airbag CHRYSLER VOYAGER 2001 User Guide

mitted on the bus even though a module may not
require all information to perform its function. It
will only respond to messages ªaddressedº to it
through binary coding process. This method of data
transmission significantly reduces the complexity
of the wiring in the vehicle and the size of wiring
harnesses. All of the information about the func-
tioning of all the systems is organized, controlled,
and communicated by the PCI bus, which is de-
scribed in the Communication Section of this gen-
eral information.
3.1 AIRBAG SYSTEM/OCCUPANT
RESTRAINT CONTROLLER SYSTEM
The 2001 Minivan Airbag System contain the
following components: Occupant Restraint Control-
ler (ORC), Airbag Warning Indicator, Clockspring,
Driver and Passenger Airbags, Seat belt Tensioners
(SBT), Hall-effect Seat Belt Switches (SBS), Left
and Right Side Airbag Control Module (SIACM),
and Seat (mounted side) Airbags.
The Occupant Restraint Controller (ORC) is a
new type of Airbag Control Module (ACM) that
supports staged airbag deployment. Staged deploy-
ment is the ability to trigger airbag system squib
inflators all at once or individually as needed to
provide the appropriate restraint for the severity of
the impact. The ORC has four major functions: PCI
Bus communications, onboard diagnostics, impact
sensing, and component deployment. The ORC also
contains an energy-storage capacitor. This capaci-
tor stores enough electrical energy to deploy the
front airbag components for two seconds following a
battery disconnect or failure during an impact. The
ORC is secured to the floor panel transmission
tunnel below the instrument panel inside the vehi-
cle. The ORC cannot be repaired or adjusted and
must be replaced.
The ORC sends and/or receives PCI Bus mes-
sages with the Instrument Cluster (MIC), Body
Control Module (BCM), and Powertrain Control
Module (PCM). Diagnostic trouble codes will be set
if the communication with these modules is lost or
contains invalid information.
The microprocessor in the ORC monitors the
impact sensor signal and the airbag system electri-
cal circuits to determine the system readiness. The
ORC also monitors bus messages from both SIACM.
If the ORC detects a monitored system fault or
SIACM fault, it sends a message to the instrument
cluster via PCI bus to turn on the airbag warning
indicator. The ORC can set both active and stored
diagnostic trouble codes to aid in the diagnosing
system problems. See ORC/SIACM DIAGNOSTIC
TROUBLE CODES in this section.
The ORC has an internal accelerometer that
senses the rate of vehicle deceleration, which pro-vides verification of the direction and severity of an
impact. A pre-programmed decision algorithm in
the ORC microprocessor determines when the de-
celeration rate is severe enough to require airbag
system protection. The Occupant Restraint Control-
ler (ORC) also uses the driver and front passenger
seat belt switch status (buckled or unbuckled) as
inputs to determine the level of airbag deployment,
low, medium, or high as well as whether or not the
seat belt tensioners should deploy. The ORC also
uses the crash severity to determine the level of
driver and front passenger deployment, low me-
dium or high. When the programmed conditions are
met, the ORC sends an electrical signal to deploy
the appropriate airbag system components.WARNING: THE AIRBAG SYSTEM IS A
SENSITIVE, COMPLEX ELECTRO-
MECHANICAL UNIT. BEFORE ATTEMPTING
TO DIAGNOSE OR SERVICE ANY AIRBAG
SYSTEM OR RELATED STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT
PANEL COMPONENTS YOU MUST FIRST
DISCONNECT AND ISOLATE THE BATTERY
NEGATIVE (GROUND) CABLE. WAIT TWO
MINUTES FOR THE SYSTEM CAPACITOR TO
DISCHARGE BEFORE FURTHER SYSTEM
SERVICE. THIS IS THE ONLY SURE WAY TO
DISABLE THE AIRBAG SYSTEM. FAILURE
TO DO THIS COULD RESULT IS ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY. NEVER STRIKE OR
KICK THE AIRBAG CONTROL MODULE, AS
IT CAN DAMAGE THE IMPACT SENSOR OR
AFFECT ITS CALIBRATION. IF AN AIRBAG
CONTROL MODULE IS ACCIDENTALLY
DROPPED DURING SERVICE, THE MODULE
MUST BE SCRAPPED AND REPLACED WITH
A NEW UNIT.
The airbag warning lamp is the only point at
which the customer can observe symptoms of a
system malfunction. Whenever the ignition key is
turned to the run or start position, the MIC per-
forms a lamp check by turning the airbag warning
indicator on for 6-8 seconds. After the lamp check, if
the indicator turns on, it means that the ORC has
checked the system and found it to be free of
discernible malfunctions. If the lamp remains on,
there could be an active fault in the system or the
MIC lamp circuit may be internally shorted to
ground. If the lamp comes on and stays on for a
period longer than 6-8 seconds then goes off, there
is usually an intermittent problem in the system.
