can bus JEEP GRAND CHEROKEE 2002 WJ / 2.G User Guide

The CD changer can only be serviced by an autho-
rized radio repair station. See the latest Warranty
Policies and Procedures manual for a current listing
of authorized radio repair stations.
OPERATION
The CD changer will only operate when the igni-
tion switch is in the On or Accessory positions, and
the radio is turned on. For more information on the
features, loading procedures and radio control func-
tions for the operation of the CD changer, see the
owner's manual in the vehicle glove box.
DIAGNOSIS AND TESTING - CD CHANGER
Following are tests that will help to diagnose the
hard wired components and circuits of the Compact
Disc (CD) changer unit. However, these tests may not
prove conclusive in the diagnosis of this unit. In
order to obtain conclusive testing of the CD changer
unit, the Programmable Communications Interface
(PCI) data bus network, the CD changer unit, the
radio receiver unit and any other electronic modules
that provide inputs to, or receive outputs from the
audio system must be checked.
Any diagnosis of the Audio system should
begin with the use of the DRB IIItdiagnostic
tool. For information on the use of the DRB
IIIt, refer to the appropriate Diagnostic Service
Manual.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
COMPACT DISC CHANGER INOPERATIVE
(1) Turn the ignition switch to the On position.
Turn the radio receiver on and check its operation. If
OK, go to Step 2. If not OK, (Refer to 8 - ELECTRI-
CAL/AUDIO/RADIO - OPERATION).(2) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the right body wire harness connector
from the CD changer connector receptacle. Check for
continuity between the power ground (Z17) circuit of
the right body wire harness connector for the CD
changer and a good ground. There should be continu-
ity. If OK, go to Step 3. If not OK, repair the open
power ground circuit to the radio receiver as
required.
(3) Reconnect the battery negative cable. Check for
battery voltage at the B(+) circuit cavity of the right
body wire harness connector for the CD changer. If
OK, go to Step 4. If not OK, go to Step 5.
(4) Turn the ignition switch to the On position.
Check for battery voltage at the ignition switch out-
put circuit cavity of the right body wire harness con-
nector for the CD changer. If OK, use a DRB scan
tool and the proper Diagnostic Procedures manual for
further diagnosis. If not OK, go to Step 6.
(5) Disconnect and isolate the battery negative
cable. Remove the radio receiver from the instrument
panel. Disconnect the 10 pin cable connector from the
radio receiver, but do not disconnect the other wire
harness connectors. Reconnect the battery negative
cable. Check for battery voltage at the B(+) circuit
cavity of the 10 pin connector receptacle on the radio
receiver. If OK, repair the open B(+) circuit to the CD
changer as required. If not OK, check for a shorted
B(+) circuit to the CD changer and repair as
required, then replace the faulty radio receiver.
(6) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the radio receiver from the instrument
panel. Disconnect the 10 pin cable connector from the
radio receiver, but do not disconnect the other wire
harness connectors. Reconnect the battery negative
cable. Turn the ignition switch to the On position.
Check for battery voltage at the ignition switch out-
put circuit cavity of the 10 pin connector receptacle
on the radio receiver. If OK, repair the open ignition
switch output circuit to the CD changer as required.
If not OK, check for a shorted ignition switch output
circuit to the CD changer and repair as required,
then replace the faulty radio receiver.
NO SOUND OR ONLY ONE CHANNEL SOUND
FROM CD CHANGER
(1) Turn the ignition switch to the On position.
Turn the radio receiver on and check its audio output
operation. If OK, go to Step 2. If not OK, (Refer to 8
- ELECTRICAL/AUDIO/SPEAKER - OPERATION).
(2) Disconnect and isolate the battery negative
cable. Disconnect the right body wire harness connec-
tor from the CD changer connector receptacle.
Remove the radio receiver from the instrument
WJAUDIO 8A - 13
CD CHANGER (Continued)

(7) Reach under the passenger side of the instru-
ment panel near the right cowl side inner panel to
reconnect the antenna coaxial cable connector halves.
