Security Alarm System

The security alarm system is armed automatically after the doors, hood, and hatch are closed and locked. For the system to arm, the ignition switch must be in the LOCK (0) position, the key must be removed from the ignition switch, and the MICU must receive inputs that the doors, hood, and hatch are closed and locked. The alarm can be disarmed at any time by unlocking the driver door with the key or pressing the UNLOCK button on the transmitter.

When everything is closed and locked, the only inputs that are grounded, and have 0 V, are the driver's door lock knob switch (LOCK position) input and the audio unit or audio-navigation unit (if equipped) security input. In other words, all of the other switches are open, and have about 10 to 12 V, including the key cylinder switches. The horn sounds and the parking lights, side marker lights, taillights and license plate lights flash to confirm the security alarm system is armed if the LOCK button is pressed a second time within 5 seconds. The security indicator in the gauge control module begins to flash immediately after the vehicle is completely closed and locked, and 15 seconds later, the security system arms. If the security indicator does not flash after the doors are locked, the system is not arming.

If one of the switches is misadjusted or shorted internally, or there is a short in one of the keyless/power door lock/security circuits, the security system will not arm. A switch that is slightly misadjusted can cause the alarm to sound for no apparent reason. In this case, a significant change in outside air temperature, the vibration of a passing truck, or someone bumping into the vehicle could cause the alarm to sound.

If anything is opened or improperly unlocked after the system is armed, the control unit receives a ground signal from that switch, and the 10 to 12 V reference drops to 0 V. If the audio unit or audio navigation unit (if equipped) is disconnected, the input loses its ground, and the input voltage goes from 0 V to 10 to 12 V. The system sounds the alarm when any of these occur:

• A door or the hatch is forced open.
• A door is unlocked without using the key or the transmitter.
• The hood is opened.
• The audio unit or audio-navigation unit (if equipped) is disconnected.
• The transmitter PANIC button is pressed.

When the system sounds the alarm, the horn sounds and the exterior lights flash for 2 minutes. The alarm can be stopped at any time by unlocking the driver's door by pressing the UNLOCK button on the transmitter.