The contact’s wife owns a 2019 GMC Terrain. The contact stated while driving 70 MPH and depressing the brake pedal, the brake pedal was firm, and the vehicle failed to respond as needed. The check engine warning light was illuminated. The contact stated that upon depressing the brake pedal with excessive force, the vehicle responded as needed. The contact stated upon inspecting underneath the brake booster, the contact noticed a lot of debris due to lack of vacuum pressure. The dealer and the manufacturer were notified of the failure and referred the contact to the NHTSA Hotline to report the failure. The vehicle was not diagnosed or repaired. The failure mileage was approximately 80,000.