standard factory-installed equipment on this model.
The power lock system allows all of the doors and the
liftgate to be locked or unlocked electrically by oper-
ating a switch on either front door trim panel. The
power lock system receives non-switched battery cur-
rent through a fuse in the Power Distribution Center
(PDC), so that the power locks remain operational,
regardless of the ignition switch position.

The power lock system for this vehicle also has a

door lock inhibit feature, which prevents the power
lock system from being energized with a power door
lock switch if a front door is open with the key in the
ignition and/or the exterior lamps are on. However,
the locks can still be operated manually, with a key
or energized with the RKE transmitter.

This vehicle also offers several customer program-

mable features, which allows the selection of several
optional electronic features to suit individual prefer-
ences. Refer to ELECTRONIC VEHICLE INFOR-
MATION

CENTER

PROGRAMMING

the

Service Procedures section of Group 8V - Overhead
Console Systems for more information on the cus-
tomer programmable feature options. Customer pro-
grammable feature options affecting the power door
lock system include:

• Auto Door Locks - Automatically locks all of

the vehicle doors and the liftgate when the vehicle
reaches a speed of about 24 kilometers-per-hour (15
miles-per-hour).

• Auto Unlock on Exit - Automatically unlocks

all of the vehicle doors and the liftgate when the
driver side front door is opened, if the vehicle is
stopped and the transmission gear selector is in the
Park or Neutral positions. This feature is linked to
the Auto Door Locks feature, and will only occur one
time following each Auto Door Lock event.

The power lock system for this vehicle can also be

operated remotely using the standard equipment
Remote Keyless Entry (RKE) system radio frequency
transmitters. Refer to Remote Keyless Entry Sys-
tem in the Remote Keyless Entry System section of
this group for more information on the RKE system.

This group covers the following components of the

power lock system:

• Driver Door Module (DDM)

• Passenger Door Module (PDM)

• Power lock motors

POWER LOCK SYSTEMS

8P - 1

• Power lock switches.
Certain functions and features of the power lock

system rely upon resources shared with other elec-
tronic modules in the vehicle over the Programmable
Communications Interface (PCI) data bus network.
The PCI data bus network allows the sharing of sen-
sor information. This helps to reduce wire harness
complexity, internal controller hardware, and compo-
nent sensor current loads. At the same time, this sys-
tem

provides

increased

reliability,

enhanced

diagnostics, and allows the addition of many new fea-
ture capabilities. For diagnosis of these electronic
modules or of the PCI data bus network, the use of a
DRB scan tool and the proper Diagnostic Procedures
manual are recommended.

The other electronic modules that may affect power

lock system operation are as follows:

• Body Control Module (BCM) - Refer to Body

Control Module in the Description and Operation
section of Group 8E - Instrument Panel Systems for
more information.

• Electronic

Vehicle

Information

Center

(EVIC) - Refer to Electronic Vehicle Information
Center in the Description and Operation section of
Group 8V - Overhead Console Systems for more
information.

• Powertrain Control Module (PCM) - Refer to

Powertrain Control Module in the Description
and Operation section of Group 14 - Fuel System for
more information.

Refer to Power Door Locks in the Contents of

Group 8W - Wiring Diagrams for complete circuit
diagrams. Following are general descriptions of the
major components in the power lock system.

OPERATION

The Passenger Door Module (PDM) contains the

power door lock control logic and a power lock switch.
The Driver Door Module (DDM) contains a power
lock switch and controls the output to the driver side
front door power lock motor, while the PDM controls
the output to the power lock motors for the remain-
ing doors and the liftgate.

When the power lock switch on the DDM is used to

lock or unlock the doors, the DDM sends a control
output to the driver side front door power lock motor
and sends lock or unlock request messages to the
PDM over the Programmable Communications Inter-
face (PCI) data bus. The PDM responds to these mes-
sages by sending control outputs to the power lock
motors of the remaining doors and the liftgate. When
the power lock switch on the PDM is used to lock or
unlock the doors, the PDM sends control outputs to
the power lock motors in the passenger side front
door, both rear doors and the liftgate, then sends lock
or unlock request messages to the DDM over the Pro-

grammable Communications Interface (PCI) data
bus. The DDM responds to these messages by send-
ing control outputs to the power lock motor of the
driver side front door.

In order to support the auto door locks and unlock

on exit features, if enabled, the power lock system
logic in the PDM needs to know the door ajar switch
status, vehicle speed, and transmission gear selector
lever position. The passenger side front door ajar
switch is the only hard wired input to the PDM. The
PDM obtains the remaining information from mes-
sages it receives from other electronic modules over
the PCI data bus network.

See the owner’s manual in the vehicle glove box for

more information on the features, use and operation
of the power lock system.

POWER LOCK SWITCH

DESCRIPTION

The power lock motors are controlled by a two-way

momentary switch mounted on the trim panel of each
front door. Each power lock switch is illuminated by
a Light-Emitting Diode (LED) that is integral to the
switch paddle.

The driver side front door power lock switch is

integral to the Driver Door Module (DDM), and the
passenger side front door power lock switch is inte-
gral to the Passenger Door Module (PDM). The
power lock switches and their lamps cannot be
adjusted or repaired and, if faulty or damaged, the
entire DDM or PDM unit must be replaced.

