2020 GMC Sierra 1500 Driver assistance Problems

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle decelerated to 30 MPH. The check engine warning light was illuminated. The vehicle was taken to a local dealer, where it was diagnosed, and determined that the timing belt needed to be replaced. The part was on back order. The vehicle was not repaired. The contact stated the vehicle previously experienced brake failure, sensor failure, and glow plug failure. The manufacturer was contacted, but no assistance was provided. The BBB referred the contact to the NHTSA Hotline to report the failure. The failure mileage was approximately 80,000.

NHTSA ID

11734531

Incident

Apr 16, 2026

Mileage

80,000 mi

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at 65 MPH, the DEF tank failed. The vehicle went into three phases of LIMP Mode and the vehicle unexpectedly decelerated while driving. The DEF system service message was displayed. The vehicle was taken to the local dealer, where it was diagnosed with DEF tank failure, and the tank needed to be replaced, even though the tank was full. The part was on backorder for several weeks. The contact was not provided with a loaner. The vehicle was repaired. The manufacturer was contacted and opened a case, but no additional assistance was provided. The failure mileage was approximately 70,000.

NHTSA ID

11726286

Incident

Jan 24, 2026

Mileage

70,000 mi

The brakes suddenly activate and cause the vehicle to rapidly stop with no warning of any kind and without any braking action being taken by the driver. Then, the brakes do not release and the vehicle cannot be moved as the brakes remain on. Turning the engine off and then restarting it or shifting to other gears does not release the brakes. The vehicle remains immobile and cannot be driven. After a few hours have passed, like overnight, the brakes release and the vehicle can started and driven just as if nothing had happened. A message briefly appears on the vehicle information screen each time this inadvertent braking occurs. It reads, “Brake Failure System”. These brake lockdowns occurred when driving on streets and in the driveway. No accident resulted but could have easily occurred. This is dangerous for a driver and occupants of a vehicle with this safety flaw as well as for other people and vehicles in the vicinity. This has happened five times. The last two instances resulted in the vehicle being loaded onto a tow truck and taken to a dealer of the vehicle’s manufacture. Thus far the dealership has not found what may be causing this intermittent braking problem.

NHTSA ID

11719518

Incident

Feb 18, 2026

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at approximately 35-40 MPH and hauling a trailer in stop-and-go traffic, there was white smoke coming from the exhaust pipe, and the vehicle started losing power. The contact was able to pull over to the side of the road, where the Electronic Stability Control (ESC) and the check engine warning lights illuminated. The parking brake was engaging and disengaging independently. After turning off the vehicle and waiting for approximately 15-20 minutes, the vehicle was restarted, and the contact drove to the nearest independent mechanic. The mechanic diagnosed the vehicle and determined that the ignition coils needed to be replaced. The vehicle was repaired; however, it was determined that the repair had not resolved the failure. The mechanic then diagnosed the vehicle's cylinder #4 failure. The mechanic was in the process of determining whether the lifter or camshaft had failed. The mechanic determined that the engine might need to be replaced. The vehicle was not repaired. The manufacturer was informed of the failure. The failure mileage was approximately 93,000.

NHTSA ID

11690794

Incident

Sep 27, 2025

Mileage

93,000 mi

The contact owns a 2020 GMC Sierra 1500. The contact stated that on several occasions while the vehicle was started, the check engine, brake system, and another unknown warning light illuminated. Additionally, the messages brake system failure, steering wheel failure, low oil, and two other unknown messages were displayed. The contact also stated that the rear-view camera remained displayed while shifted into drive, and the instrument panel failed to operate as intended. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 65,000.

NHTSA ID

11685227

Incident

Sep 15, 2024

Mileage

65,000 mi

My GMC had a terminal engine failure around 5/3/25. This disengaged the ESC, parking brake, and driver assist abilities as well as making the truck undrivable. GMC service diagnosed the truck needed an entire new engine. The repair took over 2 months to complete and now that I have the truck back, the adaptive cruise control is not working.

NHTSA ID

11674781

Incident

May 3, 2025

1. Lane Keeping Assistantance: The green vehicle indicator on the dashboard will disappear and stay off while driving. When it is off, it is unsafe. 2. Parking Collision Warning: The front and back sensors will disappear and become nonfunctional while driving and parking. Sometimes they activate for no reason as well. 3. Both exterior mirrors: After starting the engine to drive off , both exterior mirrors will lower automatically from my setting. After the truck is started and driven off, they must be rest again.

