Power Liftgate System: Operation: Notes

WARNING: This page is about a different car, the 2005 Dodge Grand Caravan, 2005 Dodge Caravan, and 2005 Chrysler Town & Country. However, it is still accessible from the selected car via links, so may be relevant.

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. The ability for the power liftgate module to detect resistance to liftgate 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 liftgate 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 III®, or equivalent scan tool, or with a complete cycle of the liftgate, using any one of the command switches. (Refer to ELECTRICAL/POWER DOORS - STANDARD PROCEDURE) for detailed instructions.

The power liftgate system is designed with a number of system inhibitors. These inhibitors are necessary for safety and/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 -12°F (-24.4°C) or greater than 143°F (61.6°C). A chime/thermistor 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.