2003 JEEP GRAND CHEROKEE abs warning

Propylene-glycol/ethylene-glycol Mixtures can
cause the destabilization of various corrosion inhibi-
tors, causing damage to the various cooling system
components. Also, once ethylene-glycol and propy-
lene-glycol based coolants are mixed in the vehicle,
conventional methods of determining freeze point will
not be accurate. Both the refractive index and spe-
cific gravity differ between ethylene glycol and propy-
lene glycol.
DESCRIPTION - ENGINE COOLANT
WARNING: ANTIFREEZE IS AN ETHYLENE GLYCOL
BASE COOLANT AND IS HARMFUL IF SWAL-
LOWED OR INHALED. IF SWALLOWED, DRINK
TWO GLASSES OF WATER AND INDUCE VOMIT-
ING. IF INHALED, MOVE TO FRESH AIR AREA.
SEEK MEDICAL ATTENTION IMMEDIATELY. DO NOT
STORE IN OPEN OR UNMARKED CONTAINERS.
WASH SKIN AND CLOTHING THOROUGHLY AFTER
COMING IN CONTACT WITH ETHYLENE GLYCOL.
KEEP OUT OF REACH OF CHILDREN. DISPOSE OF
GLYCOL BASE COOLANT PROPERLY, CONTACT
YOUR DEALER OR GOVERNMENT AGENCY FOR
LOCATION OF COLLECTION CENTER IN YOUR
AREA. DO NOT OPEN A COOLING SYSTEM WHEN
THE ENGINE IS AT OPERATING TEMPERATURE OR
HOT UNDER PRESSURE, PERSONAL INJURY CAN
RESULT. AVOID RADIATOR COOLING FAN WHEN
ENGINE COMPARTMENT RELATED SERVICE IS
PERFORMED, PERSONAL INJURY CAN RESULT.
CAUTION: Use of Propylene Glycol based coolants
is not recommended, as they provide less freeze
protection and less corrosion protection.
The cooling system is designed around the coolant.
The coolant must accept heat from engine metal, in
the cylinder head area near the exhaust valves and
engine block. Then coolant carries the heat to the
radiator where the tube/fin radiator can transfer the
heat to the air.
The use of aluminum cylinder blocks, cylinder
heads, and water pumps requires special corrosion
protection. MopartAntifreeze/Coolant, 5
Year/100,000 Mile Formula (MS-9769), or the equiva-
lent ethylene glycol base coolant with organic corro-
sion inhibitors (called HOAT, for Hybrid Organic
Additive Technology) is recommended. This coolant
offers the best engine cooling without corrosion when
mixed with 50% Ethylene Glycol and 50% distilled
water to obtain a freeze point of -37ÉC (-35ÉF). If it
loses color or becomes contaminated, drain, flush,
and replace with fresh properly mixed coolant solu-
tion.CAUTION: MoparTAntifreeze/Coolant, 5
Year/100,000 Mile Formula (MS-9769) may not be
mixed with any other type of antifreeze. Mixing of
coolants other than specified (non-HOAT or other
HOAT), may result in engine damage that may not
be covered under the new vehicle warranty, and
decreased corrosion protection.
COOLANT PERFORMANCE
The required ethylene-glycol (antifreeze) and water
mixture depends upon climate and vehicle operating
conditions. The coolant performance of various mix-
tures follows:
Pure Water-Water can absorb more heat than a
mixture of water and ethylene-glycol. This is for pur-
pose of heat transfer only. Water also freezes at a
higher temperature and allows corrosion.
100 percent Ethylene-Glycol-The corrosion
inhibiting additives in ethylene-glycol need the pres-
ence of water to dissolve. Without water, additives
form deposits in system. These act as insulation
causing temperature to rise to as high as 149ÉC
(300ÉF). This temperature is hot enough to melt plas-
tic and soften solder. The increased temperature can
result in engine detonation. In addition, 100 percent
ethylene-glycol freezes at -22ÉC (-8ÉF).
50/50 Ethylene-Glycol and Water-Is the recom-
mended mixture, it provides protection against freez-
ing to -37ÉC (-34ÉF). The antifreeze concentration
must alwaysbe a minimum of 44 percent, year-
round in all climates. If percentage is lower, engine
parts may be eroded by cavitation. Maximum protec-
tion against freezing is provided with a 68 percent
antifreeze concentration, which prevents freezing
down to -67.7ÉC (-90ÉF). A higher percentage will
freeze at a warmer temperature. Also, a higher per-
centage of antifreeze can cause the engine to over-
heat because specific heat of antifreeze is lower than
that of water.