2
GENERAL INFORMATION

3.1.1 DRIVER AIRBAG
The airbag protective trim cover is the most
visible part of the driver side airbag system. The
protective trim cover is fitted to the front of the
airbag module and forms a decorative cover in the
center of the steering wheel. The module is
mounted directly to the steering wheel. Located
under the trim cover are the horn switch, the airbag
cushion, and the airbag cushion supporting compo-
nents. The airbag module includes a housing to
which the cushion and hybrid inflator are attached
and sealed. The 2001 Minivan is equipped with
driver airbag with dual stage inflators that include
a small canister of highly compressed argon gas.
The Occupant Restraint Controller (ORC) uses ve-
hicle crash severity, driver seat belt switch status
(buckled or unbuckled) as inputs to determine the
level of airbag deployment. When supplied with the
proper electrical signal, the hybrid inflator or infla-
tors discharge the compressed gas it contains di-
rectly into the cushion. The airbag module cannot
be repaired, and must be replaced if deployed or in
any way damaged.
WARNING: THE DRIVER AIRBAG MODULE
CONTAINS ARGON GAS PRESSURIZED TO
OVER 17236.89 Kpa (2500 PSI). DO NOT
ATTEMPT TO DISMANTLE AN AIRBAG
MODULE OR TAMPER WITH ITS INFLATOR.
DO NOT PUNCTURE, INCINERATE, OR
BRING INTO CONTACT WITH ELECTRICITY.
DO NOT STORE AT TEMPERATURE
EXCEEDING 93ÉC (200ÉF). REPLACE AIRBAG
SYSTEM COMPONENTS ONLY BUT
INTERNAL DIFFERENCES MAY RESULT IN
INFERIOR OCCUPANT PROTECTION. THE
FASTENERS, SCREWS, AND BOLTS
ORIGINALLY USED FOR THE AIRBAG
SYSTEM COMPONENTS HAVE SPECIAL
COATINGS AND ARE SPECIFICALLY
DESIGNED FOR THE AIRBAG SYSTEM. THEY
MUST NEVER BE REPLACED WITH ANY
SUBSTITUTES. ANY TIME A NEW FASTENER
IS NEEDED, REPLACE IT WITH THE
CORRECT FASTENERS PROVIDED IN THE
SERVICE PACKAGE OR SPECIFIED IN THE
MOPAR PARTS CATALOG.
CAUTION: Deployed Front Air Bags may or may not have live pyrotechnic material within the
air bag inflator. Do not dispose of 2001 Model Year Driver and Passenger Airbags unless you
are sure of complete deployment. Please refer to the Hazardous Substance Control System for
Proper Disposal. Dispose of deployed air bags in a manner consistent with state, provincial,
local, and federal regulations. Use the following table to identify the status of the Airbag Squib.
AIRBAG SQUIB STATUS
(1) Using a DRBIIItread Airbag DTC'sIfthe following active codes are present:
ACTIVE DTC CONDITIONS SQUIB STATUS
Driver Squib 1 open
Driver Squib 2 openCheck the stored DTC'sAND IFthe stored min-
utes for both are within 15 minutes of each other.Both Driver Squib 1
and 2 were used.
Driver Squib 1 open
Driver Squib 2 openCheck the stored DTC'sAND IFthe stored min-
utes for Driver Squib 2 open is GREATER than
the stored minutes for Driver Squib 1 by 15 min-
utes or more.Driver Squib 1 was
used;
Driver Squib 2 is live.
Driver Squib 1 open
Driver Squib 2 openCheck the stored DTC'sAND IFthe stored min-
utes for Driver Squib 1 open is GREATER than
the stored minutes for Driver Squib 2 by 15 min-
utes or more.Driver Squib 1 is live;
Driver Squib 2 was
used.
IfDriver Squib 1 openAND IFDriver Squib 2 opens is NOT an active
code.Driver Squib 1 was
used;
Driver Squib 2 is live.
IfDriver Squib 2 openAND IFDriver Squib 1 open is NOT an active
code.Driver Squib 1 is live;
Driver Squib 2 was
used.
3
GENERAL INFORMATION

Ifneither of the following codes is an active code:
ACTIVE DTC SQUIB STATUS
Driver squib 1 open Status of Airbag is
Driver Squib 2 open Unknown.
3.1.2 CLOCKSPRING
The clockspring is mounted on the steering col-
umn behind the steering wheel. This assembly
consist of a plastic housing which contains a flat,
ribbon-like, electrically conductive tape that winds
and unwinds with the steering wheel rotation. The
clockspring is used to maintain a continuous elec-
trical circuit between the instrument panel wiring
and the driver airbag, the horn, and the vehicle
speed control switches if equipped. The clockspring
must be properly centered when it is reinstalled on
the steering column following any service proce-
dure, or it could be damaged. The clockspring can-
not be repaired and it must be replaced.
