2004 CHRYSLER VOYAGER lock

motors, and fuel pumps that have been found to be
potential sources of RFI or EMI.
OPERATION
There are two common strategies that can be used
to suppress Radio Frequency Interference (RFI) and
ElectroMagnetic Interference (EMI) radio noise. The
first suppression strategy involves preventing the
production of RFI and EMI electromagnetic signals
at their sources. The second suppression strategy
involves preventing the reception of RFI and EMI
electromagnetic signals by the audio system compo-
nents.
The use of braided ground straps in key locations
is part of the RFI and EMI prevention strategy.
These ground straps ensure adequate ground paths,
particularly for high current components such as
many of those found in the starting, charging, igni-
tion, engine control and transmission control sys-
tems. An insufficient ground path for any of these
high current components may result in radio noise
caused by induced voltages created as the high cur-
rent seeks alternative ground paths through compo-
nents or circuits intended for use by, or in close
proximity to the audio system components or circuits.
Preventing the reception of RFI and EMI is accom-
plished by ensuring that the audio system compo-
nents are correctly installed in the vehicle. Loose,
corroded or improperly soldered wire harness connec-
tions, improperly routed wiring and inadequate audio
system component grounding can all contribute to
the reception of RFI and EMI. A properly grounded
antenna body and radio chassis, as well as a shielded
antenna coaxial cable with clean and tight connec-
tions will each help reduce the potential for reception
of RFI and EMI.
REMOTE SWITCHES
DESCRIPTION
A remote radio control switch option is available on
some models. Two rocker-type switches are mounted
on the back (instrument panel side) of the steering
wheel spokes (Fig. 12). The switch on the left spoke
is the seek switch and has seek up, seek down, and
preset station advance functions. The switch on the
right spoke is the volume control switch and has vol-
ume up, and volume down functions. The switch on
the right spoke also includes a ªmodeº control that
allows the driver to sequentially select AM radio, FM
radio, cassette player, CD player or CD changer (if
equipped).
OPERATION
These switches are resistor multiplexed units that
are hard-wired to the Body Control Module (BCM)
through the clockspring. The BCM sends the proper
messages on the Programmable Communications
Interface (PCI) data bus network to the radio
receiver. For diagnosis of the BCM or the PCI data
bus, the use of a DRB IIItscan tool and the proper
Diagnostic Procedures manual are recommended. For
more information on the operation of the remote
radio switch controls, refer to the owner's manual in
the vehicle glove box.
DIAGNOSIS AND TESTING - REMOTE
SWITCHES
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
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
Fig. 12 Remote Radio Switch Operational View
1 - PRESET SEEK
2 - SEEK UP
3 - VOLUME UP
4 - MODE
5 - VOLUME DOWN
6 - SEEK DOWN
8A - 12 AUDIORS
RADIO NOISE SUPPRESSION COMPONENTS (Continued)

INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
(1) Install remote radio switch to the steering
wheel.
(2) Install three screws securing steering wheel
rear cover.
(3) Connect the wire harness to the remote radio
switch.
(4) Install the steering wheel. Refer to STEERING/
COLUMN/STEERING WHEEL.
(5) Install the driver side airbag module. Refer to
ELECTRICAL/RESTRAINTS/DRIVER AIRBAG.
(6) Connect the battery negative cable.
SPEAKER
DIAGNOSIS AND TESTING - SPEAKER
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.
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.
CAUTION: The speaker output of the radio is a
ªfloating groundº system. Do not allow any speakerlead to short to ground, as damage to the radio
may result.
(1) If all speakers are inoperative, check the radio
fuses in the junction block. If OK, go to Step 2. If not
OK, repair the shorted circuit or component as
required and replace the faulty fuse.
(2) Turn the ignition switch to the ON position.
Turn the radio receiver ON. Adjust the balance and
fader control controls to check the performance of
each individual speaker. Note the speaker locations
that are not performing correctly. Go to Step 3.
(3) Turn the radio receiver OFF. Turn the ignition
OFF. Disconnect and isolate the battery negative
cable. Remove the radio receiver.
(4) Check both the speaker feed (+) circuit and
return (-) circuit cavities for the inoperative speaker
at the radio receiver wire harness connector for con-
tinuity to ground. There should be no continuity. If
OK, go to Step 5. If not OK, repair the shorted
speaker feed (+) and/or return (-) circuits(s) to the
speaker as required.
