GMC 1994 Sonoma Owner's Manual page 135

8. Press BAND and 000 will appear 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 rEP will appear for 5 seconds and then 000 will
appear.
the radio is secure.
11. Repeat steps 6 through 10. This time SEC will appear-indicating
that
To Unlock The System After A Power Loss
When battery power is reapplied to a secured radio, the radio won't turn on
and LOC will appear on the display.
Enter your secret code as follows: pause no more than 15 seconds between
steps.
1. Turn the ignition on. (Radio off.)
2. Depress the SET button. The display will show
000.
3. Enter the six digits of the code following steps 6-9 above. The display
will show the numbers as entered.
4. Depress the BAND knob and the time appears
-
indicating that the
disabling sequence was successful. If the display indicates SEC, the
numbers did not match and the unit is still secured.
Disabling The Theft System
1.
2.
3.
4.
5 .
6.
Depress presets 1 and 4 for 5 seconds with ignition on and radio power
off. The display will show SEC, indicating the unit is in the secure
mode.
Depress the SET button. The display will show 000.
Enter the first three digits of the code following steps 6 and 7 of the
preceding paragraphs. The display will show the numbers as entered.
Depress the BAND knob. The radio will display 000.
Enter the second three digits of the code. The display will show the
numbers as entered.
Depress the BAND knob. If the display shows
"-
- -
", the disabling
sequence was successful. The numbers matched the user-selected code
or the factory back-up code, and the unit is in the UNSECURED mode.
If the display shows SEC, the disabling sequence was unsuccessful and
the numbers did not match either of the codes and the unit will remain
in the SECURED mode.