Principles Of Operation

Anti-Theft

Principles of Operation

NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).

The SJB controls the operation of the perimeter alarm based on inputs from all the ajar switch inputs, keyless entry keypad, driver door lock cylinder set/reset switch, and the Remote Keyless Entry (RKE) transmitters. If the SJB receives an input indicating an unauthorized entry into the vehicle, the SJB activates the perimeter alarm. When the perimeter alarm is activated, the horn sounds and both the turn signals and courtesy lights flash in regular intervals.

The SJB module receives hardwired inputs from the door lock control switches, hood switch, all door ajar switches, and the liftgate ajar input from the liftgate latch (manual liftgate) or the Liftgate/Trunk Module (LTM) (power liftgate) and the keyless entry keypad. The SJB also receives wireless signals from the Integrated Keyhead Transmitter (IKT).

If the driver door is unlocked by using a key in the door lock cylinder and then opened, the perimeter alarm starts a 12-second countdown. During the 12-second countdown there is a chime from the Instrument Cluster (IC) and the message center displays "TO STOP ALARM START VEHICLE". If the alarm is not deactivated during this countdown, the perimeter alarm activates.

Once the SJB receives the inputs, it either activates, deactivates, or triggers the perimeter alarm.

Battery Disconnect

If the battery is disconnected and then reconnected, the perimeter alarm remains in the same state (disarmed, pre-armed, armed, or activated) it was prior to the battery disconnect.

Alarm Event PIDs

The SJB has PIDs available that show what caused the last alarm events. The SJB has 4 alarm event PIDs and are AL_EVT1 through 4. The most recent alarm event is always listed in the first alarm event or trigger PID. These PIDs display what caused the alarm to trigger and can be a very useful tool when trying to identify the cause of a false alarm trigger.