GM Service Manual Online
For 1990-2009 cars only

The theft-deterrent system is designed to discourage theft of the radio. When the radio and vehicle are turned off, the radio has a blinking red light to indicate that the theft-deterrent system is activated.

The theft-deterrent system also activates when the audio system has been disconnected from the battery. When this occurs, the AF code and security code will have to be entered in order to operate the radio. An identification card stamped with the AF code and security code will be provided with the vehicle. Keep it in a safe place, not in the vehicle.

To enter the security code do the following:

  1. Turn the ignition to ACC or ON.
  2. Turn the radio on. AF or COdE will flash on the display. If AF flashes on the display, go to Step 3. If COdE flashes on the display, go to Step 4.
  3. Enter the AF code by using the preset pushbuttons. COdE will flash on the display.
  4. Enter the security code by using the preset pushbuttons. Press the first number of the security code twice. When the security code has been entered, the code will flash three times.
  5. If the security code is not entered correctly, Err will appear on the display for a few seconds. When COdE appears back on the display, repeat Step 4.

    If the incorrect AF code is entered, an incorrect frequency level may be chosen and the radio reception may be affected. If this occurs, reset the audio system by removing and re-installing the AUDIO fuse. See "Instrument Panel Fuse Block" under Fuses and Circuit Breakers for more information. Then repeat Steps 1 through 4.