(5) Disconnect wire harness connector at the inop-
erative speaker. Check for continuity between the
speaker feed (+) circuit cavities of the radio receiver
wire harness connector and the speaker wire harness
connector. Repeat the check between the speaker
return (-) circuit cavities of the radio receiver wire
harness connector and the speaker wire harness con-
nector. In each case, there should be continuity. If
OK, replace the faulty speaker. If not OK, repair the
open speaker feed (+) and/or return (-) circuits(s) as
required.
REMOVAL
D-PILLAR SPEAKER
(1) Disconnect and isolate the battery negative
cable.
(2) Remove rear header trim (right side speaker).
(3) Remove jack cover (left side speaker).
(4) Remove liftgate scuff plate.
(5) Remove upper seat belt bolt. (Refer to 8 -
ELECTRICAL/RESTRAINTS/SEAT BELT OUT-
BOARD FRONT - REMOVAL).
(6) Partially remove quarter trim panel to access
the D-pillar speaker.
(7) Slide the speaker from the retainer (Fig. 14).
(8) Disconnect the wire harness connector from the
speaker.
FRONT DOOR SPEAKER
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the front door trim panel. (Refer to 23
- BODY/DOOR - FRONT/TRIM PANEL - REMOV-
AL).
8A - 14 AUDIORS
REMOTE SWITCHES (Continued)

(3) Check drivers seat belt buckle switch input
(from Occupant Restraint Controller (ORC) for a
closed circuit when not buckled. If input not seen,
look for open in wiring or switch. The switch is
grounded when belt is not buckled.
(4) Verify Programmable Communication Interface
(PCI) data bus communication between ORC and
BCM.
NO FASTEN SEAT BELT LAMP WHEN IGNITION
SWITCH IS TURNED ON.
(1) Check for burned out lamp.
(2) Using a voltmeter check for voltage at the clus-
ter connector:
(a) Pin 2 of the mechanical instrument cluster
for battery feed.
(b) Pin 11 of the mechanical instrument cluster
for ignition voltage.
(3) Repair as necessary.
FASTEN SEAT BELT LAMP OR TONE CONTINUES
FOR MORE THAN 10 SECONDS AFTER SEAT
BELTS ARE FASTENED AND DRIVER'S DOOR IS
CLOSED.
Refer to the proper Body Diagnostic Procedures
manual.
NO TONE WHEN PARK OR HEADLAMPS ARE ON
AND DRIVER'S DOOR IS OPEN.
Make sure ignition is in lock position with the key
removed.
(1) Check the BCM DTC's and BCM sensors to
verify the door is open. Repair as necessary.
(2) Actuate Chime (BCM actuates).
(3) Inspect BCM connectors and wires for proper
connection.
(4) Measure with a voltmeter the voltage (12v) on
BCM connector (PX2) pin 34 with harness connected.
(5) Check BCM sensors to verify headlamp switch
position.
