brake fluid JEEP LIBERTY 2002 KJ / 1.G Owner's Manual

INSPECTION
Inspect the cylinder bore. Light discoloration and
dark stains in the bore are normal and will not
impair cylinder operation.
The cylinder bore can be lightly polished but only
with crocus cloth. Replace the cylinder if the bore is
scored, pitted or heavily corroded. Honing the bore to
restore the surface is not recommended.
Inspect the cylinder pistons. The piston surfaces
should be smooth and free of scratches, scoring and
corrosion. Replace the pistons if worn, scored, or cor-
roded. Do not attempt to restore the surface by sand-
ing or polishing.Discard the old piston cups and the spring and
expander. These parts are not reusable. The original
dust boots may be reused but only if they are in good
condition.
ASSEMBLY
(1) Lubricate wheel cylinder bore, pistons, piston
cups and spring and expander with clean brake fluid.
(2) Install first piston in cylinder bore. Then
install first cup in bore and against piston.Be sure
lip of piston cup is facing inward (toward
spring and expander) and flat side is against
piston.
(3) Install spring and expander followed by
remaining piston cup and piston.
(4) Install boots on each end of cylinder and insert
push rods in boots.
(5) Install cylinder bleed screw.
INSTALLATION
(1) Install cylinder mounting bolts and tighten to
20 N´m (15 ft. lbs.) (Fig. 44).
(2) Connect brake line to cylinder and tighten to
14 N´m (124 in. lbs.).
(3) Install the brake shoe return springs.
(4) Remove the brake pedal prop rod.
(5) Install the brake drum.
(6) Install the wheel and tire assembly (Refer to 22
- TIRES/WHEELS/WHEELS - STANDARD PROCE-
DURE).
(7) Bleed base brake system (Refer to 5 - BRAKES
- STANDARD PROCEDURE).
PARKING BRAKE
DESCRIPTION
The parking brake is a hand lever and cable oper-
ated system used to apply the rear brakes.
OPERATION
A hand operated lever in the passenger compart-
ment is the main application device. The front cable
is connected between the hand lever and the rear
cables with an equalizer.
The rear cables are connected to the actuating
lever on each primary brake shoe. The levers are
attached to the brake shoes by a pin either pressed
into, or welded to the lever. A clip is used to secure
the pin in the brake shoe. The pin allows each lever
to pivot independently of the brake shoe.
To apply the parking brakes, the hand lever is
pulled upward. This pulls the rear brake shoe actu-
ating levers forward, by means tensioner and cables.
As the actuating lever is pulled forward, the parking
brake strut (which is connected to both shoes), exerts
Fig. 44 WHEEL CYLINDER
1 - WHEEL CYLINDER
2 - SUPPORT PLATE
Fig. 45 Wheel Cylinder Components±Typical
1 - SPRING
2 - CYLINDER
3 - PISTON CLIP
4 - BOOT
5 - PUSH ROD
6 - PISTON
7 - BLEED SCREW
8 - CUP EXPANDERS
KJBRAKES - BASE 5 - 29
WHEEL CYLINDERS (Continued)

BRAKES - ABS
TABLE OF CONTENTS
page page
BRAKES - ABS
DESCRIPTION.........................32
OPERATION...........................32
DIAGNOSIS AND TESTING - ANTILOCK
BRAKING SYSTEM....................33
STANDARD PROCEDURE - ABS BRAKE
BLEEDING...........................33
SPECIFICATIONS.......................33
ELECTRICAL
DESCRIPTION.........................34
OPERATION...........................34FRONT WHEEL SPEED SENSOR
REMOVAL.............................34
INSTALLATION.........................34
REAR WHEEL SPEED SENSOR
REMOVAL.............................35
INSTALLATION.........................35
HCU (HYDRAULIC CONTROL UNIT)
DESCRIPTION.........................35
OPERATION...........................35
REMOVAL.............................36
INSTALLATION.........................36
BRAKES - ABS
DESCRIPTION
ANTILOCK BRAKING SYSTEM
The purpose of the antilock system is to prevent
wheel lockup during periods of high wheel slip. Pre-
venting lockup helps maintain vehicle braking action
and steering control.
