1998 GMC Suburban Owner's Manual - Page 187

Activating the Theft-Deterrent Feature The instructions which follow explain how to enter your secret code to activate the THEFTLOCK system. It is recommended that you read through all nine steps before starting the procedure. 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. NOTE: I f yo11allow more than IS seconds to elapse between any steps, the radio autolnatically 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 to ACCESSORY or R U N . 3. Turn the radio off. Unlocking the Theft-Deterrent Feature After a Power 1,oss Enter your secret code a s follows; pause no more than 15 seconds between steps: 1. LOC appears when the ignition is on. 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. 2. Press MN and 000 will appear on the display. 3. Press MN again to make the last two digits agree 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. 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. 3-25