8B - 2 CHIME/BUZZERRS
CHIME/BUZZER (Continued)

ELECTRONIC CONTROL MODULES
TABLE OF CONTENTS
page page
ELECTRONIC CONTROL MODULES
STANDARD PROCEDURE - PCM/SKIM
PROGRAMMING.......................2
BODY CONTROL MODULE
DESCRIPTION..........................3
OPERATION............................3
REMOVAL.............................4
INSTALLATION..........................5
CONTROLLER ANTILOCK BRAKE
DESCRIPTION..........................5
OPERATION............................5
REMOVAL.............................6
INSTALLATION..........................6
DATA LINK CONNECTOR
DESCRIPTION..........................6
OPERATION............................7
FRONT CONTROL MODULE
DESCRIPTION..........................7
OPERATION............................7
DIAGNOSIS AND TESTING - FRONT
CONTROL MODULE....................7
REMOVAL.............................8
INSTALLATION..........................8
HEATED SEAT MODULE
DESCRIPTION..........................8
OPERATION............................9
DIAGNOSIS AND TESTING - HEATED SEAT
MODULE.............................9
REMOVAL.............................9
INSTALLATION.........................10
MEMORY SEAT/MIRROR MODULE
DESCRIPTION.........................10
OPERATION...........................10
DIAGNOSIS AND TESTING - MEMORY
SEAT/MIRROR MODULE................10
REMOVAL.............................10
INSTALLATION.........................10
POWER LIFTGATE CONTROL MODULE
DESCRIPTION.........................10
OPERATION...........................11
REMOVAL.............................11
INSTALLATION.........................11
POWERTRAIN CONTROL MODULE
DESCRIPTION
DESCRIPTION........................11OPERATION - SENSOR RETURN - PCM
INPUT..............................15
OPERATION - DATA BUS COMMUNICATION
RECEIVE - PCM INPUT.................15
OPERATION - IGNITION SENSE - PCM
INPUT..............................15
OPERATION - PCM GROUND............15
OPERATION
OPERATION - 8-VOLT SUPPLY - PCM
OUTPUT - SBEC CONTROLLER..........15
OPERATION - 5 VOLT SUPPLY - PCM
OUTPUT............................15
STANDARD PROCEDURE
STANDARD PROCEDURE - OBTAINING
DIAGNOSTIC TROUBLE CODES..........15
STANDARD PROCEDURE - PINION
FACTOR SETTING.....................15
STANDARD PROCEDURE - QUICK LEARN
PROCEDURE........................16
REMOVAL
REMOVAL - SBEC CONTROLLER.........16
REMOVAL - NGC CONTROLLER..........17
INSTALLATION
INSTALLATION - SBEC CONTROLLER.....17
INSTALLATION.......................17
SENTRY KEY IMMOBILIZER MODULE
DESCRIPTION.........................18
OPERATION...........................18
REMOVAL.............................18
INSTALLATION.........................19
SLIDING DOOR CONTROL MODULE
DESCRIPTION.........................19
OPERATION...........................19
REMOVAL.............................19
INSTALLATION.........................20
TRANSMISSION CONTROL MODULE
DESCRIPTION.........................20
OPERATION...........................20
STANDARD PROCEDURE
STANDARD PROCEDURE - PINION
FACTOR SETTING.....................23
STANDARD PROCEDURE - QUICK LEARN
PROCEDURE........................23
REMOVAL.............................23
INSTALLATION.........................24
RSELECTRONIC CONTROL MODULES8E-1

ELECTRONIC CONTROL
MODULES
STANDARD PROCEDURE - PCM/SKIM
PROGRAMMING
NOTE: Before replacing the PCM for a failed driver,
control circuit or ground circuit, be sure to check
the related component/circuit integrity for failures
not detected due to a double fault in the circuit.
Most PCM driver/control circuit failures are caused
by internal component failures (i.e. relay and sole-
noids) and shorted circuits (i.e. pull-ups, drivers
and switched circuits). These failures are difficult to
detect when a double fault has occurred and only
one DTC has set.
When a PCM (SBEC) and the SKIM are replaced
at the same time perform the following steps in
order:
(1) Program the new PCM (SBEC)
(2) Program the new SKIM
(3) Replace all ignition keys and program them to
the new SKIM.
PROGRAMMING THE PCM (SBEC)
The SKIS Secret Key is an ID code that is unique
to each SKIM. This code is programmed and stored
in the SKIM, PCM and transponder chip (ignition
keys). When replacing the PCM it is necessary to
program the secret key into the new PCM using the
DRB III. Perform the following steps to program the
secret key into the PCM.
(1) Turn the ignition switch on (transmission in
park/neutral).
(2) Use the DRB III and select THEFT ALARM,
SKIM then MISCELLANEOUS.
(3) Select PCM REPLACED (GAS ENGINE).
(4) Enter secured access mode by entering the
vehicle four-digit PIN.
(5) Select ENTER to update PCM VIN.
NOTE: If three attempts are made to enter secure
access mode using an incorrect PIN, secured
access mode will be locked out for one hour. To
exit this lockout mode, turn the ignition to the RUN
position for one hour then enter the correct PIN.
(Ensure all accessories are turned off. Also monitor
the battery state and connect a battery charger if
necessary).
(6) Press ENTER to transfer the secret key (the
SKIM will send the secret key to the PCM).