3.1.3 PASSENGER AIRBAG
The airbag door in the instrument panel top cover
the glove box is the most visible part of the passen-
ger side airbag system. The airbag door has a living
hinge at the top, which is secured to the instrument
panel top cover. Located under the airbag door is
the airbag cushion and its supporting components.
The airbag module includes a housing to which the
cushion and hybrid inflators are attached and
sealed. The 2001 Minivan is equipped with front
passenger airbag with dual stage inflators that
include a small canister of highly compressed argon
gas. The ORC uses vehicle crash severity, front
passenger seat belt switch status (buckled or un-
buckled) inputs to determine the level of airbag
deployment. When supplied with the proper electri-
cal signal, the hybrid inflator or inflators discharge
the compressed gas it contains directly into the
cushion. The airbag module cannot be repaired, and
must be replaced if deployed or in any way dam-
aged.
WARNING: THE PASSENGER AIRBAG
MODULE CONTAINS ARGON GAS
PRESSURIZED TO 17236.89 Kpa (2500 PSI).
DO NOT ATTEMPT TO DISMANTLE AN
AIRBAG MODULE OR TAMPER WITH ITS
INFLATOR. DO NOT PUNCTURE,
INCINERATE, OR BRING INTO CONTACT
WITH ELECTRICITY. DO NOT STORE AT
TEMPERATURE EXCEEDING 93ÉC (200ÉF).
REPLACE AIRBAG SYSTEM COMPONENTS
ONLY WITH PARTS SPECIFIED IN THE
MOPAR PARTS CATALOG. SUBSTITUTE
PARTS MAY APPEAR INTERCHANGEABLE,
BUT INTERNAL DIFFERENCES MAY RESULT
IN INFERIOR OCCUPANT PROTECTION. THE
FASTENERS, SCREWS, AND BOLTS
ORIGINALLY USED FOR THE AIRBAG
SYSTEM COMPONENTS HAVE SPECIAL
COATINGS AND ARE SPECIFICALLY
DESIGNED FOR THE AIRBAG SYSTEM. THEY
MUST NEVER BE REPLACED WITH ANY
SUBSTITUTES. ANY TIME A NEW FASTENER
IS NEEDED, REPLACE IT WITH THE
CORRECT FASTENERS PROVIDED IN THE
SERVICE PACKAGE OR SPECIFIED IN THE
MOPAR PARTS CATALOG.
4
GENERAL INFORMATION

CAUTION: Deployed Front Air Bags may or may not have live pyrotechnic material within the
air bag inflator. Do not dispose of 2001 Mopar Year Driver and Passenger Airbags unless you
are sure of complete deployment. Please refer to the Hazardous Substance Control System for
Proper Disposal. Dispose of deployed air bags in a manner consistent with state, provincial,
local, and federal regulations. Use the following table to identify the status of the Airbag Squib.
AIRBAG SQUIB STATUS
(1) Using a DRBIIItread Airbag DTC'sIfthe following active codes are present:
ACTIVE DTC CONDITIONS SQUIB STATUS
Passenger Squib 1 open
Passenger Squib 2 openCheck the stored DTC'sAND IFthe stored min-
utes for both are within 15 minutes of each other.Both Passenger Squib 1
and 2 were used.
Passenger Squib 1 open
Passenger Squib 2 openCheck the stored DTC'sAND IFthe stored min-
utes for Passenger Squib 2 open is GREATER
than the stored minutes for Passenger Squib 1 by
15 minutes or more.Passenger Squib 1 was
used; Passenger Squib
2 is live.
Passenger Squib 1 open
Passenger Squib 2 openCheck the stored DTC'sAND IFthe stored min-
utes for Passenger Squib 1 open is GREATER
than the stored minutes for Driver Squib 2 by 15
minutes or more.Passenger Squib 1 is
live; Driver Squib 2
was used.
IfPassenger Squib 1
openAND IFPassenger Squib 2 open is NOT an ac-
tive code.Passenger Squib 1 was
used; Passenger Squib
2 is live.
IfPassenger Squib 2
openAND IFPassenger Squib 1 open is NOT an ac-
tive code.Passenger Squib 1 is
live; Passenger Squib 2
was used.
Ifneither of the following codes is an active code:
ACTIVE DTC SQUIB STATUS
Passenger squib 1 open Status of Airbag is
Passenger squib 2 open Unknown.
3.1.4 SEAT BELT TENSIONER (SBT)
The driver and passenger seat belt (buckle) ten-
sioners are mounted to the inboard side of the front
seats. The seat belt buckle and seat belt switch are
connected directly to the seat belt tensioner cable.
At the onset of an impact event the ORC uses the
seat belt tensioner to rapidly retract the seat belt
buckles. With the slack removed, the occupant's
forward motion in an impact will be reduced as will
the likelihood of contacting interior components.
The seat belt tensioner cannot be removed, the
occupant's forward motion in an impact will be
reduced as will the likelihood of contacting re-
paired, if damaged or defective it must be replaced.
