2020 GMC SIERRA 2500 Complaints

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

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.

I was travelling south bound on the highway at 70 mph when out of no where the left rear tire failed. The tread peeled back like an alligator skin and tore apart the side of my truck and caused me to fishtail all over the highway. I was able to avoid colliding with other vehicles on the road and miraculously made it to the shoulder of the highway. The tire is a Goodyear Wrangler TrailRunner AT in a size LT275/65/R20. I still have the remaining parts of the tire. My vehicle is still under manufacturer warranty, but the GMC dealer turned me away and told me I had to deal with Goodyear directly. I reached out to Goodyear to file a claim for the tire failure and damages related to it. They have been ignoring me for over a week, so I have filed a claim with my insurance company to handle the damages. I'm currently waiting to get my truck into the shop for repairs. There were no indications of any issues with the tire. I had them rotated as recommended by the manufacturer and kept the tire pressure at the recommended levels through the dealer when my vehicle was serviced. The TPMS light came on as soon as the tire failed and lost pressure showing the vehicle tire pressure monitoring system was working properly when the tire failed.

The rear window of my 2020 GMC Sierra developed major water leaks across the entire window in 2021. GM has documented this issue with a service bulletin and the dealership has documented their resolution to the first repair under warranty. GM knows of this manufacturing issue and continued to install a faulty back window. Not only did the back window leak large amounts of water into the cab causing a potential dangerous mold issue, the security and integrity of the back window breaking or falling onto rear passengers is a major safety hazard. The integrity of the back window falling out into traffic is another safety hazard to consider. GM issued a service bulletin for leaking back windows for their Sierra trucks due to the known problems. GM has documented their problem and remedied a quick inexpensive solution. Many other GM Sierra truck owners have documented their issues and frustration with GM, and the BBB. GM has invested this issue and found the rear window plastic frame was installed or will develop stress cracked in the frame. GM’s remedy is to use a silicon window caulk and apply the silicon between the outside top section of the glass to the cab. This did not address the safety aspect of the situation. It only delayed the issue temporarily until vehicle owners were out of warranty. GM’s solution usually only last for one or two years before the issue develops again. After GM and the dearship siliconed the rear window per the service bulletin in 2021, my vehicle once again developed the same leak as before. The dealer ship once again inspected the rear window, but this time told me the issue and replaced the entire rear window because of the “stress cracks”. It’s amazing that GM wants to replace the rear window at the customer’s expense since I am out of warranty. It preposterous that GM knew of this safety issue and created a temporary correction that would last a short time until vehicle owners are out of warranty and stick them with a bill.

Rear sliding window leak and has saturated seat and carpet causing an unhealthy environment. Spoke with dealer and was told it is a design flaw and repairs are not covered under extended warranty. I was also told it is only a temporary fix and “ leak will reoccur”. I only realized of the problem when soap residue was seen on the inside of the widow. Dealer gave estimate of repair.

Low coolant light keeps coming on and dealership checks and confirms coolant is not low. The end result is the sensor In the resivor is bad and requires the entire tank to be replaced rather than just the sensor

When towing a trailer a notice to service trailer brakes comes on and the trailer brakes are disabled

Check engine came on Sunday morning the code that through was P0 526 u062F. After calling the dealer and setting maintenance to be done one day later, the truck broke down while driving on the side of the road. The dealer is saying that the belt came off and the tensioner locked up doing damage to the fan clutch and connector. The case, because the code that ran is saying that the belt wasn’t going the speed that it was supposed to because the tensioner failed. The vehicle only has 55,000 miles on it.

There is an issue that is causing the batteries to die. This in return causes the Vehicle to go into Limp home mode with no warning. The "issue" was supposed to be resolved by the Dealer in March 2022. The resolution was that one battery was bad. The vehicle is equipped with two batteries. Each of which is sufficient to run the vehicle. A single battery failure should not have caused the truck to have a power limitation. Furthermore the issue was not resolved and General Motors and the Local dealership refuse to continue to work on the issue. This is even after filling complaints with BBB. As of November 2022 the issue has cause both batteries to go bad. The dealer has refused to work on the vehicle and it has been out of service for more than 30 days. Secondary issue. The dealer has refused to work on the vehicle but computer is locked by GM so that only GM equipment can see full scope of codes. This means I can not have third parties work on the vehicle. This is can get the vehicle stuck in areas where there is not GM facilities and GM will not provide any assistance as it is not under warranty. This has also prevented me from finding the actual resolution to the problem.

1. The Engine Block heater sparked and created a small flash underneath the truck. It can be inspected whenever you would like. 2. Electric spark/fire 3. The problem has not been reproduced nor inspected by the dealer. I would not dare to plug it back in. 4. There were not any warning messages. It happened the first time the engine block heater was plugged in. February of 2022.