Antitheft and Alarm Systems: Description and Operation

VEHICLE THEFT SECURITY SYSTEM
The Vehicle Theft Security System (VTSS) is designed to protect against whole vehicle theft. The system monitors vehicle doors, decklid, and ignition action for unauthorized operation. The alarm activates:
- Sounding of the horn
- Flashing of the park and tail lamps
- Flashing of the headlamps

Upon failure of proper SKIM communication to the PCM, the PCM will shut off fuel after 2 seconds of run time. The engine will not re-crank on the key cycle that the failure occurred, a full key down sequence must be performed for the engine to crank again. After six consecutive fuel shut-offs, the engine will no longer crank on subsequent key cycles. The failure must be corrected and a valid communication process between the SKIM and the PCM must occur for the engine to crank and start again.

The electronics for the VTSS are part of the Body Control Module (BCM). The system is armed when the vehicle is locked using the:
- Power door lock switches (with any door ajar)
- Remote Keyless Entry transmitter.
- Door Cylinder Lock Switches.

For vehicles equipped with SKIS, the doors do not have to be locked to enable the fuel shut off feature.

After the vehicle is locked and the last door is closed, the set LED indicator in the top cover will flash quickly for 16 seconds, indicating that arming is in progress. If no monitored systems are activated during this period, the system will arm. The LED will extinguish unless the decklid is open. If the decklid is open, the LED will flash at a slower rate. This indicates that the system is armed.

If fault is detected on any key cylinder input, the indicator LED will remain solid during the arming process, although the system will still arm. If the indicator LED does not illuminate at all upon door closing it indicates that the system is not arming.

Passive disarming occurs upon normal vehicle entry by unlocking either door with the ignition key/remote transmitter. This disarming will also halt the alarm once it has been activated.

A tamper alert exists to notify the driver that the VTSS had been activated. This alert consists of 3 horn pulses when the vehicle is disarmed.

NOTE: The VTSS will not arm by pushing down the door lock mechanism. This will manually override the system.

For Door Cylinder Lock Switch Removal and Installation , refer to Electrical, Power Locks, Door Cylinder Lock Switch, Removal , and Installation.

If the VTSS is triggered, the horn will pulse, head- lamps/marker lamps will flash, and the VTSS warning lamp will flash. If the BCM determines the threat to be false and the VTSS is not triggered again, the system will shut down and rearm itself after 3 minutes. If a trigger is still active, the alarm will continue for an additional 15 minutes without the horn. The VTSS monitoring portion of the system is split into two sections.

Arming The VTSS
1. With the key removed from the ignition lock and any door open (excluding decklid), actuate one of the following:
- Power door lock button to LOCK,
- Key fob LOCK button
- Door lock key cylinder to locked position.
2. Close all opened doors, decklid can remain open.

NOTE: If the decklid is open, it will not be secure. Once the decklid is closed, a separate 16 second counter will start. Once 16 seconds has been reached, the decklid will then be secure, providing a VTSS disarm request has not been received during the 16 second decklid arming period.

3. After the last door is closed, an arming timeout period of 16 seconds will start, then the VTSS will become armed.
4. If a 16 second time-out sequence was in process and a new arm signal was actuated, the 16 second timeout will restart from the time of the second actuation.

If the security lamp does not illuminate at all upon final door closure, it indicates that the system is not arming.

The current VTSS status armed or disarmed shall be maintained in memory to prevent battery disconnects from disarming the system.

Triggering The VTSS
After the VTSS is armed, the following actions will trigger the alarm:
- Opening any door.
- Turning the ignition to the ON, ACC, or UNLOCK position.
- Opening decklid without first receiving a RKE input or decklid key input.

CAUTION: The VTSS indicator LED will trigger and engine will continue to run if the vehicle is equipped with SKIS and the proper key is used to start the vehicle. This condition will occur if the VTSS has been triggered. If valid key is used, VTSS will disarm

SENTRY KEY IMMOBILIZER SYSTEM
The Sentry Key Immobilizer System (SKIS) is available as a factory-installed option on this vehicle. It is designed to provide passive protection against unauthorized vehicle use by disabling the engine, after two (2) seconds of running, whenever an invalid key is used to start the vehicle. The SKIS is active whenever the ignition is on and does not require any customer intervention. The primary components of the system are the Sentry Key Immobilizer Module (SKIM), Sentry Key (ignition key with a transponder molded into the head), indicator light, Body Control Module (BCM), and the Powertrain Control Module (PCM). The SKIM is mounted to the steering column with the molded, integral antenna mounted on the light halo surrounding the ignition lock cylinder. The indicator light, is located in the message center.

The SKIS includes keys from the factory which are pre-programmed. Each SKIM will recognize a maximum of eight Sentry Keys. If the customer would like to own additional keys other than those provided with the vehicle, they can be purchased from any authorized dealer. These keys must be programmed to the SKIM on the vehicle in order for the system to recognize them as valid keys. This can be done by the dealer with a DRB III scan tool or by a customer if this feature is available in their market and they have two (2) valid keys already available to them. Refer to the Service Procedures portion of this system for additional details. The SKIS performs a self-test each time the ignition switch is turned to the ON position and will store Diagnostic Trouble Codes (DTC's) if a system malfunction is detected. The SKIS can be diagnosed and any stored DTC's can be retrieved using a DRB III scan tool as described in the appropriate Body Diagnostic Procedures manual.

Sentry Key Immobilizer Transponder:

TRANSPONDER KEY
The Sentry Key Immobilizer System (SKIS) uses a transponder chip that is integral to each ignition key to communicate with the Sentry Key Immobilizer Module (SKIM). Ignition keys are supplied with the vehicle when it is shipped from the factory. The transponder chip is undermolded within the head of the key This undermold is hidden beneath an overmolded rubber cap.

