If by "off" you mean the screen is dark, try pressing and holding the volume button. That's the full system on/off toggle, as opposed to just radio on/off with a short press.
If by "off" you mean the screen is dark, try pressing and holding the volume button. That's the full system on/off toggle, as opposed to just radio on/off with a short press.
@Mickben
Try reset button as sugested by Merlin......press and hold for more than 1 second. If still no display then possibly a fuse....check cluster to lower right of steering wheel.