GMC Sierra Complaints (2020)

626 consumer complaints on file.

#11619466October 12, 2024
POWER TRAIN
Transmission failed at 75,000 miles, yes it is available for inspection. Truck went into limp mode on the highway and turned into a very dangerous situation, I was barely able to exit the highway. Yes the dealership Martys GMC in Kingston MA has confirmed that it is transmission failure. My vehicle has been sitting on the lot of Marty's GMC since September 13, 2024 waiting for a backordered part to fix the transmission at an estimated cost of $2,500. The warning check engine light followed by every single lamp on the dash appearing on [XXX] which is the date of transmission failure. After careful research of this issue I have found this is a widespread problem with this particular 10 speed GMC transmission in my 2020 GMC Sierra that I am still paying car payments on. I have rented a vehicle at my own cost for the past 4 plus weeks to get back and forth to work. 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
#11619484October 12, 2024
POWER TRAIN, ENGINE, FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING
At 103,000 my 2020 AT4 5.3L V8 had a P0307 code thrown. Cylinder 7 misfire. Driving highway speeds, sudden loud pop and then the service engine light came on and automatic braking engaged, and the idle got extremely rough. Ended up being a bad lifter, bent rod, tore lobe off of the camshaft. Roughly 8,000 for the repair, new cam, new lifters, spark plugs and coil packs. Now only about 3,000 miles later, driving, sped up to pass on the interstate and another misfire, P0306 this time Cylinder 6. Same symptoms check engine light, automatic braking, rough idle. Seems to be another failed lifter and bent rod. Currently awaiting diagnostic for this second misfire issue. When speaking with the tow truck driver and the mechanic both mentioned a significant rise in cases like this. There is definitely something wrong with the design that the manufacturer needs to be help responsible for. I have less than a month ago replaced all the lifters only to have another one fail again.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11617829October 3, 2024
ENGINE
The contact owns a 2020 GMC Sierra 1500. The contact stated that while the vehicle was parked and being driven, the vehicle was shaking violently. There were no warning lights illuminated. The contact stated that the failure was related to Technical Service Bulletin: 22-NA-186. The vehicle was taken to a local dealer, where it was diagnosed that the motor mount brackets needed to be replaced. The vehicle was repaired, but the failure persisted. The manufacturer was contacted, opened a case, and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 100,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11617607October 1, 2024
SERVICE BRAKES, HYDRAULIC
The contact owns a 2020 GMC Sierra 1500. The contact stated that the vehicle failed to start. The battery was replaced, and the failure was remedied. On another occasion, the contact stated that the brake percentage was low on the instrument panel and that the lights were becoming dim. The vehicle was taken to a dealer where the brakes were replaced; however, the computer failed to detect the repair; and the message "1 More Mile Left to Drive" was displayed. The contact also stated that two weeks later while driving 45 MPH, the brake pedal failed to respond and felt abnormally loose. The vehicle was driven over a concrete sidewalk to stop the vehicle. There was no crash, and no injuries were sustained. The vehicle was towed to the residence. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure and confirmed that the VIN was not under recall. The approximate failure mileage was 102,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11617620October 1, 2024
FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL, FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING
On two separate occasions, while traveling at highway speeds with the adaptive cruise control system on, my truck randomly started braking hard as if it was sensing a vehicle or obstacle in front of me but my lane was completely clear. The most recent time, I was almost rear ended because of this issue.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11615818September 22, 2024
SERVICE BRAKES, ELECTRICAL SYSTEM, UNKNOWN OR OTHER
My truck 2020 gmc sierra 1500 AT4 denali is not working properly since July 2024. I took it to 2 different dealership to get a diagnostic and i finally ended doing the repairs for brake issues. I have been towed 6 or more times and almost experienced 2 car accidents since I drive the truck after the supposedly repairs where done but i ended stranded again with no brakes. The dealership has repair the truck 3 times but im still getting sevaral codes the fact that i had to pay out of pocket and have to deal with this and expose myself to danger and my family in driving a vehicle that is no safety condition its absurd. I call several times the recall GM hotline and i was told GMC 1500 are included in the recalls just not the AT4 and i have a family member with the same truck and same issues she ended up trading in the truck recently since she kept experiencing the same issues over and over again just like me.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11615574September 20, 2024
