Not sure but on mine (import) it's a Snow/Power button.
Probably the same as yours.
Only down side is, i keep knocking it onto snow when i stop at lights etc.
Pulls away slowly all the time.
Need to knock it into neutral and then switch it off.
Am i right in thinking that is only on automatics. Otherwise it is blank
Ah, that might be it...
I never mentioned it was an automatic.
It has Traction control as well.
Is it a manual then?
http://www.350z-uk.com/topic/16915-snowatpower-button-whats-it-do/