1. Find your radio code. You can find it by looking in the owner's manual booklet or by contacting your nearest Mercedes dealership. If you provide your vehicle's VIN number and proof of ownership, the dealership can give you your radio code.
2. Turn on your Mercedes C220, so that the radio is powered.
3. Enter the five-digit code when the radio asks you. You will see a phrase like 'Enter Code' appear on the radio screen. Use the numbered radio buttons to enter the code. Shortly after, your radio will unlock and can be used.