(8) Install the trim panel onto the right inner cowl
side. (Refer to 23 - BODY/INTERIOR/COWL TRIM -
INSTALLATION) for the procedures.
(9) Install the scuff plate onto the right front door
sill. (Refer to 23 - BODY/INTERIOR/DOOR SILL
SCUFF PLATE - INSTALLATION) for the proce-
dures.
(10) Reconnect the battery negative cable.
QUARTER GLASS INTEGRAL
ANTENNA - EXPORT
DESCRIPTION
The integral radio antenna element is bonded to
the right rear quarter glass and is replaced with the
glass assembly only.
OPERATION
The integral antenna receives RF (Radio Frequen-
cies) and sends them to the antenna module for
amplification.
DIAGNOSIS AND TESTING - QUARTER GLASS
INTEGRAL ANTENNA - EXPORT
For complete circuit diagrams, refer to the Appro-
priate Wiring Information. To detect breaks in the
integral antenna elements, the following procedure is
required:
(1) Disconnect the antenna module connector from
the antenna.
(2) Using a Ohmmeter, place both leads onto the
connector pins on the integral antenna. If continuity
is present antenna grid is Okay. If continuity is not
present move one lead through the grid in progres-
sion until continuity is detected. A break in the
antenna grid can be repaired using a Mopar Rear
Window Defogger Repair Kit (Part Number 4267922)
or equivalent. (Refer to 8 - ELECTRICAL/WINDOW
DEFOGGER/REAR WINDOW DEFOGGER GRID -
STANDARD PROCEDURE)
RADIO
DESCRIPTION
Available factory-installed radio receivers for this
model include an AM/FM/cassette with CD changer
control feature (RBB sales code), an AM/FM/CD/2-
band graphic equalizer with CD changer control fea-
ture (RBK sales code), or an AM/FM/CD/cassette/2-
band graphic equalizer (RBP sales code). All factory-
installed radio receivers can communicate on theProgrammable Communications Interface (PCI) data
bus network through a separate wire harness connec-
tor. All factory-installed receivers are stereo Electron-
ically Tuned Radios (ETR) and include an electronic
digital clock function.
These radio receivers can only be serviced by an
authorized radio repair station. See the latest War-
ranty Policies and Procedures manual for a current
listing of authorized radio repair stations.
All vehicles are equipped with an Ignition-Off
Draw (IOD) fuse that is removed when the vehicle is
shipped from the factory. This fuse feeds various
accessories that require battery current when the
ignition switch is in the Off position, including the
clock. The IOD fuse is removed to prevent battery
discharge during vehicle storage.
When removing or installing the IOD fuse, it is
important that the ignition switch be in the Off posi-
tion. Failure to place the ignition switch in the Off
position can cause the radio display to become scram-
bled when the IOD fuse is removed and replaced.
Removing and replacing the IOD fuse again, with the
ignition switch in the Off position, will correct the
scrambled display condition.
The IOD fuse should be checked if the radio or
clock displays are inoperative. The IOD fuse is
located in the Power Distribution Center (PDC).
Refer to the fuse layout label on the underside of the
PDC cover for IOD fuse identification and location.
OPERATION
The radio receiver operates on ignition switched
battery current that is available only when the igni-
tion switch is in the On or Accessory positions. The
electronic digital clock function of the radio operates
on fused battery current supplied through the IOD
fuse, regardless of the ignition switch position.
For more information on the features, setting pro-
cedures, and control functions for each of the avail-
able factory-installed radio receivers, refer to the
owner's manual. For complete circuit diagrams, refer
to the appropriate wiring information. The wiring
information includes wiring diagrams, proper wire
and connector repair procedures, details of wire har-
ness routing and retention, connector pin-out infor-
mation and location views for the various wire
harness connectors, splices and grounds.
DIAGNOSIS AND TESTING - RADIO
Any diagnosis of the Audio system should
begin with the use of the DRB IIItdiagnostic
tool. For information on the use of the DRB
IIIt, refer to the appropriate Diagnostic Service
Manual.
