Lincoln Navigator: Body Closures / Body Closures - System Operation and Component Description. Description and Operation

System Operation

System Diagram

Network Message Chart

  RGTM Network Input Messages

  IPC Network Input Messages

Power Liftgate

Power Open

The power liftgate power open operation begins when:

• the RGTM detects the front power liftgate switch is activated.
• the RGTM detects the rear exterior liftgate release switch is activated.
• the RGTM receives a message from the BCM (indicating a request from a programmed RKE transmitter or a passive entry feature request).

Once the RGTM receives an open request, the power liftgate opens by carrying out the following:

• The RGTM checks the gear selector lever position and vehicle speed status from the messages received.
• The RGTM supplies power to the unlatch motor, releasing the liftgate latch
• The RGTM monitors the liftgate ajar state (the liftgate latch pawl switch opens and both forkbolt switches close to indicate the latch has fully released).
• When the RGTM detects the power liftgate latch is fully unlatched, it supplies power to the drive motors, opening the power liftgate.
• While the power liftgate is opening, the RGTM monitors the liftgate motor position sensor for liftgate position and velocity. If an obstruction is detected, the RGTM stops the liftgate drive motors.
• When the power liftgate reaches the full open position, the RGTM removes the power from the drive motors.

If any of the power liftgate switches is activated, a request for the hands-free feature is detected or a double press of the button on a RKE transmitter occurs during a power open, the liftgate stops and holds its position.

Power Close

The power liftgate power close operation begins when:

• the RGTM detects the front power liftgate switch is pressed.
• the RGTM detects the rear interior power liftgate switch is pressed.
• the RGTM receives a message from the BCM (indicating a request from a programmed RKE transmitter or a passive entry feature request).

Once the close request is received, the power liftgate closes by carrying out the following:

• The RGTM checks the gear selector lever position and vehicle speed status from the messages received.
• The RGTM starts an audible chime via the audio system.
• The RGTM supplies power to the drive motors.
• While the power liftgate is closing, the RGTM monitors the power liftgate motor position sensor (for liftgate position and velocity) and the anti-pinch switches. If an obstruction is detected, the power liftgate stops and reverses.
• The RGTM monitors the liftgate ajar state.
• When the RGTM detects the latch has engaged the striker (switches in the latch changing state), power is supplied to the cinching motor to pull the liftgate into the primary latch position and power is removed from the liftgate drive motors.
• When the RGTM detects the primary latch position has been reached (liftgate is fully closed), the RGTM reverses the direction of the cinching motor until the sector gear switch indicates a start position.

If any of the power liftgate switches is activated, a request for the hands-free feature is detected or the button on the RKE transmitter is double pressed during a power close, the liftgate stops and holds its position.

NOTE: The power liftgate may not operate correctly under the following conditions:

• Excessive weight (such as snow or ice) is present on the liftgate.
• A low voltage or drained battery.
• A disconnected battery.
• Repairs/adjustments have been made to the power liftgate strut, the power liftgate motors, the liftgate striker or the liftgate hinges.

If any of these conditions have occurred, the power liftgate must be re-initialized.
Refer to: Power Liftgate Initialization (501-03 Body Closures, General Procedures).

The liftgate only operates with the transmission in park (P).

Four warning tones sound as the liftgate begins to power close. If there is a problem one of the following may occur with the open or close request.

• One tone sounds if the ignition is on and the transmission is not in park (P).
• Three tones sound if the battery voltage is below the minimum operating
• One tone sounds if the vehicle speed is at or above 3 mph (5 km/h)
• Two tones sound and the lift gate stops closing and returns to the fully open position on the third close request if the passenger doors are closed and locked with the key fob inside the vehicle.

Power Liftgate Open Height Programming

The power liftgate open height can be programmed to open to a height other than the full open position. To program the power liftgate open height:

• Open the liftgate.
• Manually move the liftgate to the desired height.
• Press and hold the rear power liftgate close switch until a chime is heard, indicating that the new power liftgate maximum open height is successfully programmed.

The programmed power liftgate height is retained when the battery is disconnected.

Power Liftgate Chime

The power liftgate chime provides audible warnings to the operator. The power liftgate chime is sounded using the audio system. The RGTM sends messages over the CAN to the ACM when requesting the chime to sound.

Power Liftgate Hands-Free Feature (if equipped)

In addition to the passive entry system, the power liftgate hands-free feature utilizes a module and 2 capacitive sensors (located behind the rear bumper cover) for operation. The BCM sends a voltage signal to the hands-free liftgate actuation module. The hands-free liftgate actuation module monitors the 2 sensors. When the correct motion is detected (forward and back such as a kicking motion under the rear bumper), the hands-free liftgate actuation module communicates to the BCM via a LIN . The LIN supports bi-directional communication between the hands-free liftgate actuation module and BCM , allowing the liftgate passive entry process to begin (as though the liftgate release button was pressed)

Hands-free liftgate DTC is set in the BCM , if any failure occurs over the LIN .

The BCM verifies a valid programmed passive key is within range of the rear keyless entry antenna and sends a message to the RGTM to open the liftgate.

