Principles of Operation

Locks, Latches and Entry Systems







Principles of Operation

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

The SJB receives inputs and delivers outputs to many of the electronically controlled features of the vehicle. The SJB constantly monitors the system under its control and reports a concern in the form of a DTC.

Power Door Locks - Without Memory

Regardless of the key position, the SJB is supplied voltage at all times. When the SJB receives a signal from the Remote Keyless Entry (RKE) transmitter, the keyless entry keypad, or the door lock control switches, the SJB supplies a ground signal to the appropriate lock or unlock relay. The ground signal closes the relay which supplies voltage to the door lock actuators. The door lock actuators then actuate to a lock or unlock position.

Power Door Locks - With Memory

Regardless of the key position, the SJB and the Driver Door Module (DDM) are supplied voltage at all times. When the SJB receives a signal from the RKE transmitter, the keyless entry keypad, or either door lock control switch, the SJB sends a command to the DDM, through the Medium Speed Controller Area Network (MS-CAN), and a ground signal to the lock and unlock relays. When the LH door lock control switch is pressed, the DDM receives the lock or unlock signal. The DDM will send a request through the MS-CAN to the SJB to lock or unlock the passenger doors. The SJB then responds to the DDM request, authorizing a lock or unlock of the driver door by the DDM. The DDM then supplies voltage and ground to the driver door lock actuator based on the lock or unlock request. The ground signal in the SJB closes the relay which supplies voltage to the remaining door lock actuators. The remaining door lock actuators then actuate to a lock or unlock position determined by the relay.

Luggage Compartment Lid Release

NOTE: When using the Integrated Keyhead Transmitter (IKT), 2 presses of the luggage compartment lid release button (within 3 seconds) are required to release the luggage compartment lid.

The luggage compartment lid release system is inhibited when the vehicle speed exceeds 8 km/h (5 mph). The luggage compartment lid latch releases the luggage compartment lid when the customer requests it be opened using either the IKT, the keyless entry keypad, or the luggage compartment lid release switch. When the SJB receives a signal to release the luggage compartment lid, the SJB supplies voltage to the luggage compartment lid latch. The luggage compartment lid latch then actuates to release the luggage compartment lid.

Remote Keyless Entry (RKE)

The keyless entry keypad is hardwired to the SJB. The SJB interprets the inputs from the keyless entry keypad and then controls the associated operation. The keyless entry keypad is illuminated for 5 seconds when any button is pressed. The SJB requests the illuminated entry feature to turn the interior lamps on when a valid entry code is received. If a lock all doors code is entered, the illuminated entry feature turns off. If enabled, the perimeter lighting turns on when the RKE transmitter unlock command is activated. When an RKE transmitter or keyless entry keypad lock command is activated, the perimeter lighting is turned off.

NOTE: The keyless entry keypad does not lock the doors if the driver door is ajar.

Either the RKE transmitter or the keyless entry keypad supplies a signal to the SJB when pressed. The SJB then supplies voltage to the appropriate door lock actuator(s) to lock or unlock the doors. The keyless entry keypad or the RKE transmitter can also be used to release the luggage compartment lid. The RKE transmitter can also be used to activate the panic alarm. The panic alarm activation can be configured using a scan tool. It can be changed from a single button press, to press and hold. Refer to Information Bus. A single press will de-activate the panic alarm. On vehicles equipped with memory, the RKE transmitter also causes the SJB to send a MS-CAN message to the Driver Seat Module (DSM) to activate all memory features to the positions associated with the RKE transmitter being used.