Theft Deterrent

WARNING: This page is about a different car, the 2008 Isuzu Ascender, 2008 GMC Envoy, and 2008 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

The 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 class 2 serial data 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 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 button presses and become inoperative. The two scenarios able to cause this condition are:

A radio is installed from another vehicle.
A module which communicates on the class 2 serial data circuit which supplies VIN information to the radio 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.

The digital radio receiver utilizes class 2 serial data to determine if it is in the appropriate vehicle. Each time the digital radio receiver receives the "run" power mode message, it compares the VIN information received from the body control module (BCM) on the class 2 serial data circuit. If a mis-match occurs, the radio display will indicate to the user the digital radio receiver is locked. The digital radio receiver cannot be unlocked, it must be replaced. The two scenarios able to cause this condition are:

A digital radio receiver is installed from another vehicle.
The BCM is replaced and not properly setup with the correct VIN information for that vehicle.