system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What exactly happens when you use the eco buttons in a vehicle? In what way does it reduce the amount of gas you waste??
gpt
It switches the priority of your onboard computer to efficiency over performance. Usually that means reducing the throttle and shifting the gears earlier when going up. There are other methods that vary by brand, Volvo will disengage from the transmission when coasting, Toyota and Hondas reduce the power of comfort features like AC or heated seats.