CAUTION: Richer antifreeze mixtures cannot be
measured with normal field equipment and can
cause problems associated with 100 percent ethyl-
ene-glycol.
COOLANT SELECTION AND ADDITIVES
The use of aluminum cylinder blocks, cylinder
heads and water pumps requires special corrosion
protection. Only MopartAntifreeze/Coolant, 5
Year/100,000 Mile Formula (glycol base coolant with
corrosion inhibitors called HOAT, for Hybrid Organic
Additive Technology) is recommended. This coolant
offers the best engine cooling without corrosion when
mixed with 50% distilled water to obtain to obtain a
freeze point of -37ÉC (-35ÉF). If it loses color or
WJLUBRICATION & MAINTENANCE 0 - 3
FLUID TYPES (Continued)

DESCRIPTION - ENGINE OIL - DIESEL
ENGINES
Use only Diesel Engine Oil meeting standardMIL-
2104Cor API ClassificationCD or higherorCCML
D4, D5.
SAE VISCOSITY GRADE
CAUTION: Low viscosity oils must have the proper
API quality or the CCMC G5 designation.
To assure of properly formulated engine oils, it is
recommended that SAE Grade 10W-40 engine oils
that meet Chrysler material standard MS-6395, be
used. European Grade 10W-40 oils are also accept-
able.
Oils of the SAE 5W-40 or 8W-80 grade number are
preferred when minimum temperatures consistently
fall below -12ÉC.
OPERATION - AUTOMATIC TRANSMISSION
FLUID
The automatic transmission fluid is selected based
upon several qualities. The fluid must provide a high
level of protection for the internal components by
providing a lubricating film between adjacent metal
components. The fluid must also be thermally stable
so that it can maintain a consistent viscosity through
a large temperature range. If the viscosity stays con-
stant through the temperature range of operation,
transmission operation and shift feel will remain con-
sistent. Transmission fluid must also be a good con-
ductor of heat. The fluid must absorb heat from the
internal transmission components and transfer that
heat to the transmission case.
FLUID FILL/CHECK
LOCATIONS
INSPECTION - FLUID FILL/CHECK LOCATIONS
The fluid fill/check locations and lubrication points
are located in each applicable group.
MAINTENANCE SCHEDULES
DESCRIPTION
9Maintenance Schedule Information not included in
this section, is located in the appropriate Owner's
Manual.9
LIFT POINTS
STANDARD PROCEDURE - HOISTING AND
JACKING RECOMMENDATIONS
FLOOR JACK
When properly positioned, a floor jack can be used
to lift a WJ vehicle (Fig. 7). Support the vehicle in
the raised position with jack stands at the front and
rear ends of the frame rails.
CAUTION: Do not attempt to lift a vehicle with a
floor jack positioned under:
²An axle tube.
²Aluminum differential.
²A body side sill.
²A steering linkage component.
²A drive shaft.
²The engine or transmission oil pan.
²The fuel tank.
²A front suspension arm.
HOIST
A vehicle can be lifted with:
²A single-post, frame-contact hoist.
²A twin-post, chassis hoist.
²A ramp-type, drive-on hoist.
NOTE: When a frame-contact type hoist is used,
verify that the lifting pads are positioned properly
(Fig. 7).
WARNING: THE HOISTING AND JACK LIFTING
POINTS PROVIDED ARE FOR A COMPLETE VEHI-
CLE. WHEN A CHASSIS OR DRIVETRAIN COMPO-
NENT IS REMOVED FROM A VEHICLE, THE
CENTER OF GRAVITY IS ALTERED MAKING SOME
HOISTING CONDITIONS UNSTABLE. PROPERLY
SUPPORT OR SECURE VEHICLE TO HOISTING
DEVICE WHEN THESE CONDITIONS EXIST.