If the vehicle is equipped with the optional remote
radio switches located on the steering wheel and the
8A - 16 AUDIOWJ
INSTRUMENT PANEL ANTENNA CABLE (Continued)

The two remote radio switch units share a common
steering wheel wire harness with the vehicle speed
control switches. The steering wheel wire harness is
connected to the instrument panel wire harness
through the clockspring. (Refer to 8 - ELECTRICAL/
RESTRAINTS/CLOCKSPRING - DESCRIPTION) for
more information on this component.
For complete circuit diagrams, refer to the appro-
priate wiring information. The wiring information
includes wiring diagrams, proper wire and connector
repair procedures, details of wire harness routing
and retention, connector pin-out information and
location views for the various wire harness connec-
tors, splices and grounds.
OPERATION
The six switches in the two remote radio switch
units are normally open, resistor multiplexed
momentary switches that are hard wired to the Body
Control Module (BCM) through the clockspring. The
BCM sends a five volt reference signal to both switch
units on one circuit, and senses the status of all of
the switches by reading the voltage drop on a second
circuit.
When the BCM senses an input (voltage drop) from
any one of the remote radio switches, it sends the
proper switch status messages on the ProgrammableCommunication Interface (PCI) data bus network to
the radio receiver. The electronic circuitry within the
radio receiver is programmed to respond to these
remote radio switch status messages by adjusting the
radio settings as requested. For diagnosis of the
BCM or the PCI data bus, the use of a DRB scan tool
and the proper Diagnostic Procedures manual are
recommended.
For more information on the features and control
functions for each of the remote radio switches, see
the owner's manual in the vehicle glove box.
DIAGNOSIS AND TESTING - REMOTE
SWITCHES
Any diagnosis of the Audio system should
begin with the use of the DRB IIItdiagnostic
tool. For information on the use of the DRB
IIIt, refer to the appropriate Diagnostic Service
Manual.
For complete circuit diagrams, refer to the appro-
priate wiring information. The wiring information
includes wiring diagrams, proper wire and connector
repair procedures, details of wire harness routing
and retention, connector pin-out information and
location views for the various wire harness connec-
tors, splices and grounds.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable. Remove the remote radio switch(es) (Fig. 16)
from the steering wheel.
(2) Use an ohmmeter to check the switch resis-
tances as shown in the Remote Radio Switch Test
chart. If the remote radio switch resistances check
OK, go to Step 3. If not OK, replace the faulty
switch.
Fig. 15 Remote Radio Switches
1 - PRESET ADVANCE
2 - SEEK
3 - MODE ADVANCE
4 - VOLUME
8A - 20 AUDIOWJ
REMOTE SWITCHES (Continued)

DIAGNOSIS AND TESTING - CHIME WARNING
SYSTEM
Refer to the appropriate wiring information. Con-
ventional diagnostic methods may not prove conclu-
sive in the diagnosis of the instrument cluster or the
Programmable Communications Interface (PCI) data
bus network. The most reliable, efficient and accu-
rate means to diagnose the BCM and the PCI data
bus network inputs for the chime warning system
requires the use of a DRBIIItscan tool and the
appropriate diagnostic information.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFOREATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
CHIME WARNING SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
NO SEAT BELT WARNING
CHIME WITH SEAT BELT
UNBUCKLED, BUT OTHER
CHIME FEATURES OK1. Seat belt switch ground
circuit open.1. Check for continuity between the ground circuit
of the wire harness connector for the seat belt
switch and a good ground. Repair the ground
circuit, if required.
2. Seat belt switch sense
circuit open.2. Check for continuity between the seat belt
switch sense circuit of the wire harness connector
for the seat belt switch and the body wire harness
junction block connector. Repair the seat belt
switch sense circuit, if required.
3. Faulty seat belt switch. 3. Check for continuity between the ground circuit
and the seat belt switch sense circuit of the seat
belt switch pigtail wire connector. There should be
continuity with the seat belt unbuckled. Replace
the faulty seat belt, if required.
