The contact owns a 2025 Ford F-350SD. The contact stated that while operating the vehicle, the message ‘499 Miles remaining of DEF’ was displayed. The contact indicated that the message was displayed even though the DEF was 75% FULL. The failure had occurred on several occasions. The vehicle was taken back to the local dealer who was unable to determine the cause of the failure. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 100.