GMC Sierra Complaints (2020)

626 consumer complaints on file.

#11570194February 6, 2024
ELECTRICAL SYSTEM
Vehicle will not start due to known GM issues. This failure left my family stranded in cold dark unsafe area once already. If we were in the flow of traffic or had to leave an area immediately we would have been unable too. Known GM issue, engine fault code P12A6 fault code. Bulletin: PIP5719A discusses this issue. I am being told by the dealer there is a newer bulletin which advises ECM update. GM dealer is stating ECM software upgrade is required to resolve at owners expense. Owner is responsible for diagnostic fee in addition to repair costs. If the issue is not resolved vehicle may continue to experience starting failure and or other electrical problems. The night the vehicle left us stranded instrumentation was erratic and not reading properly on the instrument cluster. Very unsafe and GM should reach out to customers to inform them a software update is needed and it should not be at the expense to the consumer if the consumer is out of the bumper to bumper warranty.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11569648February 3, 2024
STRUCTURE:BODY
The back window leaks, I brought it in they told me it wasn't warranty so I paid to have it fixed. Still leaks.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11569714February 3, 2024
SERVICE BRAKES
Lost break, second time this month, showing break failed 40 mph max speed, abs light on, break light on, and 2 more light on the car with antislipiring or something like that, the another one no idea what it is
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11565626January 15, 2024
POWER TRAIN, BACK OVER PREVENTION: WARNINGS, FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING
Lifters Failed in November 2023 and had repaired major engine damage including 4 cylinders, cam shaft, lifters, gaskets etc. After major repair work done. Truck is now doing same exact thing in January 2024. The dealership is stating they will not look at the vehicle unless i buy a new battery. I asked them to try a used battery to see if that makes a difference. And then if it is the battery i will replace. I was hung up on after the technician doug Pedersen stated ill have a supervisor call you back.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11563552January 4, 2024
VISIBILITY/WIPER
Rear sliding window is leaking water into the cabin
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11563034January 2, 2024
AIR BAGS
Driving on state highway at posted speed. A deer ran into the right front and side of vehicle. Side airbags deployed. When the right side airbag deployed, it burned a hole in my passengers winter coat that completely went through the right sleeve forearm and scorched the sweatshirt that she was wearing under the coat. Smoke was visibly apparent in the cab of the vehicle. We thought the truck was on fire , then finally determined it was the sleeve of here coat.
Crash:
Yes
Fire:
Yes
Injuries:
0
Deaths:
0
#11563107January 2, 2024
STEERING
While driving, the power steering (electronic) failed. Driver Info Center gave no waring until the system failed. After failure the DEC gave a warning to "Service Poser steering".
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11560834December 19, 2023
VISIBILITY/WIPER, UNKNOWN OR OTHER
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.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11560290December 15, 2023
TIRES, TIRES:TREAD/BELT
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.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11559106December 8, 2023
POWER TRAIN
The contact owns a 2020 GMC Sierra 3500. The contact stated that after stopping at a stop light, the light turned green and the contact depressed the accelerator pedal however, the vehicle failed to accelerate as intended. The contact drove a short distance and noticed that the failure was reoccurring. The contact drove the vehicle to a safe location and turned off the vehicle. The contact exited the vehicle and noticed that the exterior of the vehicle was covered with transmission fluid. The contact stated that the transmission fluid was also on the undercarriage of the vehicle and on the ground. The vehicle was towed to the dealer where it was diagnosed with a failed transmission fluid line. The contact was informed that the transmission fluid line needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and advised the contact to report the failure to the NHTSA Hotline. The failure mileage was approximately 28,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11557049November 27, 2023
ENGINE
timing chain failure, timing chain components are available for inspection. Costly premature repair/failure. Could leave occupants stranded in unsafe environment which could lead to death. The vehicle has been diagnosed by the dealership and OEM manufacturer has been notified. There was a warning lamp.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11556481November 22, 2023
UNKNOWN OR OTHER
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.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11554317November 9, 2023
FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL:SOFTWARE
The contact owns a 2020 GMC Sierra Denali. The contact stated while driving 75 MPH, the Adaptive Cruise Control feature became inoperable. The contact stated that when the vehicle got too close to another vehicle, the Adaptive Cruise Control feature failed to activate as designed. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was not made aware of the failure. The failure mileage was approximately 6,700. The VIN was unavailable.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11553907November 7, 2023
SERVICE BRAKES, FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING
ABS LIGHT LIMITED TO 43 MPH ESC system Steering assist reduced Service Trailer Brake System Engine light on
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11547265September 29, 2023
UNKNOWN OR OTHER
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.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11546253September 24, 2023
VISIBILITY/WIPER
The rear window on this vehicle is leaking water and has been for some time. It has become quite bad and is causing an odor and discoloration in the carpet. I could not find the cause of the problem until recently with the plastic cracking more. The vehicle has 41,000 miles and the dealer stated that is out of warranty and all repairs would be a cost to me. I researched this and have found it is a common fault this this vehicle.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11543333September 8, 2023
POWER TRAIN, STEERING, SUSPENSION
The right side started clicking out of no where when I turn the steering wheel
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11542885September 6, 2023
ENGINE
I have a 202 GMC Sierra 1500 with a 3.0 Duramax with 95,000 miles. I have hade 2 glow plugs replaced under warranty and took in for a third glow plug. They stated that the there was a software update that could fix it, but I would have to pay for it. The vehicle has a 100,000 mile warranty and the software update is to fix a powertrain item that is covered under the 100,000 mile warranty. This is also an issue with bad software that disables the remote start. Not sure why I have to pay for this software upgrade to to a GM issue from day 1.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11541548August 29, 2023
ENGINE
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
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11541089August 28, 2023
SERVICE BRAKES
The contact owns a 2020 GMC Sierra 1500. The contact stated while driving 60 MPH, the service brake, check engine, and ABS warning lights were illuminated. The contact took the vehicle to an independent mechanic to be diagnosed and it was determined that the passenger’s side rear caliper needed to be replaced. The vehicle was not repaired. The vehicle was taken to the local dealer to be diagnosed, and the contact was informed that the rear passenger’s side caliper needed to be replaced. The vehicle was not repaired due to the parts not being available. Upon investigation, the contact associated the failure with NHTSA Campaign Number: 20V116000 (Service Brakes, Hydraulic) however, the VIN was not included. The manufacturer had been informed of the failure. The failure mileage was approximately 69,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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