Page 425 of 2339

POWER LIFTGATE SYSTEM
DESCRIPTION
the components of the power liftgate system are:
²Liftgate gear motor assembly
²Latch assembly
²Lift gear and rod
²Power liftgate control module
²Chime/thermistor
²Full open switch
²Engage actuator
²Pinch sensor
²Liftgate handle switch
²Overhead console switch
²Key fob switches (Fig. 1)
²Pawl switch
²Ratchet 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 closing
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, sim-
ilar 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 IIItor equiv-
alent, 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 8 - ELECTRI-
CAL/POWER DOORS - OPERATION). 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 SER-
VICE OF THE POWER LIFTGATE SYSTEM OR COM-
PONENTS.
OPERATION
With the push of a power liftgate open/close com-
mand switch (key fob or overhead console mounted) a
signal is sent out on the Programmable Communica-
tion 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, depend-
ing 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 lift-
gate, the power liftgate control module will immedi-
ately 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
Fig. 1 KEY FOB
1 - LEFT SLIDING DOOR SWITCH
2 - RIGHT SLIDING DOOR SWITCH
3 - LIFTGATE SWITCH
8N - 2 POWER LIFTGATE SYSTEMRS
Page 426 of 2339

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 mod-
ule 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 IIIt, or equiva-
lent scan tool, or with a complete cycle of the liftgate,
using any one of the command switches. (Refer to 8 -
ELECTRICAL/POWER DOORS - STANDARD PRO-
CEDURE) for detailed instructions.
The power liftgate system is designed with a num-
ber of system inhibitors. These inhibitors are neces-
sary for safety and / or feasibility of the power
liftgate system. The power liftgate system inhibitors
are:
²The Power Liftgate may not operate in extreme
temperatures. These extreme temperatures will be
approximately less than -12É F (-24.4É C) or greater
than 143É F (61.6É C). A chime/thermister assembly
in the rear light bar assembly monitors the outside
temperature.
²The vehicle transmission must be in Park or
Neutral for the power liftgate to start a cycle.
²If multiple obstacles are detected during the
same power open or close cycle, the liftgate goes into
manual operation.
²If severe problems occur, Diagnostic Trouble
Codes (DTC) are stored in the power liftgate control
module.
POWER LIFTGATE SYSTEM CAUTIONS AND
WARNINGS
WARNING: ALWAYS DISCONNECT THE BATTERY
NEGATIVE CABLE BEFORE ATTEMPTING ANY
POWER LIFTGATE SYSTEM SERVICE.
WARNING: THERE IS A SMALL AREA ON BOTH
SIDES OF THE LOWER POWER LIFTGATE WHICH
IS NOT PROTECTED BY PINCH SENSORS.
EXTREME CARE MUST BE TAKEN TO PREVENT
OBJECTS FROM ENTERING THIS AREA ONCE THELIFTGATE REACHES THE SECONDARY LATCH
CONTACT (APPROXIMATELY 1/2 INCH BEFORE
FULLY CLOSED).
WARNING: NEVER ATTEMPT TO ENTER OR EXIT
THE VEHICLE WITH THE LIFTGATE IN MOTION.
YOU COULD DAMAGE THE POWER LIFTGATE SYS-
TEM AND/OR COMPONENTS AND/OR CAUSE PER-
SONAL INJURY.
WARNING: NEVER STICK OBJECTS IN THE POWER
LIFTGATE WHEN CINCHING CLOSED. YOU COULD
DAMAGE THE VEHICLE, POWER LIFTGATE SYS-
TEM COMPONENTS AND/OR CAUSE PERSONAL
INJURY.
DIAGNOSIS AND TESTING
POWER LIFTGATE SYSTEM
The power liftgate system contains many compo-
nents and modules. In order to obtain conclusive
testing the Programmable Communications Interface
(PCI) data bus network and all of the electronic mod-
ules that provide inputs to, or receive outputs from
the power liftgate system must be checked.
The power liftgate system can be diagnosed with
an appropriate scan tool, such as the DRB IIItor
equivalent. The DRB IIItcan be used to observe var-
ious switch statuses throughout the power liftgate
system to help diagnose an inoperative switch or
component. The DRB IIItcan also be used to actuate
various components throughout the power liftgate
system to help diagnose an inoperative component.
Before any testing of the power liftgate system is
attempted, the battery should be fully charged, all
built-in power liftgate system inhibitors read and
understood, and all wire harness and ground connec-
tions inspected around the affected areas on the vehi-
cle.
The following are quick reference diagnostic tables
to help when diagnosing and testing the power lift-
gate system.
RSPOWER LIFTGATE SYSTEM8N-3
POWER LIFTGATE SYSTEM (Continued)
Page 427 of 2339