The antilock CAB activates the system whenever
sensor signals indicate periods of high wheel slip.
High wheel slip can be described as the point where
wheel rotation begins approaching 20 to 30 percent of
actual vehicle speed during braking. Periods of high
wheel slip occur when brake stops involve high pedal
pressure and rate of vehicle deceleration.
Battery voltage is supplied to the CAB ignition ter-
minal when the ignition switch is turned to Run posi-
tion. The CAB performs a system initialization
procedure at this point. Initialization consists of a
static and dynamic self check of system electrical
components.
The static check occurs after the ignition switch is
turned to Run position. The dynamic check occurs
when vehicle road speed reaches approximately 30
kph (18 mph). During the dynamic check, the CAB
briefly cycles the pump and solenoids to verify oper-
ation.
If an ABS component exhibits a fault during ini-
tialization, the CAB illuminates the amber warning
light and registers a fault code in the microprocessor
memory.
ELECTRONIC BRAKE DISTRIBUTION
The electronic brake distribution (EBD) functions
like a rear proportioning valve. The EBD system usesthe ABS system to control the slip of the rear wheels
in partial braking range. The braking force of the
rear wheels is controlled electronically by using the
inlet and outlet valves located in the HCU.
OPERATION
ANTILOCK BRAKING SYSTEM
During normal braking, the master cylinder, power
booster and wheel brake units all function as they
would in a vehicle without ABS. The HCU compo-
nents are not activated.
During antilock braking fluid pressure is modu-
lated according to wheel speed, degree of slip and
rate of deceleration. A sensor at each wheel converts
wheel speed into electrical signals. These signals are
transmitted to the CAB for processing and determi-
nation of wheel slip and deceleration rate.
The ABS system has three fluid pressure control
channels. The front brakes are controlled separately
and the rear brakes in tandem. A speed sensor input
signal indicating a high slip condition activates the
CAB antilock program. Two solenoid valves are used
in each antilock control channel. The valves are all
located within the HCU valve body and work in pairs
to either increase, hold, or decrease apply pressure as
needed in the individual control channels. The sole-
noid valves are not static during antilock braking.
They are cycled continuously to modulate pressure.
Solenoid cycle time in antilock mode can be mea-
sured in milliseconds.
ELECTRONIC BRAKE DISTRIBUTION
Upon entry into EBD the inlet valve for the rear
brake circuit is switched on so that the fluid supply
from the master cylinder is shut off. In order to
decrease the rear brake pressure the outlet valve for
5 - 32 BRAKES - ABSKJ

the rear brake circuit is pulsed. This allows fluid to
enter the low pressure accumulator (LPA) in the
HCU resulting in a drop in fluid pressure to the rear
brakes. In order to increase the rear brake pressure
the outlet valve is switched off and the inlet valve is
pulsed. This increases the pressure to the rear
brakes. This will continue until the required slip dif-
ference is obtained. At the end of EBD braking (no
brake application) the fluid in the LPA drains back to
the master cylinder by switching on the outlet valve
and draining through the inlet valve check valve. At
the same time the inlet valve is switched on to pre-
vent a hydraulic short circiut in case of another
brake application.The EBD will remain functional
during many ABS fault modes. If the red and amber
warning lamps are illuminated the EBD may have a
fault.
DIAGNOSIS AND TESTING - ANTILOCK
BRAKING SYSTEM
The ABS brake system performs several self-tests
every time the ignition switch is turned on and the
vehicle is driven. The CAB monitors the systems
input and output circuits to verify the system is oper-
ating correctly. If the on board diagnostic system
senses that a circuit is malfunctioning the system
will set a trouble code in its memory.
