It really is a dealer thing. It's part of what Toyota calls Customizable Body Electronic Settings, or C-BEST. You need to have a Toyota OBD scan tool to change it.
Toyota seems to be getting away from C-BEST and they're moving more toward the really wacky sequences of turning the key on and off and hitting buttons. That would allow DIY changes. I would imagine that the next gen 4Runner will have more DIY settings.