Theftlock is a theft prevention system designed into GM-brand radios starting in the mid-1990’s. This system is designed to lock the radio from use in the event of a loss of power, either from being disconnected or when the battery loses its charge. If the radio is removed from the vehicle and installed in another car, it is rendered useless without the radio unlock code.
More often than not, the Theftlock feature locks out the original, lawful owner of the vehicle instead of a thief. You can go to a Chevrolet dealership to have your radio unlocked, but some dealers can charge high fees to unlock the radio. Even if they unlock your radio for you, they may not give you the radio code to use in the event of future radio lockouts.
Theftlock radios have evolved over time but are still used in some vehicles currently. Vehicles from the mid-90’s until mid-to late 2000’s can be unlocked using a few simple steps.
Part 1 of 4: Determine if your radio can be unlocked at home
There are several radio designs that were used in the same era as the Theftlock radio. Before you try to unlock your car’s radio on your own, you need to identify the style of your radio.
Step 1: Look at your radio. Check and see if the code “RDS” is written on the face of the radio. If “RDS” is present, contact a GM dealership to have your radio unlocked by them.
Step 2: Check for the identification code. Press buttons 2 and 3 for 8-10 seconds. If a code does not appear on the display, you won’t be able to unlock your radio in this manner.
Part 2 of 4: Retrieve your radio’s serial number
In order to obtain your radio unlock code, you need to find your radio’s serial number. You can get the radio serial number directly from your radio.
Step 1: Turn on the ignition. Turn the key to “accessory” mode or “on” mode.
Step 2: Turn on the radio. Press the power button to turn on the radio.
If your radio displays any functions such as playing a CD, cassette, or a radio station, your radio is not locked. If no sound is heard, you may need to replace your radio unit.
If your radio is locked, “LOC” is displayed on the screen.
If “INOP” is displayed, keep your ignition on for 60 minutes with “INOP” on the display. After the hour is up, it should change to “LOC.” After this you can proceed with the next step.
Step 3: Write down the code. Press buttons 2 and 3 at the same time and hold for 8-10 seconds. Write down the three-digit code that is displayed.
Step 4: Note down the code. Immediately press the AM/FM button. Another three-digit code is displayed. Write it down as well.
This is your six-digit radio serial number.
Part 3 of 4: Obtain the radio unlock code
Now that you have your radio’s serial number, you can obtain the radio unlock code from General Motors. Be ready with a pen and paper to write down your radio unlock code.
Step 1: Contact the GM radio hotline. From any landline or cell phone, call the toll-free GM Radio hotline at 1(800) 537-5140.
Step 2: Enter the code. When it requests a code, enter “106010” on the keypad, followed by the pound (#) sign.
Step 3: Enter the radio serial number. You will be prompted to enter the radio serial number you have just obtained.
At the prompt, enter the number followed by the pound sign.
Step 4: Write down the radio unlock code. The prompt will read out your four-digit radio unlock code. Write it down precisely.
Part 4 of 4: Enter the radio unlock code
Now that you’ve obtained your Chevrolet radio unlock code, you need to enter it into your radio.
Step 1: Switch on the radio. Turn your ignition on and press the radio power button. Your radio will display “LOC.”
Step 2: Enter the first two digits of the radio unlock code. Press the hour button on the radio to enter the first two numbers of your radio unlock code.
Continue pressing the button repeatedly until the first two digits of the radio unlock code are displayed.
Step 3: Enter the last two digits of the unlock code. Press the minute button until the last two numbers of the radio unlock code are displayed.
Repeatedly press until they match the two digits you need.
Step 4: Confirm the code. When the code matches, press the AM/FM button. “SEC” will display on the radio, indicating a successful attempt to enter your radio code.
If you enter the code incorrectly eight times, the display will switch from “LOC” to “INOP." You’ll need to leave the ignition on for an hour as described in Part 2 before you can retry.
Write the radio unlock code in a safe place such as in your owner’s manual for future use.
Most car dealers will charge you a lot of money just to get the code for you. If you follow the right steps, you can get the code for free and be able to start listening to the radio again in just a few minutes!
This article originally appeared on YourMechanic.com as How to Unlock a Chevrolet Theftlock Radio and was authored by Jason Unrau.