SEAT BELT WARNING
CHIME WITH SEAT BELT
BUCKLED1. Seat belt switch sense
circuit shorted.1. With the wire harness connector for the seat
belt switch and the body wire harness junction
block connector disconnected, there should be no
continuity between the seat belt switch sense
circuit and a good ground. Repair the seat belt
switch sense circuit, if required.
2. Faulty seat belt switch. 2. Check for continuity between the ground circuit
and the seat belt switch sense circuit of the seat
belt switch pigtail wire connector. There should be
no continuity with the seat belt buckled. Replace
the faulty seat belt, if required.
WJCHIME/BUZZER 8B - 3
CHIME WARNING SYSTEM (Continued)

INSTALLATION
(1) Install the module on the mounting pins in the
vehicle.
(2) Reconnect the electrical connector.
(3) Install the two mounting clips for the module
(Fig. 1).
(4) Install the adjustable pedal motor. (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/PEDAL -
INSTALLATION).
(5) Install the steering column opening cover
(Refer to 23 - BODY/INSTRUMENT PANEL/STEER-
ING COLUMN OPENING COVER - INSTALLA-
TION).
(6) Install the cluster bezel (Refer to 23 - BODY/
INSTRUMENT PANEL/CLUSTER BEZEL -
INSTALLATION).
(7) Reconnect the negative battery cable.
BODY CONTROL MODULE
DESCRIPTION
A Body Control Module (BCM) is concealed below
the driver side end of the instrument panel (Fig. 2).
The BCM utilizes integrated circuitry and informa-
tion carried on the Programmable Communications
Interface (PCI) data bus network along with many
hard wired inputs to monitor many sensor and
switch inputs throughout the vehicle. In response to
those inputs, the internal circuitry and programming
of the BCM allow it to control and integrate many
electronic functions and features of the vehiclethrough both hard wired outputs and the transmis-
sion of electronic message outputs to other electronic
modules in the vehicle over the PCI data bus. The
electronic functions and features that the BCM sup-
ports or controls include the following:
The BCM for this model is serviced only as a com-
plete unit. Many of the electronic features in the
vehicle controlled or supported by the BCM are pro-
grammable using either the Electronic Vehicle Infor-
mation Center (EVIC) user interface, or the DRBIIIt
scan tool. In addition, the BCM software is Flash
compatible, which means it can be reprogrammed
using Flash reprogramming procedures. A BCM can
only be repaired by or replaced through an autho-
rized electronic warranty repair station. Refer to the
latest version of the Warranty Policies and Proce-
dures manual for a current listing of authorized elec-
tronic repair stations.OPERATION
The Body Control Module (BCM) is designed to
control and integrate many of the electronic features
and functions of the vehicle. The microprocessor-
based BCM hardware and software monitors many
hard wired switch and sensor inputs as well as those
resources it shares with other electronic modules in
the vehicle through its communication over the PCI
data bus network. The internal programming of the
BCM microprocessor allows the BCM to determine
the tasks it needs to perform and their priorities. The
Fig. 1 ADJUSTABLE PEDALS MODULE
1 - ELECTRICAL CONNECTOR
2 - MODULE MOUNTING BRACKET
3 - BRAKE BOOSTER
4 - ADJUSTABLE PEDALS MOUNTING BRACKET
5 - ADJUSTABLE PEDALS CONTROL MODULE
6 - HOLD DOWN CLIPS
Fig. 2 Body Control Module
1 - JUNCTION BLOCK
2 - SCREWS (4)
3 - BODY CONTROL MODULE
4 - FUSE COVER LOCATOR CHANNELS
5 - FUSE COVER MOUNTING SLOTS
6 - INSTRUMENT PANEL WIRE HARNESS CONNECTORS
WJELECTRONIC CONTROL MODULES 8E - 3
ADJUSTABLE PEDALS MODULE (Continued)

BCM programming then performs those tasks and
provides features through both PCI data bus commu-
nication with other electronic modules and hard
wired outputs to a number of relays. These relays
provide the BCM with the ability to control numer-
ous high current accessory systems in the vehicle.
