My changed my battery in my 1997 GMC Yukon and my Delco Electronics THEFTLOCK radio locked. Is there a default code I can use to unlock it? I changed the factory code years ago and I don't remember the code number.Thanks

Unlock GM Theftlock Radio

How to Unlock Your Chevy or GMC Radio Without Paying Dime

How to Unlock Your Locked GM Theftlock Radio

i can link more from my quick google search, but you should get the idea after those links and video

On you tube Go here for more Info.http://audioxpress.org/delco-radio-theftlock-unlock-codes/ WE CAN UNLOCK YOUR RADIO IF ITS A DELCOLOC II OR A DELCO THEFTLOCK RADIO

You have to enter the theft code which was set into the radio. The owners manual will tell you how AS LONG AS YOU HAVE THE CODE. If you don't have the code, any GM dealer will help you out and call in to get your code. They will want to make sure you own the vehicle.

if you get to step 4 email the code to me at [email protected]


Service Information

1999 Chevrolet Chevy K Pickup - 4WD ' Escalade, Pickup Classic, Suburban, Tahoe, Yukon VIN C/K Service Manual ' Document ID: 522597 Radio Displays LOC, LOCKED, or CODE Step
Action
Value(s)
Yes
No
1

1. Turn the ignition off.
2. Disconnect the negative battery cable for 1 minute.
3. Reconnect the battery cable.
4. Turn the ignition to run.
5. Turn the radio on.

Does radio now operate?
--
--
Go to Step 2
2
Important: It will say Theftlock® on the face of the radio.
Does the Radio have Theftlock?
--
Go to Step 3
--
3
Is it possible to get the security code from the customer?
--
Go to Radio/Audio System Operation
Go to Step 4
4

1. Turn the ignition on.
2. Turn the radio off.
3. Depress and hold Pre-set buttons 2 and 3.
4. Write down the first three digits that appear on the radio display.
5. Depress AM/FM, write down the second three digits that appear on the radio display.

Did you receive the 6 digit Radio Display Code?
--
Go to Step 5
Send Radio in for repair
5
Contact Delco Assistance to obtain a "Radio Back-up Code".
--
Go to Step 6
--
6

1. Use the hours and minutes buttons on the radio and install the 4 digit "Radio Back-up Code".
2. Depress the AM/FM button.
"SEC" should display.

Did the radio unlock?
--
Go to Step 7
Repeat Step 6
7
Important: This will remove the original owner's code. The owner will then be able to reinstall their own personal security code.
Step 6 only unlocked the radio, if the original code is not known, repeat step 6.
Did the radio display?
--
--
Repeat Step 7

Your '05 is too new to unlock on your own.

There are 2 types of GM Theftlock, Theftlock I and Theftlock II. The Theftlock I is found in pre 2000 vehicles, and Theftlock II is in the later models.


Theftlock I - Uses a volatile user settable code that is input through the key pad on the front of the Radio. If the power is lost (dead battery etc.) the code is gone and must be re-entered for the radio to work. But with the correct procedure the owner can unlock it.

Theftlock II - Uses an EPROM (erasable/programmable read only memory) or a PROM (the difference is you can not alter the prom once it is programmed).

In either case the code is burned in and holds even when the power is lost. With Theftlock II the radio is married to the vehicle by way of the VIN. When the vehicle is started the computer compares the number in the radio with the VIN in the body control module. If they match, the radio works, if not the radio displays LOC and you are finished, there is no easy way around it. The radio will not work until you make a trip to the dealer.

The dealer will use a TECH 2 scanner to change the VIN stored in the radio. The radio does not need to be removed (for the serial number or any other nonsense). The technician just plugs into the computer and resets the VIN in the radio.
Thank you for using fixya and keep us posted.

Does your GM car or truck Radio display LOC and does not turn on? Chevrolet, Buick, Pontiac, GMC, Cadillac, Oldsmobile vehicles used a theft system to lock the radio when power is lost. This system was used from the ealy 1990's to the early 2000's.

Instructions:

1. If your radio displays the word LOC, you can retrieve a set of factory numbers in the radio that enable you to get a backup unlock code. If the radio says INOP, you will have to leave the key in the "ON" position, or let the car run for at least 1 hour before you attempt any unlock procedure. INOP means a secondary theft lock due to too many false attempts to unlock the radio.
2. Looking at the face of your GM Delco radio, hold down the preset buttons 1 & 4 OR 2 & 3 (Depending on year and model) for approximately 10 seconds or until a set of 2 or 3 numbers comes up on the display. Write the numbers down.
3. Next press the AM / FM button. A new set of 3 numbers will now show. Write these numbers down. You will then need to call a 1-800 phone number with these numbers to get the unlock code. There are many sites on the internet that can get it for you- for a small fee. Or, try calling your local GM Dealer and ask for them to do it. Many times they will do it for free. It only takes a minute.
4. Once you have the unlock code, enter it by pressing the MIN button until the display shows the last 2 digits of the unlock code, then press the HR button until the first 2 numbers or shown. Then press the AM / FM button to enter the code. The radio will now display SEC, and normal function is restored.

