Among the requirements for ECO to function:
Climate control should be set to auto
Engine is warmed up
Vehicle interior set temp is reached
Battery is charged
Windshield is not fogged up
Hood is closed
Driver's seat belt is fastened
Foot is on brake or car is in park
Steering wheel is not being turned
I get a kick out of mine but I turn it off in stop and go traffic. The eco starts the car very fast, faster then when I first start the car. Also, the MB system worked better than the *** (Automatic Start Stop) system in the BMW I tested. I noticed the BMW salesman turned it off as soon as I started the BMW I had to turn it on.
But I wonder does it use the car's engine compartment battery or is there another battery? Like what is that box in the trunk beside the spare tire?