NHTSA ID

11673021

Incident

Dec 24, 2024

The contact owns a 2020 GMC Sierra 1500. The contact stated while driving 40 MPH, the vehicle failed to properly respond. There were no warning lights illuminated; however, the message ESC was displayed. The contact stated that the brakes, steering, and a message to check the trailer brakes was also displayed. The contact pulled over to the side of the road and the brake pedal was depressed several times however, the brakes failed to respond, and the vehicle was difficult to control. The vehicle was towed by AAA and then towed to a dealer however, the vehicle was not yet diagnosed. The contact stated that the brakes were inoperable, and the control center was destabilized. The vehicle was not yet repaired. The manufacturer was made aware of the failure and referred the contact to the NHTSA Hotline. The failure mileage was approximately 125,000.

NHTSA ID

11656277

Incident

Apr 23, 2025

Mileage

125,000 mi

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!

NHTSA ID

11652117

Incident

Mar 19, 2025

I have had no issues with my vehicle since I purchased it in July 2022 and keep up with the routine maintenance on it. About 2.5 weeks ago I was driving to work like I normally do and the truck started making a knocking noise and all these sensors lights came on the dash. The alerts were saying to service the parking brake, service ESC, and that steering assist is reduced and to drive with care. The vehicle also started shaking and would not accelerate properly or shift gears. We ended up taking it to the closest GMC dealership and they were in able to diagnose it just by simply hooking it up, they had to fully dismantle the engine in order to diagnose it. They came back and said cylinder number 4 is damaged as well as the lifters and cam shaft. I am no car expert but it is weird that a car that is relatively new and has the maintenance kept up on it should not experience a serious malfunction like this. What is even weirder is my sister in law has a 2020 Chevy Silverado where the almost identical thing just happened to theirs and it too is now in the show as well needing its engine and stuff repaired.

NHTSA ID

11640437

Incident

Jan 21, 2025

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.

NHTSA ID

11637570

Incident

Jan 17, 2025

ADDITIONAL INFORMATION RE ODI 116346689: Tried to report to GM using 800-462-8782 provided by you. Agent would not accept ANY information that I tried to provide, including year/make /model and would not confirm or deny that the issue was known by them. Agent said that the dealer would report their inability to fix the issue directly to GM, and that I could not. I have no way of knowing if the dealer made this report to GM. Calling this number was an infuriating, complete waste of time.

NHTSA ID

11637297

Incident

Jan 7, 2025

The contact owns a 2020 GMC Sierra. The contact stated that while driving at speeds over 38 MPH, and the Lane Departure Warning System was activated the seat indicator did not vibrate or sound an alert as intended. The vehicle was taken to the dealer where the software was reset but the failure persisted. The manufacturer was not notified of the failure. The failure mileage was 47,000.

NHTSA ID

11634689

Incident

Dec 23, 2024

Mileage

47,000 mi

The contact owns a 2020 GMC Sierra 1500. The contact stated while reversing the vehicle, the rearview camera image failed to display as needed, and the radio was inoperable. The vehicle was taken to the dealer, but the cause of the failure could not be determined. The vehicle was not repaired. The manufacturer was made aware of the failure and a case was opened. The failure mileage was approximately 3,500.

NHTSA ID

11630330

Incident

May 1, 2021

Mileage

3,500 mi

Shuttering while in motion at a speed of 35mph or above. My 2020 GMC SIERRA 1500 AT4 CarbonPro while driving at or above speeds of 35mph experiences a hesitation and severe Shuttering while trying to maintain any speed of 35mph or above. The hesitation causes extreme vibrations and hesitation when lifting or applying foot to the accelerator. This happens in any drive mode also with cruise control on or off as well as shifting into low and being in any gear trying to prevent it. It also does this on any road and condition. It feels like a slip in the transmission or torque converter, possibly could be the rear end or variable valve timing as well. And when taking of from a red-light or stop sign it slips as if the truck has lost traction, but it hasn't. This is very dangerous and could be the cause of a serious accident when trying to accelerate. If your traveling at hwy speeds it feels as if the brakes are being applied and the tires are going over a washboard which could cause a collision, tire wear, or driveline damage.

