If you disconnect the battery in your Honda Civic for any period of time -- even if you reconnect it properly -- you might be dismayed when you get in the car later and discover that the stock radio no longer turns on. Instead, the radio's display will prompt you to enter a code. Without the code, the radio will not work. This is an anti-theft measure that makes that stock radio from your Honda Civic useless to anyone who steals it out of your car--unless they have access to your particular Civic's specific security code.
Locate your vehicle identification number (VIN); the VIN is a 17-character alphanumeric string used to identify your particular car -- no two VINs are alike. Standing outside the Civic, look through the extreme lower portion of the windshield, on the driver's side of the car, for a small, rectangular metal plate fastened to the dash. Record this number on paper. Check your work to ensure you got the VIN written down correctly.
Call your local Honda dealer or the support number located in your Civic's manual. Explain that you need the code for your radio and provide them the VIN. Write the code down and store it in a safe place. If you ever change your battery, which you or the next owner will, you'll need it again.
Turn the car ignition key to the "on" position. Enter the five-digit code by pressing the corresponding keys (preset buttons) on the radio's face.
Turn the ignition key to the "off" position then back to the "on" position to ensure that the radio functions.