The ORC continuously monitors the resistance of
the seat belt tensioner circuits an open or shorted
conditions.
3.1.5 SEAT BELT SWITCHES (SBS)
The hall-effect driver and front passenger seat
belt switches provide the seat belt status, buckledor unbuckled, via hardwired inputs to the ORC. The
ORC uses seat belt switch inputs to determine the
appropriate level of airbag deployment. If the seat
belt switches are damaged or defective the seat belt
tensioner must be replaced. The ORC continuously
monitors the seat belt switch circuits for an open or
shorted conditions.
3.1.6 SIDE IMPACT AIRBAG CONTROL
MODULE (SIACM)
Supplemental driver and front passenger seat
airbags provide side impact protection for the front
seat occupants. Each side airbag has it own side
impact airbag control module (SIACM) to provide
independent impact sensing and deployment. SI-
ACM are located on the left and right B post just
above the seat belt retractor. One, same part num-
ber, side impact airbag control module (SIACM) is
used on both side of the vehicle. However, for proper
PCI bus operation each SIACM must have a unique
module identification. To provide the unique mod-
ule identification for both, left and right, the
SIACM software looks for a ground on cavity 5 of
the SIACM connector. If cavity 5 is grounded the
SIACM communicates as a left SIACM otherwise it
communicates as a right SIACM. The SIACM per-
forms self diagnostics and circuit tests to determine
5
GENERAL INFORMATION

if the system is functioning properly. If the test
finds a problem the SIACM will set both active and
stored diagnostic trouble codes. If a DTC is active
the SIACM will request that the airbag warning
lamp be turned on. The results of the system test
are transmitted on the PCI Bus to the ORC once
each second or on change in lamp state. If the
warning lamp status message from the either SI-
ACM contains a lamp on request, the ORC will set
an active DTC. At the same time as the DTC is set
the ORC sends a PCI Bus message to the mechan-
ical instrument cluster (MIC) requesting the airbag
warning lamp be turned on. Observe all ORC warn-
ing and caution statements when servicing or han-
dling the SIACM. SIACM are not repairable and
must be replaced if they are dropped.
WARNING: THE AIRBAG SYSTEM IS A
SENSITIVE, COMPLEX ELECTRO-
MECHANICAL UNIT. BEFORE ATTEMPTING
TO DIAGNOSE OR SERVICE ANY AIRBAG
SYSTEM OR RELATED STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT
PANEL COMPONENTS YOU MUST FIRST
DISCONNECT AND ISOLATE THE BATTERY
NEGATIVE (GROUND) CABLE. WAIT TWO
MINUTES FOR THE SYSTEM CAPACITOR TO
DISCHARGE BEFORE FURTHER SYSTEM
SERVICE. THIS IS THE ONLY SURE WAY TO
DISABLE THE AIRBAG SYSTEM. FAILURE
TO DO THIS COULD RESULT IN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY. NEVER STRIKE OR
KICK THE AIRBAG CONTROL MODULE, AS
IT CAN DAMAGE THE IMPACT SENSOR OR
AFFECT ITS CALIBRATION. IF AN AIRBAG
CONTROL MODULE IS ACCIDENTALLY
DROPPED DURING SERVICE, THE MODULE
MUST BE SCRAPPED AND REPLACED WITH
A NEW UNIT.
The airbag warning lamp is the only point at
which the customer can observe symptoms of a
system malfunction. Whenever the ignition key is
turned to the run or start position, the MIC per-
forms a lamp check by turning the airbag warning
indicator on for 6-8 seconds. After the lamp check, if
the indicator turns on, it means that the ORC has
checked the system and found it to be free of
discernible malfuctions. If the lamp remains on,
there could be an active fault in the system or the
MIC lamp circuit may be internally shorted to
ground. If the lamp comes on and stays on for a
period longer than 6-8 seconds then goes off, there
is usually an intermittent problem in the system.
3.1.7 SEAT AIRBAGS (SAB)
The left and right seat airbag modules are located
in the outboard end of the front seat backs. The
airbag module contains a bag, an inflator (a small
canister of highly compressed argon gas) and a
mounting bracket. The seat airbag module cannot
be repaired and must be replaced if deployed or in
any way damaged. When supplied with the proper
electrical signal the inflator seals the hole in the
airbag cushion so it can discharge the compressed
gas it contains directly into the cushion. Upon
deployment, the seat back trim cover will tear open
and allow the seat airbag to fully deploy between
the seat and the door.
