NHTSA Complaint #11700050 — 2019 GMC YUKON

MEMORANDUM To: National Highway Traffic Safety Administration (NHTSA) Subject: Safety Defect Report – 2019 GMC Yukon Denali 6.2L V8 (L87) with AFM/DFM I am reporting a serious and recurring safety defect involving my 2019 GMC Yukon Denali equipped with the 6.2L V8 L87 engine and GM’s AFM/DFM system. In the past twelve months, I have experienced two separate engine failures, both occurring at highway speeds and both involving valve-train/VLOM failures on the same side of the engine. In each incident, the vehicle suddenly lost power, misfired violently, and became unable to maintain speed. This created an extremely dangerous situation for my family. One failure occurred while my wife was driving; the other occurred while my [XXX] son was driving. Both were forced to maneuver across high-speed traffic with a failing engine to reach the shoulder. These events posed a clear risk of a high-speed crash, injury or even a fatality. There are hundreds—possibly thousands—of documented complaints from owners of GM vehicles with AFM/DFM-equipped engines reporting the same issues: collapsed lifters, valve failures, VLOM malfunctions, and sudden loss of propulsion. These failures often occur without warning and show a consistent pattern across multiple model years and engine variants, including the L87. The sudden loss of power at highway speeds represents a significant safety hazard. The frequency of similar reports suggests a systemic mechanical defect rather than isolated incidents. I respectfully request that NHTSA open a formal investigation into AFM/DFM-related failures in GM’s L87 and related V8 engines, with a focus on lifter, valve, and VLOM failures that lead to abrupt engine shutdown. Appropriate safety action, including a mandatory recall, should be done immediately to prevent potential injuries or fatalities. I will provide repair documentation, service reports, and other additional information. [XXX] , Esq. [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B