NOTE: An audible noise may be heard during the
self-test. This noise should be considered normal.NOTE: The MDS or DRB III scan tool is used to
diagnose the ABS system. For additional informa-
tion refer to the Electrical, Electronic Control Mod-
ules section. For test procedures refer to the
Chassis Diagnostic Manual.
STANDARD PROCEDURE - ABS BRAKE
BLEEDING
ABS system bleeding requires conventional bleed-
ing methods plus use of the DRB scan tool. The pro-
cedure involves performing a base brake bleeding,
followed by use of the scan tool to cycle and bleed the
HCU pump and solenoids. A second base brake bleed-
ing procedure is then required to remove any air
remaining in the system.
(1) Perform base brake bleeding,(Refer to 5 -
BRAKES - STANDARD PROCEDURE) OR (Refer to
5 - BRAKES - STANDARD PROCEDURE).
(2) Connect scan tool to the Data Link Connector.
(3) Select ANTILOCK BRAKES, followed by MIS-
CELLANEOUS, then ABS BRAKES. Follow the
instructions displayed. When scan tool displays TEST
COMPLETE, disconnect scan tool and proceed.
(4) Perform base brake bleeding a second time,(Re-
fer to 5 - BRAKES - STANDARD PROCEDURE) OR
(Refer to 5 - BRAKES - STANDARD PROCEDURE).
(5) Top off master cylinder fluid level and verify
proper brake operation before moving vehicle.
SPECIFICATIONS
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Hydraulic Control
Unit/Controller Antilock
Brakes Mounting Nuts14.1 Ð 125
Hydraulic Control
Unit/Controller Antilock
Brakes Brake Lines20.3 Ð 180
Controller Antilock Brakes
Mounting Screws1.8 Ð 16
Wheel Speed Sensors
Front Mounting Bolt12 Ð 132
Wheel Speed Sensor
Rear Mounting Bolt9Ð80
KJBRAKES - ABS 5 - 33
BRAKES - ABS (Continued)

REAR WHEEL SPEED SENSOR
REMOVAL
(1) Raise vehicle on hoist.
(2) Disconnect the sensor wire harness.
(3) Remove mounting stud from the sensor (Fig. 2).
(4) Remove sensor.
INSTALLATION
(1) Connect harness to sensor.Be sure seal is
securely in place between sensor and wiring
connector.
(2) Install O-ring on sensor (if removed).
(3) Insert sensor in differential housing.
(4) Install the sensor mounting stud and tighten to
9 N´m (80 in. lbs.).
(5) Install the sensor electical connector.
(6) Lower vehicle.
HCU (HYDRAULIC CONTROL
UNIT)
DESCRIPTION
The HCU consists of a valve body, pump motor,
and wire harness.
OPERATION
Accumulators in the valve body store extra fluid
released to the system for ABS mode operation. The
pump provides the fluid volume needed and is oper-
ated by a DC type motor. The motor is controlled by
the CAB.The valves modulate brake pressure during
antilock braking and are controlled by the CAB.
The HCU provides three channel pressure control
to the front and rear brakes. One channel controls
the rear wheel brakes in tandem. The two remaining
channels control the front wheel brakes individually.
During antilock braking, the solenoid valves are
opened and closed as needed. The valves are not
static. They are cycled rapidly and continuously to
modulate pressure and control wheel slip and decel-
eration.
During normal braking, the HCU solenoid valves
and pump are not activated. The master cylinder and
power booster operate the same as a vehicle without
an ABS brake system.
During antilock braking, solenoid valve pressure
modulation occurs in three stages, pressure increase,
pressure hold, and pressure decrease. The valves are
all contained in the valve body portion of the HCU.
PRESSURE DECREASE
The outlet valve is opened and the inlet valve is
closed during the pressure decrease cycle.