WARNING: SEAT AIRBAG CONTAINS ARGON
GAS PRESSURIZED TO OVER 17236.89 Kpa
(2500 PSI). DO NOT ATTEMPT TO
DISMANTLE AN AIRBAG MODULE OR
TAMPER WITH ITS INFLATOR. DO NOT
PUNCTURE, INCINERATE, OR BRING INTO
CONTACT WITH ELECTRICITY. DO NOT
STORE AT TEMPERATURE EXCEEDING 93ÉC
(200ÉF). REPLACE AIRBAG SYSTEM
COMPONENTS ONLY WITH PARTS
SPECIFIED IN THE CHRYSLER MOPAR
PARTS CATALOG. SUBSTITUTE PARTS MAY
APPEAR INTERCHANGEABLE, BUT
INTERNAL DIFFERENCES MAY RESULT IN
INFERIOR OCCUPANT PROTECTION. THE
FASTENERS, SCREWS, AND BOLTS
ORIGINALLY USED FOR THE AIRBAG
SYSTEM COMPONENTS HAVE SPECIAL
COATINGS AND ARE SPECIFICALLY
DESIGNED FOR THE AIRBAG SYSTEM. THEY
MUST NEVER BE REPLACED WITH ANY
SUBSTITUTES. ANY TIME A NEW FASTENER
IS NEEDED, REPLACE IT WITH THE
CORRECT FASTENERS PROVIDED IN THE
SERVICE PACKAGE OR SPECIFIED IN THE
MOPAR PARTS CATALOG.
3.1.8 ORC/SIACM DIAGNOSTIC TROUBLE
CODES
Airbag diagnostic trouble codes consist of active
and stored codes. If more than one code exists,
diagnostic priority should be given to the active
codes. Each diagnostic trouble code is diagnosed by
following a specific testing procedure. The diagnos-
tic test procedures contain step-by-step instructions
for determining the cause of the trouble codes. It is
not necessary to perform all of the tests in this book
to diagnose an individual code. Always begin by
reading the diagnostic trouble codes using the DRB.
Always begin diagnostic with the Table of Contents
6
GENERAL INFORMATION

section 7.0. This will direct you to the specific test(s)
that must be performed. Active diagnostic trouble
codes for the airbag system are not permanent and
will change the moment the reason for the code is
corrected. In certain test procedures within this
manual, diagnostic trouble codes are used as a
diagnostic tool.
3.1.9 ACTIVE CODES
The code becomes active as soon as the malfunc-
tion is detected or key-on, whichever occurs first. An
active trouble code indicates an on-going malfunc-
tion. This means that the defect is currently there
every time the airbag control module checks that
circuit or component. It is impossible to erase an
active code. Active codes automatically erase by
themselves when the reason for the code has been
corrected. With the exception of the warning lamp
trouble codes or malfunctions, when a malfunction
is detected, the airbag lamp remains lit for a mini-
mum of 12 seconds or as long as the malfunction is
present.
3.1.10 STORED CODES
Airbag codes are automatically stored in the
ORC's memory as soon as the malfunction is de-
tected. The exception is the Loss of Ignition Run
Only code which is an active code only. A stored code
indicates there was an active code present at some
time. However, the code currently may not be
present as an active code, although another code
could be active. When a trouble code occurs, the
airbag warning indicator illuminates for 12 seconds
minimum (even if the problem existed for less than
12 seconds). The code is stored, along with the time
in minutes it was active, and the number of times
the ignition has been cycled since the problem was
last detected. The minimum time shown for any
code will be one minute, even if the code was
actually present for less than one minute. Thus, the
time shown for a code will be one minute, even if the
code was actually present for less than one minute.
Thus, the time shown for a code that was present
for two minutes 13 seconds, for example, would be
three minutes. If a malfunction is detected a diag-
nostic trouble code is stored and will remain stored.
When and if the malfunction ceases to exist, an
ignition cycle count will be initiated for that code. If
the ignition cycle count reaches 100 without a
reoccurrence of the same malfunction, the diagnos-
tic trouble code is erased and that ignition cycle
counter is reset to zero. If the malfunction reoccurs
before the count reaches 100, then the ignition cycle
counter will be reset and diagnostic trouble code
will continue to be a stored code. If a malfunction is
not active while performing a diagnostic test proce-
dure, the active code diagnostic test will not locatethe source of the problem. In this case, the stored
code can indicate an area to inspect. If no obvious
problems are found, erase stored codes, and with
the ignition on wiggle the wire harness and connec-
tors, rotate the steering wheel from stop to stop.
Recheck for codes periodically as you work through
the system. This procedure may uncover a malfunc-
tion that is difficult to locate.
3.2 AUDIO SYSTEM
The following radios are all on the PCI Bus
system - RBB, RBK, RAZ, RAD, RBT, and RBY. The
remaining radio also available, the RAS, is NOT on
the PCI Bus. The PCI Bus inputs into the radio are
used for VF dimming, remote steering wheel con-
trols and cabin EQ preference. PCI Bus outputs
from the radio are used for the Name Brand
Speaker (NBS) relay activation, as well as cabin EQ
preference.
The RBB and RBK radios have the capability of
containing multiple vehicle unique equalization
curves (cabin EQ preferences) within the radio.
These curves will reside in the radio's flash memory.
