GMC Sierra Complaints (2020)

626 consumer complaints on file.

#11662056May 20, 2025
ENGINE
Engine started rough idle, reduced power, poor acceleration, ticking and knocking noises, and a check engine light and a few other lights came on the dash. Safety was not a risk at time of incident. Problem has NOT been diagnosed yet BUT have done a ton of research and it’s all leading towards lifter failure/misfire issues. No warning lights or symptoms prior to sudden problems.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11661868May 19, 2025
POWER TRAIN, ENGINE
This car had lifter motor failure at 135K miles and Transmission failure at 145k miles, the torque converter of this truck is the culprit of many issues as the lifter issues.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11661973May 19, 2025
ENGINE
The contact owns a 2020 GMC Sierra 1500. The contact stated that while attempting to start the vehicle, the vehicle vibrated abnormally. The engine warning light was illuminated. The contact stated that on another occasion, while driving at an undisclosed speed, there was an abnormal knocking sound coming from the engine. There was no warning light illuminated. The vehicle was towed to the dealer; however, a cause for the failure was not found. The vehicle was not repaired. The failure recurred and the contact stopped driving the vehicle. The manufacturer was not made aware of the failure. The failure mileage was approximately 110,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11661608May 17, 2025
UNKNOWN OR OTHER
I purchased a 2020 GMC Denali Sierra 1500. My oil light has came on twice and I have taken it into the dealer and dealer has said that that's normal. That car loses oil. I'm retired so I do not utilize the vehicle every day I think since I've had the vehicle I've put on several thousand miles very very low mileage put on. And I'm being told that I need to check the oil basically before I take the vehicle anywhere. During the first time when I bought the vehicle in when the light came on the mechanic said in the paperwork from GMC service that my engine oil was extremely low. This last time that I did take it in, I have some type of mechanical background, so I pulled the dipstick out and it was halfway full with oil. I took a picture of that dated the picture and said I took it in before service while when I took it into the service department of course when I came home, they said that everything's fine and so on and so on and that didn't sit well with me. So I went ahead and let the car settle. Let the car cool down several hours later. I went ahead and checked the dipstick and the dipstick was full. They went ahead and put oil into my vehicle and told me that everything's fine. And I have noticed that there are lawsuits out in regards to oil consumption issues on these vehicles. When somebody spends the amount of money they spend for these vehicles we should not have to be checking the oil almost every time we drive it. I've had multiple vehicles on 50 years old and I've never had to check the Oil like it was 1914 before you go on a trip or even drive your vehicle. I am not trying to blame the Dealership only being told that everything's fine but GMC the company needs to rectify this problem because there is going to be a time that people are going to forget about the oil and burn up an engine and then you're putting them out thousands of thousands of dollars because of a mistake GMC made they're trying to cover it up as you see with the current recall in regards t
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11661620May 17, 2025
POWER TRAIN
After the transmission recall was completed, I’m now having erratic shifting. Having the recall adding software monitoring for a hardware issue is inadequate. Now that I am out of warrentee, gm has not resolved the issue and now I am having shifting problems.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11661486May 16, 2025
FUEL/PROPULSION SYSTEM, LANE DEPARTURE: WARNING, EXTERIOR LIGHTING
My IntelliBeam function stops working sometimes, I can still use the lights as normal but the IntelliBeam function stops every so often and starts working after about 2 to 10 mins. Lane departure warning stops every so often and will start working after 1 to 10 mins, I have noticed that when it stops working at night time then the IntelliBeam function stops working also. When I press the on/off button for lane departure then it will say that lane departure is unavailable right now. I have been getting a p20ee code showing something is wrong with SCR nox sensor 2. Scan tool reveals that the sensor works normal and then stops. Once I clear the code then it works good for a few days.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11661497May 16, 2025
POWER TRAIN
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the transmission unexpectedly downshifted. There was no warning light illuminated. The vehicle was able to restart. The vehicle was taken to the dealer, where it was diagnosed and determined that the transmission had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 70,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11661225May 15, 2025
SERVICE BRAKES, ELECTRICAL SYSTEM
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?
