Principles of Operation

Handles, 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 - Fusion/Milan

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 - MKZ

The SJB controls all of the passenger door lock actuators and receives input from the passenger door lock control switch. The Driver Door Module (DDM) controls only the driver door lock actuator and receives input from the driver door lock control switch. The 2 modules communicate the lock or unlock commands through the Medium Speed Controller Area Network (MS-CAN).

The SJB and the DDM are supplied voltage at all times. When the SJB receives a signal from the Remote Keyless Entry (RKE) transmitter, the keyless entry keypad, or the RH door lock control switch, the SJB sends a command to the DDM through the 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 sends 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 (within 3 seconds) of the luggage compartment lid release button 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 SJB interprets radio frequency signals from the Remote Keyless Entry (RKE) transmitters. The SJB requests the illuminated entry feature to turn the interior lamps on when an unlock command is received. If a lock command is received, the illuminated entry feature turns off.

The RKE transmitter supplies a signal to the SJB when any button is pressed. The SJB then supplies voltage to the appropriate door lock actuator(s) to lock or unlock the doors. The RKE transmitter can also be used to release the luggage compartment lid or activate the panic alarm. On MKZ, the RKE transmitter also causes the SJB to send an MS-CAN message to the Driver Seat Module (DSM) to activate all memory features to the positions associated with the RKE transmitter being used.

Keyless Entry Keypad

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.

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

The keyless entry keypad supplies a signal to the SJB when the buttons are pressed. The SJB then supplies voltage to the appropriate door lock actuator(s) to lock or unlock the doors. The keyless entry keypad can also be used to release the luggage compartment lid. On MKZ, the keyless entry keypad also causes the SJB to send an MS-CAN message to the Driver Seat Module (DSM) to activate all memory features to the positions associated with the personal entry code entered on the keypad.