SERVICE BRAKES, UNKNOWN OR OTHER
I HAVE A 5TH WHEEL WITH SOLAR AND MY BRAKE CONTROLER STOPS WORKING PERIODICALLY. I HAVE A CASE# WITH GM 9-13676268071. I ALSO HJAVE AN EXTENDED WARRANTY WITH GM AND IT'S NOT COVERED DUE TO MY VIN# NOT BEING ON A BULLENTIN# 23-NA-149. GM ALSO HAS A CUSTOMER SATISFACTION PROGREAM # N232414840 AND STILL WON'T COVER IT. THIS IS A MAJOR SAFETY ITEM AND CONCERN FOR ME.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11611486August 28, 2024
ELECTRICAL SYSTEM, SERVICE BRAKES, VEHICLE SPEED CONTROL
My brakes failed 2 times. One time I almost got into a horrible wreck with my daughter in the truck. "Brake system failure" " max speed 43mph" I have not had any brake work or anything done. The dealer is trying to charge me to replace the whole brake system when [XXX] this says to reprogram. Still waiting on gmc to tell me if it's covered under warranty. From my own research this has been a major problem for hundreds of people if not more. I could have died because of a faulty brake system or a bad software update. I need help with this and so do the countless other 2020 gm owners. There is a recall on the 2019 for the exact problem but not the 2020s. GM safety recall N192268090 please advise 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
#11610388August 23, 2024
STEERING
Without warning power steering went out. Flashed code: service power steering; service esm and traction control light. After two restarts, went away like it never happened. I was backing a 24 ft trailer at the time of occurrence. There are numerous other people with the same problem in online forums. I cannot believe that there has not been a recall or even service bulletin regarding this problem. It is a MAJOR safety concern
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11607029August 7, 2024
SERVICE BRAKES, PARKING BRAKE
The contact owns a 2020 GMC Sierra 2500. The contact stated that while driving 65 MPH, the message "Check Service Brakes Now" was displayed. The vehicle was taken to an independent mechanic, where it was diagnosed with electric parking brake malfunction. The mechanic informed the contact that the electric parking brake had been engaged unintendedly, causing the rear driver's side brake calipers to seize. The vehicle was repaired; however, the failure recurred on the rear passenger's side while driving. The vehicle was taken to the dealer, where it was diagnosed with electric parking brake circuitry failure. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 62,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11605969August 1, 2024
STRUCTURE:BODY
There is a current safety recall N232426400 on GMC pickups including the year of my truck. GMC is saying that my VIN is not covered by the recall. However, I have the multi-pro tailgate and it came open about 6 months ago on its own as i was backing up and it caused me to run into my trailer with the tailgate. I put my tailgate up after moving my truck from under my trailer and then when i went to back up somehow the tailgate popped open and i didnt know and it contacted the top of tailgate while it was down.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11604873July 27, 2024
POWER TRAIN
The AFM/DFM system in these trucks are making the engines and transmissions go out around 70k miles. The lifters fail right around the same time factory warranty runs out then your left with a 6 thousand dollar bill to have it fixed. I hope this becomes a recall because numerous people I talk to are getting rid of they're gmcs and chevys and going elsewhere.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11603243July 18, 2024
UNKNOWN OR OTHER
Well, we ended up having a problem with our transmission in our 2020 truck. I am the wife and I was driving down the highway and all of a sudden the truck started bucking and went down to 35 mph. I was in a middle lane on the highway when this happened which Was very scary! Then I was stranded along side the highway until I could get help. Here we found that our transmission went out already only after four years, which is crazy. Very crazy! We bought this truck because we were told with the weight of this truck and all that it would pull out 42 foot fifth wheel we have. So of course we did use this truck to pull our trailer and now four years later we have been without a truck because we cannot even find a transmission with our transmission code of OMEF. Now today we found a possibility which is going to cost $7000 which is Love Ludacris! We buy a $65,000 truck just for years ago and now had to put $7000 out for a transmission. Is there anything we can do to rectify this situation??
