System Information

The Universal Theft Deterrent (UTD) System is designed to sound the horns and flash the exterior lights, when the system is armed and entry is gained forcibly through the doors or trunk.

Alarms
Operation of the exterior lights and horns when activated, is controlled by the Theft Deterrent Module via the Theft Deterrent Relay. Fuse B3 applies voltage to the Theft Deterrent Relay's coil at all times. When the alarm is active the Theft Deterrent Module cycles the alarm system control driver (terminal F) on and off once per second. During this cycle ground is applied to the Theft Deterrent Relay coil and then removed. This causes the relay to energize and de-energize. The relay contacts will now cycle open and closed at the same rate as the alarm system control driver. When the Theft Deterrent Relay's contacts are closed, the Horn, Park Lights, and Headlight Relays are grounded through the Diode Pack, and CKT 624. The relays now energize and the relays respective circuits will turn on. The Diode Pack is installed in the circuit to provide circuit isolation. If the diode pack were to short some unusual symptoms might occur such as the headlights light when the horn is sounded.

Arming
Arming the Universal Theft Deterrent System is a four step procedure. The arming sequence begins when the ignition is turned OFF. This removes battery voltage at module terminal K, the ignition 1 input. Step 2 occurs when a door is opened and ground is applied to module terminal J, the tamper input. The system is still not armed so grounding the tamper input at this time does not set off the alarms. The SECURITY indicator flashes to alert the operator the system is not armed. Step 3 occurs when the doors are locked electrically, this applies battery voltage to the module's terminal G, the system arm input. The SECURITY indicator is on steady to indicate that the system is armed. The arming sequence is completed when all doors are closed, removing ground from the module's terminal J, the tamper input. The system is now armed. The SECURITY indicator will remain on for a few seconds.

The Keyless Entry System can also arm the Universal Theft Deterrent System if the ignition is off. When the Keyless Entry Module locks the doors it simulates a door being opened and then closed by momentarily grounding the Theft Deterrent Module's tamper input, terminal J. The Keyless Entry Module does this by applying ground through its automatic door lock inhibit terminal C9 and CKT 263. The Keyless Entry Module applies battery voltage to the theft module's system arm input terminal G when it locks the doors. Once the doors are locked the Keyless Entry Module opens its automatic door lock inhibit, this simulates the doors being closed and completes the arming procedure.

Cancellation
The arming sequence can be canceled by unlocking the doors electrically prior to closing the door. When the doors are unlocked, voltage is momentarily applied to the theft module's terminal M. This signals the module not to arm and the module will ignore the door being closed.

Disarming
When one of the front doors is unlocked with a key, the Front Door Lock Cylinder Switch closes. This grounds the Theft Module's disarm input, terminal H. The system is now disarmed and no alarms will operate when a door is opened.

Two other methods of disarming the system are turning the ignition to RUN using the key and using the Keyless Entry transmitter to unlock the doors.

When the Keyless Entry Module unlocks the doors it simulates a door lock cylinder switch closing to disarm the system. The Keyless Entry Module does this by grounding the Theft Module's disarm input terminal H. This is done through CKT 262 and the low side output driver at the Keyless Entry Module's terminal C8.

Turning the ignition to RUN will not disarm the system when the alarm is active.

Tampering
The alarms are set off when the Theft Module's tamper input, terminal J, is momentarily grounded after the system has been armed. This will occur when a door is opened causing a door ajar switch to ground or when Trunk Lid Tamper Switch closes due to tampering at the trunk lid lock.

Security Indicator
The Security indicator reminds the operator to arm the system by flashing and indicates that the system is armed when it stays on steady. The Theft Deterrent Module controls the indicator by grounding it through the indicator control driver at terminal D. The PASS-Key II system also uses the SECURITY indicator to inform the driver about its status.