For detailed information on the liftgate passive entry feature,
Refer to: Handles, Locks, Latches and Entry Systems - System Operation and Component Description (501-14 Handles, Locks, Latches and Entry Systems, Description and Operation).

Component Description

Front Power Liftgate Switch

The front power liftgate switch (located on the instrument panel) is a momentary contact switch that routes the voltage signal from the RGTM to ground when pressed. Pressing this switch either opens, closes or stops the motion of the power liftgate.

Rear Interior Power Liftgate Switch

The rear interior power liftgate switch (located on the bottom of the liftgate trim panel) is a momentary contact switch that routes the voltage signal from the RGTM to ground when pressed. Pressing this switch closes the power liftgate. The power liftgate does not open or release the latch from the rear interior power liftgate switch.

Rear Exterior Liftgate Release Switch

The rear exterior liftgate release switch is a momentary contact switch that routes the voltage signal to ground when pressed. The signal is sent from the BCM and the RGTM .

If the doors were not previously electronically unlocked when the rear exterior liftgate release switch is pressed, the BCM activates the liftgate passive entry feature. If the BCM detects a valid programmed passive key, the BCM sends a message to the RGTM to open the liftgate. If no passive key is detected, the request is ignored.

If the doors were previously electronically unlocked when the liftgate switch is pressed, the RGTM opens the liftgate. The RGTM receives the door lock/unlock status from the BCM over the CAN .

Any subsequent presses of the switch stops the motion or reverses direction.

Power Liftgate Latch

The power liftgate latch is responsible for unlatching, latching and cinching the liftgate. The power liftgate latch contains an unlatch motor, a cinching motor, a pawl switch, forkbolt primary and secondary switches, and a sector gear switch.

Unlatch Motor

The unlatch motor is only driven in one direction to unlatch the liftgate, similar to an actuator activating. A spring returns the unlatch motor to a rest position.

Cinching Motor

The cinching motor is driven in one direction to cinch the liftgate and in the opposite direction to its start position.

During a cinch operation, power is supplied to the cinching motor by the RGTM when the secondary latch position is reached during a power close operation. When the motor activates, it pulls the liftgate into the primary latch position. When the fully latched position is reached, the RGTM reverses the polarity to the cinching motor until it reaches its start position.

Pawl Switch, Forkbolt Primary and Secondary Switches

The pawl, forkbolt primary and secondary switches provide input to the RGTM to determine the liftgate latch position. The liftgate is in the primary position when the liftgate is in the full closed position. The liftgate is in the unlatched position when the liftgate is open and completely out of the striker. The RGTM receives input from the power liftgate pawl, forkbolt primary and secondary switches in the following manner:

  Latch Switch States

Sector Gear Switch

The sector gear switch opens and closes to provide input to the RGTM to determine the position of the cinching motor sector gear. During a cinching operation, the RGTM deactivates the cinching motor once the latch is detected as being in the primary latch position. The RGTM then reverses the direction of the cinching motor until the sector gear switch indicates the sector gear has returned to the start position.

Power Liftgate Motor

The power liftgate motors raises and lowers the liftgate. The power liftgate motors is bi-directional and contains a position sensor that provides input to the RGTM for liftgate position and velocity.

Position Sensor

The RGTM provides power and ground to the hall-effect sensors within the position sensor. It also supplies voltage signals to the position sensor on a valid open command or when the liftgate is in the open position. The position sensor has 2 data lines the RGTM monitors to determine liftgate movement and position. The RGTM uses the liftgate position information to determine which direction to power the liftgate (open or close) when a valid operation command is received. The movement is monitored to identify obstructions.

Anti-Pinch Switch

The liftgate anti-pinch switches are membrane-style switches. When the liftgate anti-pinch switch is compressed, the resistance change indicates to the RGTM an obstacle is present and prevents the liftgate from closing.

When the liftgate anti-pinch switch is not compressed, it has an approximate resistance of 5,700–6,700 ohms. When the liftgate anti-pinch switch is compressed, it has an approximate resistance of 0–200 ohms.

Hands-Free Liftgate Actuation Module

The hands-free liftgate actuation module is located behind the rear bumper cover on the right side of the vehicle. The hands-free liftgate actuation module receives a 12-volt signal from the BCM while monitoring 2 capacitive sensors. When the correct motion is detected from the upper and lower sensors, the hands-free liftgate actuation module communicates to the BCM via a LIN .

Hands-Free Liftgate Actuation Sensors

The hands-free liftgate actuation sensors are capacitive sensors and generate capacitive fields near the rear bumper. The capacitive fields are disrupted when an object (such as a leg) enters the area. The hands-free liftgate actuation module uses this information to interpret movement near the rear bumper.

RGTM

The RGTM sends voltage signals to the front and rear interior power liftgate switches and the exterior liftgate release switch. The signal is routed to ground when a switch is pressed, pulling the signal low to indicate a request to open or close the liftgate.

The RGTM receives a message from the BCM upon a valid request from the passive entry system or a RKE transmitter.

The RGTM controls the opening and closing of the power liftgate based on the inputs it receives.

The RGTM requires PMI when it is replaced.