The radio is capable of storing up to 20 unique
equalization curves. The latent curves can be se-
lected via the Front Control Module transmitting a
PCI Bus message to the radio in response to a radio
request for equalization message. Upon receipt of a
valid equalization select message response, the ra-
dio will switch to output the corresponding equal-
ization curve.
All the radios, except the RAS, are capable of
displaying faults and allowing certain actuation
tests through the use of the DRBIIIt. When at-
tempting to perform PCI Bus diagnostics, the first
step is to identify the radio in use in the vehicle.
When trouble shooting output shorts or ªoutputº
error messages, the following applies:
On radios without an external amplifier, the term
output refers to the path between the radio and the
speaker. This type of circuit can be monitored all
the way through the speaker connections by the
radio assembly. When the radio displays a shorted
output DTC with this type of system, the speaker,
radio, or wiring could be at fault. The output DTC
could refer to the front or rear output or a left or
right output. The reason for the difference is the
pairing of the output sections of the radio. Some are
paired left and right, others are paired front and
rear.
On radios with an external amplifier, the term
ªoutputº refers to the circuit between the radio
connector and the amplifier. The radio is capable of
monitoring only this portion and can tell nothing
about the circuit between the amplifier and the
speakers. Consequently, a shorted output DTC on
7
GENERAL INFORMATION

this type of system would only refer to this circuit.
A faulty speaker could not cause this DTC.
3.2.1 REMOTE RADIO CONTROLS
These radios can be controlled via remote radio
switches (optional). These switches are located on
the back side of the steering wheel. They control
mode, preset, seek up, seek down, volume up and
volume down functions.
These functions are inputs to the Body Control
Module and can be read with the DRBIIItunder
ªbody computerº. The switches are a multiplexed
signal to the BCM. The radio control MUX circuit is
a 5 volt line that is pulled to ground through
different value resistors built into the switches.
This causes a voltage drop to be seen by the BCM
and it sends a specific message to the radio on the
PCI Bus circuit. The radio then responses to the
message.
This circuit is fairly simple to troubleshoot. The
circuit must be complete from the switches in the
steering wheel to the BCM. The ground must be
complete so that the switches can cause the voltage
drop for the BCM to see. The circuit passes through
the clockspring so continuity through this devise
must be verified.
3.2.2 CD CHANGER
The new in-dash CD Changer is designed to fit
into the existing cubby bin in the center stack. This
new cartridge-less CD Changer is controlled by
your radio, and allows you to individually load up to
four discs at a time. However, due to its compact
design, the CD Changer can only carry out one
operation at a time. For example, you can not load
a new disc while playing another at the same time.
Each operation happens sequentially.
The radio unit installed with your system pro-
vides control over all features of the CD Changer
with the exception of the CD load and eject func-
tions, which are controlled by buttons located on the
front of the CD Changer. The radio also supplies the
power, ground, PCI Bus, left and right speaker
output thru a single DIN cable. All features you
would expect, such as Disc Up/Down, Track Up/
Down, Random and Scan are controlled by the
radio, which also displays all relevant CD Changer
information on the radio display.
The CD Changer contains a Load/Eject button
and an indicator light for each of the four disc
positions. The individual light indicates whether a
CD is currently loaded in that particular chamber of
the CD Changer. Pressing the individual Load/Eject
button for a particular chamber will eject a disc
currently present in that chamber. If the chamber iscurrently empty, actuating the Load/Eject button
will position that chamber to receive and load a new
disc in that chamber.
3.3 BODY CONTROL MODULE
The body control module (BCM) supplies vehicle
occupants with visual and audible information and
controls various vehicle functions. To provide and
receive information, the module is interfaced to the
vehicle's serial bus communications network (PCI).
This network consists of the powertrain control
module (PCM), the engine control module (ECM) -
diesel only, the transmission control module (TCM),
the mechanical instrument cluster (MIC), the front
control module (FCM), the occupant restraint con-
troller (ORC), the compass/mini-trip (CMTC), the
electronic vehicle information center (EVIC), the
controller antilock brake (CAB), the HVAC control
module (ATC & MTC), the power sliding door (Left
& Right) modules (PSD), the power liftgate module
(PLG), the Audio system, the side impact airbag
control (left & right) modules (SIACM), the memory
seat/mirror module (MSMM), the RKE/thatcham
alarm module and the sentry key immobilizer mod-
ule (SKIM). The BCM is operational when battery
power is supplied to the module.
The body control module provides the following
features:
²Power Door Locks
²Automatic Door Lock
²Door Lock Inhibit
²Central Locking (with VTSS Only)
²Battery Protection
²The BCM will automatically turn off all exterior
lamps after 3 minutes and all interior lamps after
15 minutes after the ignition is turned off, if they
are not turned off by the driver.
