NHTSA widened its GM brake probe to every vehicle sharing the eBoost system
NHTSA upgraded a two-year-old Cadillac Lyriq investigation into an engineering analysis covering an estimated 1.16 million General Motors vehicles built with the eBoost brake system, plus two Honda-badged models GM builds under joint venture.
The Office of Defects Investigation opened engineering analysis EA26006 into General Motors on August 21, escalating preliminary evaluation PE24011, which it had opened on April 11, 2024 after complaints of a loss of brake assist in 2023 model-year Cadillac Lyriq vehicles.
ODI put the affected population at an estimated 1,164,820 vehicles and described the problem as failure of the eBoost system causing loss of braking and steering assist functions. Its failure report summary lists 745 incidents once duplicates are removed, of which 227 reached ODI directly and 531 came from the manufacturer, along with 22 crashes or fires, five injury incidents and six injuries. No fatalities are recorded.
GM told the agency that when an eBoost spindle fractures, anti-lock braking, stability control and traction control keep working until the vehicle comes to a complete stop, at which point those functions and brake assist are lost. The resulting condition sets one of three diagnostic trouble codes for the electronic brake control module, which trigger a chime, a “Service Brake System” message and warning lights for the anti-lock brakes, traction control and brakes. Vehicle speed is then limited to 70 km/h.
ODI said some reports it has continued to receive describe symptoms inconsistent with that account, alleging an immediate loss of brake assist rather than one occurring after the vehicle stops.
The analysis covers 2023–2026 Lyriq, Chevrolet Colorado and GMC Canyon; 2024–2026 Buick Enclave and Envision, Chevrolet Blazer EV, Equinox EV and Traverse, Cruise Origin and GMC Acadia; and 2025–2026 Cadillac Celestiq and Optiq. The Acura ZDX and Honda Prologue, built by GM in a joint venture with Honda, are included as peer vehicles.