The BCM circuitry operates on battery current
received through fuses in the Junction Block (JB) on a
non-switched fused B(+) circuit, a fused ignition switch
output (start-run) circuit, and a fused ignition switch
output (run-accessory) circuit. This arrangement allows
the BCM to provide some features regardless of the
ignition switch position. The BCM circuitry is grounded
through the chassis beneath the center console.
The BCM monitors its own internal circuitry as
well as many of its input and output circuits, and
will store a Diagnostic Trouble Code (DTC) in elec-
tronic memory for any failure it detects. These DTCs
can be retrieved and diagnosed using a DRBIIItscan
tool. Refer to the appropriate diagnostic information.
HARD WIRED INPUTS
The hard wired inputs to the BCM include the fol-
lowing:
²A/C switch signal
²Ambient temperature sensor signal
²Body control module flash enable
²Coolant level switch sense
²Door ajar switch sense (two circuits - one left
rear, and one right rear)
²Driver seat heater switch mux
²Fog lamp switch sense
²Fused B(+)
²Fused ignition switch output (run-acc)
²Fused ignition switch output (st-run)
²Ground (five circuits - two Z1, and three Z2)
²Hazard switch sense
²Headlamp switch mux
²High beam switch sense
²Hood ajar switch sense (export)
²Key-in ignition switch sense
²Liftgate ajar switch sense
²Liftgate courtesy disable
²Liftgate flip-up ajar switch sense
²Panel lamps dimmer signal
²Park lamp relay output
²Passenger seat heater switch mux
²PCI bus
²Radio control mux
²Rear window defogger switch sense
²Seat belt switch sense
²Ultralight sensor signal
²Washer fluid switch sense
²Washer pump switch sense
²Windshield wiper switch mux
²Wiper park switch sense
MESSAGING
The BCM uses the following messages received
from other electronic modules over the PCI data bus:
²Accessory Delay Control (DDM/PDM)
²Battery Temperature (PCM)
²Chime Request (EMIC, EVIC, SKIM)
²Cylinder Lock Switch Status (DDM)
²Door Ajar Status/Front Doors (DDM/PDM)
²Door Lock Status (DDM/PDM)
²Engine Model (PCM)
²Engine RPM (PCM)
²Engine Temperature (PCM)
²English/Metric Default (EMIC)
²Fuel Tank Level (PCM)
²Fuel Used/Injector Pulses (PCM)
²Panic Control (PDM)
²Programmable Features Preferences/Audible &
Optical Chirps/Headlamp Delay (EVIC)
²RKE Status (PDM)
²Vehicle Identification Number (PCM)
²Vehicle Speed (PCM)
The BCM provides the following messages to other
electronic modules over the PCI data bus:
²A/C Switch Status (PCM)
²Ambient Temperature Data (AZC/EVIC/PCM)
²Average/Instantaneous Fuel Economy (EVIC)
²Country Code (EMIC)
²Courtesy Lamp Status (DDM/PDM)
²Distance To Empty (EVIC)
²Elapsed Ignition On Timer (EVIC)
²English/Metric Status (EMIC)
²Front & Rear Door Ajar Status (EVIC)
²Front & Rear Fog Lamp Status (EMIC)
²Heated Seat Switch Status (HSM/MHSM)
²High Beam Status (EMIC)
²Ignition Off Timer (EVIC)
²Ignition Switch Position (DDM/PDM)
²Key-In Ignition Status (DDM/PDM)
²Low Beam Status (EMIC)
²Panel Lamp Status (AZC/EMIC/Radio)
²Rear Window Defogger Relay Status (DDM/
PDM)
²Remote Radio Switch Status (Radio)
²Seatbelt Status (EMIC/MHSM/MSM)
DIAGNOSIS AND TESTING - BODY CONTROL
MODULE
The hard wired inputs to and outputs from the
Body Control Module (BCM) may be diagnosed and
tested using conventional diagnostic tools and proce-
dures. Refer to the appropriate wiring information.
