19NA273

Bulletin No.:
Service Bulletin
Date:
19-NA-273
December, 2019
INFORMATION
Subject:
Information on Procedure to Unlock Delco Radio with Theftlock
This bulletin replaces PIC4696E. Please discard PIC4696E.
Brand:
Model:
All GM
Passenger
Cars
All Delco
Theftlock
equipped
vehicles
Model Year:
VIN:
from
to
1994
2002
from
to
Engine:
Transmission:
All
All
Involved Region or Country
United States, Canada, Mexico, N.A. Export Regions
Condition
Some customers may comment that after a loss of power to the radio, the Delco Theftlock
radio is locked.
Correction
Unlock the radio using the Service Procedure below.
Service Procedure
Note: Please read the following carefully! There are
time limits associated with some of these steps.
Therefore, if the directions are not followed properly,
unnecessary wait time will occur. The mode the radio
theft deterrent system is in will determine which steps
to be followed.
The Theftlock logo will appear on the face plate of the
radio to indicate this radio has the protection of
Theftlock. The Pontiac, Buick, Chevrolet and Light
trucks will have an indicator light that blinks when the
vehicle is off and this feature is activated. Oldsmobile
radios do not have this indicator. The feature is
activated by the customer programming a code into the
radio. Instructions are in the vehicle Owner Manual.
The procedures in this section explain how to operate
the theft lock security system. This includes unlocking
the radio, removing and entering customer's code,
obtaining the radio display code, and changing the
customer's code.
Radio Display Definitions:
LOC: The radio is locked and there is a customer code
stored in the radio.
InOP: Too many wrong codes have been entered and
the radio must be left on up to one hour with battery and
ignition applied before three more attempts can
be made.
Copyright 2019 General Motors LLC. All Rights Reserved.
Note: Install a GM Authorized power supply charger to
maintain system voltage. Refer to
www.gmdesolutions.com for further information. If not
available, connect a fully charged 12V jumper or
booster pack disconnected from the AC voltage supply.
DO NOT connect a battery charger.
SEC: There is a customer code stored, but the radio is
unlocked.
- - -: There is no customer code stored and the radio is
unlocked.
REP: The customer code has been entered once, and
the radio now wants the code repeated to verify the
code being entered.
Index of Procedures:
A. Retrieving Scrambled Backup Code from Radio
B. Retrieving a Backup Code from an Electronic
Service Center (ESC)
C. Unlocking/Deactivating Radio with Four-Digit
Backup Code or Customer Code
D. Removing a Customer Code
E. Adding a Customer Code
F. Changing a Customer Code
G. InOP Second Level Lock Condition
Page 2
December, 2019
A. Retrieving Scrambled Backup Code from Radio
Note: Requires battery and ignition voltages applied
and radio power is on.
1. If the radio is in the locked condition (LOC is
displayed), proceed to step 2. Otherwise, press
and hold presets 1 and 4 for about four seconds.
The display will show either SEC or - - -.
2. Press and hold presets 2 and 3 for about six
seconds until the first three digits of the display
code are displayed. Record these numbers.
3. Press the AM/FM button to display the second set
of three digits of the scrambled code. Record these
numbers. The radio will revert to the initial display,
prior to code retrieval sequence, after
approximately five seconds or if another button is
pressed.
Note: If the display does not change after pressing the
AM/FM button, your second set of 3 digits will be the
same as the first 3 digits (Example: if 123 came up first,
your scrambled code will be 123123).
B. Retrieving a Backup Code from an Electronic
Service Center (ESC)
1. Obtain the six-digit scrambled backup code by
following procedure A. Retrieving Scrambled
Backup Code from Radio.
Note: It may not be possible for an ESC to retrieve all
backup unlock codes that exist. There may be a service
fee related to unlocking a radio. Any cost associated
with unlocking a radio is the responsibility of the
customer.
2. Contact your local authorized ESC with the
six-digit scrambled backup code to request a
four-digit backup unlock code.
C. Unlocking/Deactivating Radio with Four-Digit
Backup Unlock Code or Customer Code
Note: Requires battery and ignition voltages applied
and radio power is off.
Note: If the display does not change from LOC to 000,
the radio is probably in the InOP stage. Refer to
procedure G. InOP Second Level Lock Condition.
