GM Service Manual Online
For 1990-2009 cars only

Theft Deterrent Feature

The AM/FM tape and the AM/FM/tape/CD radios are equipped with a programmable theft deterrent feature intended to discourage theft by causing the player to be inoperable if the theft deterrent feature is armed (in the SEC state) and the power is interrupted for more than 20 seconds between the battery and the radio. Power can be interrupted if the radio is removed from the vehicle, if the battery is disconnected, or if the 10A RADIO (BAT) fuse is removed or opened.

When the vehicle is first purchased, the radio theft deterrent feature is unarmed. The customer must program a 4-digit code to secure (arm) the radio.

The theft deterrent feature causes three main radio operating states: vulnerable (unarmed) mode, secure (armed) mode, and locked mode.

    • VULNERABLE (UNARMED) MODE- the radio does not have a four-digit code stored. If stolen, the radio will not lock and will retain normal operation when battery power is resupplied.
    • SECURE (ARMED) MODE - The radio has a four digit code stored. To deactivate the feature, the four digit code must be reentered. If battery power is removed for more than 20 seconds while in the armed mode, the radio will enter the Locked Mode.
    • LOCKED MODE - The radio has been removed from battery power for more than 20 seconds or the wrong deactivation code has been entered three times while in the Armed Mode. The radio will only return to normal operation if the code is re-entered as outlined below.

Before performing service on a vehicle, verify that the theft deterrent feature is unarmed. This can be done by turning the ignition On and turning the radio Off. Then press and hold presets 1 and 2 for 5 seconds. If the theft deterrent feature is armed, a 4-digit number will appear on the radio display. Ask the customer to deactivate the feature. If no number appears, the theft deterrent feature is unarmed and service may be performed on the vehicle.

Vulnerable (Unarmed) System: Activation Of The Theft Deterrent Feature

The AM/FM tape and the AM/FM/tape/CD radios will be in the vulnerable state if the radio is new, remanufactured, or if the theft deterrent feature has been deactivated. To activate the theft deterrent feature, the following steps need to be followed:

  1. Turn the ignition key to ON.
  2. Turn the radio power OFF.
  3. Press and hold preset buttons 5 and 6, at the same time, for 5 seconds. The radio display will show "- - - -".
  4. Have the customer select a 4-digit code. Suggest a number that is familiar to them such as the beginning of their phone number, their birth date, or their address.
  5. Enter the 4-digit code by using the SEEK/SCAN and TUNE rocker buttons. The numbers will start at 0 0 0 0 and will increase on the display each time the corresponding side of the rocker button is pushed.
  6. 5.1. Press the down arrow side of the SEEK/SCAN rocker button to change the left digit.
    5.2. Press the up arrow side of the SEEK/SCAN rocker button to change the second to left digit.
    5.3. Press the down arrow side of the TUNE rocker button to change the third digit.
    5.4. Press the up arrow side of the TUNE rocker button to change the last digit.
  7. Push the AM/FM button to store the code once the 4-digit code has been entered correctly.
  8. The display will show REP (repeat) requesting verification that the code was entered correctly.
  9. Again, enter the same four digit code by using the SEEK/SCAN and TUNE rocker buttons. The numbers will start at 0 0 0 0 and will increase on the display each time the corresponding side of the rocker button is pushed.
  10. 8.1. Press the down arrow side of the SEEK/SCAN rocker button to change the left digit.
    8.2. Press the up arrow side of the SEEK/SCAN rocker button to change the second to left digit.
    8.3. Press the down arrow side of the TUNE rocker button to change the third digit.
    8.4. Press the up arrow side of the TUNE rocker button to change the last digit.
  11. Push the AM/FM button to store the code once you are finished reentering your personal 4-digit code
  12. If everything has been entered correctly, the display will indicate that the radio is secure by displaying SEC. The radio will then return to normal operation, but will now be in the Armed Mode

If the radio displays "Err1", "Err2", or "LOCK", then the radio is already in the secure state and is armed with a different code other than the code that was entered. Proceed to the appropriate part of this Theft Deterrent section to deactivate the system if deactivation is desired.

Secure (Armed): Deactivation Of Theft Deterrent Feature When System Is Secure (SEC)

When the theft deterrent feature is secure (armed), the customer has already assigned a personal 4-digit code to the radio. While the radio is in the secure state, the theft deterrent feature will be armed and the radio will function correctly.

Before performing service on a vehicle, verify that the radio theft deterrent feature is not armed and if it is, have the customer deactivate the theft deterrent feature.

To deactivate the system, enter the 4-digit code (either the code from the customer or the factory unlock code) using steps 1 through 9 above. After completing those steps, the display will show OFF indicating that the radio is in the Unarmed Mode.