Conventional diagnostic methods may not prove
conclusive in the diagnosis of the BCM. In order to
obtain conclusive testing of the BCM, the Program-
mable Communications Interface (PCI) data bus net-
work and all of the electronic modules that provide
8E - 4 ELECTRONIC CONTROL MODULESWJ
BODY CONTROL MODULE (Continued)

inputs to or receive outputs from the BCM must also
be checked. The most reliable, efficient, and accurate
means to diagnose the BCM, the PCI data bus net-
work, and the electronic modules that provide inputs
to or receive outputs from the BCM requires the use
of a DRBIIItscan tool and the appropriate diagnostic
information. The DRBIIItscan tool can provide con-
firmation that the PCI data bus network is func-
tional, that all of the modules are sending and
receiving the proper messages over the PCI data bus,
and that the BCM is receiving the proper hard wired
inputs and responding with the proper hard wired
outputs needed to perform its many functions.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel fuse cover.(Refer
to 8 - ELECTRICAL/POWER DISTRIBUTION/FUSE
COVER - REMOVAL).
(3) Access and disconnect the instrument panel
wire harness connectors from the BCM (Fig. 3).
(4) Remove the mounting screws (Torx T-20) that
secure the BCM to the JB.(5) Pull the BCM straight out towards the dash
panel far enough to disconnect the integral BCM to
JB connector.
(6) Remove the BCM.INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Position the Body Control Module (BCM) to its
mounting location (Fig. 3).
(2) Align the terminal pins of the BCM connector
with the connector on the JB.
(3) Engage the BCM integral connector into the
JB.
(4) Install the four screws. Tighten the screws to
2.2 N´m (20 in. lbs.).
Fig. 3 Body Control Module Remove/Install
1 - JUNCTION BLOCK
2 - SCREWS (4)
3 - BODY CONTROL MODULE
4 - FUSE COVER LOCATOR CHANNELS
5 - FUSE COVER MOUNTING SLOTS
6 - INSTRUMENT PANEL WIRE HARNESS CONNECTORS
WJELECTRONIC CONTROL MODULES 8E - 5
BODY CONTROL MODULE (Continued)

(5) Connect the two instrument panel wire harness
connectors to the BCM.
(6) Reinstall the instrument panel fuse cover to
the bottom of the BCM and JB unit. (Refer to 8 -
ELECTRICAL/POWER DISTRIBUTION/FUSE
COVER - INSTALLATION).
(7) Connect the battery negative cable.
COMMUNICATION
DESCRIPTION
The Programmable Communication Interface (PCI)
data bus system is a single wire multiplex system
used for vehicle communications. Multiplexing is a
system that enables the transmission of several mes-
sages over a single channel or circuit.
Many of the control modules in a vehicle require
information from the same sensing device. Multiplex-
ing reduces wire harness complexity, sensor current
loads and controller hardware because each sensing
device is connected to only one controller, which
reads and distributes the sensor information to the
other controllers over the data bus. Also, because
each controller on the data bus can access the con-
troller sensor inputs to every other controller on the
data bus, more function and feature capabilities are
possible.
A multiplex system allows the information flowing
between controllers to be monitored using a diagnos-
tic scan tool. This system allows a control module to
broadcast message data out onto the bus where all
other control modules can read the messages that are
being sent. When a module reads a message on the
data bus that it requires, it relays that message to
its microprocessor. Each module ignores the mes-
sages on the data bus that it dosen't recognize.
OPERATION
Data exchange between modules is achieved by
serial transmission of encoded data over a single wire
broadcast network. The PCI data bus messages are
carried over the bus in the form of Variable Pulse
Width Modulated (VPWM) signals. The PCI data bus
speed is an average 10.4 Kilo-bits per second (Kbps).
The voltage network used to transmit messages
requires biasing and termination. Each module on
the PCI data bus system provides its own biasing
and termination. Each module (also referred to as a
node) terminates the bus through a terminating
resistor and a terminating capacitor. The Powertrain
Control Module (PCM) is the only dominant node for
the PCI data bus system.
