Tl* the contact owns a 2016 hyundai sonata hybrid. when driving the vehicle up or down an hill, it failed to maintain the desired speed. instead, the vehicle's speed would increase or decrease 5-6 mph from the desired speed. the contact also stated that the vehicle's resume feature failed to return the vehicle back to the desired speed when driving. the feature set the vehicle at the automatic set speed of 40 mph. the contact took the vehicle to the dealer where it was discovered that the speed control only worked on high incline type of road conditions. in addition, the resume feature failed. the vehicle's computer system was reset; however, the failure recurred. the manufacturer was made aware of the failure and believed it may be part of the design feature. the approximate failure mileage was 8,000. *tr