Ever stare at that spot on your dash that has a piece of plastic where a button should be? Ever wonder what that button would do if it were installed? More and more Prius owners are finding out that that empty spot on their dashes is occupied on Euro-spec Prius models by a button that switches the hybrid into electric-only mode while driving locally at low speeds.

While North America Prius cars can be powered solely by their electric motors at low speeds, anyone who has driven the king of hybrids in the States knows that operating in EV mode for extended periods is nearly impossible. Any adjustment of the throttle is immediately interpreted by the onboard computer as acceleration, which instantly calls upon the gas engine for assistance.

Toyota claims that this feature was disabled for the North American market because U.S. law mandates a minimum 8-year warranty on the hybrid drivetrain, which includes the battery pack. By disabling the option of operating solely on battery power for extended periods the company can better assure a longer life for the car's battery pack, despite the fact that much better fuel mileage is being sacrificed.

Fear not, though. The Prius has already proved to be immensely hackable and computer geeks have already discovered how to enable that missing button's function in North American models. This article from CNET also shows how far Prius hacking can go, including one that allows the nav system to be operated at speed as well as while the vehicle's in Park.

BTW - We're not entirely certain that button we circled above is the missing one in question. Any enlightenment our Euro readers could shed on the button and its exact whereabouts on the dash would be greatly appreciated.

Fear not, though. The Prius has already proved to be immensely hackable and computer geeks have already discovered how to enable that missing button's function in North American models.