(7) Press Page Back to get to the Select System
menu and select ENGINE, MISCELLANEOUS, and
SRI MEMORY CHECK.(8) The DRB III will ask, Is odometer reading
between XX and XX? Select the YES or NO button on
the DRB III. If NO is selected, the DRB III will read,
Enter odometer Reading. Enter
the odometer reading from the Instrument Panel and
press ENTER.
PROGRAMMING THE SKIM
(1) Turn the ignition switch on (transmission in
park/neutral).
(2) Use the DRB III and select THEFT ALARM,
SKIM then MISCELLANEOUS.
(3) Select PCM REPLACED (GAS ENGINE).
(4) Program the vehicle four-digit PIN into SKIM.
(5) Select COUNTRY CODE and enter the correct
country.
NOTE: Be sure to enter the correct country code. If
the incorrect country code is programmed into
SKIM, the SKIM must be replaced.
(6) Select YES to update VIN (the SKIM will learn
the VIN from the PCM).
(7) Press ENTER to transfer the secret key (the
PCM will send the secret key to the SKIM).
(8) Program ignition keys to SKIM.
NOTE: If the PCM and the SKIM are replaced at the
same time, all vehicle keys will need to be replaced
and programmed to the new SKIM.
PROGRAMMING IGNITION KEYS TO THE SKIM
(1) Turn the ignition switch on (transmission in
park/neutral).
(2) Use the DRB III and select THEFT ALARM,
SKIM then MISCELLANEOUS.
(3) Select PROGRAM IGNITION KEY'S.
(4) Enter secured access mode by entering the
vehicle four-digit PIN.
NOTE: A maximum of eight keys can be learned to
each SKIM. Once a key is learned to a SKIM it (the
key) cannot be transferred to another vehicle.
If ignition key programming is unsuccessful, the
DRB III will display one of the following messages:
Programming Not Attempted - The DRB III
attempts to read the programmed key status and
there are no keys programmed into SKIM memory.
Programming Key Failed (Possible Used Key From
Wrong Vehicle) - SKIM is unable to program key due
to one of the following:
²faulty ignition key transponder
²ignition key is programmed to another vehicle.
8 Keys Already Learned, Programming Not Done -
SKIM transponder ID memory is full.
8E - 2 ELECTRONIC CONTROL MODULESRS

(5) Obtain ignition keys to be programmed from
customer (8 keys maximum).
(6) Using the DRB III, erase all ignition keys by
selecting MISCELLANEOUS and ERASE ALL CUR-
RENT IGN. KEYS.
(7) Program all ignition keys.
Learned Key In Ignition - Ignition key transponder
ID is currently programmed in SKIM memory.
BODY CONTROL MODULE
DESCRIPTION
The Body Control Module (BCM) is located in the
passenger compartment, attached to the bulkhead
underneath the left side of the instrument panel.
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 vehicle
through both hard wired outputs and the transmis-
sion of electronic message outputs to other electronic
modules in the vehicle over the PCI data bus.
OPERATION
The Body Control Module (BCM) supplies vehicle
occupants with visual and audible information and
controls various vehicle functions. To provide and
receive information, the BCM is interfaced to the
vehicle's serial bus communications network, referred
to as the Programmable Communications Interface
(PCI) bus.
This network consists of the;
²Powertrain Control Module (PCM)
²Transmission Control Module (TCM)
²Mechanical Instrument Cluster (MIC)
²Occupant Restraint Controller (ORC)
²Compass/Mini-Trip Computer (CMTC)
²Electronic Vehicle Information Center (EVIC)
²Controller Antilock Brake (CAB)²HVAC Control Module
²Sliding Door Control Modules (driver and pas-
senger side doors)
²Power Liftgate Module (PLG)
²Audio system equipped with RAZ, RBU, RBK,
and RBB radios.
²Side Impact Airbag Control Module (SIACM)
²Memory Seat Module (MSM)
²Sentry Key Immobilizer Module (SKIM)
The BCM is operational when battery power is
supplied to the module.
The BCM provides the following features:
²Power Door Locks
²Automatic Door Locks
²Battery Protection - The 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 Control
²Compass/Mini-Trip support.
