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Home >> Lincoln >> 2018 >> MKZ Select, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 600 (Handles, Locks, Latches And Entry Systems) >> Description And Operation >> Handles, Locks, Latches and Entry Systems - With Intelligent Access (IA) >> System Operation

System Operation

WARNING: This page is about a different car, the 2017 Lincoln Navigator and 2017 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

System Diagram 

GFD137807Courtesy of FORD MOTOR COMPANY

Network Message Chart 

Remote Function Actuator (RFA) Module Network Input Messages 

Broadcast Message Originating Module Message Purpose
Vehicle lock status Body Control Module (BCM) The BCM sends this message to the RFA module when a door lock door lock control switch is pressed. The RFA module locks or unlocks the doors based on the data in the message.
Door ajar status BCM The RFA module uses this data for the smart unlock feature.

Body Control Module (BCM) Module Network Input Messages 

Broadcast Message Originating Module Message Purpose
Vehicle speed Powertrain Control Module (PCM) The BCM uses the vehicle speed data for autolock/auto-unlock and to ignore requests to open the liftgate when the vehicle is in motion.

Power Door Locks 

The RFA module controls the door locks by using a series of relays (driver door unlock/passenger doors unlock/all doors lock) integrated within it. When the relays are not energized, ground is provided on both circuits to the door lock actuators. When an unlock relay energizes, voltage is provided to one side of the door lock actuator to unlock the door(s). When the lock relay energizes, the polarity is reversed and the door lock actuators lock the doors.

NOTE: The door lock and the unlock relays are internal to the RFA module and are non-serviceable.

The BCM sends voltage signals to the left and right door lock control switches. When a door lock control switch is pressed, the voltage signal is routed to ground, indicating a request to lock/unlock the doors. When the BCM detects a request to lock or unlock the doors, it sends a message to the RFA module over the Medium Speed Controller Area Network (MS-CAN).

Based upon input from the BCM, the Radio Transceiver Module (RTM), and the keyless entry keypad, the RFA module energizes the lock all relay, the unlock driver door relay or unlock all relay. When the all lock relay is energized, the RFA module supplies voltage on the all door lock circuit and ground on the driver and passenger door unlock circuits. When the unlock driver door relay or unlock all relay is energized, the voltage and ground are reversed. When the lock and unlock relays are not energized, continuity to ground is supplied on all door lock actuator circuits. A dedicated RFA module ground circuit is provided for the lock and unlock relays.

Liftgate Glass Latch Release 

The BCM sends a voltage signal to the liftgate glass release switch. When the liftgate glass release switch is pressed, the voltage signal is routed to ground, indicating a request to release the liftgate glass latch. The BCM momentarily provides voltage to the liftgate glass latch to actuate the release motor.

The BCM releases the liftgate glass latch only after electronically unlocking the doors first.

Power Liftgate Open/Close 

Refer to Body Closures for information on the power liftgate.

Keyless Entry Keypad 

The RFA module sends voltage signals on 3 separate circuits to the keyless entry keypad. When an individual keypad button is pressed, an individual or combination of the input circuits is routed to ground. Based on these inputs, the RFA module determines which button was pressed and locks/unlocks the door(s).

When a keypad button is pressed, the buttons illuminate to provide better visibility. The keypad also illuminates any time the illuminated entry feature is active. If the lock all doors command is entered or 5 seconds have elapsed since the last button press, the keypad illumination turns off.

The keyless entry keypad can be used to:

Vehicles equipped with a keypad are programmed with a 5-digit entry code. This code is provided to the customer through a wallet card in the Owner's Literature. In addition, this code is available through a scan tool and is printed on the BCM label. When entering codes, each digit must be entered within 5 seconds of the previous button press.

NOTE: The code displayed on the scan tool is from the RFA module. If it does not match the code on the BCM label, reset the keyless entry keypad code. Refer to Remote Function Actuator (RFA) Module Keyless Entry Keypad Code Reset in Keyless Entry Keypad Code Programming .

Locking the Doors with the Keyless Entry Keypad System 

It is not necessary to enter the factory set or personal code prior to locking all doors. To lock all doors, press the 7/8 and 9/0 buttons at the same time.

Unlocking the Doors with the Keyless Entry Keypad System 

To unlock the driver door, enter either the factory set code or a personal code (each digit must be pressed within 5 seconds of the prior digit). The illuminated entry feature activates unless disabled.

To unlock all doors, enter the factory set code or a personal code (driver door unlocks) and then press the 3/4 button within 5 seconds. This feature can be changed to a 1-step unlock so that all of the doors unlock when a valid code is entered. Refer to Stepped Unlock Programming .

NOTE: Vehicles with passive entry come from the factory with 1-step unlock enabled.

Anti-Scan Feature 

To provide added security, the keypad is disabled for 1 minute after 35 button presses without a valid entry code being entered. The keypad flashes during this 1 minute mode with all functionality disabled except for 7/8 and 9/0 still being allowed to lock the vehicle.

Anti-scan turns off after 1 minute of keypad inactivity, the unlock button is pressed on a Remote Keyless Entry (RKE) transmitter, or the ignition is switched to RUN.

Factory Keycode Retrieval 

The factory keycode for the keyless entry keypad can be retrieved from a label on the BCM or using a diagnostic scan tool.

Remote Keyless Entry (RKE) 

The RKE system uses a passive key. The passive key incorporates both the Passive Anti-Theft System (PATS) and the RKE transmitter functions in a single device.

