Table 1 shows one common vehicle speed control related problems of the 2021 Chevrolet Silverado 2500.
| Problem Category | Number of Problems |
|---|---|
| Vehicle Speed Control problems |
I own a 2021 Chevrolet Silverado 2500hd duramax diesel with approximately 100,300 miles. The truck began displaying a “service emissions system” warning and a countdown message that in a certain number of miles the vehicle will be limited in speed (for example to 65 mph). Gm’s own duramax diesel owner’s supplement explains that when a “service emission system” message appears it is accompanied by a distance-until-speed-limit countdown and that the truck will progressively limit speed first to about 65 mph and then to about 55 mph if the condition is not corrected, telling the owner to see the dealer. This creates a safety risk because the derate can occur while driving on highways or rural roads, where an unexpected limit on maximum speed can interfere with merging, passing, and keeping up with traffic. This is our only vehicle, and we must use it for important medical appointments, including cardiology and surgery-related visits. The condition started only about 300 miles beyond gm’s 5-year / 100,000-mile powertrain warranty. I opened a case with Chevrolet / gm corporate (service request no. Xxx) and took the truck to sons Chevrolet in columbus, georgia on November 17, 2025 for this issue and a rear wheel lockup recall. The dealer kept the truck from about 9:00 a. M. To 3:00 p. M. And indicated they might need to keep it for at least two more days, but I was not given a clear written explanation of the diagnostic trouble codes or a firm repair plan. Because gm’s own manuals describe this “service emission system” message together with speed-limit countdowns, and because the vehicle can actively limit speed on the road if the fault is not resolved, I am concerned this represents a broader emissions/derate defect on late-model silverado hd duramax trucks. I request that NHTSA review similar complaints and consider whether further investigation or a safety recall is warranted. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).
The contact owns a 2021 Chevrolet Silverado 2500. The contact stated that while slowing down and coming to a stop, the accelerator pedal was depressed while in drive; however, the vehicle started to roll backwards. The contact depressed the brake pedal to prevent the vehicle from rolling backwards, and the rpm became elevated to 5,000 rpm. The contact immediately turned off the vehicle to prevent the rpm from continuing to increase. The vehicle was shifted to park, restarted, and then shifted to drive(d) and the brakes released. While releasing the brake pedal, the failure reoccurred. The vehicle was immediately turned off and towed to the residence. The dealer was informed of the failure of the clutch pack, which was welded together from friction. The dealer scheduled an appointment; however, the vehicle was not diagnosed or repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 100,000.