Here's what it says in the 2016 C-Max Owner Manual: EcoSelect is a drive mode for non-plugin vehicles designed to offer the best possible fuel economy with only a slight impact to vehicle performance and comfort. To switch EcoSelect on, press the ECO button. A graphic displays on your information display when EcoSelect is on. Your vehicle will remember the last selected mode whenever you start your vehicle. EcoSelect allows your vehicle to operate more efficiently. You will notice: • Less aggressive heating and cooling. • Softer acceleration. • More regenerative braking. • Changes in engine behavior. • ECO cruise control activation.