For 1990-2009 cars

### Vehicle Theft Deterrent (VTD) System

The theft deterrent system has been incorporated into the remote control door lock receiver (RCDLR). The theft deterrent is provided in order to prevent the vehicle operation if the correct keyless entry transmitter is not used in order to start the vehicle. The ignition button is pressed and the keyless entry console and headliner antennas broadcast a challenge to the transmitter. If the challenge is met, the keyless entry transmitter will transmit via RF to the RCDLR to enable the vehicle to start. This is accomplished by the RCDLR sending a fuel enable message to the engine control module (ECM).

The design of the keyless access with push button start system is to prevent vehicle theft by disabling the engine unless the correct key fob is present when attempting to start the vehicle. The system is similar in concept to the PASS-Key III system. However, the keyless access with push button start system eliminates the need for a key; the keyless entry transmitter is considered to be the key. The components of the keyless access with push button start system are as follows:

• | Start Button

• | The #1 - #4 keyless entry transmitters

• | Headliner and Console Antenna

• | Console Enable Antenna

• | Instrument Panel Module (IPM)

• | Remote Control Door Lock Receiver (RCDLR)

• | Security Indicator

• | Engine Control Module (ECM)

### Start Button

The start button is located at the upper right side of the steering column on the instrument panel. The start button is used to start the vehicle engine, turn OFF the vehicle engine, put the vehicle in accessory (ACC) mode or put the vehicle in RUN mode.

### Keyless Entry Transmitter

The keyless entry transmitters are not only used to passively or actively lock and unlock the vehicle, they are also used to enable the vehicle engine to be started. If the remote control door lock receiver (RCDLR) does not receive a valid RF signal after the fob is challenged by an active antenna, the RCDLR will not send a fuel enable message to the engine control module. A message will display on the driver information center (DIC) stating, NO FOB DETECTED.

When any one of the 4 allowable programmed transmitters are challenged by a keyless entry antenna by pressing the start button, they will passively send a RF signal to the RCDLR; the RCDLR will then send a serial data message to the engine control module (ECM) to enable fuel so the vehicles engine can be started.

### Headliner and Console Antennas

The keyless entry headliner and console antennas have a dual purpose. The antennas are used for both keyless entry and vehicle theft deterrent functions. In the keyless entry functions, they can be used to find the keyless entry transmitter inside the vehicle. In the antennas theft deterrent functions, they transmit and receive the needed communications with the keyless entry transmitter to enable vehicle starting.

The keyless entry headliner antenna is located under the vehicles headliner. The console antenna is located in the vehicle center console. The use of two antennas and the placement of the antennas is to ensure complete coverage of the vehicle interior. The antenna is controlled by the remote control door lock receiver (RCDLR). These antennas share a driver and are controlled simultaneously by the RCDLR. When the start button is pressed, both antennas send out an identical challenge to the keyless entry transmitter.

### Console Active Antenna

The keyless entry console active antenna is located in the vehicle center console. It has a small pocket next to it where the key fob can be inserted if the key fobs battery is dead, weak or the RF signal is being jammed.

The purpose of the console active antenna is to send a low frequency RF challenge to a programmed key fob when the start button is pressed. The console active antenna is controlled by the RCDLR.

### Instrument Panel Module (IPM)

Important: The remote control door lock receiver (RCDLR) is not on the GM LAN high speed bus, therefore the RCDLR and the engine control module (ECM) must use the instrument panel module (IPM) as a gateway in order to communicate.

The IPM is a multifunction module. The IPM is used in the vehicle theft deterrent system as a gateway for the RCDLR to send a fuel enable message to the ECM. The remote control door lock receiver (RCDLR) is not on the GM LAN high speed bus. The RCDLR will send a serial data message through the IPM as a gateway to the ECM to receive the fuel enable password.

### Remote Control Door Lock Receiver (RCDLR)

Important: The remote control door lock receiver (RCDLR) is not on the GM LAN high speed bus, therefore the RCDLR and the engine control module (ECM) must use the body control module (BCM) as a gateway in order to communicate.

The RCDLR is a multi-function module located in the rear compartment area, on the underside of the rear shelf. The RCDLR can be accessed from the rear compartment. The RCDLR controls all the vehicles antennas for passive and active keyless entry, as well as vehicle theft deterrent and vehicle starting. The RCDLR will send an AC voltage signal and provide ground to the headliner and console antennas when the start button is pressed. This will enable the antennas to send out the low frequency broadcast challenge to a key fob in range. The RCDLR is the module responsible for sending the fuel enable serial data message if all the vehicle theft deterrent requirements are met.

### Security Indicator

The security indicator is located on the instrument panel. If the SECURITY telltale flashes or if the SECURITY telltale illuminates continuously during the vehicle operation, there is a problem with the vehicle theft deterrent system and it should be serviced by the dealer. The SECURITY telltale is a dual purpose indicator, and with the ignition OFF, it is controlled by the content theft deterrent system. With the ignition ON it is controlled by the vehicle theft deterrent system.

### Engine Control Module (ECM)

Important: The remote control door lock receiver (RCDLR) is not on the GM LAN high speed bus, therefore the RCDLR and the engine control module (ECM) must use the body control module (BCM) as a gateway in order to communicate.

The ECM communicates with the IPM via the GM LAN high speed bus. When the RCDLR determines a no start condition, it sends a serial data password, via the IPM, to the ECM in order to disable the starting system. If the RCDLR receives a valid key fob RF transmitted frequency, the RCDLR sends a serial data password, via the IPM, to the ECM in order to enable the starting system. The ECM then allows the vehicle to start. If the serial data password from the RCDLR to the ECM is not within the Vehicle Security Status Message, the vehicle will not start. If the ECM does not receive the same password from the RCDLR as the last learned one, the vehicle will not start.