NHTSA Escalates GM Brake Probe as Field Reports Contradict GM's Diagnosis

NHTSA upgraded its GM brake investigation to an engineering analysis after field reports of sudden brake-assist loss did not match GM's identified cause: eBoost spindle fractures. The gap points to a second, uncharacterized failure mode. The probe covers over 1 million vehicles, hundreds of incidents, 20-plus crashes or fires, and at least six injuries.