A pressure decrease cycle is initiated when speed
sensor signals indicate high wheel slip at one or
more wheels. At this point, the CAB closes the inlet
then opens the outlet valve, which also opens the
return circuit to the accumulators. Fluid pressure is
allowed to bleed off (decrease) as needed to prevent
wheel lock.
Once the period of high wheel slip has ended, the
CAB closes the outlet valve and begins a pressure
increase or hold cycle as needed.
PRESSURE HOLD
Both solenoid valves are closed in the pressure
hold cycle. Fluid apply pressure in the control chan-
nel is maintained at a constant rate. The CAB main-
tains the hold cycle until sensor inputs indicate a
pressure change is necessary.
PRESSURE INCREASE
The inlet valve is open and the outlet valve is
closed during the pressure increase cycle. The pres-
sure increase cycle is used to counteract unequal
wheel speeds. This cycle controls re-application of
fluid apply pressure due to changing road surfaces or
wheel speed.
Fig. 2 REAR WHEEL SPEED SENSOR
1 - DIFFERENTIAL HOUSING
2 - MOUNTING BOLT
3 - WHEEL SPEED SENSOR
KJBRAKES - ABS 5 - 35

this purpose. Dirt, grease, or similar materials will
prevent proper cylinder seating and could result in
vacuum leak.
(9) Align and install master cylinder on the
booster studs. Install mounting nuts and tighten to
17.5 N´m (155 in. lbs.).
(10) Connect vacuum hose to booster check valve.
(11) Remount the cruise control servo to the origi-
nal location. Tighten bracket mounting nuts to 17.5
N´m (155 in. lbs.).(12) Connect and secure the brake lines to HCU
and master cylinder. Start all brake line fittings by
hand to avoid cross threading.
(13) Connect the wire to fluid reservoir.
(14) Install the air box.
(15) Fill and bleed base brake system,(Refer to 5 -
BRAKES - STANDARD PROCEDURE).
(16) Verify proper brake operation before moving
vehicle.
5s - 2 BRAKESKJ
POWER BRAKE BOOSTER (Continued)

this purpose. Dirt, grease, or similar materials will
prevent proper cylinder seating and could result in
vacuum leak.
(9) Align and install master cylinder on the
booster studs. Install mounting nuts and tighten to
17.5 N´m (155 in. lbs.).
(10) Connect vacuum hose to booster check valve.
(11) Remount the cruise control servo to the origi-
nal location. Tighten bracket mounting nuts to 17.5
N´m (155 in. lbs.).(12) Connect and secure the brake lines to HCU
and master cylinder. Start all brake line fittings by
hand to avoid cross threading.
(13) Connect the wire to fluid reservoir.
(14) Install the air box.
(15) Fill and bleed base brake system,(Refer to 5 -
BRAKES - STANDARD PROCEDURE).
(16) Verify proper brake operation before moving
vehicle.
5s - 2 BRAKESKJ
POWER BRAKE BOOSTER (Continued)

The cooling system also provides a means of heat-
ing the passenger compartment and cooling the auto-
matic transmission fluid (if equipped). The cooling
system is pressurized and uses a centrifugal water
pump to circulate coolant throughout the system.
OPERATION - HOSE CLAMPS
The spring type hose clamp applies constant ten-
sion on a hose connection. To remove a spring type
hose clamp, only use constant tension clamp pliers
designed to compress the hose clamp.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ON-BOARD
DIAGNOSTICS (OBD)
COOLING SYSTEM RELATED DIAGNOSTICS
The powertrain control module (PCM) has been
programmed to monitor certain cooling system com-
ponents:
²If the engine has remained cool for too long a
period, such as with a stuck open thermostat, a Diag-
nostic Trouble Code (DTC) can be set.
²If an open or shorted condition has developed in
the relay circuit controlling the electric radiator fan,
a Diagnostic Trouble Code (DTC) can be set.
If the problem is sensed in a monitored circuit
often enough to indicated an actual problem, a DTC
is stored. The DTC will be stored in the PCM mem-
ory for eventual display to the service technician.