LIFTGATE SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
Liftgate opens unexpectedly Inoperative Power Liftgate Module or
Body Control Module (BCM)Disconnect then reconnect the battery
negative cable to reset module. Cycle the
power liftgate, if the power liftgate is still
not operating properly check for loose wire
connections, refer to the appropriate
diagnostic information
Inoperative latch assembly Check for blown fuse and loose wiring
connections
Check for Diagnostic Trouble Codes
(DTCs), replace latch as necessary
Inoperative open/close command
switchCheck for shorted or inoperative switch.
Replace switch as necessary
Liftgate will not open from
outside of vehicle manuallyInoperative key cylinder assembly Check for inoperative key cylinder
assembly. Replace key cylinder as
necessary
Check link rod connections at the latch and
key cylinder assembly
Check for binds or kinks in link rod
Check for foreign matter preventing the
operation of key cylinder assembly
Replace the components as necessary
Inoperative latch assembly Check for blown fuse and loose wiring
connections
Check for foreign matter preventing the
operation of latch assembly
Replace latch assembly as necessary
Binding or sticking of components Check for foreign matter preventing the
operation of door
Establish location of binding
Replace the components as necessary
Liftgate will not open/close
under powerInoperative Power Liftgate Module or
BCMDisconnect then reconnect the battery
negative cable to reset module. Cycle the
power liftgate, if the power liftgate is still
not operating properly check for loose wire
connections, refer to the appropriate
diagnostic information
Inoperative latch assembly Check for blown fuse and loose wiring
connections
Check for foreign matter preventing the
operation of latch assembly
Refer to the appropriate diagnostic
information. Replace latch assembly as
necessary
8N - 4 POWER LIFTGATE SYSTEMRS
POWER LIFTGATE SYSTEM (Continued)
Page 428 of 2339

CONDITION POSSIBLE CAUSES CORRECTION
Inoperative motor assembly Refer to the appropriate diagnostic
information.
Inoperative full open switch Refer to the appropriate diagnostic
information.
Binding or sticking of components Establish location of binding and replace
components as necessary
Power loss during Liftgate
operationLow battery voltage Charge battery
Inoperative Power Liftgate Module or
BCMDisconnect then reconnect the battery
negative cable to reset module. Cycle the
power liftgate, if the power liftgate is still
not operating properly check for loose wire
connections, refer to the appropriate
diagnostic information
Inoperative motor assembly Check for no drive condition
No power latching in
primary and/or secondary
positionsInoperative latch assembly Check for blown fuse and loose wiring
connections
Check for foreign matter preventing the
operation of latch assembly
Refer to the appropriate diagnostic
information. Replace latch assembly as
necessary
Binding or sticking of components Establish location of binding and replace
components as necessary
Inoperative Power Liftgate or BCM Disconnect then reconnect the battery
negative cable to reset module. Cycle the
power liftgate, if the power liftgate is still
not operating properly check for loose wire
connections, refer to the appropriate
diagnostic information
Door seal force too high Inspect seals for damage, mis-assembly,
foreign matter or other possible obstruction
Inoperative motor assembly Check for no drive condition
Latch will not fully release
from primary positionInoperative latch assembly Check for blown fuse and loose wiring
connections
Check for foreign matter or damaged
components preventing the operation of
latch assembly
Refer to the appropriate diagnostic
information. Replace latch assembly as
necessary
Inoperative outside handle switch Refer to the appropriate diagnostic
information. Replace switch as necessary
RSPOWER LIFTGATE SYSTEM8N-5
POWER LIFTGATE SYSTEM (Continued)
Page 429 of 2339

