1997 GMC Sonoma Owner's Manual - Page 132

1. Write down any three or four-digit number from 000 to 1999 and keep it in a safe placeseparate from the vehicle. 2. Turn the ignition to ACCESSORY or RUN. 3. Turn the radio off. Unlocking the Theft-Deterrent Feature After a Power Loss Enter your secret code as follows; pause no more than 15 seconds between steps: 1. LOC appears when the ignition is on. 2. Press MN and 000 will appear on the display. 4. Press the 1 and 4 buttons together. Hold them down until --- shows on the display. Next you will use the secret code number which you have written down. 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. The display will show SEC, indicating the radio is now operable and secure. 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. The display will show REP to let you know that you need to repeat Steps 5 through 7 to confirm your secret code. 9. Press AM-FM and this time the display will show SEC to let you know that your radio is secure. The indicator by the volume control will begin flashing when the ignition is turned off. 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 toenter the correct code before INOP appears. If you lose orforget your code, contact your dealer. 3-18