no , these navi sys are quite simple the disc is the series of maps the navi reader sends req. for position from sat. and applies to the map . now check your sat. reading how many is your car picking up ???? you need at least 2 but 3 for pin pointing . this can be done using the menu button on the ml command center , scroll to sys info. there should be sat. reception (a picture of a sat. and a # ) thats how many are receiving you. it takes time its not high speed access . when you install a new disc one with different maps you havbe to let the car sit outside in a open position where 3 sat. are receiving you and allow the car to find its self . calling mb usa will do nothing they will tell you the same thing i am . if no sat. are reading you andyou tried different areas of receptionyoumay have a antenna problem or possibly a navi reader .also you can fin the little picture of a sat. (in white) nottom corner of top corner of command center when you select current position in the display menu and you see a picture of a map and the little triangle which is your ml .