Principles of Operation
Anti-Theft
Principles of Operation
NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
On early-build vehicles a door lock cylinder disarm switch is present and can be used for disarming the perimeter alarm. On late-build vehicles, the door lock cylinder disarm switch is deleted and a 12-second chime is used in its place with disarming taking place after the key is turned to the on position.
The perimeter anti-theft system consists of the following:
- Door ajar switches (part of the door latch)
- Door lock control switch
- Driver door lock cylinder disarm switch (early build vehicles)
- Exterior lamps
- Hood switch
- Horn
- Key-in-ignition switch
- Keyless entry keypad (if equipped)
- Remote Keyless Entry (RKE) transmitter (if equipped)
- Turn signal lamps
- SJB
The perimeter anti-theft feature is controlled by the SJB. The alarm can only be armed by using one of 3 actions:
- Pressing the LOCK button on the RKE transmitter
- Pressing the door lock control switch to lock with the accompanying door open, then closing the door
- Pressing the 7/8 and 9/0 buttons simultaneously on the keyless entry keypad (if equipped)
The SJB monitors the door ajar switches and the hood switch (all doors and the hood must be closed and the key must be out of the ignition lock cylinder). There is a 20-second pre-arm delay after which each door and the hood is armed. From the time each individual input is closed to the time the perimeter alarm is armed for that particular input, is the pre-arm phase. The pre-arm phase is separate for each individual input. If the door lock control switch was pressed to lock with the accompanying door open, all of the inputs that are closed (hood and rest of the doors) would immediately begin their pre-arm phase. After the door (that was open) is closed, then that door would begin its pre-arm phase. This would cause the other inputs to be armed a few seconds before that door. The perimeter alarm arms in stages in relation to which input was closed first after the arming action was received.
In the event of an unauthorized entry, the alarm is activated by the SJB. When the alarm is activated, the SJB intermittently grounds the horn relay, causing the horn to sound in regular intervals, and intermittently powers the turn signals, causing the turn signal lamps to flash in regular intervals.
An unauthorized entry is identified by the SJB whenever a door or hood is detected as having been opened without being disarmed first. If this occurs, the SJB activates the perimeter alarm immediately.
An authorized entry is identified by the SJB as any of the ajar switch inputs detected open after the system has been disarmed.
The door lock control switches cannot disarm the perimeter alarm.
The perimeter alarm can be disarmed only by using one of the following actions:
- Pressing the UNLOCK button on the RKE transmitter (if equipped)
- Using a key to turn the ignition switch to the ON position (this will also deactivate an activated alarm)
- Entering the correct vehicle unlock code on the keyless entry keypad (if equipped)
- Turning the driver door lock cylinder disarm switch to the unlock position (early build vehicles)
The perimeter alarm can be deactivated (not disarmed), by pressing the PANIC button on the RKE transmitter. This action will not disarm the alarm, but stops the alarm from activation (horn sounding and turn signal lamps flashing). The perimeter alarm continues to be armed.