2021 GMC Sierra 1500 Reliability Score & Common Problems

Owners of the 2021 GMC Sierra 1500 frequently report engine-related issues, with many mentioning abnormal shaking, loss of motive power, and engine stalling. Symptoms often include illuminated check engine lights and unusual noises such as knocking or metallic sounds. These problems are often reported at mileages ranging from approximately 20,000 to 137,000 miles. Multiple owners describe their vehicles being towed due to the inability to restart, and some report prolonged waiting periods for recall-related repairs. While no crashes or fires are explicitly mentioned, the loss of power while driving could have safety implications, making this a critical consideration for potential buyers.

Owners of the 2021 GMC Sierra 1500 frequently report issues with the power steering system, including sudden loss of power steering assistance and steering wheel lock-up, often accompanied by warning messages such as "Service Power Steering" and "ESC." These problems are commonly observed around 13,000 to 80,000 miles, with some reports indicating parts backorders for necessary repairs. Safety implications are significant, as one complaint involves a crash resulting from steering and brake failure, and others describe near-miss situations due to loss of steering control. Additionally, some owners mention loose steering components and complete separation of the steering wheel, which could pose serious safety risks. Buyers considering this model should be aware of these potential issues and the associated repair challenges.

Owners of the 2021 GMC Sierra 1500 frequently report issues with the vehicle's engine, transmission, and various electronic components. Common symptoms include sudden loss of power, fluctuating engine temperatures due to coolant control valve failure, and erratic transmission behavior such as bucking and jerking. These problems often arise at varying mileage, with some occurring as early as 16,000 miles. Safety concerns are prominent, with reports of engine failure leading to loss of propulsion, and one instance of a fire originating from the air vents. Additionally, one crash was reported due to potential camera system calibration issues. Buyers should be aware of these recurring issues and the potential safety risks associated with this model.

Owners of the 2021 GMC Sierra 1500 frequently report issues with the electronic parking brake (EPB) not releasing properly, leading to premature wear on brake rotors and pads. Complaints often describe symptoms such as unexpected braking, difficulty in releasing the brakes, and warning lights indicating brake system failures. These issues are typically noted at mileage ranging from approximately 21,000 to 36,000 miles. Safety implications are highlighted by reports of brakes failing entirely, leading to a crash in one instance, and instances of brakes seizing while driving. Additionally, several owners mention problems with trailer brake controllers disconnecting, which could compromise towing safety. These patterns suggest potential reliability concerns for used car buyers considering this model.

Owners of the 2021 GMC Sierra 1500 frequently report issues with the vehicle's tailgate, particularly with the inner tailgate door failing to open or spontaneously opening, which could potentially lead to cargo falling out. Some complaints mention that these tailgate issues occur around 6,000 to 45,000 miles. Additionally, there are reports of water leaking through the rear sliding window and structural vibrations due to a detached dash line, with some cases leading to further mechanical diagnoses. While no crashes or fires are reported, the tailgate malfunction poses a potential safety risk if cargo falls onto the road. Buyers should be aware of these issues, especially if considering vehicles within the mentioned mileage range.

Owners of the 2021 GMC Sierra 1500 frequently report issues with the airbag system, including non-deployment during collisions and intermittent "Service Safety Restraint System" warnings. Two complaints involve crashes where airbags failed to deploy, with one incident resulting in an injury and smoke in the cabin. Other reports describe warning lights indicating potential airbag malfunctions, often occurring shortly after service visits or with low mileage, as seen with vehicles under 5,600 miles. These symptoms suggest potential safety implications, particularly in crash scenarios, making it crucial for prospective buyers to be aware of the airbag system's reliability concerns.

Owners report several issues with the fuel and propulsion system of the 2021 GMC Sierra 1500. Commonly mentioned problems include fuel tank leaks and injector failures, with one owner detailing violent shaking during acceleration following an injector failure. Some complaints also highlight issues with the DEF system, where alerts for insufficient fluid levels occur despite the tank being full, and related repairs can be costly. Another owner notes intermittent power loss and multiple warning lights, including check engine, airbag, and traction control, with the vehicle having less than 200 miles. These issues appear at varying mileages, from a few hundred miles to over 74,000 miles, and may lead to potential safety concerns like power loss.