Vehicle Theft Security System (VTSS)

This passive system is designed to protect against vehicle theft. The Vehicle Theft Security System (VTSS) is part of the body control module, which monitors vehicle doors and the ignition for unauthorized operation. The alarm activates by sounding the horn, flashing the headlamps, park and tail lamps, and the VTSS indicator lamp, and providing an engine "no run" feature.

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 on the dash 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 possible loss of communication with the PCM.

When something triggers the alarm, the system will signal the headlamps, park lamps, and horn for about 3 minutes.

Tamper Alert - The VTSS indicator lamp will flash twice quickly 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.

When an unauthorized entry into the vehicle occurs, the VTSS sends a message via the CCD bus to the powertrain control module that it is not OK to start the engine. The powertrain control module then zeroes out the pulse width to the fuel injectors after the engine has been started, thus shutting down the engine (start and stall condition). The engine will not start until the system is disarmed.

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.
4. Close the driver's door. NOTE: After the doors are closed, locking the doors with RKE will also arm the system.

NOTE: 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.

System Self-Tests.

NOTE: System self-tests can be entered only with the DRB (scan tool) or MDS Machine.

Upon entering diagnostics, the headlamps and tail/park lamps will flash. In addition, the horn will sound twice. Removing the ignition key will stop the lamps from flashing while keeping the system in diagnostics.

While in diagnostics mode, a horn pulse should occur at each of the following events, which indicates proper operation.

1. Begin with all doors closed, then open and close each door. The horn will sound when each door ajar switch closes, and then again when the switch opens. There must be a 1-second delay between closing and opening the switch.
2. Rotate the key in each door lock cylinder to the lock and unlock positions. The horn will sound as the switch changes states. There must be a 1-second delay between changing switch states, or the horn will not sound.
3. Activate the power door lock switches to the unlock then lock positions. The horn will sound after each activation.
4. Activate the remote keyless entry in both the lock and unlock directions. The horn will sound after each activation.
5. Cycle the key to the ignition RUN position. A single horn pulse will indicate proper operation of the ignition input. This also will take the module out of the diagnostics mode.

For any of these tests, if the switch does not remain open or closed for at least 1 second, the horn will only sound once.

The lack of a horn pulse during any operation indicates either:
- A switch failure
- The lack of that input to the module a failure internal to the module
- A faulty horn system

Check for continuity at the switch. If this is good, check for an open or shorted wire between the switch and body control module. Also, check if the powertrain control module (PCM) has been replaced recently.

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 CCD bus communication with the powertrain control module possible has been lost.

Diagnostic trouble codes - There are no diagnostic trouble codes for the vehicle theft security system, only symptoms.

CIRCUIT OPERATION
The optional Vehicle Theft Security System (VTSS) is used to protect the vehicle from theft by monitoring the vehicle doors, ignition switch, power door lock circuits, and the trunk key cylinder to determine if the alarm should be sounded and the ignition system disabled.

The Body Control Module (BCM) is used as the control for the system. The inputs for the system are divided in two sections. The trunk area and the passenger compartment. If there is a malfunction in the trunk area switch the system will still ARM, but the switch will not be monitored. If the switch becomes functional while the system is ARMED it will be used as an input to the BCM. A problem in any passenger compartment switch will not allow the system to ARM.

The VTSS system uses a Light Emitting Diode (LED) located on the top of the instrument panel to indicate when the system is ARMED. The LED is supplied power on circuit M1. This circuit is the Ignition-Off Draw (IOD) circuit and protected by a 10 Amp fuse located in cavity 13 of the junction block. The BCM controls ground for the LED on circuit G69.