GMC Sierra Complaints (2021)

671 consumer complaints on file.

#11688270September 19, 2025
POWER TRAIN
Transmission failure at a little over 120,000 miles while towing a side by side on the highway. This highway has a speed limit of 80 which is dangerous when the vehicle stops working properly for myself and any other drivers in itself. Earlier this year the transmission had been updated due to a recall and was deemed to work good by the dealership but didn’t notice any difference. Had an engine light pop up a couple hours before but no messages or any other signs to inform me of the issue and was still working fine with no struggle until it gave out
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11688167September 18, 2025
POWER TRAIN
Torque Converter failure confirmed by dealer: was driving at high way speeds when I noticed a slipping sensation from the transmission upon any sort of acceleration. No warning lights were illuminated or any symptoms leading up to the failure. This could have potentially caused me to lose any form of acceleration that would enable me to get off of the highway or away from a situation requiring sudden acceleration.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11687893September 17, 2025
SERVICE BRAKES
The 2021 GMC Sierra 1500 has an Electronic Parking Brake (EPB) that bolts on to the rear calipers. The EPB does not release, in order for service, you have to long press the parking brake, then the truck goes into service mode & will release the brakes for service, some newer models may not have this feature. The vehicle has 36,000 miles on it & the inside rear brake rotors are worn down from the EPB dragging & not releasing as supposed to, causing excessive premature wear & that could cause a safety hazard fleet wide. The EPB should not be in use while the vehicle is moving, but it is coded to not release, meaning whenever you press the brake it never moves back out away from the rotor, causing drag & or even can cause warping of the rotor. I do not understand the thought process in regards to not letting the EPB release, it acts like the screw type caliper that would have the same issues of every time it moves out it will not go in until taken apart & screwed in, again meaning the brake pad is constantly dragging on the rotor which could in turn also affect the miles per gallon. I see the thought process to use EPB as useful but not a good execution by the manufacturer.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11687527September 16, 2025
POWER TRAIN
I have contacted local GMC repair facility (Frank Brown in Lubbock Tx.) about the safety recall on my 6.2 liter engine to attempt to schedule an inspection of my engine and cannot get them to inspect the engine which the recall notice said they would do. They continue to stall and say the inspection isn't approved by GM. I've tried 3 different times to address this isuue without satisfactory results. I recieved the GM safety recall N252494000 notice for my vehicle in May 2025
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11687570September 16, 2025
ENGINE AND ENGINE COOLING
The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling); however, the part to do the recall repair was not yet available. The contact then received a notice that parts for the recall were available. The vehicle was taken to the dealer, and the contact was informed that the recall remedy was for the dealer to use a higher viscosity oil. The contact expressed concerns that the remedy was not a sufficient repair and that the engine was still vulnerable to failure. The vehicle was repaired under the recall. The manufacturer was not made aware of the failure. The contact had not experienced a failure.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11687380September 15, 2025
ENGINE
Engine lifters bent a pushrod and scratched my camshaft in my engine causing me to be stranded with minor children. 3rd time since I bought this in 2021 that I have had engine faults in this truck.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11686554September 11, 2025
STEERING
My power steering completely failed. This is a safety issue and could have caused bodily harm. I have looked on line and I am not the only one with this issue, and as I investigated it shows that this issue was recall situation on earlier models. My truck is currently in the shop and looks like it will cost $5,000 to do the full repair.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11686699September 11, 2025
ELECTRICAL SYSTEM
When I’m in reverse the up the cameras turn off. On one incident I was backing up and the camera turned off causing me to back up into the wall of my house
Crash:
Yes
Fire:
No
Injuries:
0
Deaths:
0
#11686255September 10, 2025
ELECTRICAL SYSTEM, UNKNOWN OR OTHER
I am experiencing a recurring issue with my 2021 GMC Sierra where the dashboard displays a “Shift to Park” warning even though the vehicle is already in Park. This typically occurs when I attempt to shut off the vehicle. The doors unlock as expected, confirming the truck is in Park, but the warning prevents me from turning off the ignition immediately. After a few seconds, the warning usually disappears, allowing me to shut off the truck. This issue is more frequent in cold weather, suggesting a temperature-sensitive electrical or mechanical fault. Based on research and community reports, this appears to be a known issue across multiple GM vehicles, often linked to a faulty micro switch or wiring harness in the shifter assembly. I am concerned about the safety implications, especially if the vehicle fails to shut off properly or if the issue worsens over time. GM has not issued a recall for this problem, and I believe it warrants further investigation due to its widespread nature and potential risk.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11686032September 9, 2025
ENGINE AND ENGINE COOLING
