The only button down there that I can think of is like one on my 2005 Prius. It controls whether or not you need the key inserted into the dash to start the car. On mine, I always have it so that the key stays attached to me in a pouch and never goes into the dash. That way, if someone tries to carjack my car by pulling me out and jumping in, he'll only get a little ways before the car stops as it is no longer in the vehicle (or near it). If you have (what is called) a key less ignition and don't usually put the key fob in, try pushing the button once and without putting that fob into the dash slot, see if it starts. If it does not start, push the button again, and with the key fob still not in the dash slot see if it will start then. My little button is a small black button near the center underside of the dash.