The National Highway Traffic Safety Administration is taking a much closer look at GM’s electronic braking system, and the scope of the investigation has grown dramatically. What began with complaints involving the 2023 Cadillac Lyriq now covers nearly 1.2 million GM vehicles equipped with the same eBoost electronic brake system. NHTSA originally opened its preliminary investigation in April 2024 after receiving reports of a hard brake pedal accompanied by a “Brake System Failure” warning. The agency’s latest action expands the investigation to all GM vehicles using the system as it tries to determine how widespread the problem could be and...