²Interior Lighting (Courtesy/Reading Lamps)
²BCM Diagnostic Reporting
²Electronic Liftgate Release (with Power Door
Locks)
²Exterior Lighting
²Headlamp Time Delay (with/without Automatic
Headlamps)
²Illuminated Entry
²Fade to Off Interior Lamps - This feature dims
the interior lighting (courtesy lamps) gradually if the
BCM does not receive any new inputs that would
cause the interior lamps to remain on.
²Pulse Width Modulated Instrument Panel Dim-
ming
²Door Lock Inhibit - This feature disables the
door lock functions if the key is in the ignition and
either front door is ajar. Pressing the Remote Keyless
Entry (RKE) lock/unlock button under these condi-
tions result in normal lock/unlock activation.
The BCM has the ability to LEARN additional fea-
tures in the vehicle, provided the appropriate switch
input and PCI data bus messages are received. Refer
to the LEARNED FEATURES table.
RSELECTRONIC CONTROL MODULES8E-3
ELECTRONIC CONTROL MODULES (Continued)

LEARNED FEATURES
FEATURE LEARNING KEY
CENTRAL LOCKING (WITH VTSS ONLY) DRIVER KEY CYLINDER SWITCH PRESENT
AUTOMATIC HEADLAMPS PCI MESSAGE FROM OVERHEAD OR HEADLAMP
SWITCH POSITION (AUTO)
REMOTE KEYLESS ENTRY RKE MESSAGE RECEIVED FROM MODULE
FRONT FOG LAMPS HEADLAMP SWITCH POSITION (PARK W/FRONT
FOG LAMPS)
POWER SLIDING DOOR PCI IFR RECEIVED FROM MODULE
THE BCM HAS FOUR SWITCH INPUTS FOR THE POWER SLIDING DOOR FEATURE; LOCATED IN THE
OVERHEAD CONSOLE ARE THE LEFT AND RIGHT SIDE SLIDING DOOR SWITCHES TO ACTIVATE EITHER
OR BOTH SLIDING DOORS UNDER THE PROPER CONDITIONS. ALSO ARE B-PILLAR SWITCHES LOCATED
ON THE LEFT AND RIGHT B-PILLAR POSTS.
POWER LIFTGATE PCI IFR RECEIVED FROM MODULE
THE BCM HAS ONE LIFTGATE INPUT LOCATED IN THE OVERHEAD CONSOLE.
POWER LOCKOUT SWITCH INPUT
THE BCM HAS ONE LOCKOUT SWITCH INPUT THAT WHEN ENABLED WILL DISABLE THE B-PILLAR
SLIDING DOOR SWITCHES FROM ACTIVATING EITHER SLIDING DOOR WHEN DEPRESSED.
PCI AUDIO SYSTEM PCI MESSAGE RECEIVED FROM MODULE
REMOTE RADIO CONTROLS REMOTE RADIO SWITCHES PRESENT
VEHICLE THEFT SECURITY DRIVER DOOR CYLINDER LOCK SWITCH
MEMORY SEAT AND MIRRORS MEMORY SEAT SWITCH PRESENT AND OR PCI
MESSAGE RECEIVED FROM MEMORY MODULE
ABS W/TRACTION CONTROL PCI MESSAGE RECEIVED FROM CAB
SENTRY KEY IMMOBILIZER SYSTEM PCI MESSAGE RECEIVED FROM SKIM OR VTSS
PRESENT
ADJUSTABLE PEDAL MODULE PCI MESSAGE RECEIVED FROM ADJUSTABLE
PEDAL MODULE (APM)
When replacing a BCM there are three modules
available:
²Base
²Midline
²RG - Export
The Midline controller is used on vehicles that
have Power Door Locks. If a vehicle is equipped with
the Vehicle Theft Security System, the Midline con-
troller becomes a Premium when the theft feature is
enabled.
CAUTION: Do not swap Body Control Modules
between vehicles or body controller's off the shelf.
The BCM has internal diagnostic capability that
assists in diagnosing the system error. When an
OPEN or a SHORT circuit exists, the diagnostic tool
can be used to read the BCM faults. The faults are
very descriptive in identifying the appropriate fea-
ture that has faulted.The only two faults that the BCM logs that con-
clude the replacement of a BCM are faults;
²# 01 - Internal BCM failure (replace BCM)
²# 1F - J1850 Internal Hardware Failure (replace
BCM)
Otherwise the appropriate diagnostic procedures
for each of the features should be taken when the
BCM logs a fault.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the lower instrument panel silencer.