The passive keys can be used to:

The passive keys have a normal operating range of approximately 100 m (328 ft).

The RKE feature is controlled by the Radio Transceiver Module (RTM) and the RFA module. When a button is pressed on a valid programmed passive key, the Transmitter Identification Code (TIC) and RKE command is received by the internal Radio Transceiver Module (RTM) antenna. If the Radio Transceiver Module (RTM) determines it is a valid and programmed TIC, it sends the RKE command and TIC to the RFA module over a Local Interconnect Network (LIN) -based circuit. When the RFA module receives the RKE data, it carries out the command by activating the door locks, sending a message to the Liftgate/Trunk Module (LTM) to open the liftgate, sending a message to the BCM to activate the horn and turn signals as required or to remote start the vehicle.

The passive keys and the RFA module also utilize a rolling code to prevent the code from being captured by a code grabber. The system advances the counter in the passive key and the RFA module every time a passive key button is pressed.

Remote Keyless Entry (RKE) Transmitter Unlock 

The RKE feature provides a stepped (if enabled) process for unlocking the doors. Upon receipt of the first request for unlocking the doors, the RKE control feature unlocks only the driver door and provides a long flash of the turn signals. If another unlock request is received within 3 seconds of the first, all the doors are unlocked. This feature can be disabled so that all the doors unlock on the first press of the unlock button. To enable/disable this feature, refer to Stepped Unlock Programming .

NOTE: Vehicles with passive entry come from the factory with 1-step unlock enabled.

Remote Keyless Entry (RKE) Transmitter Lock 

The RKE feature requests that all of the doors lock when the lock button is pressed. On any press of the lock button with all doors closed, the doors lock and the turn signals flash once. If the hood, the liftgate or any door is ajar, no flash occurs. As soon as the opening is closed, the turn signals flash.

If 2 presses of the lock button are received within 3 seconds, the horn chirps once and the turn signals flash twice to indicate that the hood, the liftgate and all of the doors are closed and locked. If the hood, the liftgate or any door is ajar when the second lock request is received within 3 seconds of the first, the RKE transmitter feature chirps the horn twice without flashing the turn signals to indicate it locked all of the doors but the hood, the liftgate or a door is ajar. When the ignition is in RUN or START, the turn signal flashes and horn chirp confirmations do not occur.

Remote Keyless Entry (RKE) Transmitter Power Liftgate Open/Close 

The passive key provides a power liftgate open and close function. The liftgate button must be pressed twice within 3 seconds for the power liftgate to open or close.

Panic Alarm 

The panic alarm feature provides audible and visual alarms which are evident from the exterior of the vehicle. The panic alarm feature requests that the turn signals flash and the horn sounds until deactivation. The flashing of the outputs occurs simultaneously.

The panic alarm can only be activated when the ignition is OFF. This feature is disabled at all other times. Deactivation of an active panic alarm is accomplished when:

Remote Start 

Vehicles with the factory-installed remote start have an extended range to allow the vehicle to be remotely started from up to approximately 100 m (328 ft) away of the vehicle in an open air environment with no obstacles or environmental interference.

To remotely start the vehicle, the buttons on the passive key must be pressed within 3 seconds of each other. Press the lock button once and then the remote start button twice. The RFA module sends the request to the BCM. The BCM acknowledges the remote start request by flashing the exterior lights twice, starting the vehicle (the horn sounds if the vehicle fails to start) and turning on the parking lamps.

The vehicle does not remote start if any of the following conditions are present:

For additional information regarding the remote start system, refer to the Owner's Literature.

Autolock 

The autolock feature locks all of the doors after all of the following have occurred:

The autolock feature repeats after all of the following have occurred:

The autolock feature can be enabled/disabled using the message center.

Auto-Unlock 

NOTE: The doors do not auto-unlock if the vehicle has been electronically locked before the driver door is opened while the ignition is in OFF or ACC.

The auto-unlock feature unlocks all of the doors after all of the following have occurred:

The auto-unlock feature can be enabled/disabled using the message center.

Smart Unlock 

The smart unlock feature prevents the doors from electronically locking when a passive key is left inside the vehicle. When a door lock control switch is pressed with one of the doors open and a passive key is detected inside the vehicle, the RFA module commands the doors to unlock and the horn chirps.

To override the smart unlock feature and intentionally lock a key in the vehicle, close all of the doors and lock the vehicle using the keyless entry keypad, press the lock button on another passive key, or lock the doors manually with the lock rod before closing the door.

Passive Entry Feature 

NOTE: The passive entry feature is a programmable parameter and can be enabled/disabled with a scan tool. If the feature is disabled, the passive entry feature to enter the vehicle and passive starting are inoperative. To start the vehicle, the passive key must be placed in the backup starting location.

The passive entry feature unlocks the doors without having to use a mechanical key or the RKE transmitter feature.

When the RFA module detects a button on the keyless entry keypad is pressed, it activates the keyless entry antenna in the left rear door. The keyless entry antenna sends out a low frequency signal to the passive key. The low frequency signal activates the passive key and the passive key then sends a high frequency signal back to the Radio Transceiver Module (RTM). The Radio Transceiver Module (RTM) interprets the high frequency signal from the passive key and sends the information to the RFA module. If the RFA module determines that it is a valid programmed key, the RFA module either unlocks the driver door or unlocks all 4 doors.

With a valid programmed passive key within 1 m (3.28 ft) outside the driver front door, press a button on the keyless entry keypad. The door(s) unlock depending on the stepped unlock programming. Refer to Stepped Unlock Programming  for programming information.