Sat 06-Apr-13 08:00 PM | edited Sat 06-Apr-13 08:01 PM by gfinlayson
Do you mean 'Commander Mode'? This is an operating mode for the on-board flash that allows it to wirelessly control remote CLS compatible Nikon Speedlites. It shouldn't affect shutter speed selection unless you're using flash.
Was the on-board flash popped up when you had this issue?