Power Liftgate System Description

Key Fob:

The components of the power liftgate system are:
- Liftgate gear motor assembly
- Latch assembly
- Lift gear and rod
- Power liftgate control module
- Chime/thermistor
- Full open switch
- Engage actuator
- Pinch sensor
- Liftgate handle switch
- Overhead console switch
- Key fob switches
- Pawl switch
- Ratchet switch

The power liftgate system has its own power lift-gate control module, located on the vehicles left body D-pillar behind the trim panel. The power liftgate gear motor assembly is located just above the control module. The latch assembly is located in the bottom center of the power liftgate, below the exterior lift-gate handle switch. The power liftgate full open switch, engage actuator, lift gear and rod are part of the liftgate gear motor assembly. The pawl and ratchet switches are part of the latch assembly. The pinch sensors are located along the right and left sides of the power liftgate, just above the body line.

The liftgate handle switch is a power release switch and is located in the rear light bar assembly, just above the license plate. The overhead console switch is a power open and close command switch located in the vehicles overhead console.

Software technology has enabled the power liftgate control module to detect resistance to liftgate travel, which allows the power liftgate to stop and reverse direction anytime an obstruction is felt or any of the command switches are operated (only in dosing direction). Battery voltage is supplied to the power liftgate system through a 40 amp fuse, located in the Integrated Power Module (IPM) assembly. If the power liftgate system develops a fault, the power lift-gate can still be operated manually with a key, similar to a manual liftgate.

The power liftgate control module communicates on the Programmable Communication Interface (PCI) Bus Circuit. Therefore, the power liftgate control module can generate and store its own Diagnostic Trouble Codes (DTC). The vehicles Body Control Module (BCM) receives and supplies messages to the power liftgate control module via the PCI bus circuit. A diagnostic scan tool, such as the DRB III(R) or equivalent, is used to read and troubleshoot these DTCs. Refer to the Body Diagnostic Manual for a complete list of diagnostic routines.

For additional information, Refer to the appropriate wiring information for complete circuit schematic or connector pin-out information.

WARNING: BE CERTAIN TO READ ALL WARNINGS AND CAUTIONS BEFORE ATTEMPTING ANY SERVICE OF THE POWER LIFTGATE SYSTEM OR COMPONENTS.

With the push of a power liftgate open/close command switch (key fob or overhead console mounted) a signal is sent out on the Programmable Communication Interface (PCI) Data Bus circuit. This signal is detected at the Body Control Module (BCM). The BCM then sends a signal out on the PCI Data Bus circuit to the power liftgate control module. The power liftgate control module then signals the power liftgate motor to start an open or close cycle, depending on what position the liftgate is in.

During a liftgate open or close cycle, if the power liftgate module detects sufficient resistance to liftgate travel, such as an obstruction in the path of the liftgate, the power liftgate control module will immediately stop the liftgate movement and reverse travel to the full open or closed position. travel is accomplished by hall effect sensors, drive motor speed and pinch sensors (tape switches).

Anytime the liftgate is opened or closed using the power liftgate system the power liftgate control module learns from the cycle. If a replacement power lift-gate component is installed or a liftgate adjustment is made, the module will relearn the effort and/or time required to open or close the liftgate. This learn cycle can be performed with a DRB Ill�, or equivalent scan tool, or with a complete cycle of the liftgate, using any one of the command switches.

The power liftgate system is designed with a number of system inhibitors. These inhibitors are necessary for safety and I or feasibility of the power liftgate system. The power liftgate system inhibitors are:
- The Power Liftgate may not operate in extreme temperatures. These extreme temperatures will be approximately less than -120° F (-24.40° C) or greater than 1430° F (61.60° C). A chime/thermister assembly in the rear light bar assembly monitors the outside temperature.
- The vehicle transmission must be in Park or Neutral for the power liftgate to start a cycle.
- If multiple obstacles are detected during the same power open or close cycle, the liftgate goes into manual operation.
- If severe problems occur, Diagnostic Trouble Codes (DTC) are stored in the power liftgate control module.