1. Press the HR button until the LOC disappears and
000 appears on the display.
Note: As if you're setting the time of day, you will not
see the 0 in the far-left side (Example: if the first two
digits of your code is 02, you will scroll with the HR
button until 2 appears on the display).
2. Set the first two digits (01-19) of the code with the
HR (Hour) button.
3. Set the next two digits (00-99) of the code with the
MIN (Minute) button.
Note: If the backup unlock code received from the
ESC does not unlock the radio, one possibility is that
the first 3 digits of the scrambled code from the radio
(Procedure A. Retrieving Scrambled Backup Code
from Radio) are reversed with second 3 digits
Bulletin No.: 19-NA-273
(Example: if the scrambled code is 123 456, then it may
be 456 123). Use Procedure B to retrieve a
backup code.
4. Press the AM/FM button to enter the code. The
radio will now be unlocked, and the display will
change to the clock. Continue to Step 5 to
deactivate the theft deterrent.
5. Press the HR button until the display changes
to 000.
6. Repeat steps 2-4 above to remove previous code
and deactivate the theft deterrent system.
D. Removing a Customer Code
Note: Requires battery and ignition voltages applied
and radio power is off.
1. Press presets 1 and 4 for about six seconds until
the display changes to SEC. If the display changes
to - - -, there is no code stored.
2. Press the HR button until the display changes
to 000.
Note: As if you're setting the time of day, you will not
see the 0 in the far-left side (Example: if the first two
digits of your code is 02, you will scroll with the HR
button until 2 appears on the display).
3. Set the first two digits (01-19) of the code with the
HR button.
4. Set the next two digits (00-99) of the code with the
MIN button.
5. Press the AM/FM button to enter the code. The
theft deterrent system will now be deactivated, and
the customer code removed. The display will show
- - - and then display the clock.
E. Adding a Customer Code
Note: Requires battery and ignition voltages applied
and radio power is off.
1. Press and hold presets 1 and 4 for about six
seconds until the display changes to - - -.
2. Press the HR button until the display changes
to 000.
Note: As if you're setting the time of day, you will not
see the 0 in the far-left side (Example: if the first two
digits of your code is 02, you will scroll with the HR
button until 2 appears on the display).
3. Set the first two digits (01-19) of the code with the
HR button.
4. Set the next two digits (00-99) of the code with the
MIN button.
5. Press the AM/FM button to enter the code.
6. When REP then 000 is displayed, repeat steps 3
through 5 before the display times out and reverts
back to the clock. By repeating those steps, it
confirms the customer code and activates the theft
deterrent system. The display will then show SEC
for secured.
Bulletin No.: 19-NA-273
December, 2019
Page 3
F. Changing a Customer Code
Note: If the radio is in LOC, the appropriate steps must
first be followed.
1. When changing a code in a radio that has already
had one programmed, the original code will have to
be removed first. If the radio is unlocked, follow
procedure D. Removing a Customer Code to
remove and deactivate the first code.
2. Follow procedure E. Adding a Customer Code to
re-enter a new code.
G. InOP Second Level Lock Condition
After eight initial failed unlock attempts (and three failed
attempts every time thereafter), the radio will be in a
second level lock condition and become inoperative for
over one hour. Any further code inputs during this hour
(or pressing any buttons) will display InOP for about
15 seconds before returning to LOC. The radio will still
be inoperative.
Note: Install a GM Authorized power supply charger to
maintain system voltage. Refer to
www.gmdesolutions.com for further information. If not
available, connect a fully charged 12V jumper or
booster pack disconnected from the AC voltage supply.
DO NOT connect a battery charger.
To reset to the normal locked (LOC) condition, battery
and ignition voltages must be continuously present for
over one hour. Do not attempt any radio entries or
functions during this time-out period.
After the radio is brought back to the normal locked
condition, the correct unlocking procedure can be
followed. Following every three unsuccessful entries,
the radio will return to the inoperative state (InOP) for
another one-hour period.
Warranty Information
Vehicles repaired for the conditions outlined in this
bulletin should not be considered warranty. Any costs
associated with the procedures and repairs outlined in
this bulletin are considered “customer pay.”
Version
1
Modified
Released November 22, 2019
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.
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