakes are NOT totally operational, meaning brake pedal has alot of play in it to bring truck to a stop. Have to turn off vehicle, sometimes repeatedly before it apparently resets computer system. This has now occurred four times in last five months. Events and dash warning message very similar to recall issued 3/3/20, but listed as "complete" on recall data base. Need to seriously and immediately looked into and corrected!

- El Paso, TX, 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

-Transmission valve body Failure, Wheel lock up, ABS Event, Loud Bang and a Flashing "D" on Driver Information Center (DIC) when Lightly or Moderately Accelerating Forcing an 8-7 or 8-6 Downshift -When all four tires lock up at a high rate of speed, this puts the driver, the passengers, and all others on the road at risk for injury or death. -Yes, the problem has been found in a document by my local dealer that this issue was added to my exact vehicle's service manual on 11/27/24. The document describes in detail the exact scenario I have been involved in multiple times. It is deemed as #21-NA-275. It locks up the tires randomly to the vehicle in mid acceleration at any speed including 80 miles per hour in one instance for me. -Yes, the dealership inspected it and found the issue to correlate with the newly added section to the service manual, 13333166. This document ID is 5925530 and the added information to the dealership is #21-NA-275. The GMC manufacturer has been contacted as of 3PM MST 3/14/25. Insurance doesn't deal with mechanical problems. The police will only be involved when there is death or injury. -No. The only warning that happens is simultaneously as the vehicle locks up the tires causing the driver (me) to inevitably try to save myself and others, swerving and trying to focus on not hurting myself or others but I did notice the "D" flash on one of these occasions. This is the most dangerous issue with a vehicle I have ever even considered. At any time, for any reason, all four tires can lock up at any rate of speed and cause multiple casualties. The way to fix this is to spend $3,000 which I am sure many people like myself do not have. This means there are thousands of these exact make and models of vehicles on the road right now. Please do not take this lightly as I have almost crashed multiple times with people in my vehicle due to no fault of my own.

- Rapid City, SD, USA

Vehicle shifting poorly, and I have had a bunch of brake and rotor issues.

- Zachary, LA, USA

My pickup was specifically purchased to pull a duel axle trailer ( brakes required by Fl. Law). The trailer weights more than the pick up. They stopped working with the electric /hydrolic Trailer brake system. I have had the Sierra in three times for Warren Ty repair. They never fixed the system. I have thoroughly test the trailer system - it works fine with another pickup. Dealer won-??t return my calls. Multiple trips taking it in for this problem. Have a case filed with GM. All just placating me, now ignoring my problem. I am stuck and they are not acting in good faith.

- St. Augustine, FL, USA

My truck 2020 gmc sierra 1500 AT4 denali is not working properly since July 2024. I took it to 2 different dealership to get a diagnostic and i finally ended doing the repairs for brake issues. I have been towed 6 or more times and almost experienced 2 car accidents since I drive the truck after the supposedly repairs where done but i ended stranded again with no brakes. The dealership has repair the truck 3 times but im still getting sevaral codes the fact that i had to pay out of pocket and have to deal with this and expose myself to danger and my family in driving a vehicle that is no safety condition its absurd. I call several times the recall GM hotline and i was told GMC 1500 are included in the recalls just not the AT4 and i have a family member with the same truck and same issues she ended up trading in the truck recently since she kept experiencing the same issues over and over again just like me.

- Houston, TX, USA

My brakes failed 2 times. One time I almost got into a horrible wreck with my daughter in the truck. "Brake system failure" " max speed 43mph" I have not had any brake work or anything done. The dealer is trying to charge me to replace the whole brake system when [XXX] this says to reprogram. Still waiting on gmc to tell me if it's covered under warranty. From my own research this has been a major problem for hundreds of people if not more. I could have died because of a faulty brake system or a bad software update. I need help with this and so do the countless other 2020 gm owners. There is a recall on the 2019 for the exact problem but not the 2020s. GM safety recall N192268090 please advise INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Zebulon, GA, USA

Lost break, second time this month, showing break failed 40 mph max speed, abs light on, break light on, and 2 more light on the car with antislipiring or something like that, the another one no idea what it

- Sebring, FL, USA

ABS LIGHT LIMITED TO 43 MPH ESC system Steering assist reduced Service Trailer Brake System Engine light

- Hallsville , TX, USA

The contact owns a 2020 GMC Sierra 1500. The contact stated while driving 60 MPH, the service brake, check engine, and ABS warning lights were illuminated. The contact took the vehicle to an independent mechanic to be diagnosed and it was determined that the passenger-??s side rear caliper needed to be replaced. The vehicle was not repaired. The vehicle was taken to the local dealer to be diagnosed, and the contact was informed that the rear passenger-??s side caliper needed to be replaced. The vehicle was not repaired due to the parts not being available. Upon investigation, the contact associated the failure with NHTSA Campaign Number: 20V116000 (Service Brakes, Hydraulic) however, the VIN was not included. The manufacturer had been informed of the failure. The failure mileage was approximately 69,000.

