NHTSA probes brake-by-wire failures in over 1.1 million GM vehicles, including EVs

The U.S. auto safety regulator has escalated its scrutiny of GM after drivers reported losing brake assist in vehicles fitted with the company's eBoost brake-by-wire system. NHTSA's Office of Defects Investigation has upgraded the case to an engineering analysis, docket EA26006, which is the highest level of investigation the office conducts and frequently the last step before regulators press an automaker for a recall . The analysis now covers more than 1.1 million vehicles, spanning gasoline pickups and SUVs, several GM electric models, and cars GM manufactures for the Honda and Acura brands .

The technical fault sits in a spindle inside the electronic brake control module, which GM says can fracture during an anti-lock braking event. When it does, drivers report an unusually hard brake pedal and an apparent loss of power assistance, either at startup or while under way, which can require substantially more pedal effort and lengthen stopping distances . GM maintains that antilock braking, traction control, and stability control remain available until the vehicle stops, but ODI has documented reports that contradict that account, indicating some drivers lose assistance before coming to a complete halt .

The numbers behind the upgrade are what make this more than a routine inquiry. NHTSA has logged 745 incident reports, including 22 crashes or fires and five reports involving injuries . The case began in April 2024 as a narrower preliminary evaluation prompted by 2023 Cadillac Lyriq owners complaining of a rock-hard brake pedal, and has since widened by more than a thousandfold in vehicle count . Because GM builds the affected models under contract for other manufacturers, the exposure reaches beyond GM's own showrooms and into partner brands including HMC.

For investors the open question is cost and timing rather than whether something happens. A recall touching a seven-figure vehicle population carries meaningful warranty and campaign expense, and a hardware fix inside a brake module is harder to push out than a software update. Watch for a formal recall filing, GM's remedy strategy and any per-vehicle repair cost disclosure, dealer service throughput once a fix is defined, and whether the publicity slows order rates on the electric models that share the eBoost architecture. A finding here could also shape how regulators evaluate brake-by-wire designs industry-wide, which matters to every automaker moving toward the technology.

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