The contact owns a 2010 Hyundai Elantra. The contact stated that while her son was driving 25 MPH and depressing the accelerator pedal, the vehicle failed to respond as needed and the engine seized. The contact stated that while her son was attempting to start the vehicle, he heard a rattling sound coming from the engine. There were no warnings light illuminated. The vehicle was towed to an independent mechanic where it was diagnosed that the engine had failed, and an undisclosed part connected to the timing belt had detached and the engine needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure and informed the contact that because the NHTSA had not completed the investigation into the failure, a recall was not issued. The approximate failure mileage was 99,500.