- Swansea, IL, USA

We were hauling a trailer and driving approximately 65-70mph with cruise control enabled. The vehicle randomly disengaged cruise and the ABS telltale illuminated, lost brake functionality completely. Safety of my family and other vehicles around us was compromised! Downshifted to try and navigate the vehicle to the side of the road and the ESC warning text came on the screen. Was able to luckily stop vehicle by downshifting. Turned off ignition and then cycled back to run, brakes and all warnings were cleared. Started driving vehicle with flashers on the side of the road see what would happen and approximately ten miles later same thing happened but this time brake functionality was reduced significantly but not completely but still had to downshift to stop. Called GMC and was told this was not a recall even though vehicle brakes randomly stopped working. Told us they would do nothing since the vehicle was out of warranty 80k miles and warranty was 60k and also since no one was hurt. We were 1-2 hours from being in the Mountains driving and not sure we would be here today if this had happened in the Mountains! Dealership ordered a new master brake booster and ABS. When installed the part would not flash and GM engineering told them to replace the part a second time.They we-??re told to keep flashing till it takes even though the second module was also bricked. Seems strange a new part would be broken as well and the master cylinder was resetting. Dealership states the vehicle is fixed but the safety of my family and others driving around me were in extreme danger when this happened. Do not feel safe driving this vehicle and not convinced this will not happen again. When we called GM they told us they are receiving many calls about this happening to AT4 vehicles but they have not issued a recall yet. Submitting this because vehicles should not randomly lose brake functionality and do not want others at risk or my family.

- Alpena, MI, USA

I own a 2020 GMC Sierra 1500 4-Cyl, Turbo, 2.7 Liter with 20K miles and I owned the truck for almost 2 years. All of a sudden my vehicle started receiving multiple warning messages. While driving I stopped, and when traffic stopped in front of me the engine died all the lights were on warning messages on the dashboard started showing up. Electronic Stability Control, Antilock Braking System, ECM, reduced Engine Power, etc., and the brakes were hard to step on it and the steering wheel hard to turn, I took my foot off the brakes and pressed it again to start. It started but the check engine light was still on, this happened FOUR times already and THREE times while parked when I tried to start, after a few tries giving few minutes intervals, it will start with all the lights on and warning messages on the dashboard start showing up. Electronic Stability Control, Antilock Braking System, ECM, reduced Engine Power, etc., and the brakes were hard to step on it and the steering wheel hard to turn.

- Aventura, FL, USA

Normal driving conditions vehicle decelerated and warning lights and notification appeared. Warning were -??Service ECS-?? and -??Steering Assist is reduced Drive with care-??. Shut off vehicle for 30 minutes and warnings were no longer present and vehicle drove normally. Happened again 24 hours later. Received email notifications from GMC to arrive within one day. This was a know recall of the previous model year.

- Two Harbors, MN, USA

i was stopped at a red light and when the light turned green I accelerated and the vehicle shut off and then came back on. when the vehicle came on i had a service esc light and a system break failure warning telling me not to exceed 62mph. i made it back to my house driving with extreme caution. the breaks were very delayed while driving.

- Bakersfield, CA, USA

Brake pad monitoring system alert came on driver information center warning screen. Brought to local dealer who told me I needed new brake pads. There is a current safety bulletin on the NHTSA.GOV website for the 2019 model year GMC Sierra, as well as the 2019 Cadillac CT6, but not he 2020 model year. The week prior my driver information center reported front brakes in the high 80's and the rears in the low 90's in terms of percentage of brake life remaining. How can the system go from being safe to being unsafe in a week (and less than 200 miles)? At this point I don't know if my vehicle has a safety problem with my brakes or if there is a sensor and programming issue as described in recall N192264451. I have no observable issues while braking - no pulsing, noise, chattering - that would indicate any brake problems. My only inclination is the alert on the driver information center. Both local dealer and GM customer service are telling me to perform service and pay out of my pocket. This seems inconsistent based on the above recall.

- Saranac Lake, NY, USA

The truck stated to have the check engine light on, by the time that happened the brakes were hard to step on it and the steering wheel hard to turn, I had been asking to GMC superior of Siloam springs to check the truck because, got scared while I couldn't make stop the truck while on traffic, but they don't had open appointments for that day or the other following days, so a week after they got one and I missed because my work, I set another one at GMC on Springdale but they want me to charge me whenever the truck has an extended warranty, so I told them to leave it like that so finally got another appointment at Siloam springs location but while driving down there the same thing happened all the light on warning messages on the dash board start showing up and the brakes were hard to step on it and the steering wheel hard to turn, I got told them what was happening, about and how exactly happened. That day after 30 minutes I got a call saying that it was fixed I still asked if they were sure he said yes, the next day I almost crashed with a neighbor at my work place because I couldn't stop the truck, so today I took back the truck and the guy at the desk told me that they may just erase the codes and don't really checked what was wrong, I'm just filling this report because even if I got full coverage on that truck, I'm not gonna be responsible if I'm involved in an accident.

- Springdale, AR, USA