THEFTLOCK® is designed to discourage theft of your vehicle's radio. It works by using a secret code to disable all radio functions whenever battery power is interrupted.

The THEFTLOCK® feature for the radio may be used or ignored. If ignored, the radio plays normally and the radio is not protected by the feature. If THEFTLOCK® is activated, the radio will not operate if stolen.

When THEFTLOCK® is activated, LOC will appear on the radio display to indicate a locked condition anytime battery power has been interrupted. If the battery loses power for any reason, you must unlock the radio with the secret code before it will operate.

The instructions which follow explain how to enter your secret code to activate the THEFTLOCK® system. Read through all nine steps before starting the procedure.

If you allow more than 15 seconds to elapse between any steps, the radio automatically reverts to time and you must start the procedure over at Step 4.

1. Write down any three or four-digit number from 000 to 1999 and keep it in a safe place separate from the vehicle.
2. Turn the ignition on.
3. Turn the radio off.
4. Press the 1 and 4 pushbuttons at the same time. Hold them down until --- appears on the display. Next you will use the secret code number which you have written down.
5. Press MN and 000 will appear on the display.
6. Press MN again to make the last two digits agree with your code.
7. Press HR to make the first one or two digits agree with your code.
8. Press AM FM after you have confirmed that the code matches the secret code you have written down. REP will appear on the display to indicate that Steps 5 through 7 need to be repeated to confirm your secret code.
9. Press AM FM again. SEC will appear on the display to indicate that the radio is secure.

Enter your secret code as follows; pause no more than 15 seconds between steps:

1. Turn the ignition on. LOC will appear on the display.
2. Press MN and 000 will appear on the display.
3. Press MN again to make the last two digits agree with your code.
4. Press HR to make the first one or two digits agree with your code.
5. Press AM FM after you have confirmed that the code matches the secret code you have written down. SEC will appear on the display, indicating the radio is now operable and secure.

If you enter the wrong code eight times, INOP will appear on the display. You will have to wait an hour with the ignition on before you can try again. When you try again, you will only have three chances, eight tries per chance, to enter the correct code before INOP appears.

If you lose or forget your code, contact your GM dealer.

Enter your secret code as follows; pause no more than 15 seconds between steps:

1. Turn the ignition on.
2. Turn the radio off.
3. Press and hold the 1 and 4 pushbuttons at the same time until SEC appears on the display.
4. Press MN and 000 will appear on the display.
5. Press MN again to make the last two digits agree with your code.
6. Press HR to make the first one or two digits agree with your code.
7. Press AM FM after you have confirmed that the code matches the secret code you have written down. --- will appear on the display, indicating that the radio is no longer secured.

If the code entered is incorrect, SEC will appear on the display. The radio will remain secured until the correct code is entered.

When battery power is removed and later applied to a secured radio, the radio will not turn on and LOC will appear on the display.

To unlock a secured radio, see "Unlocking the Theft-Deterrent Feature After a Power Loss" earlier in this section.