ECO stands for Economic Cooperation Organization.
CARS.COM — Hyundai's Active Eco mode is a feature that allows the vehicle to perform at its optimal level. In short, this mode controls the vehicle's shifting patterns to decrease fuel consumption. If you're a Hyundai Sonata owner, for example, you may be wondering when you should be using this eco mode setting. The short answer: Owners should use this energy-saving mode whenever they want to save fuel — which theoretically should be all the time.
Active Eco Mode, engaged by a dashboard switch to the left of the steering wheel, modifies engine operation so you get more gradual acceleration, and the transmission tends to shift to higher gears sooner and isn’t as quick to automatically downshift for passing.
This mode also cuts off the fuel supply during deceleration, and Hyundai says all this electronic management can increase fuel economy as much as 7 percent.
When driving in this mode, the Active Eco system restricts engine and transmission performance in favor of fuel economy. So when you turn on Active Eco mode, your Sonata may feel less responsive accelerating up a hill or when trying to pass cars on the highway. You can also turn it off if you’d rather burn rubber instead of saving fuel. Active Eco is standard on the Sonata SE and Limited and included with the optional automatic transmission on the GLS.
The Sonata also has a green Eco indicator light in the gauge cluster that illuminates and acts as a pat on the back when the car is being driven for maximum fuel efficiency, meaning that you are going light on the gas pedal on your own without the help of Active Eco settings.