Antitheft and Alarm Systems: Description and Operation

INTRODUCTION
The Vehicle Theft Security System (VTSS) is an available factory-installed option on this model.

Vehicle Theft Security System
The Vehicle Theft Security System (VTSS) is designed to provide perimeter protection against unauthorized use or tampering by monitoring the vehicle doors and the ignition system. If unauthorized use or tampering is detected, the system responds by sounding the horn, flashing the headlamps, and providing an engine no-run feature.

Refer to the owner's manual in the vehicle glove box for more information on the features, use and operation of the vehicle theft security system.

Enabling
If the vehicle is so equipped, the Vehicle Theft Security System (VTSS) feature is enabled in the high-line Central Timer Module (CTM) before the vehicle is shipped from the factory. However, if a vehicle with VTSS requires CTM replacement, the VTSS feature must be enabled in the new CTM using a DRB scan tool. Refer to the Vehicle Theft Security System menu item on the DRB scan tool for the procedures.

The VTSS engine no-run feature is disabled when it is shipped from the factory. This is done by programming within the Powertrain Control Module (PCM). The logic in the PCM prevents the VTSS engine no-run feature from arming until the engine start counter within the PCM sees twenty engine starts. The VTSS no-run feature must be enabled when the vehicle is received from the assembly plant.

Once the VTSS engine no-run feature has been enabled, it cannot be disabled unless the PCM is replaced with a new unit. The same VTSS engine no-run feature enable logic will apply anytime the PCM is replaced with a new unit.

Arming
Passive arming of the Vehicle Theft Security System (VTSS) occurs when the vehicle is exited with the key removed from the ignition switch, the headlamps are turned off, and the doors are locked while they are open using the power lock switch. The power lock switch will not function if the key is in the ignition switch or the headlamps are turned on with the driver side front door open. The VTSS will not arm if the doors are locked using the key in the lock cylinder or using the mechanical lock button.

Active arming of the VTSS occurs when the Remote Keyless Entry (RKE) transmitter is used to lock the vehicle. For active arming to occur, the doors must be closed and the ignition switch must be in the Off position when the RKE transmitter Lock button is depressed. However, once the VTSS arming process has been completed, the ignition switch can be turned to the Accessory position without triggering the alarm.

Once the VTSS begins passive or active arming, the security lamp in the instrument cluster will flash rapidly for about fifteen seconds. This indicates that the VTSS arming is in progress. Turning a key in the ignition switch, opening a door, or unlocking a door by any means during the fifteen second arming process will cause the security lamp to stop flashing and the arming process to abort. Once the fifteen second arming function is successfully completed, the security lamp will flash at a slower rate to indicate that the VTSS is armed.

Disarming
Passive disarming of the Vehicle Theft Security System (VTSS) occurs when the vehicle is unlocked using the key to unlock either door. Active disarming of the VTSS occurs when the vehicle is unlocked by depressing the Unlock button of the Remote Keyless Entry (RKE) transmitter.

Once the alarm has been activated (horn sounding, headlamps flashing, and the engine no-run feature), either disarming method will also deactivate the alarm.

Power-up Mode
When the armed Vehicle Theft Security System (VTSS) senses that the battery has been disconnected and reconnected, it enters its power-up mode. In the power-up mode the alarm system remains armed following a battery failure or disconnect. If the VTSS was armed prior to a battery disconnect or failure, the system will have to be actively or passively disarmed after the battery is reconnected.

The power-up mode will also apply if the battery goes dead while the system is armed, and battery jump-starting is attempted. The engine no-run feature will prevent the engine from starting until the alarm system has been actively or passively disarmed.

Tamper Alert
The Vehicle Theft Security System (VTSS) tamper alert will sound the horn three times upon disarming, if the alarm was triggered and has since timed-out (about fifteen minutes). This feature alerts the vehicle operator that the VTSS was activated while the vehicle was unattended.

RKE/VTSS
If the vehicle is equipped with Remote Keyless Entry (RKE), programming of additional transmitters and horn chirp are customer programmable features. The highline CTM provides for RKE and the Vehicle Theft Security System (VTSS). The base CTM is not able to provide these functions. The presence of either of these options dictates that the vehicle is equipped with a highline CTM. The VTSS system monitors the door ajar switches and ignition switch to detect unauthorized entry into the vehicle. Once the vehicle is "armed", any one of these inputs can cause the VTSS system to be tripped. Once tripped, the horn and lights will pulse for 3 minutes and if an attempt is made to start the engine, it will start and stall, If the trigger condition is still present, the lights will continue to flash for an additional 15 minutes After 15 minutes the system will stop pulsing the lights and return to the "armed" state.The cause of the last 4 alarm triggers is stored by the CTM and may be retrieved by the DRB III(R).The system may be disarmed by either an unlock command from a valid RKE key fob or by using a key in either door. Both front door key cylinders are equipped with disarm switches. There is also a VTSS lamp on the dash that provides information to the driver about the state of the vehicle theft system.

The RKE system is placed in the programming mode by the DRB III(R), or by using the customer programming sequence. The system will store up to four key fob codes. Two fobs are supplied with the truck, additional fobs may be purchased through parts department. The additional fobs can be programmed with the DRB III(R), or by using the customer programming sequence. Through the DRB III(R), erasing and programming of one key fob without deleting the others is possible. If the key fob is stolen, all the fob codes stored previously may be erased to provide the owner of the vehicle with an extra sense of security.