2020 GMC Sierra 1500: adaptive cruise control problems

Filed Aug 4, 2025 · Electrical, Engine · 250 miles · OR

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving with cruise control mode set at 55 MPH, the vehicle independently accelerated to 98 MPH, and then the vehicle lost motive power. Additionally, the contact stated that the vehicle had failed to turn off upon pressing the Engine Start/Stop button. No warning light was illuminated. The vehicle was able to restart and was taken to a local dealer to be diagnosed, but the cause of the failure could not be determined. Additionally, the contact noticed that water was leaking inside the vehicle through the rear window on rainy days. The contact stated that the infotainment screen had failed to turn on as intended on some occasions, and the screen had displayed a rearview camera image while the vehicle was in drive(D) on other occasions. The contact stated that while driving at various speeds, the transmission made an abnormal sound, and the RPMs failed to decrease as intended, but suddenly dropped while decelerating. Additionally, the contact stated that the headlights, the fuel pump, and the main pulley were replaced at the local dealer. The vehicle was not repaired. The manufacturer was notified of the failure and referred the contact to the federal safety agency Hotline for assistance. The failure mileage was approximately 250.

Filed Jul 19, 2025 · Driver assistance, Engine · MA

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.

Filed Dec 4, 2024 · Acceleration, Fuel system · LA

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.

Filed Oct 1, 2024 · Driver assistance · KY

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.

Filed May 13, 2023 · Brakes · MI

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.

Filed Aug 31, 2021 · Acceleration, Driver assistance · FL

Issue 1: Front left sensor(s), after a rain, car wash and now after an oil change, continuously vibrates the drivers seat and the red light warning stays lite indicating that an obstacle is located near the left front of the truck. This has happened on several occasions and after a time both indicator stop. Issue 2: When traveling on a freeway, twice now, the cruise control suddenly disengaged or decreased mileage, as if it had detected a vehicle in front of us. There was no vehicle within a quarter mile of us front or back, nor any vehicles on the side. No debris in the road either. Usually when the adaptive cruise is set and detects something in front the icons on the dash turn orange and starts to flash. That didn't happen, rather the cruise icon changed to blue in color and the truck slowed. This I would consider a safety risk. Both instances (December 2020 and April 2021) have been reported to a dealership and noted in a file. When the customer care person attempted to get malfunction codes, nothing appeared to be wrong with the vehicle.

Filed Apr 22, 2021 · Acceleration · 16,000 miles · VT

The vehicle has made "panic stops" at highway speeds 5 times when using adaptive cruise control with no input from driver or surrounding environment I.e.. Clear road, no traffic, sun or no sun.