2020 GMC Sierra owner complaints

I started to notice changes in performance around 75k miles. Seemed like performance was subpar compared to what was the norm. Seemed to lose some power. Minimal at first, more so just recently around 90k. Oil consumption was starting to accelerate at each oil change at 75k, 80k, 85k, 90k. To the point around 85k and 90k that I would not go over even 1 mile from the 5k threshold without changing the oil. Around 90k I could tell it was not getting any better, deficiencies were accelerating it seemed. At 91k miles I started to hear clicking noises and loss of power, starts were getting rough, bouncing at idle. I stopped driving it, only driving it to the dealership where I brought for a look at it. Will be driving it again for them to do a deeper diagnostic. Many misfires at cylinder 5. PO

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving approximately 35 MPH, the vehicle lost automotive power with the check engine warning light illuminated and the message "Vehicle Might Lose Power" displayed. The vehicle remained at the residence, and the contact used a self-diagnostic tool to retrieve a fault code related to the coolant valve D. The contact determined that the coolant valve D needed to be replaced. The vehicle was taken to an independent mechanic; however, the contact was unaware of the part that needed to be fixed in the vehicle. The vehicle was repaired. The contact researched and was made aware of an unknown NHTSA Campaign Number; however, the VIN was not under recall. The manufacturer was contacted and confirmed that the VIN was not under r

Fuel management system caused a lifter to fail (stuck) which resulted in camshaft damage at 77,611 miles. GM refused to cover the repair, although there is a pending class action lawsuit against GM for this very issue. Truck was repaired at a GM dealership - Sunrise Collierville, TN. Repair costs was approximately $7,000. This occurred during a 2.5 hour road trip which put lives at risk. The truck began to vibrate, and the check engine light came on. There was no other warning before the failure occurred. No police or insurance were involved. This occurred on 9/27/25. It took the dealership 32 days to diagnose and repair the issue. Thanks.

In December of 2023 my 2020 GMC Sierra 1500 was driving down the freeway, experienced a jerking and low oil pressure. Pulled over and shut vehicle off and wouldn't turn back on, engine locked up. The vehicle received a brand new 6.2l replacement motor in April of 2024- $15k in parts and labor. This vehicle was not included in the recent recall, but obviously experienced a similar issue. This was at 75k miles. The car was owned by a different owner at the time of the engine failure. I bought the vehicle as a repo and proceeded to get the engine fixed on it.

Engine lost all power while driving highway speed. Vehicle towed to Cavender Chevrolet dealer in Boerne, TX. Dealer inspected and determined cam bearings damaged. Engine replaced with remanufactured engine.

GDI fuel pump went bad needed replacement.

The rear window was leaking a substantial amount of water soaking the back seat. Had the service bulletin done, which did not work. Then under further inspection found cracks in the rear power window track. Dealer told me GM would not cover replacement because it was out of the 3 year warranty. Then was told it would cost me 1200 dollars to replace. GM should cover this because it will lead to black mold.

The fuel pump module failed according to the dealer at 34000 miles . Car stop while driving. Cranks but no start. After resting it for hours I was able to start. Drive couple of miles about 39000 miles it stops middle of driving and couldn’t start anymore but still cranks

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.

On two separate occasions, the truck has been dead when attempting to crank. There were no lights or devices left on after the previous time the truck had been used. Something is drawing power from the battery causing it to be dead. After recharging the battery, the check engine codes read that there is a problem with 'brake light illumination.' help in determining wha t is causing the battery to die on such a new vehicle would greatly appreciated! I'm uncertain at this time as to whether or not the brake light illumination is causing a safety hazard.

The morning of December 12th, 2025 I used my vehicle to transport my daughter approximately 5 miles round trip from our home to drop her off at daycare and then I returned home. I used my front and rear defrost elements to expedite removal of heavy condensation which had formed on all windows overnight. This was approximately 7 AM. I parked my truck in the driveway and went inside until approximately 11:45 AM when I went to leave in my truck and noticed the rear sliding window had shattered. The window shattered and distributed tempered glass fragments all over the inside of the cab. Only approximately 10% of the window remained intact. I then reviewed the security camera footage from my driveway and discovered that the window failed entirely on its own with nothing hitting/striking/touchi

After having all sorts of warnings over time like "service ESC," "service parking brake," and more, I now see "brake system failure: 62 MPH top speed" flash across my dash. I am reading and hearing that this is a very dangerous problem. New truck. Brand new. Had it less than a year. Brake message always on start up.

The contact owned a 2020 GMC Sierra 1500. The contact stated that after the vehicle was purchased and while driving at an undisclosed speed, the check engine warning light illuminated. The dealer was contacted. However, the check engine light turned off, and the dealer refused to inspect the vehicle. The contact stated that while driving at an undisclosed speed, the vehicle jerked and the check engine light illuminated. The dealer was contacted. However, the warranty had expired, and the dealer refused to inspect the vehicle. The manufacturer was contacted, and the contact was offered a five-hundred-dollar coupon. The vehicle was taken back to the dealer. However, no cause for the failure was found. The contact stated that an unknown part was replaced. The contact stated that the failure p

Car was idling and parked. Warning code showed up on dashboard ESC, electronic stability control, reduced engine power. Vehicle then displayed transmission disruption, warning light displayed as well. I was able to drive it to the dealership but the performance of the vehicle was limited by the reduced engine power. Transmission was hesitating and clunky during gear changes. My sierra has 5,000 miles on it and the transmission was already replaced at 2,000 miles. GMC has a serious problem with this make and model. Unsure what the resolution will be, but I am no longer confident in the product GMC is selling.

The contact owns a 2020 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 24V797000 (Power Train); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The contact stated that there was a loud clanking sound underneath the vehicle while starting the vehicle. There were no warning lights illuminated. The vehicle had been taken to the dealer and was diagnosed with transmission failure. The contact stated that the transmission had been repaired twice however, the failure persisted. The vehicle was taken to the dealer again and the transmission was replaced. The dealer was contacted about the recall and confirmed that the VIN was included in the recall howev

While driving on the interstate at 70 mph, the transmission began to shudder. It continued the duration of the trip of 90 mins. Following day, the transmission is continuing to shudder and is now shifting hard.

Tl* the contact owns a 2020 GMC sierra 1500. The contact stated that while driving approximately 35 MPH the driver lost control of the vehicle and drove off the road and down an embankment before crashing to the ground. During the crash the vehicle sustained severe damage to the front end but the air bags did not deploy. The driver sustained head and shoulder injuries which required medical treatment. The vehicle was towed away. No police report was taken. The cause of the failure was not determined. The local dealer mayse earnhardt auto group located at 2032 s elliott ave, aurora, mo was notified of the failure. The manufacturer was not contacted. The failure mileage was 10,000.

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.

When making right turns in the dark the headlights do not cast light to the right so you can see where you are turning. This is especially a problem in the rural without streetlights it is totally black from the drivers seat looking over the right side of the hood or out the right window.

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.