The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the vehicle inadvertently lost motive power. The contact was able to pull over to the shoulder of the roadway, where the vehicle failed to restart. No warning lights were illuminated. The vehicle was not taken to the dealer or an independent mechanic. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling); the VIN was included, but parts were not yet available. The manufacturer was not notified of the failure. The failure mileage was 60,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11685727September 8, 2025
POWER TRAIN, POWER TRAIN:AUTOMATIC TRANSMISSION:INTERNAL:SHAFT:OUTPUT
The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving 15 MPH, the vehicle briefly jerked and jolted, prompting him to discontinue driving the vehicle. The vehicle returned to normal functionality, but the failure became a regular occurrence. The check engine warning light was illuminated. The vehicle was taken to the dealer, who diagnosed failures with the output shaft speed sensor and the transmission control module. The vehicle was not repaired. The manufacturer was notified of the failure but provided no assistance. The failure mileage was 89,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11685740September 8, 2025
ELECTRICAL SYSTEM, VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM
The contact owns a 2021 GMC Sierra 3500. The contact stated that while his wife had the vehicle idling with the rear defroster activated, shortly afterwards, she observed smoke coming from the plastic on the rear sliding window. After a visual inspection, the contact's wife observed that the plastic was melting, prompting her to deactivate the rear defroster. No warning lights were illuminated. The vehicle was taken to the dealer, who was unable to determine the cause of the failure. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 26,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11685257September 5, 2025
ENGINE AND ENGINE COOLING
See attached document for complaint. I am writing as the owner of a 2021 GMC Sierra 1500 equipped with the 6.2-liter engine that has recently been included in a significant recall. I've been advised that the engine may need to be replaced entirely. As you can imagine, this is extremely concerning given the scale of the defect and the vital role this truck plays i'n my dayto- day responsibilities.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11685301September 5, 2025
ENGINE AND ENGINE COOLING
See attached document for complaint.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11684939September 4, 2025
ENGINE AND ENGINE COOLING
See attached document for complaint. This law firm represents [XXX] . [XXX] owns a GMC truck with VIN: xxxxxx which is subject to the above referenced recall. Please accept this letter as Mr. [XXX] 's written complaint due to his dealer's failure to remedy the defect covered under the above referenced recall. 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
#11684406September 2, 2025
ENGINE AND ENGINE COOLING
The contact owns a 2021 GMC Sierra 1500. The contact received notification of NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experienced a failure.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11684278September 1, 2025
ENGINE
Complete engine failure on July 17, 2025, related to current recall for defective engine parts on 6.2L V8 L87 engine. Towed to dealer same day. Dealer continues to report no ETA available on replacement engine. Dealer has had possession of my unrepaired truck for 46 days now and counting.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11684017August 29, 2025
ENGINE, UNKNOWN OR OTHER
Coolant control valve failure. Instantly reduces power on truck. National back order on parts. No remedy.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11683690August 28, 2025
ENGINE, POWER TRAIN
Have owned my 2021 GMC Sierra 1500 with the 3.0 Duramax for a year and the check engine light has come on multiple times for a "Coolant Control Valve" issue. The truck runs the fans at 100% and puts the truck into reduced power at least once a day. I have read that GM sometimes will not cover this repair under powertrain warranty even though it's an engine problem. Please fix this issue! To answer the previous questions, the coolant control valve is malfunctioning, and the truck is currently at the dealer being inspected. Yes the dealer has said this issue is common on these trucks (confirmed by National GMC in American Fork, Utah). Yes the check engine light has appeared multiple times. These issues started appearing in June 2025
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11683220August 26, 2025
LATCHES/LOCKS/LINKAGES
The contact owns a 2021 GMC Sierra 2500. The contact received Manufacturer's Recall Number: N232426400, for water intrusion into the electronic gate-release switch. The vehicle was repaired. The contact stated that six months after the vehicle was repaired, the tailgate failed to operate as intended. While at the residence, the taillights and headlights were flashing. The contact also became aware that the tailgate had unlatched independently while the vehicle was parked. The message "Integrated Tailgate Open or Integrated Tailgate not Latched" was displayed. The contact stated that there was an abnormal clicking sound coming from the actuator when the tailgate opened independently. The vehicle was taken to the dealer, where it was diagnosed that there was water in the switch. The dealer informed the contact that the repairs were already made and, due to the water intrusion into the switch, the dealer refused to redo the repair under the previous recall. The vehicle was repaired. The manufacturer was notified of the failure, and denied assistance since the recall repair was already performed. The failure mileage was approximately 53,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

← Back to GMC Sierra