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11660995May 14, 2025
UNKNOWN OR OTHER
Cracks in the rear sliding window plastic upper rail glass guide causing Rear window leaking water and causing mold from water leaking. GMC has a service bulletin number 18-NA-383 knowing of this issue and not telling customers purchasing the GMC vehicle. The service bulletin was released in 2019 before purchasing the truck and they still didn't inform the customers. My child rides in the back in a car seat and now has been breathing in this mold and mildew for how long. I have had my vehicle in with Titus will Gmc in olympia multiple times for service and inspection of various recalls and still didn't inform me of this issue.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11660879May 14, 2025
ENGINE AND ENGINE COOLING, ENGINE
The contact owns a 2020 GMC Sierra 1500. The contact stated while driving 5 MPH, the vehicle made an abnormal popping sound. The check engine and the ABS warning lights were illuminated. The messages "Parking Brake Service" and "ESC Service" were displayed. Additionally, the contact stated the vehicle experienced a reduced fuel range. The vehicle was taken to the dealer, where it was diagnosed that the lifters had fractured, causing damages to the engine. The dealer determined that the engine needed to be replaced, and the part was ordered. The vehicle was not repaired. The contact related the failure to NHTSA Action Number: PE25001 (Engine, Engine and Engine Cooling). The manufacturer was notified of the failure. The failure mileage was approximately 80,100.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11660582May 13, 2025
UNKNOWN OR OTHER
Tailgate unlatches unexpectedly. Has happened while parked and while driving. Almost caused accident to others.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11659914May 9, 2025
ENGINE
Motor failed with no warning, motor was replaced at a GM dealer for $12,000. Mechanic stated he believed it was a main bearing failure. Not under warranty.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11659771May 8, 2025
SUSPENSION, STEERING
The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle started pulling to the left, and the vehicle ended up in the next lane. The vehicle returned to normal functionality, but the failure became a regular occurrence. No warning lights were illuminated. The vehicle was taken to the dealer, who was unable to duplicate the failure. The vehicle was not repaired. The contact stated that the vehicle had been taken to the dealer six times because of the failure. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the NHTSA Hotline for assistance. The failure mileage was 17,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11658913May 5, 2025
POWER TRAIN
Check engine and ECM errors. The dealer replaced one bank lifter. Shortly after, a similar issue was caused by reassembly. Approximate mileage: 30 K. A month later, the same issue, but this time the vehicle was not drivable, with very low engine power. The dealer stated lifter failure and camshaft damage, engine replaced January 2024, mileage 31 K. Currently 42K and had one instance of ECM error, which only lasted a few seconds, but the engine faltered and lost power. At the most recent oil change, the dealer said no error codes were present. GM indicated that my VIN is not covered under the most current recall. Since the engine was replaced in 2024, there is virtually no possibility that the engine replacement was not a new engine and should fall under this most current recall.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11659058May 5, 2025
ENGINE
On [XXX] at around noon I was driving my 2020 GMC Sierra northbound on [XXX] 26 miles north of Moab Utah. My truck died and I attempted to coast to the next passing lane but did not make it. The shoulder was about 3 feet wide and then had a steep drop off. I pulled over as far as I could but the majority of my truck and trailer was still in the only northbound lane. The northbound traffic was forced to cross over the double yellow into the oncoming southbound traffic. The concern was getting rear-ended by northbound traffic behind me or a head-on collision with the northbound traffic veering into southbound traffic. I made several attempts to restart the truck and the dash just goes blank with no attempt from the starter. We waited for a tow-truck and about an hour into this wait Utah Highway Patrol arrived and parked behind us with his lights on warning traffic from both directions. There were no precursors to this failure or notifications. I didn’t even hear any noises. There was no physical damage or any leaking fluids. It just quietly stopped. John Elway Chevrolet informed me the bearings failed and the engine seized. I wanted to keep the core for evidence due to learning about the numerous catastrophic failures of the L87 engine I had. Keeping the seized core was going to cost me double the cost of a rebuilt one ($7000). When I asked the service Manager, Ben why its twice the cost? He said, “GM doesn't want you keeping the core and they can set whatever price they want .” I have had this truck since it was new (6 miles) and noticed unusual oil consumption early on. I would never make it to the next oil change without having to add oil, even with the very first oil change. I inquired about this with the dealer and told this extreme oil consumption was normal and given Bulletin 01-06-01-011M. I did not involve my insurance because they do not cover engine failure. I paid $12,653.97 for a remanufactured long block. Of that was $2469.93 was for parts not need INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INF
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11659060May 5, 2025
ENGINE, SEAT BELTS
Our middle seat belt has stopped working in the back seat- we have not had it replaced yet. No damage was done on it by us, but will not click into the buckle. Driving on the hi-way engine started making awful noises. We pulled over and had the truck towed to Royal Moore GMC in Hillsboro Oregon as we didn't want to cause any more harm to the engine. Royal Moore GMC informed us the engine rod bearing failed on [XXX], leading to breaching of the engine block by the rod. This caused us to replace the entire engine at the cost of over 13,000$ and no vehicle for over 3 months. (Along with engine replaced they told us we had to replace the O2 sensor as the light came on after the engine was replaced). We had to take a hardship loan to get the engine replaced, and had the truck back for 1 day before we had a o2 error l light came back on. At this time (May 5th) we are still waiting for our truck back. Royal Moore doesn't know why the engine light is on- and contacted TAC for GMC. We also contacted GMC multiple times when we were waiting for the engine. They have offered no help to us besides empty promises to call us back later. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11658829May 4, 2025
ENGINE
I was driving on the frontage road that enters the freeway when then engine suddenly failed and stalled. It lost power and seemed like it was misfiring. All the warning lights on the dashboard came on as this happened but there were no warnings lights, messages, or symptoms before this happened. The sudden loss of power posed a risk to my safety because it could have caused a crash or left me stranded. I had my vehicle towed to the Freeway Chevrolet dealer in Chandler, AZ where they inspected the vehicle and confirmed the engine had a camshaft and lifter failure.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11658708May 3, 2025
ENGINE
Engine Lifters failure. Problems with Dynamic Fuel Management System
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11658438May 2, 2025
ENGINE AND ENGINE COOLING
The contact owns a 2020 GMC Sierra 1500. The contact stated that occasionally while driving at various speeds, several unknown warning lights remained illuminated, and the vehicle lost motive power. The vehicle was taken to a local dealer to be diagnosed, and the contact was informed that DTC: P0016 was retrieved, and it was confirmed that the engine had failed and needed to be replaced. The vehicle was not repaired. The contact referenced NHTSA Campaign Number: 25V274000 (ENGINE AND ENGINE COOLING). The contact expressed a concern that the remedy was the same engine that was prone to failure. The manufacturer was notified of the failure. The approximate failure mileage was 150,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11658495May 2, 2025
ELECTRICAL SYSTEM, POWER TRAIN, UNKNOWN OR OTHER
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.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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