My 03 cadillac Seville radio reads theftlock and will not turn on,what to do?

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.

key fob need re-programming

Use a scan tool to reset the anti-theft function in the radio.

The monsoon radio's in 03 jetta's and newer seem to have a problem with going out. Your probably looking at getting a new one!---------------------------------------------------------------------------
FGTech Galletto 2-Master EOBD2

You will need to contact Cadillac service at your local dealership. Give them the serial number on the radio. They can then pull the anti theft lock code from their companies archive. The serial number on the radio is typically tied to a VIN, but since you bought just the part, they can't search that way. Hope that helps.

If you never entered a lockout code for your radio, youll have to take it to the dealer to get them to clear it out.

Your '04 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, you can try removing the fuse to your radio for 5 min and reconnect it. This will reset the radio back to default and re-read the Vin number to the PCM to match with the radio. At most time this will get your radio working again and all you have to do is to re program the pre-set and clock.

You need enter the unlock CODE for extract your CDs; check in your owners manual (any label in the last page .

THEFTLOCK is designed to discourage theft of your vehicle’s radio. The feature works automatically by learning a portion of the Vehicle Identification Number (VIN). If the radio is moved to a different vehicle, it will not operate. If the radio is removed from your vehicle, the original VIN in the radio can be used to trace the radio back to your vehicle.

With THEFTLOCK® activated, the radio will not operate if stolen.

Fot other details can check 2005-Cadillac-STS-Owners-Manual

Hope helps.

You need to enter a code from the cadilac dealer

any time radio is disconect wll lock up,if is factoru radio install.on 2007 car will hawe 5 y or 100000m waranty just call near diler and will fix for yu wit no carge