September `10` - Corvette THEFTLOCK

Flagler County Corvette Club — Newsletter
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Technical Notes — September ‘10’ - Corvette THEFTLOCK
THEFTLOCK is a security system for Corvette radios that was introduced
with the C5 generation. Now, this is not the vehicle theft-deterrent system that was first introduced in the C3 generation. In the C5 and C6
Corvettes, the radio has this separate security system to deter thieves
from breaking into your vehicle and stealing the radio for use in another
car. As is often the case, however, thieves can be quite technically sophisticated and can defeat even nearly every security system if the item is
Vic Natiello
in high enough demand on the black market. Unfortunately, these sysTechnical Committee —Chair tems can do more to frustrate the legitimate, but technically challenged,
car owner than the thief. So, let’s look at the procedures for setting and
disabling the security mode on the C5 and how to recover use of the radio should the security system activate.
Since most late model Corvettes come with an owner’s manual that looks a lot like a college-level physics
book, I’ll try to keep this simple with plenty of pictures. Here is a page discussing radio security from a
typical C5 Owner’s Manual.
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Flagler County Corvette Club — Newsletter
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Technical Notes — September ‘10’ - Corvette THEFTLOCK
Please note the statement at the end of Step 9. Corvette engineers intentionally wanted to alert thieves
that the radio in your car had the security system activated. In my opinion, however, this feature could
be considered as an invitation rather than a warning. If the light is not flashing, you are basically telling
every thief you are an easy mark. Thus, you might not only return to a vehicle with a big hole in the front
console, but a lot of glass in one of the seats where the window was smashed by a crowbar.
Let me show some images of how the radio will look during these procedures. First, remember, the radio
must be off to set your personal security code. First, write down a code between “000” and “1999”. Let
chose “1234” for this example. At Step 4:
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Flagler County Corvette Club — Newsletter
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Technical Notes — September ‘10’ - Corvette THEFTLOCK
Now let’s suppose your radio is security enabled and your battery tender fails while your out West making your fortune. When you return to Palm Coast, you find your C5 battery is dead as a doornail. Well,
first remember that the Corvette radio interprets the battery failure as radio theft. The radio will not operate once you’ve fixed the electrical system, until you enter your security code. Thus, when you first
turn the ignition on, “LOC” (locked) will appear in the radio display. The following owner’s manual page
shows the procedures to get your radio functioning again. It actually tells you two procedures: (1) How
to unlock your radio after electrical interruption with “LOC” displayed and (2) How to disable the security feature, if, let’s say, you were to sell your car in the future.
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Flagler County Corvette Club — Newsletter
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Technical Notes — September ‘10’ - Corvette THEFTLOCK
But, what if you lost or forgot your code after you got your new battery? In that case, you have two
choices. First, you could drive the car for the rest of your life singing to yourself, a cappella. However, if
have a spouse, that won’t work, so you’ll have to go back to the owner’s manual to figure out how to get
your radio back in operation. Look at the statement at the bottom of the left column on page 3-27. If
you enter the wrong code 8 times, you must wait an hour with the ignition on before you can try
again. Then, you only get 3 more chances before you see the dreaded word, “INOP”. Of course, male
owners will try all eleven times to guess at their code, and then take their car to the dealer. Women
owners are more likely admit to failure early and go to the dealer after a few failed attempts. In either
case, don’t forget to bring your wallet.
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Flagler County Corvette Club — Newsletter
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Technical Notes — September ‘10’ - Corvette THEFTLOCK
Your radio will now function, but is in the secure mode. The security code will be the four digits you obtained via the phone. If you want to reinstall your own personal 4-digit code, follow the steps to clear
the security code and reinstall your own four numbers. Unfortunately, the special numbers “139010”
shown in the procedure above are no longer valid. GM changed that key a while ago. For security reasons, the correct digits should not be divulged over the Internet. If you need the current numbers, you
need to find a mechanic who knows them or you could try to “pretty please” your local Chevy service
writer. If you really felt lucky, however, you could also ask around at Woody’s and someone there might
just know the key.
Now for this month’s bonus question: C5 radios, whether cassette or disc, have identical buttons and
the same display. On the other hand, C6 radios come with or without NAV, and as a result have distinctly different radio heads. How can you C6 owners enter your security code in those two distinctively
different systems to enable the C6 THEFTLOCK system?