The eco light on a Mitsubishi Mirage when on means that the car is operating in a fuel efficient manner or that you're currently driving in a way which is optimal for the best fuel economy.
When the eco light is off on the Mitsubishi Mirage it means that your using more fuel than what is considered best for the economy and are driving in a way that uses more fuel.
When the ECO light on the Mitsubishi Mirage comes on it is a good thing and means that you're getting the best fuel mileage.
The ECO light can mean one of two things depending on the model of vehicle.
ECO lights can come on when ECO Mode is on or active and it can come on or appear and disappear based on your driving habits, which can indicate an economical driving style.
Whenever you accelerate in a gentle and measured way, the ECO light on the Mitsubishi Mirage lights up.
And the more lights you get the better you're doing, and helps you develop better driving habits, which lower your fuel costs and also helps to contribute to a cleaner environment.
ECO mode when you turn it on is ideal for city driving as it reduces your vehicle's acceleration and throttle response and so keeping ECO mode on in your vehicle is not bad but it may sometimes make a vehicle feel a sluggish and unresponsive on busier roads.