0 - 6 LUBRICATION & MAINTENANCEWJ
FLUID TYPES (Continued)

FRONT
TABLE OF CONTENTS
page page
FRONT
DESCRIPTION..........................6
STANDARD PROCEDURE - SERVICE
WARNINGS AND CAUTIONS..............6
SPECIFICATIONS
TORQUE CHART......................7
SPECIAL TOOLS
FRONT SUSPENSION...................8
BUSHINGS
REMOVAL.............................9
INSTALLATION..........................9
HUB / BEARING
DESCRIPTION..........................9
OPERATION............................9
REMOVAL.............................9
INSTALLATION.........................10
KNUCKLE
DESCRIPTION.........................10
OPERATION...........................10
REMOVAL - STEERING KNUCKLE..........10
INSTALLATION.........................10
LOWER BALL JOINT
REMOVAL.............................11
LOWER CONTROL ARM
DESCRIPTION.........................11
OPERATION...........................11
REMOVAL.............................11
INSTALLATION.........................11SHOCK
DESCRIPTION.........................12
OPERATION...........................12
REMOVAL.............................12
INSTALLATION.........................12
SPRING
DESCRIPTION.........................12
OPERATION...........................13
REMOVAL.............................13
INSTALLATION.........................13
STABILIZER BAR
DESCRIPTION.........................14
OPERATION...........................14
REMOVAL.............................14
INSTALLATION.........................14
TRACK BAR
DESCRIPTION.........................14
OPERATION...........................14
REMOVAL.............................14
INSTALLATION.........................14
UPPER BALL JOINT
REMOVAL.............................15
UPPER CONTROL ARM
DESCRIPTION.........................16
OPERATION...........................16
REMOVAL.............................16
INSTALLATION.........................16
FRONT
DESCRIPTION
The front suspension (Fig. 1) is a link/coil design
comprised of :
²Drive axle
²Shock absorbers
²Coil springs
²Upper and lower suspension arms
²Stabilizer bar
²Track bar
²Jounce bumpers
CAUTION: Components attached with a nut and cot-
ter pin must be torqued to specification. Then if the
slot in the nut does not line up with the cotter pin
hole, tighten nut until it is aligned. Never loosen the
nut to align the cotter pin hole.CAUTION: Suspension components with rubber
bushings must be tightened with the vehicle at nor-
mal ride height. It is important to have the springs
supporting the weight of the vehicle when the fas-
teners are torqued. If springs are not at their normal
ride position, vehicle ride comfort will be affected
and cause premature bushing wear.
STANDARD PROCEDURE - SERVICE
WARNINGS AND CAUTIONS
CAUTION: Suspension components with rubber
bushings must be tightened with the vehicle at nor-
mal ride height. It is important to have the springs
supporting the weight of the vehicle when the fas-
teners are torqued. If springs are not at their normal
ride position, vehicle ride comfort will be affected
and cause premature bushing wear.
2 - 6 FRONTWJ

REAR
TABLE OF CONTENTS
page page
REAR
DESCRIPTION.........................17
WARNING.............................17
DIAGNOSIS AND TESTING - REAR
SUSPENSION........................18
SPECIFICATIONS
TORQUE CHART......................18
SPECIAL TOOLS
REAR SUSPENSION...................19
LOWER CONTROL ARM
DESCRIPTION.........................19
OPERATION...........................19
REMOVAL.............................19
INSTALLATION.........................19
SHOCK
DESCRIPTION.........................19
OPERATION...........................19
REMOVAL.............................19
INSTALLATION.........................19
SPRING
DESCRIPTION.........................20OPERATION...........................20
REMOVAL.............................20
INSTALLATION.........................20
STABILIZER BAR
DESCRIPTION.........................21
OPERATION...........................21
REMOVAL.............................21
INSTALLATION.........................21
UPPER BALL JOINT
DESCRIPTION - UPPER SUSPENSION ARM,
BUSHINGS, AND BALL JOINT............21
OPERATION - UPPER SUSPENSION ARM,
BUSHINGS, AND BALL JOINT............21
REMOVAL.............................21
INSTALLATION.........................22
UPPER CONTROL ARM
DESCRIPTION.........................22
OPERATION...........................22
REMOVAL.............................22
INSTALLATION.........................23
REAR
DESCRIPTION
The rear suspension (Fig. 1) is comprised of :
²Drive axle
²Shock absorbers
²Coil springs
²Lower suspension arms
²Upper suspension arm
²Stabilizer bar
CAUTION: Suspension components with rubber/ure-
thane bushings should be tightened with the vehi-
cle at normal ride height. It is important to have the
springs supporting the weight of the vehicle when
the fasteners are torqued. This will maintain vehicle
ride comfort and prevent premature bushing wear.
WARNING
WARNING:: Suspension components with rubber
bushings must be tightened with the vehicle at nor-
mal ride height. It is important to have the springs
supporting the weight of the vehicle when the fas-
teners are torqued. If springs are not at their normalride position, vehicle ride comfort will be affected
and cause premature bushing wear.
