How can I unlock the theft lock?

If your 2005 Cadillac STS is displaying "TheftLock" on the navigation and radio screen after replacing the battery, it means that the anti-theft system has been activated. Here are the steps you can take to unlock the system:
1. Turn the ignition key to the "On" position. Don't start the car, just turn the key to "On" position.
2. Wait for the "TheftLock" message to disappear from the navigation and radio screen. This may take up to 10 minutes.
3. Press and hold the "1" and "4" buttons on the radio simultaneously for several seconds until "000" appears on the screen.
4. Use the "TUNE" knob to enter the code that was provided with the vehicle's owner's manual. If you don't have the code, you will need to contact a Cadillac dealership or a certified mechanic to retrieve it for you.
5. Once you entered the correct code, press the "AM/FM" button to unlock the radio and navigation system.

If all doesn't work, it's time to contact a Cadillac dealership or a certified mechanic to help you sort it out.

You will need the 4 digit radio code supplied with the owners manual/documentation. The code is printed on something the size of a credit card and will say radio code.

When you disconnect your battery and then reconnect it again, it disables the radio. This is an anti-theft protection for your car radio.
The enable your radio the activation code is in your vehicle owner's manual. If you do not have this code you need to go to your vehicle manufacturer's service centre and get them to enter this code for you.

When you disconnect your battery and then reconnect it again, it disables the radio. This is an anti-theft protection for your car radio.
The enable your radio the activation code is in your vehicle owner's manual. If you do not have this code you need to go to your vehicle manufacturer's service centre and get them to enter this code for you.

When you disconnect your battery and then reconnect it again, it disables the radio. This is an anti-theft protection for your car radio.
The enable your radio the activation code is in your vehicle owner's manual. If you do not have this code you need to go to your Chrysler service centre and get them to enter this code for you.

When you disconnect your battery and then reconnect it again, it disables the radio. This is an anti-theft protection for your car radio.
The enable your radio the activation code is in your vehicle owner's manual. If you do not have this code you need to go to your vehicle manufacturer's service centre and get them to enter this code for you.

to turn off the theft system, all you have to do is put the key in the door lock and lock and unlock the door, this shuts down the anti theft system,now this has nothing to do with the radio, the only way the radio would ask for the code is if it was removed or the battery unhooked,anyway try the unlocking of the door even try the passenger door, hope this helps.

If you have installed a radio from another car chances are it locked. Its a security device in the radio to prevent theft. If its the original radio in your car then the dealer might have the unlock codes you need.

notify dealer they have code the radio code is a security[anti theft ]code but it also activates when battery dies or changed out

If you are refering to the Theft Lock code, you must first push the right sequence of radio buttons to enter the un lock mode in the radio's computer. Once the radio's Theft Lock Identifier code is displayed, you then enter the un lock code into the radio. Ususally, this is a dealer operation as they have the online program to retrieve the unlock code after they submit your Theft Lock ID code. I'm wondering how you were able to get a unlock code without the dealer's assistance.