Check Engine Light On problems of the 2011 Dodge Ram 2500

The contact owns a 2011 Dodge Ram 2500. The contact stated that while driving at various speeds, the check engine light would illuminate on the insutrumenatl panel and the vehicle would exhibit a decrease in fuel efficiency. The vehicle was taken to an authorized dealer, where they were unable to diagnose the failure. The vehicle was not repaired. The manufacturer was notified and offered no assistance. The failure mileage was approximately 6,355.