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
ACCESSING DIAGNOSTIC TROUBLE CODES
To read DTC's and to obtain cooling system data,
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
ERASING TROUBLE CODES
After the problem has been repaired, use the DRB
scan tool to erase a DTC. Refer to the appropriate
Powertrain Diagnostic Procedures service informa-
tion for operation of the DRB scan tool.
DIAGNOSIS AND TESTING - PRELIMINARY
CHECKS
ENGINE COOLING SYSTEM OVERHEATING
Establish what driving conditions caused the com-
plaint. Abnormal loads on the cooling system such as
the following may be the cause:
²PROLONGED IDLE
²VERY HIGH AMBIENT TEMPERATURE
²SLIGHT TAIL WIND AT IDLE
²SLOW TRAFFIC
²TRAFFIC JAMS
²HIGH SPEED
²STEEP GRADES
Driving techniques that avoid overheating are:
²Idle with A/C off when temperature gauge is at
end of normal range.
(1) TRAILER TOWING:
Consult Trailer Towing section of owners manual.
Do not exceed limits.
(2) RECENT SERVICE OR ACCIDENT REPAIR:
Determine if any recent service has been per-
formed on vehicle that may effect cooling system.
This may be:
²Engine adjustments (incorrect timing)
²Slipping engine accessory drive belt(s)
²Brakes (possibly dragging)
²Changed parts. Incorrect water pump, or pump
rotating in wrong direction due to belt not correctly
routed
²Reconditioned radiator or cooling system refill-
ing (possibly under filled or air trapped in system).
NOTE: If investigation reveals none of the previous
items as a cause for an engine overheating com-
plaint, refer to following Cooling System Diagnosis
charts.
These charts are to be used as a quick-reference
only. Refer to the group text for information.
Fig. 2 Spring Clamp Size Location
1 - SPRING CLAMP SIZE LOCATION
KJCOOLING 7 - 3
COOLING (Continued)

OPERATION
OPERATION - COOLING SYSTEM
The cooling system regulates engine operating tem-
perature. It allows the engine to reach normal oper-
ating temperature as quickly as possible. It also
maintains normal operating temperature and pre-
vents overheating.
The cooling system also provides a means of heat-
ing the passenger compartment and cooling the auto-
matic transmission fluid (if equipped). The cooling
system is pressurized and uses a centrifugal water
pump to circulate coolant throughout the system.
OPERATION - HOSE CLAMPS
The spring type hose clamp applies constant ten-
sion on a hose connection. To remove a spring type
hose clamp, only use constant tension clamp pliers
designed to compress the hose clamp.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ON-BOARD
DIAGNOSTICS (OBD)
COOLING SYSTEM RELATED DIAGNOSTICS
The powertrain control module (PCM) has been
programmed to monitor certain cooling system com-
ponents:
²If the engine has remained cool for too long a
period, such as with a stuck open thermostat, a Diag-
nostic Trouble Code (DTC) can be set.
²If an open or shorted condition has developed in
the relay circuit controlling the electric radiator fan,
a Diagnostic Trouble Code (DTC) can be set.
If the problem is sensed in a monitored circuit
often enough to indicated an actual problem, a DTC
is stored. The DTC will be stored in the PCM mem-
ory for eventual display to the service technician.
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
ACCESSING DIAGNOSTIC TROUBLE CODES
To read DTC's and to obtain cooling system data,
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
ERASING TROUBLE CODES
After the problem has been repaired, use the DRB
scan tool to erase a DTC. Refer to the appropriate
Powertrain Diagnostic Procedures service informa-
tion for operation of the DRB scan tool.
