How do you enter the code for Mercedes-Benz e320?

To enter the code for a Mercedes-Benz E320, turn on the ignition without starting the engine. Use the radio controls to input the security code; usually, you need to press the corresponding buttons for each digit of the code. Once all digits are entered correctly, press the "OK" or "Enter" button to confirm. If entered correctly, the radio will unlock and resume normal function.