Also, its possible that you need RESET your GM Radio; this is the procedure: While performing maintenance on your car, you may disconnect the radio from the battery in your GM vehicle. GM cars contain Delco radios that are protected by Theftlock, which locks the radio after it has been disconnected from a power source. Iit can only be reset and unlocked with a car-specific security code. Identifying the security code for your GM vehicle is the only way to reset the car radio and disable the Theftlock protection device.

Instructions:

1. Turn on your car. Your Delco radio will show "LOC" in the LED display.
2. Press and hold down both the second and third preset buttons. Hold these buttons down for at least six seconds.
3. Write down the two- or three-digit code that appears in the LED display.
4. Press the AM/FM button on the radio.
5. Write down the next two- or three-digit code that appears in the LED display. You should be left with either a four- or six-digit number. Turn off your car.
6. Call the Delco radio automated customer support line at 1-800-537-5140.
7. Press "1" and then press the pound sign. The automated voice should respond "Invalid code, try again."
8. Enter the number 139010 into your phone and then press the "*" sign.
9. Enter the four- or six-digit number you wrote down from Steps 3 and 5, and then press the "*" button.
10. Write down the four-digit code given by the automated voice.
11. Turn on your car. Enter the Delco unlock code using the procedure outlined by your GM owner's manual. Normally, the unlock code is entered with the "HR" and "MN" buttons on your radio.
12. Press the AM/FM button. If you have entered the code correctly, your LED display will read "SEC" and the radio will be unlocked.
    

Also can check your Does your GM car or truck Radio display LOC and does not turn on? Chevrolet, Buick, Pontiac, GMC, Cadillac, Oldsmobile vehicles used a theft system to lock the radio when power is lost. This system was used from the ealy 1990's to the early 2000's.
jQuery('.intro .thumbnail').each(function(i,e){ jQuery(e).find('img').one('error',function(){ jQuery(e).remove(); }); });
Instructions:

1. If your radio displays the word LOC, you can retrieve a set of factory numbers in the radio that enable you to get a backup unlock code. If the radio says INOP, you will have to leave the key in the "ON" position, or let the car run for at least 1 hour before you attempt any unlock procedure. INOP means a secondary theft lock due to too many false attempts to unlock the radio.
2. Looking at the face of your GM Delco radio, hold down the preset buttons 1 & 4 OR 2 & 3 (Depending on year and model) for approximately 10 seconds or until a set of 2 or 3 numbers comes up on the display. Write the numbers down.
3. Next press the AM / FM button. A new set of 3 numbers will now show. Write these numbers down. You will then need to call a 1-800 phone number with these numbers to get the unlock code. There are many sites on the internet that can get it for you- for a small fee. Or, try calling your local GM Dealer and ask for them to do it. Many times they will do it for free. It only takes a minute.
4. Once you have the unlock code, enter it by pressing the MIN button until the display shows the last 2 digits of the unlock code, then press the HR button until the first 2 numbers or shown. Then press the AM / FM button to enter the code. The radio will now display SEC, and normal function is restored.

Also, its possible that you need RESET your GM Radio; this is the procedure: While performing maintenance on your car, you may disconnect the radio from the battery in your GM vehicle. GM cars contain Delco radios that are protected by Theftlock, which locks the radio after it has been disconnected from a power source. Iit can only be reset and unlocked with a car-specific security code. Identifying the security code for your GM vehicle is the only way to reset the car radio and disable the Theftlock protection device. jQuery('.intro .thumbnail').each(function(i,e){ jQuery(e).find('img').one('error',function(){ jQuery(e).remove(); }); });
Instructions:

1. Turn on your car. Your Delco radio will show "LOC" in the LED display.
2. Press and hold down both the second and third preset buttons. Hold these buttons down for at least six seconds.
3. Write down the two- or three-digit code that appears in the LED display.
4. Press the AM/FM button on the radio.
5. Write down the next two- or three-digit code that appears in the LED display. You should be left with either a four- or six-digit number. Turn off your car.
6. Call the Delco radio automated customer support line at 1-800-537-5140.
7. Press "1" and then press the pound sign. The automated voice should respond "Invalid code, try again."
8. Enter the number 139010 into your phone and then press the "*" sign.
9. Enter the four- or six-digit number you wrote down from Steps 3 and 5, and then press the "*" button.
10. Write down the four-digit code given by the automated voice.
11. Turn on your car. Enter the Delco unlock code using the procedure outlined by your GM owner's manual. Normally, the unlock code is entered with the "HR" and "MN" buttons on your radio.
12. Press the AM/FM button. If you have entered the code correctly, your LED display will read "SEC" and the radio will be unlocked.
    

