Hey Nick,

are all the "gear lights" on? In this special case you gaerbox is in an electrical emergency mode -> only third gear.

I´d the same fault a couple of month ago. First you should check your throttle-valve sensor aspecially the plug. If this doesn´t work you could check the Hall sensor on right distributer, if there is a short circuit your throttle-valve senser doesn´t work either! (Same circuit!!)

Die linke Hand zum Gruße