The 2003 Honda Civic radio came with a standard theft-deterrent feature for EX and LX models. This feature disables the radio if it should lose its power connection, such as from a dead battery. A code is required to unlock the radio, which was supplied on a card with the original owner's manual at the time of purchase. If you no longer have the card, call a Honda dealer to obtain the original code.
Turn on the Civic to power the audio system. The radio should read "Code" in its display to signify that a code is necessary to deactivate the theft-deterrent system.
Enter your five-digit password into the radio by using any of the numbered preset buttons. The preset buttons are labelled one through six.
Listen for the radio to start playing. If it does not, "Code" should read in the display again. Try to enter the correct code again.
Go to the Honda Owner Link website to get your passcode online or access your owner's manual for more information. Sign-up is required.