Also can check 1999-Pontiac-Firebird-Owners-Manual (page 163), there are several information about to lock and unlock.


Hope this help (remember comment and rated this).

Does your GM car or truck Radio display LOC and does not turn on? Chevrolet, Buick, Pontiac, GMC, Cadillac, Oldsmobile vehicles used a theft system to lock the radio when power is lost. This system was used from the ealy 1990's to the early 2000's.
jQuery('.intro .thumbnail').each(function(i,e){ jQuery(e).find('img').one('error',function(){ jQuery(e).remove(); }); });
Instructions:

1. If your radio displays the word LOC, you can retrieve a set of factory numbers in the radio that enable you to get a backup unlock code. If the radio says INOP, you will have to leave the key in the "ON" position, or let the car run for at least 1 hour before you attempt any unlock procedure. INOP means a secondary theft lock due to too many false attempts to unlock the radio.
2. Looking at the face of your GM Delco radio, hold down the preset buttons 1 & 4 OR 2 & 3 (Depending on year and model) for approximately 10 seconds or until a set of 2 or 3 numbers comes up on the display. Write the numbers down.
3. Next press the AM / FM button. A new set of 3 numbers will now show. Write these numbers down. You will then need to call a 1-800 phone number with these numbers to get the unlock code. There are many sites on the internet that can get it for you- for a small fee. Or, try calling your local GM Dealer and ask for them to do it. Many times they will do it for free. It only takes a minute.
4. Once you have the unlock code, enter it by pressing the MIN button until the display shows the last 2 digits of the unlock code, then press the HR button until the first 2 numbers or shown. Then press the AM / FM button to enter the code. The radio will now display SEC, and normal function is restored.

Also, its possible that you need RESET your GM Radio; this is the procedure: While performing maintenance on your car, you may disconnect the radio from the battery in your GM vehicle. GM cars contain Delco radios that are protected by Theftlock, which locks the radio after it has been disconnected from a power source. Iit can only be reset and unlocked with a car-specific security code. Identifying the security code for your GM vehicle is the only way to reset the car radio and disable the Theftlock protection device. jQuery('.intro .thumbnail').each(function(i,e){ jQuery(e).find('img').one('error',function(){ jQuery(e).remove(); }); });
Instructions:

1. Turn on your car. Your Delco radio will show "LOC" in the LED display.
2. Press and hold down both the second and third preset buttons. Hold these buttons down for at least six seconds.
3. Write down the two- or three-digit code that appears in the LED display.
4. Press the AM/FM button on the radio.
5. Write down the next two- or three-digit code that appears in the LED display. You should be left with either a four- or six-digit number. Turn off your car.
6. Call the Delco radio automated customer support line at 1-800-537-5140.
7. Press "1" and then press the pound sign. The automated voice should respond "Invalid code, try again."
8. Enter the number 139010 into your phone and then press the "*" sign.
9. Enter the four- or six-digit number you wrote down from Steps 3 and 5, and then press the "*" button.
10. Write down the four-digit code given by the automated voice.
11. Turn on your car. Enter the Delco unlock code using the procedure outlined by your GM owner's manual. Normally, the unlock code is entered with the "HR" and "MN" buttons on your radio.
12. Press the AM/FM button. If you have entered the code correctly, your LED display will read "SEC" and the radio will be unlocked.
    

Hope this help.

Free code entry instructions for DELCO can be found here

http://www.radio-code.co.uk/code-entry-help.php

I dont know if holden barina uses the same stereo as a US GM vehicle, but if it is a delco stereo (same as US models) then any gm dealer can retrieve the scrambled code and call their automated system to get the unscrambled unlock code. Just make sure if they do this for you to have them disable the theftlock system. With theftlock disabled a dead battery will not cause you any further problem. Hope this helps.

if you bought the car new then there should be writen in the manual the code for the theft lock system on the radio. if pre-owned then it might ,might not be in there. or if you dont have one at all. go to your nearest GM dealer and have them fix it by finding the code. make sure to have them write it down for you incase this happens again.