DIAGNOSIS AND TESTING - PRELIMINARY
CHECKS
ENGINE COOLING SYSTEM OVERHEATING
Establish what driving conditions caused the com-
plaint. Abnormal loads on the cooling system such as
the following may be the cause:
²PROLONGED IDLE
²VERY HIGH AMBIENT TEMPERATURE
²SLIGHT TAIL WIND AT IDLE
²SLOW TRAFFIC
²TRAFFIC JAMS
²HIGH SPEED
²STEEP GRADES
Driving techniques that avoid overheating are:
²Idle with A/C off when temperature gauge is at
end of normal range.
(1) TRAILER TOWING:
Consult Trailer Towing section of owners manual.
Do not exceed limits.
(2) RECENT SERVICE OR ACCIDENT REPAIR:
Determine if any recent service has been per-
formed on vehicle that may effect cooling system.
This may be:
²Engine adjustments (incorrect timing)
²Slipping engine accessory drive belt(s)
²Brakes (possibly dragging)
²Changed parts. Incorrect water pump, or pump
rotating in wrong direction due to belt not correctly
routed
²Reconditioned radiator or cooling system refill-
ing (possibly under filled or air trapped in system).
NOTE: If investigation reveals none of the previous
items as a cause for an engine overheating com-
plaint, refer to following Cooling System Diagnosis
charts.
These charts are to be used as a quick-reference
only. Refer to the group text for information.
DIAGNOSIS AND TESTING - COOLING SYSTEM
LEAKS
ULTRAVIOLET LIGHT METHOD
A leak detection additive is available through the
parts department that can be added to cooling sys-
tem. The additive is highly visible under ultraviolet
light (black light). Pour one ounce of additive into
cooling system. Place heater control unit in HEAT
position. Start and operate engine until radiator
upper hose is warm to touch. Aim the commercially
available black light tool at components to be
checked. If leaks are present, black light will cause
additive to glow a bright green color.
7s - 2 COOLING - 2.4LKJ
COOLING - 2.4L (Continued)

ever occurs first. The overspeed warning feature is
only enabled on a BCM that has been programmed
with a Middle East Gulf Coast Country (GCC) coun-
try code.
²No Airbag Indicator Message Warning- The
EMIC chime tone generator will generate one, short,
ªbong-likeº chime tone and turn on the ªAirbagº indi-
cator when the ignition switch is in the On position,
and a PCI data bus ªAirbagº indicator on or off mes-
sage is not received from the ACM for six consecutive
seconds.
²No Antilock Brake Indicator Message Warn-
ing- The EMIC chime tone generator will generate
one, short, ªbong-likeº chime tone and turn on the
ªABSº indicator when the ignition switch is in the On
position, and a PCI data bus ªABSº indicator on or
off message is not received from the CAB for six con-
secutive seconds.
²No Fuel Level Message Warning- The EMIC
chime tone generator will generate one, short, ªbong-
likeº chime tone and turn on the ªLow Fuelº indica-
tor when the ignition switch is in the On position,
and a PCI data bus fuel level message is not received
from the PCM for twelve consecutive seconds.
²Remote Keyless Entry Transmitter Pro-
gramming- On vehicles so equipped, the EMIC
chime tone generator will generate a single ªbong-
likeº chime tone when an electronic message is
received over the PCI data bus from the BCM indi-
cating that a Remote Keyless Entry (RKE) transmit-
ter has been successfully programmed by the
customer into the RKE module memory.
²Sentry Key Immobilizer System Transpon-
der Programming- On vehicles so equipped, the
EMIC chime tone generator will generate a single
ªbong-likeº chime tone when an electronic message is
received over PCI data bus message from the Sentry
Key Immobilizer Module (SKIM) indicating that the
Sentry Key Immobilizer System (SKIS) has been
placed in the ªCustomer Learnº programming mode,
and again each time a new SKIS transponder has
been successfully programmed by the customer.
