Trunk / Liftgate: Description and Operation

POWER LIFTGATE

The power liftgate feature allows the customer to automatically open or close the liftgate by activating the interior open/close switch, the remote keyless entry transmitter, or by lifting the liftgate exterior handle. The power liftgate uses a power cinching system to latch the liftgate.

The power liftgate feature suspends a power open or power close when the ignition key is moved to the START position. The clutch will remain active to hold the liftgate in place during a start operation. Once the ignition key is no longer in the START position, the liftgate power open or power close will resume.

The power liftgate system consists of the following components:
- power liftgate control switch (located in the overhead console)
- power liftgate motor (located behind the LH rear quarter trim panel)
- position sensor (located on the power liftgate motor assembly)
- pinch strip switches (located on the body above the left and right taillamps)
- power liftgate latch (located in the middle lower portion of the liftgate)
- forkbolt switches (located in the power liftgate latch)
- detent switch (located in the power liftgate latch)
- unlatch actuator (located in the power liftgate latch)
- cinching actuator (located in the power liftgate latch)
- lock/unlock actuator (located in the power liftgate latch)
- power liftgate module (located behind the left rear quarter trim panel)

The power liftgate is controlled by the power liftgate module.

The power liftgate module receives inputs from:
- the forkbolt switch - primary (determines the position of the latch).
- the forkbolt switch - secondary (determines the position of the latch).
- the detent switch (determines the position of the latch).
- the power liftgate open/close switch (activates the power liftgate from the interior of the vehicle).
- the pinch strip switches (determines if an obstacle is between the pinch strip and liftgate).
- the position sensor (determines the direction, travel speed and obstacle detection of the liftgate).
- the ISO serial communication link.

The power liftgate module sends outputs to:
- the liftgate motor.
- the liftgate clutch.
- the cinching actuator.
- the unlatch actuator.
- the liftgate close chime.

The liftgate close chime provides the sounding of an audible chime (housed in a unit external from the power liftgate module) whenever a powered closing operation is initiated. The chime sound serves as a warning to alert the vehicle occupants and any bystanders that the liftgate is being moved in a closing direction by a powered operation. The power liftgate module controller will activate the external chime unit's continuous chime mode through a discrete high side drive output signal. The output will be active for 4 seconds, resulting in the chime sounding for a period of 4 seconds. The gate will not be moved for the first second, as a pre-warning of impending gate movement. During that initial first second, the power liftgate module may energize the gate drive system at a low power level that is intended to cause little (3 degrees maximum) to no gate movement. This is done to take up drive unit slack in advance, so that gate closure times meet the open/close cycle time requirement.

The power liftgate may not operate under the following conditions:
- low voltage or dead battery.
- disconnected battery.
- power liftgate that has been left open for more than 6 hours.
- power liftgate that has been manually closed and left ajar.

If any of these conditions have occurred, the power liftgate must be reset before carrying out any pinpoint tests.