As the pumps in the power-assist brakes put out less vacuum power than is needed, "customers may experience increased brake pedal effort, hard brake pedal, and/or potentially increased stopping distance".
The recall comes following a lengthy investigation by the National Highway Traffic Safety Administration, which began a year ago in November. At the time the agency had nine reports of crashes that had caused two injuries.
GM said dealers will reprogram the Electronic Brake Control Module with a new calibration that will improve how the system utilizes the hydraulic brake boost assist function when vacuum assist is depleted. Owners can expect to be notified if their truck is subject to recall this month.
GM discovered the problem and reported it to the National Highway Traffic Safety Administration, according to the report. The reprogramming will activate the secondary system faster. If the problem surfaces, owners will see a message on their dashboard telling them to service the brake assist system, Flores said. Reuters reports that GM is also recalling 270,000 other vehicles in the USA, including 177,000 2018 Chevrolet Malibu cars with 1.5L turbo engines because an engine error can disable the fuel injectors and 91,000 2019 Chevrolet Express and GMC Savana vehicles due to a seatbelt-unfastened warning-light issue.