CONDITION POSSIBLE CAUSES CORRECTION
Inoperative Power Liftgate Module or
BCMDisconnect then reconnect the battery
negative cable to reset module. Cycle the
power liftgate, if the power liftgate is still
not operating properly check for loose wire
connections, refer to the appropriate
diagnostic information
Binding or sticking of components Establish location of binding and replace
components as necessary
Key fob, Outside Handle or
overhead console switches
do not power operate
liftgateBlown Fuse Check fuse and replace
Battery voltage low Charge or replace battery in key fob or
vehicle
Inoperative latch assembly Check for foreign matter preventing the
operation of latch assembly
Check wire connection
Pawl and/or ratchet switch inoperative.
Replace latch as necessary
Inoperative BCM Check electrical connections
Refer to the appropriate diagnostic
information for additional checks
Replace BCM as necessary
Inoperative key fob Verify inoperative key fob by trying other
key fob functions
Replace key fob battery
Reprogram key fob
Replace key fob as necessary
Inoperative Power Liftgate Module Disconnect then reconnect the battery
negative cable to reset module. Cycle the
power liftgate, if the power liftgate is still
not operating properly check for loose wire
connections, refer to the appropriate
diagnostic information
Inoperative liftgate motor assembly Check for foreign matter preventing the
operation of gear motor assembly
Check wire connections
Motor clutch does not engage. Replace
liftgate motor assembly
Full open switch inoperative, replace switch
as necessary
Liftgate does not stay open Inoperative liftgate prop rods Check for broken attachments. Replace
prop rods as necessary
High inside/outside opening
effortInoperative liftgate prop rods Check for broken attachments. Replace
prop rods as necessary
8N - 6 POWER LIFTGATE SYSTEMRS
POWER LIFTGATE SYSTEM (Continued)
Page 430 of 2339

CONDITION POSSIBLE CAUSES CORRECTION
Gear motor did not disengage Refer to the appropriate diagnostic
information. Replace components as
necessary
Binding or sticking of components Establish location of binding and replace
components as necessary
Liftgate continues to cinch
closed during power modeInoperative latch assembly Check for blown fuse and loose wiring
connections
Check for foreign matter preventing the
operation of latch assembly
Refer to the appropriate diagnostic
information. Replace components as
necessary
Inoperative Power Liftgate Module or
BCMDisconnect then reconnect battery to reset
module, function liftgate, if no function
exists check for loose wire connections,
see Body Diagnostic Manual for detailed
procedures
Liftgate continues to open
during power mode
(runaway motor)Inoperative Power Liftgate Module or
BCMDisconnect then reconnect the battery
negative cable to reset module. Cycle the
power liftgate, if the power liftgate is still
not operating properly check for loose wire
connections, refer to the appropriate
diagnostic information
Inoperative full open switch Check wire connections
Replace switch, if necessary
Inoperative motor assembly Check for continuous drive condition
Liftgate opens very slowly Inoperative liftgate motor assembly Check wire connections
Replace motor assembly as necessary
Inoperative liftgate prop rods Replace prop rods as necessary
Binding or sticking of components Establish location of binding and replace
components as necessary
Grade of vehicle too steep for power
operationOperate liftgate manually
Squeaks, Noises and rattles Foreign material in door
compartmentRemove foreign material
Loose components Check and tighten loose components as
necessary
RSPOWER LIFTGATE SYSTEM8N-7
POWER LIFTGATE SYSTEM (Continued)
Page 431 of 2339