²Turn Signal Cancel Warning- The EMIC
chime tone generator will generate repetitive ªbong-
likeº chime tones at a slow rate when the vehicle is
driven for a distance of about 3.2 kilometers (about
two miles) with a turn signal indicator flashing. The
EMIC uses an electronic message received over the
PCI data bus from the PCM, and a hard wired input
from the turn signal switch circuitry of the multi-
function switch to determine when to sound the turn
signal cancel warning. The PCM uses internal pro-
gramming and distance pulse information received
over a hard wired vehicle speed pulse input from the
BCM to determine the proper vehicle speed messages
to send to the EMIC. The BCM uses an internallyprogrammed electronic pinion factor and a hard
wired input from the rear wheel speed sensor to cal-
culate the proper distance pulse information to send
to the PCM. The electronic pinion factor represents
the proper tire size and axle ratio information for the
vehicle. These chimes will continue to sound until
the turn signal is turned Off, until the hazard warn-
ing system is turned On, or until the ignition switch
is turned to the Off position, whichever occurs first.
²Water-In-Fuel Warning- On vehicles equipped
with a diesel engine, each time the ignition switch is
turned to the On position, the EMIC chime tone gen-
erator will generate a single ªbong-likeº chime tone
the first time an electronic message is received over
the PCI data bus from the PCM requesting ªWater-
in-Fuelº indicator illumination. The PCM uses inter-
nal programming and a hard wired input from the
water-in-fuel sensor to determine the proper water-
in-fuel messages to send to the EMIC. This warning
will only occur once during an ignition cycle.
The EMIC provides chime service for all available
features in the chime warning system. The EMIC
relies upon its internal programming and hard wired
inputs from the turn signal (multi-function) switch,
the washer fluid level switch, and the engine coolant
level sensor (diesel engine only) to provide chime ser-
vice for the turn signal cancel warning, the low
washer fluid warning, and the low coolant warning
respectively. The EMIC relies upon electronic mes-
sage inputs received from other electronic modules
over the PCI data bus network to provide chime ser-
vice for all of the remaining chime warning system
features. Upon receiving the proper inputs, the EMIC
activates the integral chime tone generator to pro-
vide the audible chime warning to the vehicle opera-
tor. The internal programming of the EMIC
determines the priority of each chime request input
that is received, as well as the rate and duration of
each chime tone that is to be generated. See the own-
er's manual in the vehicle glove box for more infor-
mation on the features provided by the chime
warning system.
The hard wired chime warning system inputs to
the EMIC, as well as other hard wired circuits for
this system may be diagnosed and tested using con-
ventional diagnostic tools and procedures. However,
conventional diagnostic methods may not prove con-
clusive in the diagnosis of the EMIC, the PCI data
bus network, or the electronic message inputs used
by the EMIC to provide chime warning system ser-
vice. The most reliable, efficient, and accurate means
to diagnose the EMIC, the PCI data bus network,
and the electronic message inputs for the chime
warning system requires the use of a DRBIIItscan
tool. Refer to the appropriate diagnostic information.
KJCHIME/BUZZER 8B - 5
CHIME WARNING SYSTEM (Continued)

eter/trip odometer switch button that extends
through the lower edge of the cluster lens, just right
of the speedometer. Actuating this switch momen-
tarily with the ignition switch in the On position will
toggle the VFD between the odometer and trip odom-
eter modes. Depressing the switch button for about
two seconds while the VFD is in the trip odometer
mode will reset the trip odometer value to zero. Hold-
ing this switch depressed while turning the ignition
switch from the Off position to the On position will
initiate the EMIC self-diagnostic actuator test. The
VFD will also display the cluster software version
level near the completion of the EMIC self-diagnostic
actuator test. Refer to the appropriate diagnostic
information for additional details on this VFD func-
tion.
The VFD is diagnosed using the EMIC self-diag-
nostic actuator test. (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND
TESTING). Proper testing of the PCI data bus and
the electronic data bus message inputs to the EMIC
that control some of the VFD functions requires the
use of a DRBIIItscan tool. Refer to the appropriate
diagnostic information. Specific operation details for
the odometer, the trip odometer, and the various
warning message functions of the VFD may be found
elsewhere in this service information.
