GMC 1996 Sonoma Owner's Manual page 125

Locking the Theft System
1. Write down any six-digit number and keep it in a
safe place separate from the vehicle.
2.
Turn the ignition to the ACCESSORY or
RUN position.
3. Press POWER to turn the radio off.
4. Press the I 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.
5. Press SET and 000 will appear on the display.
6. Press SCAN to make the first digit appear.
7. Press SEEK right arrow or SEEK
left arrow to
make the next two digits agree with your code.
8. Press BAND and 000 will appear on the display
again. Now you are ready to enter the last three
digits of your code.
9. Repeat Steps 6 and 7 for the last three digits of
your code.
10. Press BAND and the display will show REP for about
five seconds and then 000 will appear on the display.
1 1.
Repeat Steps 6 through 10. This time the display will
show SEC to let you know that your radio is secure.
Unlocking the Theft System After a Power Loss
Enter your secret code as follows; pause no more than
15 seconds between steps:
1.
2.
3.
4.
5 .
6.
7 .
Turn the ignition on with the radio off.
Press SET and 000
will appear
on
the display.
Press SCAN to make the first digit appear.
Press SEEK right arrow or SEEK left arrow to make
the next two digits agree with your code.
Press BAND and 000 will appear on the display
again. Now you are ready to enter the last three
digits of your code.
Repeat Steps 3 and 4 for the last three digits of
your code.
Press BAND after you have confirmed that the code
matches the secret code you have written down. The
time will be displayed indicating that the system is
disabled. If the display shows SEC, the numbers
entered did not match your secret code and the unit
is still secured.
When battery power is given to a secured radio, the
radio won't turn on and LOC will appear on the display.
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