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Do you have the right radio code?
Ok, first hook up a small battery charger. Next leave the key on for an hour or more until the word "wait" goes away and the word "code" appears. Next power down the vehicle and remove tha radio. Take the radio to BMW Parts Counter. They can look up the code for you. Install the radio and put the code in you were given. Done. If the radio wont take the code than it may have to be sent out to a radio shop. Most cases it takes the code. See below for all procedures. Im sending all the radio procedures for your year so some may not be for your vehicle, just go through them.
CLICK HERE FOR PROCEDURES