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11602485July 15, 2024
POWER TRAIN
driving 65mph on interstate, attempted to change lanes to pass slower vehicle and pressed upon accelerator pedal...truck violently skidded to a stop and sent me onto shoulder, many vehicles behind me swerved to avoid my vehicle. GM wont repair and says since they cant replicate its not really happening. this has happened twice in last 2 weeks.
Crash:
Yes
Fire:
No
Injuries:
0
Deaths:
0
#11598370July 2, 2024
POWER TRAIN
driving 65mph when vehicle attempted to downshift itself for no reason when instead the rear axles locked up and made a massively loud bang as if axle fell off, let off gas, smoke pouring from rear tires, skidded about 8 feet, it released then locked up 2 more times within 30 secs before I could get off road out of traffic flow. mfd has a tsb for this issue(#21-NA-275 GM) not sure if its transmission or braking system Dealer service could not replicate and told me it was probably my trailer(wasnt traveling with trailer) no warnings, no codes occurred initially at 56000 mile, has happened 10 or 12 times since then. very scary, im afraid to drive or tow now that dealer mentioned trailer brakes.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11598426July 2, 2024
POWER TRAIN
driving 45 mph westbound i70 at eisenhower tunnel, vefhicle made loud bang, brakes locked up momentarily slowing vehicle to around 25mph. multiple vehicles had to make evasive manuevers to avoid collision. vehicle released after a 15FT skid. pulled over to safety and inspect for damage, tires were falt spotted but no damage was visible. called dealer servcei and was told to make appt and set for diagnostic. service could not replicate or find damage so I was sent on my way and told if it does it again let us know. I am scared to drive this vehicle its unsafe
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11598428July 2, 2024
POWER TRAIN, SERVICE BRAKES, UNKNOWN OR OTHER
driving approximately 50 mph when vehicle suddenly made loud bang and locked up rear brakes for 25' coming to a stop in road side ditch, numerous vehicles had to make evasive actions to avoid me and other vehicles. flat spotted tire abut no visible physical damage. sat on side of road for transmission temp to cool down then drove to shop without repeat. called dealer was told the earliest appt was a month away. have not been able to repeat incident so far. this has happened a few times and is becoming more frequent, mfg has tsb issued but indicates they cant assist because my warranty has expired so i will have to pay 225 per hour diagnostic fee. this is untenable and dangerous. this needs a recall and repair ASAP.
Crash:
Yes
Fire:
No
Injuries:
0
Deaths:
0
#11595742June 21, 2024
STRUCTURE
The contact owns a 2020 GMC Sierra 2500. The contact stated that when the vehicle was parked, the contact's husband noticed that rainwater had entered the rear interior of the vehicle. The contact stated that the rainwater had entered through the rear sliding window. In addition, the contact stated that the aluminum casing around the rear window had fractured. The contact stated that due to the failure, the interior of the vehicle had a moldy odor. The vehicle was taken to the dealer where it was diagnosed with a fractured window frame. The contact was informed that the rear window and frame needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure. The contact was informed that the repair would not be covered under warranty. The failure mileage was approximately 69,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11595813June 21, 2024
POWER TRAIN
The transmission went at 67,000 miles and posed a safety issue when my husband was driving & suddenly couldn't drive above 1st gear. Vehicle is at the GM dealer and has been for weeks, but there have been so many issues with the transmissions of this year, make & model, that the transmissions are on back order and we are told it can be MONTHS before they get one in. The dealer already has another one that has been waiting for once since April. We know of others with this same issue on this make/model/yr, as well as engine issues, but yet there are NO recalls for this issue. The only warning that came on was when the issue occurred- no prior warning or indications. GM is involved but make no comment on why there isn't a recall for an obvious known issue.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11595566June 20, 2024
FUEL/PROPULSION SYSTEM
Fuel Pump Driver Module
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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