Fig. 1 Rear Suspension
1 - SHOCK
2 - UPPER SUSPENSION ARM
3 - COIL SPRING
4 - STABILIZER BAR
5 - LOWER SUSPENSION ARM
WJREAR 2 - 17

BRAKES
TABLE OF CONTENTS
page page
BRAKES - BASE........................... 1BRAKES - ABS........................... 41
BRAKES - BASE
TABLE OF CONTENTS
page page
BRAKES - BASE
DESCRIPTION..........................2
DIAGNOSIS AND TESTING - BASE BRAKE
SYSTEM.............................2
STANDARD PROCEDURE
STANDARD PROCEDURE - MANUAL
BLEEDING............................5
STANDARD PROCEDURE - PRESSURE
BLEEDING............................5
SPECIFICATIONS
BRAKE COMPONENTS..................6
TORQUE CHART......................6
SPECIAL TOOLS
BASE BRAKES........................7
BRAKE FLUID LEVEL SWITCH
REMOVAL.............................7
INSTALLATION..........................7
RED BRAKE WARN INDICATOR SWITCH
DESCRIPTION..........................7
OPERATION............................7
DIAGNOSIS AND TESTING - RED BRAKE
WARNING LAMP.......................7
ADJUSTABLE PEDAL SWITCH
REMOVAL.............................8
INSTALLATION..........................8
BRAKE LINES
DESCRIPTION..........................8
DIAGNOSIS AND TESTING - BRAKE HOSES
AND LINES...........................8
STANDARD PROCEDURE
STANDARD PROCEDURE - DOUBLE
INVERTED FLARING....................9
STANDARD PROCEDURE - ISO FLARING . . . 9
BRAKE PADS / SHOES
DESCRIPTION
DESCRIPTION - FRONT DISC BRAKE
SHOES.............................10DESCRIPTION - REAR DISC BRAKE SHOES . 10
OPERATION
OPERATION - FRONT DISC BRAKE SHOES . 10
OPERATION - REAR DISC BRAKE SHOES . . 10
REMOVAL
REMOVAL- FRONT DISC BRAKE SHOES . . . 11
REMOVAL - REAR DISC BRAKE SHOES....12
INSTALLATION
INSTALLATION - FRONT DISC BRAKE
SHOES.............................13
INSTALLATION - REAR DISC BRAKE
SHOES.............................14
DISC BRAKE CALIPERS
REMOVAL
REMOVAL - FRONT DISC BRAKE CALIPER . 14
REMOVAL - REAR DISC BRAKE CALIPER . . 15
DISASSEMBLY
DISASSEMBLY - FRONT DISC BRAKE
CALIPER............................17
DISASSEMBLY - REAR DISC BRAKE
CALIPER............................18
CLEANING - DISC BRAKE CALIPER.........19
INSPECTION - DISC BRAKE CALIPER.......19
ASSEMBLY
ASSEMBLY - FRONT DISC BRAKE CALIPER . 20
ASSEMBLY - REAR DISC BRAKE CALIPER . 21
INSTALLATION
INSTALLATION - FRONT DISC BRAKE
CALIPER............................22
INSTALLATION - REAR DISC BRAKE
CALIPER............................22
FLUID
DIAGNOSIS AND TESTING - BRAKE FLUID
CONTAMINATION.....................22
SPECIFICATIONS
BRAKE FLUID........................23
FLUID RESERVOIR
REMOVAL.............................23
WJBRAKES 5 - 1

SPECIAL TOOLS
BASE BRAKESBRAKE FLUID LEVEL SWITCH
REMOVAL
(1) Remove the wire connector from the fluid level
sensor.
(2) From the same side of the master cylinder res-
ervoir release the sensor locking taps with a small
screw driver.
(3) Pull the sensor out of the reservoir from the
connector side of the sensor.
INSTALLATION
(1) Install the sensor with a new o-ring into the
reservoir until the locking tabs are engaged.
(2) Install the wire connector to the fluid level sen-
sor.
RED BRAKE WARN INDICATOR
SWITCH
DESCRIPTION
A red warning lamp is used for the service brake
portion of the hydraulic system. The lamp is located
in the instrument cluster.
OPERATION
The lamp is turned on momentarily when the igni-
tion switch is turn to the on position. This is a self
test to verify the lamp is operational.
The red warning light alerts the driver if the fluid
level is low or the parking brakes are applied. A red
warning lamp with an amber warning lamp may
indicate a electronic brake distribution fault.
DIAGNOSIS AND TESTING - RED BRAKE
WARNING LAMP
The red warning lamp illuminates when the park-
ing brake is applied or when the fluid level in the
master cylinder is low. It will also illuminate at start
up as part of a bulb check.