(3) Remove the knee blocker and reinforcement
(Refer to 23 - BODY/INSTRUMENT PANEL/KNEE
BLOCKER REINFORCEMENT - REMOVAL).
(4) Disconnect the five wire connectors from the
bottom of the Body Control Module (BCM).
(5) Move bulkhead wiring aside.
8E - 4 ELECTRONIC CONTROL MODULESRS
BODY CONTROL MODULE (Continued)

(6) Remove the screws holding the BCM to the
bulkhead.
(7) Remove the BCM from the mounting bracket.
INSTALLATION
(1) Install the BCM to the mounting bracket.
(2) Install the screws holding the BCM to the
bulkhead.
(3) Connect the five wire connectors to the bottom
of the Body Control Module (BCM).
(4) Install the knee blocker and reinforcement
(Refer to 23 - BODY/INSTRUMENT PANEL/KNEE
BLOCKER REINFORCEMENT - INSTALLATION).
(5) Install the lower instrument panel silencer.
(6) Connect the battery negative cable.
(7) Verify proper operation of BCM and its func-
tions.
CONTROLLER ANTILOCK
BRAKE
DESCRIPTION
The controller antilock brake (CAB) is a micropro-
cessor-based device which monitors the antilock
brake system (ABS) during normal braking and con-
trols it when the vehicle is in an ABS stop. The CAB
is mounted to the HCU as part of the integrated con-
trol unit (ICU) (Fig. 1). The CAB uses a 24-way elec-
trical connector on the vehicle wiring harness. The
power source for the CAB is through the ignition
switch in the RUN or ON position. The CAB is on
the PCI bus.
OPERATION
The primary functions of the controller antilock
brake (CAB) are to:
²Monitor the antilock brake system for proper
operation.
²Detect wheel locking or wheel slipping tenden-
cies by monitoring the speed of all four wheels of the
vehicle.
²Control fluid modulation to the wheel brakes
while the system is in an ABS mode.
²Store diagnostic information.
²Provide communication to the DRBIIItscan tool
while in diagnostic mode.
²Illuminate the amber ABS warning indicator
lamp.
²(With traction control only) Illuminate the TRAC
ON lamp in the message center on the instrument
panel when a traction control event occurs.
²(with traction control only) Illuminate the TRAC
OFF lamp when the amber ABS warning indicator
lamp illuminates.
The CAB constantly monitors the antilock brake
system for proper operation. If the CAB detects a
fault, it will turn on the amber ABS warning indica-
tor lamp and disable the antilock braking system.
The normal base braking system will remain opera-
tional.
NOTE: If the vehicle is equipped with traction con-
trol, the TRAC OFF lamp will illuminate anytime the
amber ABS warning indicator lamp illuminates.
The CAB continuously monitors the speed of each
wheel through the signals generated by the wheel
speed sensors to determine if any wheel is beginning
to lock. When a wheel locking tendency is detected,
the CAB commands the CAB command coils to actu-
ate. The coils then open and close the valves in the
HCU that modulate brake fluid pressure in some or
all of the hydraulic circuits. The CAB continues to
control pressure in individual hydraulic circuits until
a locking tendency is no longer present.
The CAB contains a self-diagnostic program that
monitors the antilock brake system for system faults.
When a fault is detected, the amber ABS warning
indicator lamp is turned on and the fault diagnostic
trouble code (DTC) is then stored in a diagnostic pro-
gram memory. A latched fault will disable certain
system functionality for the current ignition cycle. An
unlatched fault will disable certain system function-
ality until the fault condition disappears. These
DTC's will remain in the CAB memory even after the
ignition has been turned off. The DTC's can be read
and cleared from the CAB memory by a technician
using the DRBIIItscan tool. If not cleared with a
DRBIIItscan tool, the fault occurrence and DTC will
Fig. 1 Integrated Control Unit (ICU)
1 - PUMP/MOTOR
2 - HCU
3 - PUMP/MOTOR CONNECTOR
4 - CAB
RSELECTRONIC CONTROL MODULES8E-5
BODY CONTROL MODULE (Continued)