²Chime
²Compass/Minitrip Support
²Interior Lighting (Courtesy/Reading Lamps)
²BCM Diagnostic Reporting
²Electronic Liftgate Release (with Power Door
Locks)
²Exterior Lighting
²Power Folding Mirrors
²Remote Radio Controls
²Headlamp Time Delay (with/without Autohead-
lamps)
²Automatic Headlamps (with electrochromatic
mirror)
²Illuminated Entry
²Fade to Off
8
GENERAL INFORMATION

3.5 COMMUNICATION
The Programmable Communication Interface or
PCI Bus is a single wire multiplexed network capa-
ble of supporting binary encoded messages shared
between multiple modules. The PCI bus circuit is
identified as D25 and is white with a violet tracer.
Additional tracer colors may be added to the violet
in order to distinguish between different module
connections. The modules are wired in parallel.
Connections are made in the harness using splices.
One splice called the Diagnostic Junction Port,
serves as the ªHubº of the bus. The Diagnostic
Junction Port provides an access point to isolate
most of the modules on the bus in order to assist in
diagnosing the circuit. The following modules are
used on the RG:
²Body Control Module
²Front Control Module
²Occupant Restraint Controller
²Left Side Impact Airbag Control Module
²Right Side Impact Airbag Control Module
²Controller Antilock Brake
²Powertrain Control Module
²Engine Control Module - Diesel Only
²Radio
²CD Changer
²Transmission Control Module
²Automatic Temperature Control Module
²A/C Heater Control Module (MTC)
²Sentry Key Immobilizer Module
²RKE/Thatcham Alarm Module
²Memory Seat/Mirror Module
²Overhead Console
²Mechanical Instrument Cluster
²Left Sliding Door Control Module
²Right Sliding Door Control Module
²Power Liftgate Module
Each module provides its own bias and termina-
tion in order to transmit and receive messages. The
bus voltage is at zero volts when no modules are
transmitting and is pulled up to about seven and a
half volts when modules are transmitting.
The bus messages are transmitted at a rate
averaging 10800 bits per second. Since there is only
voltage present when the modules transmit and the
message length is only about 500 milliseconds, it is
ineffective to try and measure the bus activity witha conventional voltmeter. The preferred method is
to use the DRBIIItlab scope. The 12v square wave
selection on the 20-volt scale provides a good view of
the bus activity. Voltage on the bus should pulse
between zero and about seven and a half volts.
Refer to the following figure for some typical dis-
plays.
The PCI Bus failure modes are broken down into
two categories. Complete PCI Bus Communication
Failure and individual module no response. Causes
of complete PCI Bus Communication Failure in-
clude a short to ground or battery on the PCI
circuit. Individual module no response can be
caused by an open circuit at either the Diagnostic
Junction Port or the module, or an open battery or
ground circuit to the affected module.
Symptoms of a complete PCI Bus Communication
Failure would include but are not limited to:
²All gauges on the MIC stay at zero
²All telltales on MIC illuminate
²MIC backlighting at full intensity
²Dashed lines in the overhead console ambient
temperature display
²No response received from any module on the PCI
bus (except the PCM)
²No start (if equipped with Sentry Key Immobi-
lizer)
Symptoms of Individual module failure could
include any one or more of the above. The difference
would be that at least one or more modules would
respond to the DRBIIIt.
Diagnosis starts with symptom identification. If a
complete PCI Bus Communication Failure is sus-
pected, begin by identifying which modules the
vehicle is equipped with and then attempt to get a
response from the modules with the DRBIIIt.Ifany
modules are responding, the failure is not related to
the total bus, but can be caused by one or more
modules PCI circuit or power supply and ground
circuits. The DRBIIItmay display ªBUS +/- SIG-
NAL OPENº or ªNO RESPONSEº to indicate a
communication problem. These same messages will
be displayed if the vehicle is not equipped with that
particular module. The CCD error message is a
default message used by the DRBIIItand in no way
indicates whether or not the PCI bus is operational.
The message is only an indication that a module is
either not responding or the vehicle is not equipped.
11
GENERAL INFORMATION

3.7.6 EXTERIOR LIGHTING BATTERY
SAVER
The BCM monitors the status of, and controls, the
Park Lamps, Headlamps and Fog Lamp relays. If
any exterior lamps are left ON after the ignition is
turned OFF, the BCM will turn them OFF after 3
minutes.
3.7.7 AUTO HEADLAMPS
This feature is available on vehicles equipped
with both the Electrocromatic Mirror (ECM) and
the Compass/Mini-Trip Computer (CMTC). When
the BCM detects a day/night signal from the CMTC,
an ECM is present and Auto Headlamp mode is
selected.
3.8 FRONT CONTROL MODULE
The Front Control Module (FCM) is an electrical
control and interface center located in the engine
compartment. When it is mated to the Power Dis-
tribution Center (PDC), it is referred to as the
Intelligent Power Module (IPM). The IPM, with its
fuses and relays provides power and signal distri-
bution throughout most of the vehicle. The FCM
receives both hard wire and digital electronic inputs
from the vehicle electrical system through the PDC.
Based on these inputs and the ignition switch
position, it provides direct power feeds and relay
control to some of the vehicles' most critical electri-
cal systems.
