Principles of Operation (How Does It Work?)

When a remote transmitter button is depressed, it transmits the appropriate command to the Central Security Module (CSM) as a radio frequency. The CSM receives the command from the remote transmitter through an antenna, that is incorporated into the harness connected to the CSM through CSM C451a.

When the CSM receives a command from a remote transmitter, it then sends the appropriate output to control the desired devices. These output devices include:
^ The driver and passenger door lock units.
^ The Central Timer Module (CTM).
^ The right and left flasher relays.
^ The liftgate release motor.

The CSM sends a signal to the CTM when courtesy lamp illumination is required.

The CSM is equipped with an Erasable Programmable Read-only Memory (EPROM) chip. This EPROM stores the Transmitter Identification Codes (TICs) for any transmitters that have been programmed to that vehicle. The codes are stored in a non-volatile memory, protecting them from power loss. Such a power loss could occur if the vehicle battery has to be disconnected for vehicle repair, or if the battery were allowed to discharge.