INDICATORS Indicators are located in various
positions within the EMIC and are all connected to
the EMIC circuit board. The turn signal indicators,
security indicator, washer fluid indicator, and coolant
low indicator (diesel engine only) use hard wired
inputs to the EMIC. The brake indicator is controlled
by PCI data bus messages from the Controller
Antilock Brake (CAB) as well as by hard wired park
brake switch and brake fluid level switch inputs to
the EMIC. The Malfunction Indicator Lamp (MIL) is
normally controlled by PCI data bus messages from
the Powertrain Control Module (PCM); however, if
the EMIC loses PCI data bus communication, the
EMIC circuitry will automatically turn the MIL on
until PCI data bus communication is restored. The
EMIC uses PCI data bus messages from the Body
Control Module (BCM), the PCM, the Airbag Control
Module (ACM), and the CAB to control all of the
remaining indicators.
The various indicators are controlled by different
strategies; some receive fused ignition switch output
from the EMIC circuitry and have a switched ground,
others are grounded through the EMIC circuitry and
have a switched battery feed, while still others are
completely controlled by the EMIC microprocessor
based upon various hard wired and electronic mes-
sage inputs. Some indicators are illuminated at a
fixed intensity, while the illumination intensity ofothers is synchronized with that of the EMIC general
illumination lamps.
In addition, certain indicators in this instrument
cluster are automatically configured or self-config-
ured. This feature allows the configurable indicators
to be enabled by the EMIC circuitry for compatibility
with certain optional equipment. The ABS indicator,
airbag indicator, SKIS indicator are automatically
configured by PCI data bus messages received by the
EMIC from the CAB, ACM, or Sentry Key Immobi-
lizer Module (SKIM) after the EMIC is installed in
the vehicle. Once these configuration settings are
learned by the EMIC, the DRBIIItscan tool must be
used to remove these settings from the EMIC non-
volatile memory. The self-configured indicators
remain latent in each EMIC at all times and will be
activated only when the EMIC receives the appropri-
ate PCI message inputs for the optional system or
equipment.
The hard wired indicators are diagnosed using con-
ventional diagnostic methods. The EMIC and PCI
bus message controlled indicators are diagnosed
using the EMIC self-diagnostic actuator test. (Refer
to 8 - ELECTRICAL/INSTRUMENT CLUSTER -
DIAGNOSIS AND TESTING). Proper testing of the
PCI data bus and the electronic data bus message
inputs to the EMIC that control each indicator
require the use of a DRBIIItscan tool. Refer to the
appropriate diagnostic information. Specific details of
the operation for each indicator may be found else-
where in this service information.
CLUSTER ILLUMINATION The EMIC has several
illumination lamps that are illuminated when the
exterior lighting is turned on with the headlamp
(multi-function) switch. The illumination intensity of
these lamps is adjusted by a 12-volt Pulse Width
Modulated (PWM) output of the EMIC when the
interior lighting control ring on the left control stalk
of the multi-function switch is rotated (down to dim,
up to brighten) to one of six available minor detent
positions. The BCM provides electronic dimming
level messages based upon internal programming
and inputs it receives from the control knob and con-
trol ring on the left (lighting) control stalk of the
multi-function switch on the steering column, then
provides a control output to energize or de-energize
the park lamp relay as appropriate. The energized
park lamp relay provides battery current to the
EMIC on the hard wired fused park lamp relay out-
put circuit, and the BCM provides the electronic dim-
ming level message to the EMIC over the PCI data
bus. The EMIC electronic circuitry provides the
proper PWM output to the cluster illumination lamps
and the VFD on the EMIC circuit board, then pro-
vides a synchronized PWM output on the hard wired
8J - 6 INSTRUMENT CLUSTERKJ
INSTRUMENT CLUSTER (Continued)