Each Sentry Key has a unique transponder identification code permanently programmed into it by the manufacturer. Likewise, the SKIM has a unique "Secret Key" code programmed into it by the manufacturer as well. When a Sentry Key is programmed into the memory of the SKIM, the SKIM stores the transponder identification code from the Sentry Key, and the Sentry Key learns the "Secret Key" code from the SKIM. Once the Sentry Key learns the "Secret Key" code of the SKIM, it is also permanently programmed into the transponder's memory Therefore, blank keys for the SKIS must be programmed by the SKIM in addition to being cut to match the mechanical coding of the ignition lock cylinder. Refer to Electrical, Vehicle Theft Security Transponder Key, Standard Procedure - Transponder Programming.

The Sentry Key's transponder is within the range of the SKIM's transceiver antenna ring when it is inserted into the ignition lock cylinder. When the ignition switch is turned to the ON position, the SKIM communicates with the Sentry Key via a radio frequency (RF) signal. The SKIM determines if a valid key is present based on the information it receives from the Sentry Key. If a valid key is detected, that fact is communicated to the PCM via the PCI bus and the vehicle is allowed to continue running. If an invalid key is received by the PCM or no status at all is communicated, the vehicle will stall after two (2) seconds of running. The indicator light will be flashing at this point. The Sentry Key's transponder can not be repaired. If it is faulty or damaged, it must be replaced.

Common communication problems:
- Two transponder keys too close together.
- Speed Pass too close to transponder key

VTSS/SKIS INDICATOR LAMP
The Sentry Key Immobilizer System (SKIS) uses an indicator light to convey information on the status of the system to the customer. This light is shared with the Vehicle Theft Security System (VTSS). The light is located in the Instrument Cluster. The indicator light is controlled by the Body Control Module (BCM) based upon messages it receives from the Sentry Key Immobilizer Module (SKIM) on the PCI bus.

When the ignition is turned ON, the BCM performs a 4 second bulb check, regardless of SKIM messages. After the bulb check, the lamp is controlled according to SKIM messages. Then, the SKIM sends messages to the BCM to operate the light based upon the results of the SKIS self tests. The light may be actuated in two possible ways, flashing or on solid. If the light comes on and stays on solid after a power-up test, this indicates that the SKIM has detected a system malfunction. If the SKIM detects an invalid key when the ignition switch is moved to the ON position, it sends a message on the PCI bus to the BCM, to flash the light. The SKIM can also send a message to flash the light and generate a single audible chime at the same time. These two events occurring simultaneously indicate that the SKIS has been placed into the "Customer Learn" mode. Refer to Electrical, Vehicle Theft Security Transponder Key, Standard Procedure - Transponder Programming for more information on the "Customer Learn" mode. If the light comes on and stays on after the power-up test, diagnosis of the SKIS should be performed using a DRB III scan tool and the appropriate Body Diagnostic Procedures manual. The light is not a serviceable component.

Solid indicator that there is a system failure.
- Loss of PCM communication. Failed antenna circuit.




This passive system is designed to protect against vehicle theft. The vehicle theft security system (VTSS) is part of the body control module (BCM), which monitors vehicle doors and the ignition for unauthorized operation. The alarm activates by sounding the horn, flashing the headlamps, courtesy lamps, and the VTSS indicator lamp. Passive arming occurs upon normal vehicle exit by turning the ignition off, opening the driver's door, locking the doors with the power lock, and closing the driver's door or locking the doors with RKE. Manual arming occurs by using the key to lock the doors after closing them. The indicator lamp in the instrument cluster will flash for 15 seconds, showing that arming is in progress. If no monitored systems are activated during this period, the system will arm and the indicator will flash at a slow rate. If the indicator lamp remains steadily lit during the arming process, this can indicate a loss of decklid cylinder lock switch. When something triggers the alarm, the system will signal the headlamps, courtesy lamps, and horn for about 3 minutes, then headlamps for an additional 15 minutes if the offending input is still present.

For complaints about the Theft Alarm going off on its own use the DRBIII(R) and select "Body Computer" then "Input/Output Display" and read the "Last VTSS Cause" status.

Tamper Alert - The VTSS indicator lamp will flash twice quickly and the horn will chirp three times when the system is disarmed to indicate a tamper condition has occurred.

Manual Override - The system will not arm if the doors are locked using the manual lock control (by hand) or if the locks are actuated by an inside occupant after the door is closed. To verify the system, proceed as follows:
1. Open the driver's door.
2. Remove the ignition key (but keep it in hand).
3. Lock the doors with the power lock switch or the RKE.
4. Close the driver's door.

NOTE:
- After the doors are closed, locking the doors with RKE will also arm the system
- If the VTSS indicator lamp flashed, the system is operational and verified. If not, there may be a problem with the system.

Arming/Disarming - Active arming occurs when the remote keyless entry transmitter is used to lock the vehicle doors, whether the doors are open or closed. If one or more doors are open the arming sequence is completed only after all doors are closed.

Passive disarming occurs upon normal vehicle entry (unlocking either front door with the key). This disarming also will halt the alarm once it has been activated.

Active disarming occurs when the remote keyless entry transmitter is used to unlock the vehicle doors. This disarming also will halt the alarm once it has been activated

NOTE: A Powertrain Control Module from a vehicle equipped with a vehicle theft security system cannot be used in a vehicle that is not equipped with a vehicle theft security system. If the VTSS indicator lamp comes on after ignition ON and stays on, the PCI bus communication with the Power-train Control Module possibly has been lost.