If the radio display shows an error code (Err1, Err2, or LOCK), then the wrong code was entered. After the wrong code is entered three times, the radio will lock. So if the customer's four-digit code is unknown, instead of locking the radio and having to wait an hour to try again, proceed to the "Unlocking a Locked System (Customer Code Unknown)" section to deactivate the system using the factory unlock code.

When the vehicle is returned to the customer, remind the customer to reactivate their system using steps for "Activation of the Theft Deterrent Feature."

- - - - Or Lock: Unlocking Locked System (Customer Code Known)

When the theft-deterrent feature is armed or secure (SEC), the radio can enter the locked state if the power is removed from the radio for a long enough period or if the customer has accidentally entered the wrong number three times. An error message is displayed after every wrong entry. When the radio is locked, LOCK appears on the display and all radio functions are disabled. Before another attempt at the correct code can be made, the radio must be On and the display must show LOCK for an hour. After an hour, "- - - -" will appear on the display and the correct code may be entered if it is known. Perform the following steps to retrieve the code to unlock a locked system using a known code.

  1. Turn the ignition ON.
  2. Press the power button on the radio. The display will show "- - - -".
  3. Enter the four digit code by using the SEEK/SCAN and TUNE rocker buttons. The numbers will start at 0 0 0 0 and will increase on the display each time the corresponding side of the rocker button is pushed.
  4. 3.1. Press the down arrow side of the SEEK/SCAN rocker button to change the left digit.
    3.2. Press the up arrow side of the SEEK/SCAN rocker button to change the second to left digit.
    3.3. Press the down arrow side of the TUNE rocker button to change the third digit.
    3.4. Press the up arrow side of the TUNE rocker button to change the last digit.
  5. Push the AM/FM button once the 4-digit code has been entered correctly.
  6. If the proper code has been entered, the radio will return to the armed mode and normal operation shall return. If the wrong code is entered, the display will momentarily show an error message and then return to display "- - - -" indicating that another try at the correct code can be attempted.

- - - - Or Lock: Unlocking Locked System (Customer Code Unknown)

When the theft-deterrent feature is armed or secure (SEC), the radio can enter the locked state if the power is removed from the radio for a long enough period or if the customer has accidentally entered the wrong number three times. (An error message is displayed after every wrong entry.) When the radio is locked, LOCK appears on the display and all radio functions are disabled. Before another attempt at the correct code can be made, the radio must be On and the display must show LOCK for an hour. After an hour, "- - - -" will appear on the display and the correct code may be entered if it is known. Perform the following steps to retrieve the code to unlock a locked system using a known code.

  1. Turn the ignition ON.
  2. Press the power button on the radio. The display will show "- - - -".
  3. Enter the 4-digit code by using the SEEK/SCAN and TUNE rocker buttons. The numbers will start at 0 0 0 0 and will increase on the display each time the corresponding side of the rocker button is pushed.
  4. 3.1. Press the down arrow side of the SEEK/SCAN rocker button to change the left digit.
    3.2. Press the up arrow side of the SEEK/SCAN rocker button to change the second to left digit.
    3.3. Press the down arrow side of the TUNE rocker button to change the third digit.
    3.4. Press the up arrow side of the TUNE rocker button to change the last digit.
  5. Push the AM/FM button once the 4-digit code has been entered correctly.
  6. If the proper code has been entered, the radio will return to the armed mode and normal operation shall return. If the wrong code is entered, the display will momentarily show an error message and then return to display "- - - -" indicating that another try at the correct code can be attempted.

- - - - Or Lock: Unlocking Locked System (Customer Code Unknown)

When the theft-deterrent feature is armed or secure (SEC), the radio can enter the locked state if the power is removed from the radio for a long enough period or if the customer has accidentally entered the wrong number three times. An error message is displayed after every wrong entry. When the radio is locked, LOCK appears on the display and all radio functions are disabled. Before another attempt at the correct code can be made, the radio must be On and the display must show LOCK for an hour. After an hour, "- - - -" will appear on the display and the correct code may be entered if it is known. You will only have three more chances to enter the code correctly before LOCK reappears.

If the customer code is unknown, perform the following steps to retrieve the customer code:

  1. Turn the ignition ON.
  2. Turn the radio power OFF.
  3. While pressing and holding presets 1 and 2 for 5 seconds, a 4-digit number will appear on the radio display. This 4-digit number is not the same as the customer's stored 4-digit code, but is needed before technical support is called.
  4. Record this number. It is the radio display code.
  5. Call the technical support system at 1-888-225-2306, using a touch-tone telephone.
  6. • Your retailer code,
    • The 4-digit radio display code obtained in step 4.
    • In response, you will receive the factory unlock code. Record this number.

    Important: The factory unlock code received is the same as the code that was entered by the customer.

  7. To unlock the radio and return to the secure state, follow the steps for "- - - - or LOCK: Unlocking a Locked System (Customer Code Known)." Use the factory unlock code as the "known code."