The contact owns a 2025 Cadillac Lyriq. The contact stated that while driving 5 MPH during dry weather conditions in traffic, the brake pedal was depressed but traveled down to the floorboard, and the vehicle failed to respond. The contact stood on the brake pedal; however, the vehicle failed to respond and crashed into the vehicle in front that had stopped due to traffic. In addition, the contact stated that the brake pedal jerked while it was depressed. No warning lights were illuminated, and the Crash Imminent Braking system failed. The driver-side and passenger-side air bags did not deploy. The contact suffered injuries to the back that did/did not require medical attention. No police report was filed. The contact drove the vehicle to the residence. The insurance company was not notified. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 10,000.