Immobilizer System

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

The immobilizer system is incorporated into the remote control door lock receiver (RCDLR). The immobilizer is provided in order to prevent the vehicle operation if an incorrect or unprogrammed keyless entry transmitter is used in an attempt to start the vehicle. When the ignition mode switch is depressed and rotated, the console passive antenna broadcasts a challenge to the transmitter. Both the RCDLR and the transmitter perform a calculation based on this challenge. The transmitter will transmit its calculation result to the RCDLR via radio frequency (RF). If both calculations match, vehicle starting will be allowed. This is accomplished by the RCDLR sending a fuel enable message to the engine control module (ECM).

The design of the immobilizer system is to prevent vehicle theft by disabling the engine unless the correct transmitter is present when attempting to start the vehicle. The system is similar in concept to conventional immobilizer system which use a normal vehicle key. The components of the immobilizer system are as follows:

Ignition mode switch
Keyless entry transmitters
Console passive keyless entry antenna
RCDLR
Security indicator
ECM