Entering radio code for 2003 BMW Z3?

To enter the radio code for a 2003 BMW Z3, first turn on the ignition and the radio. If the radio displays "CODE," use the preset buttons (1-4) to input the code: press the corresponding button for each digit of the code. After entering the full code, the radio should unlock and resume normal operation. If you don't have the code, you may need to consult the owner's manual or contact a BMW dealership for assistance.