I just purchased the 2018 Tucson value edition yesterday. While test driving the car with only 8 miles on it, the sales guy switched the drive mode to sport, then to normal. For a split second he was able to turn on the "eco" mode, but it turned back off. I read the manual, thinking there was a special way to activate the ECO Mode, but it just showed the cycle of Normal--> ECO --> Sport when clicking the button. I called him today and he explained that the "green light" that I saw on the dash under the RPM area may have been a different light indicator and that only some models have the option, and mine most likely doesn't. I've tried clicking it fast, double clicking, and holding down the drive mode button, but it still doesn't appear. Does anyone know if it was a system glitch or if my vehicle has it, but I just am not using it correctly?