General Motors is under increased federal investigation due to brake system issues affecting many of its electric vehicles, including some models developed with Honda. The U.S. National Highway Traffic Safety Administration (NHTSA) escalated its probe after receiving hundreds of incident reports, including more than twenty crashes or fires and at least six injuries. The problems are mostly linked to GM’s proprietary “eBoost” brake-by-wire system, which replaces the traditional mechanical connection between the brake pedal and brakes with electronic controls. Over a million vehicles could be impacted, including popular EVs like the Chevrolet Blazer EV, Equinox EV, Cadillac Lyriq, and some models from Buick and GMC.

NHTSA initially began investigating in April 2024 following complaints from owners of 2023 Cadillac Lyriq models who experienced brake warnings and failures. Despite GM conducting internal investigations pointing to fractured spindles within the eBoost system as a root cause, the agency has continued to receive reports of sudden loss of brake assistance during active braking. These incidents raise concerns because they could significantly extend stopping distances and increase the risk of serious collisions or injuries. As a result, NHTSA’s Office of Defects Investigation has upgraded the inquiry to an “engineering analysis,” which is the agency’s most thorough investigation phase and often precedes mandate of a vehicle recall.

GM acknowledged the heightened scrutiny but maintained that its internal reviews concluded the brake issues do not pose an unreasonable safety risk. The automaker emphasized its commitment to customer safety and pledged full cooperation with NHTSA’s ongoing investigation. Since the eBoost technology’s debut in 2019, it has been incorporated into a growing number of GM’s EVs and several joint venture models with Honda, further multiplying the scale of potential impact. A notable example is the Cruise Origin autonomous vehicle, which also used eBoost before GM discontinued the project in 2024.

Some individual crash reports illustrate the severity of the problem, such as a 2025 Cadillac Lyriq driver who lost braking while parking and crashed into a store, and a 2024 Blazer EV driver who had to ram a concrete curb to avoid a catastrophic collision at an intersection. These cases highlight the urgent need for NHTSA’s in-depth technical review and possible corrective action by GM. For now, the investigation continues as authorities assess the full extent of the brake system’s failures and the best way to safeguard drivers of the affected vehicles.