OPERATION

The front door power lock switches provide a lock

and unlock signal to the door module circuitry. The
Driver Door Module (DDM) circuitry controls the out-
put to the driver side front door power lock motor,
while the Passenger Door Module (PDM) circuitry
controls the output to the passenger side front door,
both rear door and the liftgate power lock motors.

When the DDM-integrated power lock switch is

actuated, the DDM circuitry sends control outputs to
the driver side front door power lock motor and sends
a message to the PDM over the Programmable Com-
munications Interface (PCI) data bus to control the
output to the passenger side front door, both rear
door and the liftgate power lock motors. When the
PDM-integrated power lock switch is actuated, the
PDM circuitry sends control outputs to the passenger
side front door, both rear door and the liftgate power
lock motors and sends a message to the DDM over
the Programmable Communications Interface (PCI)
data bus to control the output to the driver side front
door power lock motor.

8P - 2

POWER LOCK SYSTEMS

DESCRIPTION AND OPERATION (Continued)

Each power lock switch is illuminated by a Light-

Emitting Diode (LED) when the ignition switch is
turned to the On position. See the owner’s manual in
the vehicle glove box for more information on the fea-
tures, use and operation of the power lock switches.

DOOR MODULE

DESCRIPTION

A Driver Door Module (DDM) and a Passenger

Door Module (PDM) are used on this model to control
and integrate many of the electronic features and
functions of the vehicle. The door modules are
mounted to the inside surface of the trim panel on
each front door. The only visible parts of the door
modules are the switches and the bezel that are
located on the outside of each front door trim panel.
Each door module houses both the front power lock
and power window switches. The DDM also houses
individual switches for each passenger door power
window, a power window lockout switch and the
power mirror switch. The remainder of both door
modules is concealed behind the front door trim pan-
els.

The DDM and PDM each contain a central process-

ing unit and interface with each other, as well as
with other electronic modules in the vehicle over the
Programmable Communications Interface (PCI) data
bus network. The PCI data bus network allows the
sharing of sensor information. This helps to reduce
wire harness complexity, reduce internal controller
hardware, and reduce component sensor current
loads. At the same time, this system provides
increased

reliability,

enhanced

diagnostics,

and

allows the addition of many new feature capabilities.

The circuitry of the door modules controls the fol-

lowing hard wired outputs:

• Door and liftgate power lock motors

• Front and rear door power window motors

• Front door courtesy lamps

• Power mirror control and heating

• Rear door power window switch control and illu-

mination.

The door modules also receive the following hard

wired inputs:

• Front door ajar switch

• Front door power window switches

• Memory switch (with the Memory System option

only)

• Power lock switches

• Power mirror position potentiometers (with the

Memory System option only)

• Power mirror switches

• Power window lockout switch.
In addition, the DDM contains the program logic

for the optional Memory System, while the PDM con-

tains the program logic and the receiver for the stan-
dard Remote Keyless Entry (RKE) System. Refer to
Memory System in the Memory System section of
Group 8R - Power Seat Systems for more information
on the features of the Memory System. Refer to
Remote Keyless Entry System in the Remote Key-
less Entry System section of this group for more
information on the features of the RKE system.

For diagnosis of the DDM, PDM, or the PCI data

bus network, a DRB scan tool and the proper Diag-
nostic Procedures manual are recommended. The
DDM and the PDM cannot be adjusted or repaired
and, if damaged or faulty, they must be replaced.

OPERATION

The functions and features provided by the door

modules are possible because of their hard wired
inputs and outputs, as well as the resources they
share with each other and with the other electronic
modules in the vehicle through their communication
over the PCI data bus network. The door modules
use their internal programming and all of these
inputs to decide which functions they should perform
and both the standard and optional features they
should provide. Refer to ELECTRONIC VEHICLE
INFORMATION CENTER PROGRAMMING in
the Service Procedures section of Group 8V - Over-
head Console Systems for more information on the
customer programmable feature options.

POWER LOCK MOTOR

DESCRIPTION

Power operated front door, rear door and liftgate

locking mechanisms are standard equipment on this
model. The lock mechanisms are actuated by a
reversible electric motor mounted within each door
and the liftgate. The power lock motors for the doors
are integral to the door latch units. The liftgate
power lock motor is a separate unit secured to the
latch brainplate near the center of the liftgate and
operates the liftgate latch lock mechanism through a
connecting linkage rod.

The power lock motors for the four doors cannot be

adjusted or repaired and, if faulty or damaged, the
entire door latch unit must be replaced. The liftgate
power lock motor cannot be adjusted or repaired and,
if faulty or damaged, the entire liftgate latch brain-
plate unit must be replaced.

OPERATION

The driver side front door power lock motor is con-

trolled by the Driver Door Module (DDM). The
remaining power door lock motors and the liftgate
power lock motor are controlled by the Passenger
Door Module (PDM). A positive and negative battery

POWER LOCK SYSTEMS

8P - 3

DESCRIPTION AND OPERATION (Continued)

Content .. 149 150 151 152 ..