Power Liftgate

Power Open 

The power liftgate power open operation begins when:

• the RGTM detects the front power liftgate switch is pressed.
• the RGTM detects the rear exterior liftgate release 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 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/cinching motor until the sector gear switches indicate end of travel, releasing the power liftgate latch.
• The power liftgate detent switch, primary forkbolt switch and secondary forkbolt switch circuits are monitored for correct latch release states.
• The RGTM performs 2 actions simultaneously.
  • The RGTM supplies power to the unlatch/cinching motor while monitoring the sector gear switches to return the sector gear to the neutral position.
  • The RGTM supplies power to the drive motor, opening the power liftgate.

• While the power liftgate is opening, the RGTM monitors the position sensor for liftgate position and velocity. If an obstruction is detected, the RGTM stops the liftgate drive motor.
• When the power liftgate reaches the full open position, the RGTM removes the power from the drive motor.
• After the power is removed from the drive motor, the position sensor briefly continues to monitor the position of the liftgate. If excessive movement in the closed direction is detected, power is reapplied to the motor and a continuous chime is initiated and remains on as the liftgate automatically closes

If any of the power liftgate switches 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 detects the rear exterior liftgate release switch is pressed.
• the RGTM receives a message from the BCM (indicating a double button press from a RKE transmitter or a hands free 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 motor.
• While the power liftgate is closing, the RGTM monitors the 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.
• The RGTM detects the secondary latch position is reached, power is supplied to the unlatch/cinching motor to pull the liftgate into the primary latch position. When primary latch position is reached, power is removed from the drive motor.
• The liftgate latch ajar switch closes to ground, indicating to the RGTM the latch has successfully latched.
• When the RGTM detects the primary latch position has been reached (liftgate is fully closed), the RGTM reverses the direction of the unlatch/cinching motor until the sector gear switches indicate the neutral position.

If any of the power liftgate switches is pressed or the button on the RKE transmitter is double pressed during a power close, the liftgate stops and holds its position.

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

If any of these conditions have occurred, the power liftgate must be re-initialized to: Power Liftgate Initialization .

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 IPC when requesting the chime to sound. The IPC is the chime arbitrator and determines which chime takes priority to: Warning Chimes - Overview (413-01 Instrumentation, Message Center and Warning Chimes, Description and Operation).

The power liftgate chime does not sound when the IPC is in sleep mode. The BCM sends the sleep mode message over the CAN when the battery saver feature activates for the demand lamps. Refer to: Interior Lighting - System Operation and Component Description .

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 momentarily grounds the signal from the BCM. When the BCM detects the ground signal, the liftgate passive entry process begins (as though the liftgate release button was pressed).

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