GM Delco Radio unlock code
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 latter models.
Theftlock I - Uses a volatile 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
If you do not have the code, you can get it by phone, email, etc.
but you will need the 6 digit Radio ID number.
To get that, just turn on the ignition and hold down the 2-3 keys
(sometimes 1-4) and the first 3 digits will appear in the display.
Then hold down the AM/FM button and the last 3 digits will
With this number you can get the unlock code. This code is
available all over the place for less then $10.00. Just search
on theftlock. Use the HR and MIN buttons to enter the code
and you are in business.
This may sound a bit complicated at first but you can do it
in less then a minute with a little practice.
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. 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.
If the radio has an EPROM the dealer will use something called
a TECH 2 DEVICE 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. It can
be done (if you know how) in less then 15 minutes.
I checked around and the going rate is about $60.00
(none of the dealers I contacted would do it for free).
That works out to $240.00 per hour, but still much
cheaper then a new GM Radio.
If the radio has a PROM then the chip must be changed
and that seems to be factory only, in other words a new
radio! The good news is, only a very few of the high end
GM vehicles are equipped with a PROM so it is highly
unlikely that your radio has this anti theft feature.
on Nov 11, 2019