The PCI bus uses low and high voltage levels to
generate signals. The voltage on the buss varies
between zero and seven and one-half volts. The lowand high voltage levels are generated by means of
variable-pulse width modulation to form signals of
varying length.
When a module is transmitting on the bus, it is
reading the bus at the same time to ensure message
integrity.
Each module is capable of transmitting and receiv-
ing data simultaneously.
The PCI data bus can be monitored using the
DRBIIItscan tool. It is possible for the bus to pass
all DRBIIIttests and still be faulty if the voltage
parameters are all within the specified range and
false messages are being sent.
CONTROLLER ANTILOCK
BRAKE
DESCRIPTION
The Controler Antilock Brake (CAB) is mounted to
the Hydraulic Control Unit (HCU) and operates the
ABS system (Fig. 4).
OPERATION
The CAB voltage is supplied by the ignition switch
in the RUN position. The CAB contains dual micro-
processors. A logic block in each microprocessor
receives identical sensor signals. These signals are
processed and compared simultaneously. The CAB
contains a self check program that illuminates the
ABS warning light when a system fault is detected.
Faults are stored in a diagnostic program memory
and are accessible with the DRBIIItscan tool. ABS
faults remain in memory until cleared, or until after
the vehicle is started approximately 50 times. Stored
Fig. 4 Controller Antilock Brakes
1 - HCU
2 - MOTOR
3 - CAB
8E - 6 ELECTRONIC CONTROL MODULESWJ
BODY CONTROL MODULE (Continued)

faults arenoterased if the battery is disconnected.
(Fig. 4)
REMOVAL
(1) Remove negative battery cable from the bat-
tery.
(2) Remove air cleaner housing,(Refer to 9 -
ENGINE/AIR INTAKE SYSTEM/AIR CLEANER
HOUSING - REMOVAL) OR (Refer to 9 - ENGINE/
AIR INTAKE SYSTEM/AIR CLEANER HOUSING -
REMOVAL).
(3) Release CAB harness connector and remove
connector (Fig. 5).
(4) Remove pump motor connector.
(5) Remove CAB mounting bolts (Fig. 6) and
remove the CAB from the HCU.
INSTALLATION
(1) Install the CAB onto the HCU and tighten
mounting bolts to 1.8 N´m (16 in. lbs.).
(2) Install pump motor connector.
(3) Install CAB harness connector and push down
connector release.
(4) Install air cleaner housing,(Refer to 9 -
ENGINE/AIR INTAKE SYSTEM/AIR CLEANER
HOUSING - INSTALLATION) OR (Refer to 9 -
ENGINE/AIR INTAKE SYSTEM/AIR CLEANER
HOUSING - INSTALLATION).
(5) Install negative battery cable to the battery.
DATA LINK CONNECTOR
DESCRIPTION - DATA LINK CONNECTOR
The data link connector (DLC) is located at the
lower edge of the instrument panel near the steering
column.
OPERATION - DATA LINK CONNECTOR
The 16±way DLC links the DRBIIItscan tool or
the Mopar Diagnostic System (MDS) with the Power-
train Control Module (PCM).
DOOR MODULE
DESCRIPTION
A door module is concealed behind the trim panel
of each front door (Fig. 7).The module on the driver
side is referred to as the Driver Door Module (DDM),
while the module on the passenger side is the Pas-
senger Door Module (PDM). Each door module
houses both the front power lock and power window
switches. In addition to the power window and power
lock switches for its own door, the DDM also houses
individual switches for each passenger door power
window, a power window lockout switch, the power
mirror switch, and the power foldaway mirror switch
for export vehicles.
