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

Power Door Locks - Fusion

Regardless of the key position, the SJB (Smart Junction Box) is supplied voltage at all times. When the SJB (Smart Junction Box) receives a signal from the Remote Keyless Entry (RKE) transmitter, the keyless entry keypad, or the door lock control switches, the SJB (Smart Junction Box) 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 (Smart Junction Box) 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 (Smart Junction Box) and the DDM (Driver Door Module) are supplied voltage at all times. When the SJB (Smart Junction Box) receives a signal from the Remote Keyless Entry (RKE) transmitter, the keyless entry keypad, or the RH door lock control switch, the SJB (Smart Junction Box) sends a command to the DDM (Driver Door Module) through the MS-CAN (Medium Speed Controller Area Network) , and a ground signal to the lock and unlock relays. When the LH door lock control switch is pressed, the DDM (Driver Door Module) receives the lock or unlock signal. The DDM (Driver Door Module) sends a request through the MS-CAN (Medium Speed Controller Area Network) to the SJB (Smart Junction Box) to lock or unlock the passenger doors. The SJB (Smart Junction Box) then responds to the DDM (Driver Door Module) request, authorizing a lock or unlock of the driver door by the DDM (Driver Door Module). The DDM (Driver Door Module) then supplies voltage and ground to the driver door lock actuator based on the lock or unlock request. The ground signal in the SJB (Smart Junction Box) 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 (Integrated Keyhead Transmitter) , the keyless entry keypad, or the luggage compartment lid release switch. When the SJB (Smart Junction Box) receives a signal to release the luggage compartment lid, the SJB (Smart Junction Box) 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 (Smart Junction Box) interprets radio frequency signals from the Remote Keyless Entry (RKE) transmitters. The SJB (Smart Junction Box) 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 (Remote Keyless Entry) transmitter supplies a signal to the SJB (Smart Junction Box) when any button is pressed. The SJB (Smart Junction Box) then supplies voltage to the appropriate door lock actuator(s) to lock or unlock the doors. The RKE (Remote Keyless Entry) transmitter can also be used to release the luggage compartment lid or activate the panic alarm. On MKZ, the RKE (Remote Keyless Entry) transmitter also causes the SJB (Smart Junction Box) to send an MS-CAN (Medium Speed Controller Area Network) message to the Driver Seat Module (DSM) to activate all memory features to the positions associated with the RKE (Remote Keyless Entry) transmitter being used.

Keyless Entry Keypad

The keyless entry keypad is hardwired to the SJB (Smart Junction Box). The SJB (Smart Junction Box) 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 (Smart Junction Box) 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 (Smart Junction Box) when the buttons are pressed. The SJB (Smart Junction Box) 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 (Smart Junction Box) to send an MS-CAN (Medium Speed Controller Area Network) 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.