GMC Sierra Complaints (2020)

626 consumer complaints on file.

#11594842June 17, 2024
FORWARD COLLISION AVOIDANCE
The contact owns a 2020 GMC Sierra 2500. The contact stated while driving 60 MPH, the vehicle independently slowed and dramatically decelerated. The vehicle returned to normal functionality, but the failure became a regular occurrence. The contact stated that when the failure occurred, the gear shifter position indicator light flashed, and once the vehicle returned to normal functionality, the light remained solid. No warning lights were illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the Forward Collision Avoidance warning sensor. The vehicle was repaired, but the failure reoccurred. The manufacturer was not notified of the failure. The failure mileage was 102,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11590544May 24, 2024
ENGINE, ELECTRICAL SYSTEM, SERVICE BRAKES, AIR:ANTILOCK
The contact owns a 2020 GMC Sierra 1500. The contact stated while driving at various speeds, the vehicle was stuck in gear. While driving there was an abnormal burning odor coming from the vehicle. The vehicle failed to start on several occasions. There were sparks from the passenger's side front seat. Several unknown warning lights were illuminated. The vehicle was taken to the local dealer, where it was diagnosed with electrical, transmission module, wiring harness, air alternator cooler, and exhaust system failures. The vehicle was repaired; however, the failure recurred. Additionally, while driving at undisclosed speeds, there was a failure with the vault meter. The OnStar system provided an error with the antilock braking system. The manufacturer was contacted, but no assistance was provided. The failure mileage was approximately 44,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11587778May 9, 2024
ELECTRICAL SYSTEM, ENGINE, FUEL/PROPULSION SYSTEM
My wiring harness which affects all systems. I was on the Interstate when out of nowhere any and all warning lights came on. The power was cut and rapidly slowed down. I also pulled into traffic and the truck just lost power. The problem was confirmed by dealership. The vehicle was inspected by dealership and wiring harness was the issue. The issues appeared out of nowhere. All the warnings lights came on at once. There has been numerous issues with this part and it’s even recognized by just.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11586679May 2, 2024
POWER TRAIN
Has happened three times. 1st and 2nd time driving down road towing trailer, rear wheels locked up for 12-15’ while driving 50-55mph. I had thought it was my trailer axel. Happened twice within 6 miles. 3rd time was 1 month later. Rear Wheels locked up driving on interstate at 70-75 mph. I estimate that i traveled 1,800 miles between the 2nd and third incident. Vehicle is at the dealership getting inspected for repairs No warning lamps before, almost every warning light came on after incident If this happened on a wet, ice, snow or dirt road this could have caused a serious accident. It would also be bad in a curve. Dealer took for road test but did not have any luck recreating the issue. They checked the differential oil And it didn't have any heavy metals. They are going to take the differential apart to inspect it to verify. They checked my battery and said it needed to be replaced. Also a wheel speed sensor needed to be replaced.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11586345May 1, 2024
STRUCTURE:BODY, UNKNOWN OR OTHER, ELECTRICAL SYSTEM
The rear sliding window leaks water inside the cab every time it rains. With water getting into the cab the issue of mold has begun and that could be a serious factor to any children or adults that ride inside the cab of the truck. There is also rust issues that are notable under the rear seats of the vehicle. Water inside the cab can also interact negatively with any electrical components of the vehicle. I tried to get ahold of the dealer and they always say they don't have time to get my truck in. I have read that this has happened to other vehicles that are the same year and model and they just fix it with caulk which does not seem appropriate for a almost new vehicle. The vehicle has not been inspected. There were no warning lamps prior to this issue. A possible symptom was that my back up camera stopped working for a day right after a rain.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11585881April 29, 2024
POWER TRAIN
I was driving approximately 60mph pulling a trailer when the back tires locked up for approximately 2 seconds. This happened 3 times within 30 minutes. I've taken it to the GM repair shop. They have seen this happen to 3 or 4 vehicles. Due to not being able to replicate the fault it has been difficult to diagnose. They are going to replace the transmission valve body hoping that will take care of the issue. This is extremely dangerous to everyone on the road when this happens. There are many forums out there that I've read and have been close to deadly accidents involving cars, trucks, RV's, and semis as they've ran off the roads. This seems to be something worth looking into and ensuring GM puts out a recall for. In my case, I am going through an extended warrant for my 2020 3500 with 112,000 miles. The warranty company wants the GM technician to replicate the fault... which isn't possible without hooking up a trailer... also very dangerous which I refuse to do until the issue if resolved. In any case, I will have to hook up a trailer once the part is replaced... praying that it won't happen again.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11582161April 10, 2024
AIR BAGS
The contact owns a 2020 GMC Sierra. The contact proceeded through the intersection when a vehicle crashed into the contact's driver's side door and wheel at unknown speeds. The contact stated that the other vehicle crashed into two vehicles, then crashed into the contact's vehicle and stopped. The contact stated that the police report stated that the vehicle that crashed into the contact was constantly moving at the posted limit of 50 MPH. The air bags did not deploy. The contact was treated for a left shoulder sprain and swollen right hand, however, it was unknown if other passengers sustained injuries. A police report was filed. The vehicle was towed to a body shop but the vehicle was not repaired. The failure mileage was approximately 34,800.