The Front Control Module provides the following
features:
Controlled power feeds:
²Front airbag system
²Side airbag system
²Headlamp power
²EATX module power (4 speed only)
²Front washer motor
²Rear washer motor
²Brake shift interlock system
Relay controls:
²Fog lamp relay (when equipped)
²Park lamp relay
²Front wiper on relay
²Front wiper high/low relay
²Accessory relay
²Horn relay
²Front & rear blower relay
²Name brand speakers (NBS) relay
²Electronic back light (EBL) run only relay
²Cabin heater relayElectrical inputs:
²Headlamp battery supplies1&2
²Module battery supply
²Power ground
²Ignition switch RUN or START position status
²Ignition switch START only status
²PCI Bus
²Stop lamp switch
²Horn switch
²Back-up switch
²Wiper park switch
²Washer fluid level switch
²Brake fluid level switch
²Ambient temperature sensor
²Right park lamp outage
²Left park lamp outage
²Battery IOD
²Battery (+) connection detection
²Flash reprogramming voltage
3.8.1 CONTROLLED POWER FEEDS
Front airbag system
The FCM provides power to the Occupant Re-
straint Control (ORC) system through two ªfuse-
lessº circuits (ORC RUN/START, and ORC RUN
only). These circuits are electronically controlled
and continuously monitored for malfunctions.
Power is supplied while the ignition switch is in the
RUN and START positions on pin 48 of the FCM
connector, and in the RUN only position on pin 29.
Side airbag system
The FCM provides power to the Side Impact
Airbag Control Module (SIACM) system through
one ªfuselessº circuit. This circuit is electronically
controlled and continuously monitored for malfunc-
tions. Power is supplied in the ignition RUN and
START positions on pin 28 of the FCM connector.
Headlamp power
The headlamp switch is a direct input to the
BCM. The BCM sends a PCI Bus message to the
FCM informing it of a headlamp switch status
change. The FCM then turns on power to the
headlamps through four ªfuselessº circuits. These
circuits are electronically controlled and continu-
ously monitored for malfunctions. Power is supplied
to each filament in a separate circuit (RH low on pin
6, RH high on pin 4, LH low on pin 3 and LH high
on pin 5). For vehicles equipped with Daytime
Running Lamps (DRL), the FCM electronically
steps down the headlamp voltage to provide the
desired illumination.
13
GENERAL INFORMATION

WARNING: BEFORE ROAD TESTING A
VEHICLE, BE SURE THAT ALL
COMPONENTS ARE REASSEMBLED.
DURING THE TEST DRIVE, DO NOT TRY TO
READ THE DRBIIITSCREEN WHILE IN
MOTION. DO NOT HANG THE DRBIIITFROM
THE REAR VIEW MIRROR OR OPERATE IT
YOURSELF. HAVE AN ASSISTANT
AVAILABLE TO OPERATE THE DRBIIIT.
5.0 REQUIRED TOOLS AND
EQUIPMENT
DRBIIIt(diagnostic read-out box)
Jumper wires
Ohmmeter
Voltmeter
Sentry Key Tester
Test Light
8310 Airbag System Load Tool
8443 SRS Airbag System Load Tool
Diagnostic Junction Port Tester 8339
6.0 GLOSSARY OF TERMS
ABSantilock brake system
ACMairbag control module
AECMairbag electronic control module
(ACM)
ASDMairbag system diagnostic module
(ACM)
AT Cautomatic temperature control
BCMbody control module
CABcontroller antilock brake
CMTCcompass/mini-trip computer
CPAconnector positive assurance
DABdriver airbag
DCHAdiesel cabin heater assist
(cabin heater)
DLCdata link connector
DTCdiagnostic trouble code
DRdriver
EBLelectric back lite (rear window de-
fogger)ECMEngine control module
EVICelectronic vehicle information center
FCMfront control module
GCCGulf Coast Countries
HVACheater ventilation, air conditioning
IPMintelligent power module
LDUlower drive unit
LHDLeft Hand Drive
MICmechanical instrument cluster
MTCmanual temperature control
MSMMmemory seat/mirror module
OBDon board diagnostics
ODOodometer
ORCoccupant restraint controller
PA Bpassenger airbag
PASSpassenger
PCIProgrammable Communication In-
terface (vehicle communication bus)
PCMpowertrain control module
PDCpower distribution center
PLGpower liftgate
PLGMpower liftgate module
PSDpower sliding door
PSDMpower sliding door module
PWMpulse width modulated
RHDRight Hand Drive
RKEremote keyless entry
SABseat airbag
SBTseat belt tensioner
SIACMside impact airbag control module
SKIMsentry key immobilizer module
SKISsentry key immobilizer system
SQUIBalso called initiator (located inside
airbag)
SRSsupplemental restraint system
TCMtransmission control module
VFDvacuum fluorescent display
VTSSvehicle theft security system
30
GENERAL INFORMATION