STANDARD PROCEDURE
LIFTGATE ADJUSTMENT
In order for the power liftgate system to function
properly the liftgate must move freely and smoothly.
The power liftgate system can accommodate for some
minor changes in the effort required to move the lift-
gate. However, in extreme conditions the liftgate may
need to be mechanically adjusted for proper fit and
finish. (Refer to 23 - BODY/DECKLID/HATCH/LIFT-
GATE/TAILGATE/LIFTGATE - INSTALLATION) for
detailed instructions.
If a problem exists with the power liftgate and it is
suspected to be extreme effort, check the liftgate prop
rods and hinges for free movement.
NOTE: Routine application of Mopar MP-50Tor
equivalent on the chrome prop rod shafts and lift-
gate latch and hinges will help keep the liftgate in
good working order.
POWER LIFTGATE LEARN CYCLE
Any time a power liftgate component is removed,
replaced or a liftgate adjustment is performed a learn
cycle must be performed. This learn cycle enables the
power liftgate control module to learn or relearn
information (travel limits, resistance to door travel,
etc.) which allows it to perform properly and safely.
Perform the following to complete a power liftgate
learn cycle:
(1) Obtain a DRBIIIt, or equivalent scan tool.
(2) Connect the scan tool to the vehicle and check
for any power liftgate system stored Diagnostic Trou-
ble Codes (DTCs), correct and erase any stored
DTCs.
(3) Using the scan tool, Go into Test Routine Menu
and select the power open command.
(4) Select the power close command.
(5) The liftgate learn cycle is complete.
If a DRBIIItor equivalent scan tool is not avail-
able, the learn cycle can be performed by actuating
the liftgate using any of the normal command
switches. Be certain to cycle the liftgate through a
complete open and close cycle before returning the
vehicle to service.
NOTE: If the power liftgate will not complete a full
cycle a problem exists with the power liftgate sys-
tem. (Refer to 8 - ELECTRICAL/POWER DOORS -
DIAGNOSIS AND TESTING).
CHIME/THERMISTOR
DESCRIPTION
The chime/thermistor assembly is a small capacitor
shaped electrical component mounted to the rear
license plate lamp housing assembly (Fig. 2) , located
just above the license plate. The chime portion of the
assembly controls the audible chime sound heard at
the rear of the vehicle when the power liftgate is in
motion. The thermistor portion of the assembly is a
temperature sensor, used by the power liftgate con-
trol module. The chime/thermistor assembly is a ser-
viceable component.
OPERATION
The chime/thermistor assembly performs two dif-
ferent functions for the power liftgate system. First,
the chime portion provides an audible chime sound
which is controlled by the power liftgate control mod-
ule. The chime/thermistor assembly is hardwired to
the power liftgate control module. Second the ther-
mistor provides a outside temperature reading by
way of a resistance reading supplied to the power
liftgate control module. As temperature increases the
resistance reading increases, as temperature
decreases the resistance reading decreases.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
Fig. 2 REAR LIGHT BAR
1 - CHIME / THERMISTOR
2 - ELECTRIC RELEASE HANDLE SWITCH
3 - LICENSE PLATE LAMPS
8N - 8 POWER LIFTGATE SYSTEMRS
POWER LIFTGATE SYSTEM (Continued)
Page 432 of 2339

(2) Remove the rear light bar assembly from the
vehicle. (Refer to 8 - ELECTRICAL/POWER DOORS/
SWITCH - REMOVAL) for the procedure.
(3) Grasp the light bar at its sides next to ther-
mistor/chime assembly and gently pull the two sides
of the light bar apart until the thermistor/chime
assembly can be removed.
INSTALLATION
(1) Gently pull the two sides of the light bar apart
until the thermistor/chime assembly can be installed.
(2) Install the rear light bar assembly on the vehi-
cle. (Refer to 8 - ELECTRICAL/POWER DOORS/
SWITCH - INSTALLATION) for the procedure.
(3) Connect the battery negative cable.
ENGAGE ACTUATOR
DESCRIPTION
The 12 volt engage actuator (Fig. 3) provides the
engagement and disengagement of the liftgate gear
motor to the lift gear by way of an over center link,
activated by a lever.
The engage actuator is a serviceable component
and cannot be repaired, if found to be inoperative it
must be replaced.
OPERATION
The engage actuators normal position is disen-
gaged. When a power liftgate open or close command
is generated from any of the command switches, the
power liftgate control module signals the engage
actuator to move its lever to the engaged position.
This engages the gear motor to the lift gear, so when
the motor turns the lift gate moves upward or down-
wards depending on its current position.
During a manual liftgate open or close cycle the
engage actuator is disengaged, allowing unrestricted
liftgate movement.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the left rear D-pillar trim from the
vehicle, (Refer to 23 - BODY/INTERIOR/LEFT
D-PILLAR TRIM PANEL - REMOVAL).
(3) Manually engage the actuator link rod, this
must be done to access one of the engage actuator
retaining screws.
(4) Remove the two engage actuator retaining
screws (Fig. 4).
(5) Disconnect the engage actuator electrical con-
nector and remove the engage actuator from the
vehicle.
Fig. 3 LIFTGATE GEAR MOTOR ASSEMBLY
1 - TRANSVERSE BRACKET
2 - ENGAGE ACTUATOR
3 - LIFT GEAR AND ROD ASSEMBLY
4 - LIFTGATE MOTOR
Fig. 4 LIFTGATE GEAR MOTOR ASSEMBLY
1 - ENGAGE ACTUATOR RETAINING SCREWS
2 - LIFT GEAR RETAINING BOLTS
RSPOWER LIFTGATE SYSTEM8N-9
CHIME/THERMISTOR (Continued)