You can enter this code by pressing the radio button on the preset menu. The most recent Honda radios have a theft deterrent feature that locks up and prevents them from starting up until a security code is entered. If an antenna is damaged, your radio will no longer receive signals from stations. This usually resolves itself by pressing the radio power button for a few seconds until the radio begins. If your Honda Accord radio detects that it has been changed or that the battery has died for some reason, you will be asked to enter a code. If this occurs, press and hold the radio power button for a few seconds until the radio begins, and there is no need to enter a code. A code is required if your Honda Accord radio detects that the battery is dying or that the radio detects that it is damaged.