If the light comes on, first verify that the parking
brakes are fully released. Then check pedal action
and fluid level. If a problem is confirmed, inspect the
brake hydraulic system for leaks.
A red warning lamp with a amber warning lamp
may indicate a electronic brake distribution fault.
Installer Caliper Dust Boot 8280
Handle C-4171
Adapter Pressure Bleeder 6921
WJBRAKES - BASE 5 - 7
BRAKES - BASE (Continued)

BRAKES - ABS
TABLE OF CONTENTS
page page
BRAKES - ABS
DESCRIPTION.........................41
OPERATION...........................41
DIAGNOSIS AND TESTING - ANTILOCK
BRAKES............................42
STANDARD PROCEDURE - BLEEDING ABS
BRAKE SYSTEM......................42
SPECIFICATIONS
TORQUE CHART......................42
ELECTRIC BRAKE
DESCRIPTION.........................43
OPERATION...........................43
FRONT WHEEL SPEED SENSOR
DESCRIPTION.........................43
OPERATION...........................43
REMOVAL.............................43INSTALLATION.........................43
G-SWITCH
DESCRIPTION.........................44
OPERATION...........................44
REMOVAL.............................44
INSTALLATION.........................44
REAR WHEEL SPEED SENSOR
DESCRIPTION.........................45
OPERATION...........................45
REMOVAL.............................45
INSTALLATION.........................46
HCU (HYDRAULIC CONTROL UNIT)
DESCRIPTION.........................46
OPERATION...........................46
REMOVAL.............................47
INSTALLATION.........................47
BRAKES - ABS
DESCRIPTION
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 hydraulic system is a three channel design.
The front brakes are controlled individually and the
rear brakes in tandem.
The ABS electrical system is separate from other
vehicle electrical circuits. A separate controller oper-
ates the system.
OPERATION
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 30kph (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.
ANTILOCK BRAKING
The antilock system prevents lockup during high
slip conditions by modulating fluid apply pressure to
the wheel brake units.
Brake fluid apply pressure is modulated according
to wheel speed, degree of slip and rate of decelera-
tion. A sensor at each wheel converts wheel speed
into electrical signals. These signals are transmitted
to the CAB for processing and determination 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 con-
trol 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 solenoid valves are not static during antilock
braking. They are cycled continuously to modulate
pressure. Solenoid cycle time in antilock mode can be
measured in milliseconds.
WJBRAKES - ABS 5 - 41

ELECTRIC BRAKE
DESCRIPTION
The electronic brake distribution (EBD) functions
like a rear proportioning valve. The EBD system uses
the 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
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
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.
FRONT WHEEL SPEED
SENSOR
DESCRIPTION
A wheel speed sensor is used at each wheel. The
front sensors are mounted to the steering knuckles.
The rear sensors are mounted at the outboard end of
the axle. Tone wheels are mounted to the outboard
ends of the front and rear axle shafts. The gear type
tone wheel serves as the trigger mechanism for each
sensor.
OPERATION
The sensors convert wheel speed into a small digi-
tal signal. The CAB sends 12 volts to the sensors.
The sensor has an internal magneto resistance
bridge that alters the voltage and amperage of the
signal circuit. This voltage and amperage is changed
by magnetic induction when the toothed tone wheel
passes the wheel speed sensor. This digital signal issent to the CAB. The CAB measures the voltage and
amperage of the digital signal for each wheel.
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the front wheel sensor mounting bolt
(Fig. 1).
(3) Remove the sensor from the steering knuckle.
(4) Disengage the sensor wire from the brackets
(Fig. 1)on the steering knuckle.
(5) Disconnect the sensor from the sensor harness
(Fig. 2)and (Fig. 3).
(6) Remove the sensor and wire.
INSTALLATION
(1) Install the sensor on the steering knuckle.
(2) Apply Mopar Lock N' Seal or Loctitet242 to
the sensor mounting bolt. Use new sensor bolt if orig-
inal bolt is worn or damaged.
(3) Install the sensor mounting bolt and tighten
bolt to 12-14 N´m (106-124 in. lbs.).
(4) Engage the grommets on the sensor wire to the
steering knuckle brackets.
(5) Connect the sensor wire to the harness connec-
tor.
(6) Check the sensor wire routing. Be sure the
wire is clear of all chassis components and is not
twisted or kinked at any spot.
(7) Remove the support and lower vehicle.
Fig. 1 Sensor Location
1 - BRACKET
2 - BRACKET
3 - WHEEL SPEED SENSOR
4 - MOUNTING BOLT
WJBRAKES - ABS 5 - 43