Cadallic 2002 radio reads locked theftlock active

Showing on what screen ?
Theftlock
Radio
The Theftlock theft deterrent system is a feature on all base and uplevel radios. There is no need to program a security code into the radio as in past model years. The theft deterrent system now utilizes GMLAN to determine if the radio is in the appropriate vehicle. Each time the radio receives the "run" power mode message, it compares the VIN information it has stored to the VIN information received from the instrument panel module (IPM) on the GMLAN circuit. If a mis-match occurs, the radio display will indicate to the user the radio is locked. Once this takes place, a DTC will set, the radio will not respond to any button presses and become inoperative. The two scenarios able to cause this condition are:
A radio is installed from another vehicle
The IPM is replaced and not properly setup with the correct VIN information for that vehicle
The only way to unlock the radio is by using a scan tool. Always refer to the table in this section to diagnose the Theftlock DTC for further information.

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

You may be able to get the code from the dealer.

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.

Your '02 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 you may want to try pulling the fuse to your radio for 2 min and then reinstalling it. This may reset your radio and have the ECM recognize the radio matching VIN number to the Trailbalzer.

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.

There is no actual "security code" in the radio as in past model years. The newer theft deterrent system utilizes the class 2 serial data to determine if the radio is in the appropriate vehicle...in other words it compares the VIN it has stored in it's memory with the VIN of the other modules (body control and PCM) in the vehicle to "check" to see that it's in the correct vehicle.

Each time the radio receives the "run" power mode message, it compares the VIN information it has stored to the VIN information received from a module on the class 2 serial data circuit responsible for transmitting that information. If a mis-match occurs, the radio display will indicate to the user the radio is locked. Once this takes place the radio will not respond to any buttons/commands and becomes inoperative. But the dealer can reestablish the radio into a different vehicle with a scanner.
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 good luck. you might get luck by removing the fuse toy our radio for 5 min and reinstalling it, this will reset the radio to default and all you need to do is reset the clock and radio presets.

how do i bypass the theftlock on my radio in my 2002 grand am

HAVE YOU OWNED THE CAR SINCE IT WAS NEW? THE POWER HAS BEEN INTERRUPTED FROM THE STEREO. IT WILL TAKE A LOCK CODE TO UNLOCK IT. REFER TO YOUR OWNERS MANUL OR TAKE IT TO THE LOCAL GM DEALERSHIP.

you need the unlock code from the manufacturer. I had a radio lock up but the company had me send it to them for them to unlock. i had to prove that i bought it and it was not stolen.