NHTSA ID

11628822

Incident

Feb 23, 2024

At 103,000 my 2020 AT4 5.3L V8 had a P0307 code thrown. Cylinder 7 misfire. Driving highway speeds, sudden loud pop and then the service engine light came on and automatic braking engaged, and the idle got extremely rough. Ended up being a bad lifter, bent rod, tore lobe off of the camshaft. Roughly 8,000 for the repair, new cam, new lifters, spark plugs and coil packs. Now only about 3,000 miles later, driving, sped up to pass on the interstate and another misfire, P0306 this time Cylinder 6. Same symptoms check engine light, automatic braking, rough idle. Seems to be another failed lifter and bent rod. Currently awaiting diagnostic for this second misfire issue. When speaking with the tow truck driver and the mechanic both mentioned a significant rise in cases like this. There is definitely something wrong with the design that the manufacturer needs to be help responsible for. I have less than a month ago replaced all the lifters only to have another one fail again.

NHTSA ID

11619484

Incident

Oct 12, 2024

On two separate occasions, while traveling at highway speeds with the adaptive cruise control system on, my truck randomly started braking hard as if it was sensing a vehicle or obstacle in front of me but my lane was completely clear. The most recent time, I was almost rear ended because of this issue.

NHTSA ID

11617620

Incident

Oct 1, 2024

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)

NHTSA ID

11611486

Incident

Aug 26, 2024

Back window frame crack led to water intrusion which flooded electric module controlling speedometer and adaptive settings. Extremely unsafe driving with faulty electrical components unknown to me. Insurance and Dealership told me this is a common GMC occurrence. Cost is near $10,000 to make truck drivable.

NHTSA ID

11575575

Incident

Mar 4, 2024

Lifters Failed in November 2023 and had repaired major engine damage including 4 cylinders, cam shaft, lifters, gaskets etc. After major repair work done. Truck is now doing same exact thing in January 2024. The dealership is stating they will not look at the vehicle unless i buy a new battery. I asked them to try a used battery to see if that makes a difference. And then if it is the battery i will replace. I was hung up on after the technician doug Pedersen stated ill have a supervisor call you back.

NHTSA ID

11565626

Incident

Jan 15, 2024

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

NHTSA ID

11553907

Incident

Nov 5, 2023

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.

NHTSA ID

11498998

Incident

Dec 27, 2022

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.

NHTSA ID

11473137

Incident

Jul 8, 2022

I investigated and Unintended Acceleration crash that occurred on 8-9-2021. The vehicle had just left a body shop where it had repairs to the left front of the vehicle near the ECM. The driver reported the vehicle would not slow down. He face timed a witness and showed her his foot was on the brake and not the accelerator pedal collaborating his statement. The 2020 GMC accelerated to 93 miles per hour crashing into the back of a Cadillac Escalade. Upon impact the fuel tank of the Cadillac exploded igniting both vehicles on fire and burning a fed-x truck that was folded in half from the sever impact. The EDR report stated the brakes were applied fully for a full 5 seconds prior to the crash while the vehicle was still accelerating. The accelerator was reading a constant 57% during the lead up to the crash and the brake rotors showed heat related glazing from excessive braking. The engine torque was also at 1023NM leading up to impact collaborating Unintended Acceleration further. Based on the evidence gathered my opinion is there was a short in the components in the left front of the vehicle most likely the ECM harness that caused the crash. It is unknown if the damage was caused by the previous crash, the body repairs or a manufacture defect at this time. The radiator had also just been replaced so moisture could have contributed to the malfunction. If moisture shorts APP-1 to APP-2 the safety systems can fail to detect a single fault because it causes redundant faults

NHTSA ID

11469521

Incident

Aug 9, 2021

Own a 2020 GMC Sierra AT4 with 13K miles and I owned the truck for 1 year. All of a sudden my vehicle started receiving multiple warning messages. Electronic Stability Control, Antilock Braking System, ECM, reduced Engine Power, etc. I see there was a recall for 2019 GMC Sierra's for the same issues. Why isn't 2020 GMC Sierra's not also part of that recall ? It is ridiculous that a brand new truck has these types of serious issues affecting so many vehicles. Why is GMC allowed to continue to sell later model trucks after the 2019 recall with the exact same ESC and Anti-lock Braking system problems ?

NHTSA ID

11435051

Incident

Sep 24, 2021