Crash:
Yes
Fire:
No
Injuries:
1
Deaths:
0
#11581595April 7, 2024
STRUCTURE:BODY, UNKNOWN OR OTHER
Rear window leak causing whole inside back to get soaked. Have paid hundreds of dollars to have sealed didn’t work. New window didn’t work it still leaks. It’s going to cause interior to mold and body to rust. Dealership and glass business both say it’s body issue and they have seen many GMC and Chevrolets with this issue. Google show 1000s with same problem.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11580419April 1, 2024
STRUCTURE:BODY
GM refuses to fix a known design flaw in the back sliding glass frame on 2020_24 gmc sierra trucks. This issue will generate toxic mold as large quantities of water enter the cabin and can be extremely harmful for certain individuals allergic to mold. GM knows about this issue and tried to secretly advise techs via TSB 18-na-383 to apply sealant on the frame and if customer returns to replace frame. However they do not want to do this outside the 3 year warranty. The back glass on a truck is not a serviceable item.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11580026March 29, 2024
SERVICE BRAKES, FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING
My vehicle inadvertently locks the rear tires at highway speeds and then releases and drives. In some instances it may brake several times causing the tires to burn rubber for a short distance causing rear traffic to either swerve to avoid rear ending me and in a couple instances causes the rear following traffic to abruptly change lanes to avoid rear ending me
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11578865March 22, 2024
FUEL/PROPULSION SYSTEM
13540028 Fuel Pump Power Control Module Part failed leaving me stranded and had to get a tow. When the failure occurred, vehicle would not crank and there was no forewarning. It worked and then it didn't. The part is on notional backorder and there seems to be a lot of vehicles out there with the same issue and that just with the mechanics\service departments I've contacted that have had the part on backorder for months. So the fail rate seems high and I'm sure others got stuck in a lot worse situation than me. Then GMC continues to produce vehicles with a newer similar part while not producing the same part for like new vehicles. Which will probably only compound the backorder issue when the newer vehicles eventually have the same issue.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11576776March 12, 2024
ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL
See attached document for complaint
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11575910March 6, 2024
ENGINE
Vehicle has excessive oil consumption. Within 5000k oil change interval, no oil on dip stick around 3000k miles.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11575575March 5, 2024
ELECTRICAL SYSTEM, VEHICLE SPEED CONTROL, VISIBILITY/WIPER
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.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11574977March 1, 2024
STRUCTURE:BODY, ELECTRICAL SYSTEM, UNKNOWN OR OTHER
Tailgate fell down when I had a trailer hooked up. I was parked, then backed up the trailer. Tailgate came down on the jack and scratched the tailgate. There is a recall on some trucks but mine says no recall. Sounds like same issue.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11573939February 26, 2024
FUEL/PROPULSION SYSTEM
Fuel Pump Drive Control Module (Part No. 13540028). This item is a recall on several other vehicles, but not identified on my year/model. On 4 separate occasions over a 3-4 week period, the engine starting running very rough lost power and stalled while traveling down the road (highways, interstate, and a side street). I was finally able to pull a fault code and research the history of this code and this part on several other GMC/Chevy modeled vehicles. The dealer advised I was lucky to find the part because most of them are on backorder due to the recall on other vehicles. The one I got was for a recall, but the customer hadn't returned in time so they sold it to me. I had a repair garage replace the component on Jan 13, 2024, and haven't had any repeat issues. The check engine light did come on each time with a P129F code. It would reset after the vehicle stalled and was powered off for 10-15 minutes and the symptoms would go away. Each time left me lucky to get my vehicle over several lanes and off the side of the road. The date below was the last time it happened. The first time it happened was on Dec 6th and the vehicle started back up in just a minute or two. I still have the old part if it needs to be sent and evaluated to compare with other recalls on the item in other vehicles.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11572789February 19, 2024
STRUCTURE:BODY
Rear Sliding Glass window frame has cracked and allows water to enter the cab of the vehicle. Yes this is available for inspection. The water entering the cab of the vehicle can create mold from moisture build up if left untreated. I was able to have the dealer service center confirm the issue noted in [XXX] but they were unable to repair it as it is outside of warranty. I was able to have an independent 3rd party glass company confirm that it was indeed a manufacturers defect with a cracked housing and not an issue with sealant around the glass itself. No warning lamps or other indications other than water in the back seat of the vehicle. 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
#11572065February 15, 2024
ENGINE
1. Valve Lifter Failure 2. While entering the [XXX] freeway and trying to merge into traffic the engine lost power and I had to swerve and brake to avoid an adjacent vehicle, and freeway traffic had to avoid my slowing down to pull over. 3.Yes, Van GMC in Scottsdale, confirmed lifter failure. 4. Yes, GMC Dealership 5. Absolutely no warning given 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
#11572201February 15, 2024
STRUCTURE:BODY, UNKNOWN OR OTHER
Rear Window Leaks due to failed sealing at the factory. If not fixed will ruin interior components and possibly rust. Yes No No
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11571977February 14, 2024
VISIBILITY:GLASS, SIDE/REAR:CRITICAL FASTENERS
The contact owns a 2020 GMC Sierra 1500. The contact stated while detailing the rear interior of the vehicle, the contact discovered water surrounding the rear windshield casing and the water was leaking into the rear seating. Additionally, the rear carpet was soiled with water. The contact used towels while attempting to soak up the water. The vehicle was taken to the dealer where it was diagnosed that the failure was due to the failed rear windshield glass fasteners. The contact was informed that the failure had damaged the rear carpet, padding, and the rear seat. In addition, the contact was informed that the carpet and padding needed to be replaced due to mold build up. The contact was informed that the vehicle was out of warranty coverage. The vehicle was not repaired. The manufacturer was made aware of the failure but provided no assistance. The failure mileage was approximately 31,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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