The DDM and PDM each utilize integrated cir-
cuitry and information carried on the Programmable
Communications Interface (PCI) data bus network
along with many hard wired inputs to monitor many
sensor and switch inputs throughout the vehicle. The
PDM also receives inputs through an integral Radio
Fig. 5 CAB Connector Release
1 - CONNECTOR RELEASE
2 - CAB
Fig. 6 CAB Mounting Bolts
1 - MOUNTING BOLTS
WJELECTRONIC CONTROL MODULES 8E - 7
CONTROLLER ANTILOCK BRAKE (Continued)

lamp flash features), Unlock with the optional RKE
unlock, and Panic Mode functions. The optional RKE
features are programmable.
²Switch Illumination- Each door module pro-
vides control of the power window and power lock
switch illumination for the front and rear doors on
the same side of the vehicle. The DDM provides con-
trol of the power mirror switch illumination.
²Window Lockout- The DDM monitors and
transmits the status of its integral window lockout
switch to provide the power window lockout feature
and coordinate power window switch knob illumina-
tion.
The door modules are serviced only as complete
units. Many of the features in the vehicle controlled
or supported by the door modules are programmable
using either the Electronic Vehicle Information Cen-
ter (EVIC) user interface, or the DRBIIItscan tool. If
a door module is damaged or faulty, the entire door
module unit must be replaced.
OPERATION
The microprocessor-based DDM and PDM hard-
ware and software monitors integral and hard wired
external switch inputs as well as those resources it
shares with other electronic modules in the vehicle
through its communication over the PCI data bus
network. The internal programming and all of these
inputs allow the DDM or PDM microprocessor to
determine the tasks it needs to perform and their
priorities, as well as both the standard and optional
features that it should provide.
The DDM and PDM are powered by a fused bat-
tery circuit so that they can operate regardless of the
ignition switch position. The DDM and PDM cir-
cuitry is grounded to the chassis beneath the front
seat.
The DDM and PDM can be diagnosed using a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information.
HARD WIRED INPUTS
The hard wired inputs to the door modules include
the following:
²Door ajar switch sense
²Driver door key cylinder switch sense (DDM)
²Fused B(+)
²Ground
²Memory switch mux (DDM)
²Mirror horizontal position signal
²Mirror vertical position signal
²PCI bus
HARD WIRED OUTPUTS
The hard wired outputs of the door modules
include the following:
²Courtesy lamp driver
²Courtesy lamp ground
²Diagnostic out (DDM)
²Door/liftgate lock driver
²Door/liftgate unlock driver
²Door switch illumination (rear power window)
²Front window driver (down)
²Front window driver (up)
²Memory set indicator driver (DDM)
²Memory switch return (DDM)
²Mirror common driver
²Mirror heater ground
²Mirror heater 12V supply
²Rear window driver (down)
²Rear window driver (up)
²Mirror horizontal driver
²Mirror sensor ground
²Mirror vertical driver
²PCI bus
²Switch illumination driver (memory - DDM)
MESSAGING
The door modules use the following messages
received from other electronic modules over the PCI
data bus:
²Accessory Delay Control (PDM)
²Courtesy Lamp Status (BCM)
²Door Ajar Status/Rear Doors (BCM)
²Door Lock Status (DDM/PDM)
²Ignition Switch Position (BCM)
²Key-In Ignition Status (BCM)
²Programmable Features Preferences/Auto Lock/
Auto Unlock/RKE Unlock Sequence/RKE Link to
Memory (EVIC)
²Memory Recall (DDM)
²Rear Window Defogger Relay Status (BCM)
²Vehicle Speed (PCM)
The door modules provide the following messages
to other electronic modules over the PCI data bus:
²Cylinder Lock Switch Status (BCM)
²Door Ajar Status/Front Doors (BCM/DDM/PDM)
²Door Lock Status (DDM/PDM)
²Memory Recall (PDM/MHSM/MSM/Radio)
²Memory Set Switch Status (PDM/MHSM/MSM/
Radio)
²Panic Control (BCM)
²Power Window Switch Status (PDM)
²RKE Status (BCM/DDM)
²Window Lockout Switch Status (PDM)
WJELECTRONIC CONTROL MODULES 8E - 9
DOOR MODULE (Continued)