Unlocking a Radio That Displays LOC When Code is Unknown

IMPORTANT: Starting in 1995, a factory back-up code can be used to erase the original code if it is unknown.

Have account number ready to enter when asked. Account number is your 5 digit dealer code followed by one of these numbers:
^ Chevrolet - 1
^ Pontiac -2
^ Oldsmobile -3
^ Buick -4
^ GMT -5
^ Cadillac -6
^ GM Canada -7
^ Saturn -8

Read all steps before starting the procedure.

If more than 15 seconds elapse between any of the steps, the radio automatically reverts to time and you must start the procedure over from step 1. In order to unlock the Theftlock(TM) system when code is unknown, perform the following steps:
1. Press and hold push buttons 2 and 3 until a three digit code appears on the display.
2. Write the three digit code on a piece of paper.
3. Press the AM/FM push button, a three digit code will appear on the display again.
4. Write the three digit code on a piece of paper.
5. Call Delco Electronics at 1 - 800 - 537 - 5140.
6. Follow the computer prompts to obtain the back-up code to be used in place of unknown code.
7. Press MN for Yukon, Denali / SEEK right button for Escalade and 000 will appear on the display.
8. Press and hold MN for Yukon, Denali / SEEK right button for Escalade until the last two digits agree with the back-up code.
9. Press and hold HR for Yukon, Denali / SEEK left button for Escalade until the first one or two digits agree with the back-up code.
10. Press the AM/FM push button after you have confirmed that the code matches the one you wrote down. If REP appears on the display, repeat steps 7 through 10.
11. The display will show "- - -"to indicate unknown code has been removed.

If the back-up code does not unlock the radio, try reversing the first and last three digits of the display code.

If this is unsuccessful, call Delco Electronics to obtain a new factory back-up code.