Short answer: The biggest problems with the 2021 GMC Sierra are engine problems, transmission issues, and electrical system problems.
Engine problems are the most common while transmission problems and electrical system problems aren’t as common. GMC has announced seven for this vehicle.
GMC’s 2021 Sierra is a full-size pickup that many drivers rely on for towing, hauling, and everyday use. While many owners are satisfied with the truck’s capability and comfort, others have reported recurring defects that affect drivability and reliability.
Below is a summary of common 2021 GMC Sierra problems involving the engine, transmission, and electrical system.
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Common 2021 GMC Sierra Problems
2021 GMC Sierra Engine Problems
Owners of the 2021 GMC Sierra have reported issues involving rough running, stalling, and reduced engine power.
Reduced Engine Power, Stalling
- Severity: Moderate to severe; engine stalling or reduced power can leave drivers unable to accelerate normally and may increase the risk of an accident depending on traffic conditions.
- Manufacturer’s Response: GM issued recall 25V-274 for engine failure related to internal engine component defects.
- Fix: Dealers will inspect and replace the engine as necessary, free of charge to the consumer.
2021 GMC Sierra Transmission Issues
Owners of the 2021 GMC Sierra have reported harsh shifting, delayed engagement, and other drivability concerns.
Harsh Shifting
- Severity: Moderate; harsh shifting can make the truck unpleasant to drive and may point to a more serious internal transmission issue if it continues.
- Manufacturer’s Response: GM issued recall 26V-083, which addresses a defect that may cause rear wheel lockup due to a transmission control valve issue. While not directly described as harsh shifting, this recall involves transmission control components and drivability safety.
- Fix: Dealers will inspect the transmission control valve body and update or replace components, along with software updates to the transmission control module, free of charge.
2021 GMC Sierra Electrical System Problems
Owners of the 2021 GMC Sierra have reported issues involving rearview camera failures and intermittent electrical malfunctions.
Black Rearview Camera Screen
- Severity: Moderate; losing the rearview camera can reduce visibility while reversing and create a safety concern.
- Manufacturer’s Response: GM issued TSB 10234186 for rearview camera image issues such as blank or intermittent display.
- Fix: Dealers may perform software updates, inspect camera connections, and repair wiring or modules as needed.
Blank Infotainment Display
- Severity: Mild to moderate; while not directly dangerous, this can interfere with vehicle controls, camera display, and alerts.
- Manufacturer’s Response: GM issued TSB #10232070, which covers infotainment system freezing, rebooting, or blank screen issues.
- Fix: Like the previous issue, potential fixes usually involve software updates and adjusting wiring if not working.
What GMC Sierra Owners Have Mentioned
“Where do I even start? I’ve owned the 2021 Sierra for one year and in that year: Engine: replace all injectors, replace right bank lifter, replace spark plugs Cosmetic: plastic panels warping off, taillight filled with moisture, paint falling off on grill On top of all the issues, GMC and Chevy has the worst customer service to help throughout all of this. I would advice to avoid GM as a whole.”
“The Intermediate speed sensor 2 and internal transmission harness failed. The repair was to replace the internal transmission harness and intermediate speed sensor. This vehicle is a 2021 and I was told this was recalled on a 2022 only.”
“Loss of power, and knocking from the engine while driving. Check brake system, check srs, check parking brake and check engine light flashing came on at the same time. The problem has been reproduced at a mechanics shop and has been determined that cylinder 6 is dead.”
Vehicle Defects and Your Rights
Lemon laws protect consumers when a vehicle develops substantial defects that the manufacturer cannot repair within a reasonable number of attempts during the warranty period.
These laws generally apply when a defect significantly affects the vehicle’s use, value, or safety. Engine stalling, harsh shifting, camera failures, and recurring electrical problems can all support a potential claim when they continue despite repeated repair visits.
A vehicle does not need to be completely inoperable to qualify. Repeated trips to the dealership, ongoing warning lights, drivability issues, or long periods out of service may all indicate that a vehicle is a lemon.
| Affected Model | Average Lemon Law Settlement |
| 2021 GMC Sierra | $79,070 |
*Please note, the figures presented in the chart are approximations based on past case results and should not be interpreted as a prediction or guarantee. Each case is unique and requires personalized legal guidance.
Act Now and Get the Help You Deserve
If your 2021 GMC Sierra continues to experience unresolved problems, you may be entitled to compensation or a manufacturer buyback. The Lemon Law Experts can help review your case and determine whether your vehicle qualifies.
Call today at (877) 885-5366 or fill out a contact form here on our website to get in touch! We hope to hear from you soon.
