2003 JEEP GRAND CHEROKEE stall

(3) Disconnect the instrument panel wire harness
connector from the SKIM connector.
(4) Remove the screw that secures the SKIM to
the bottom of the steering column housing (Fig. 16).
(5) Disengage the antenna ring of the SKIM from
around the ignition lock cylinder housing.
(6) Remove the SKIM from the steering column.
INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Position the SKIM to the underside of the
steering column (Fig. 16).
(2) Engage the antenna ring of the SKIM around
the ignition lock cylinder housing.
(3) Install and tighten the screw that secures the
SKIM to the bottom of the steering column hous-
ing.Tighten the screw to 3.4 N´m (30 in lbs.).
(4) Reconnect the instrument panel wire harness
connector to the SKIM connector.(5) Reinstall the steering column opening cover
onto the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - INSTALLATION).
(6) Reconnect the battery negative cable.
(7) Perform the SKIS Replacement procedure
using the DRBIIIt.
(8) Perform the SKIS Initialization Procedure
using the DRBIIIt.
TRANSMISSION CONTROL
MODULE
DESCRIPTION
The Transmission Control Module (TCM) is located
in the engine compartment on the right (passenger)
side and is mounted to the inner fender (Fig. 17).
OPERATION
The Transmission Control Module (TCM) controls
all electronic operations of the transmission. The
TCM receives information regarding vehicle opera-
tion from both direct and indirect inputs, and selects
the operational mode of the transmission. Direct
inputs are hardwired to, and used specifically by the
TCM. Indirect inputs originate from other compo-
nents/modules, and are shared with the TCM via the
vehicle communication bus.
Some examples ofdirect inputsto the TCM are:
²Battery (B+) voltage
²Ignition ªONº voltage
²Transmission Control Relay (Switched B+)
²Throttle Position Sensor
²Crankshaft Position Sensor
²Transmission Range Sensor
Fig. 16
Fig. 17 Transmission Control Module Location
1 - TRANSMISSION CONTROL MODULE (TCM)
2 - 60±WAY CONNECTOR
WJELECTRONIC CONTROL MODULES 8E - 19
SENTRY KEY IMMOBILIZER MODULE (Continued)

ENGINE SYSTEMS
TABLE OF CONTENTS
page page
BATTERY SYSTEM......................... 1
CHARGING.............................. 24STARTING............................... 29
BATTERY SYSTEM
TABLE OF CONTENTS
page page
BATTERY SYSTEM
DESCRIPTION..........................2
OPERATION............................2
DIAGNOSIS AND TESTING - BATTERY
SYSTEM.............................2
CLEANING.............................5
INSPECTION...........................6
SPECIFICATIONS........................6
SPECIAL TOOLS........................7
BATTERY
DESCRIPTION..........................7
OPERATION............................8
DIAGNOSIS AND TESTING - BATTERY.......8
STANDARD PROCEDURE
STANDARD PROCEDURE - BATTERY
CHARGING...........................9
STANDARD PROCEDURE - USING MICRO
420 ELECTRICAL TESTER..............10
STANDARD PROCEDURE - BUILT-IN
INDICATOR TEST.....................11
STANDARD PROCEDURE - OPEN-CIRCUIT
VOLTAGE TEST.......................12
STANDARD PROCEDURE - IGNITION-OFF
DRAW TEST.........................13STANDARD PROCEDURE - CHECKING
BATTERY ELECTROLYTE LEVEL.........14
REMOVAL.............................15
INSTALLATION.........................15
BATTERY HOLDDOWN
DESCRIPTION.........................16
OPERATION...........................16
REMOVAL.............................16
INSTALLATION.........................16
BATTERY CABLE
DESCRIPTION.........................17
OPERATION...........................18
DIAGNOSIS AND TESTING - BATTERY
CABLES............................18
REMOVAL.............................19
INSTALLATION.........................20
BATTERY TRAY
DESCRIPTION.........................21
OPERATION...........................22
REMOVAL.............................22
INSTALLATION.........................23
WJENGINE SYSTEMS 8F - 1

BATTERY SYSTEM
DESCRIPTION
A single 12-volt battery system is standard factory-
installed equipment on this model. All of the compo-
nents of the battery system are located within the
engine compartment of the vehicle. The service infor-
mation for the battery system in this vehicle covers
the following related components, which are covered
in further detail elsewhere in this service manual:
²Battery- The storage battery provides a reli-
able means of storing a renewable source of electrical
energy within the vehicle.
²Battery Cables- The battery cables connect
the battery terminal posts to the vehicle electrical
system.
²Battery Holddown- The battery holddown
hardware secures the battery in the battery tray in
the engine compartment.
²Battery Tray- The battery tray provides a
secure mounting location in the vehicle for the bat-
tery and an anchor point for the battery holddown
hardware.
For battery system maintenance schedules and jump
starting procedures, see the owner's manual in the vehi-
cle glove box. Optionally, refer to Lubrication and Main-
tenance for the recommended battery maintenance
schedules and for the proper battery jump starting pro-
cedures. While battery charging can be considered a
maintenance procedure, the battery charging procedures
and related information are located in the standard pro-
cedures section of this service manual. This was done
because the battery must be fully-charged before any
battery system diagnosis or testing procedures can be
performed. Refer to Standard procedures for the proper
battery charging procedures.
OPERATION
The battery system is designed to provide a safe,
efficient, reliable and mobile means of delivering and
storing electrical energy. This electrical energy is
required to operate the engine starting system, as
well as to operate many of the other vehicle acces-
sory systems for limited durations while the engine
and/or the charging system are not operating. The
battery system is also designed to provide a reserve
of electrical energy to supplement the charging sys-
tem for short durations while the engine is running
and the electrical current demands of the vehicle
exceed the output of the charging system. In addition
to delivering, and storing electrical energy for the
vehicle, the battery system serves as a capacitor and
voltage stabilizer for the vehicle electrical system. It
absorbs most abnormal or transient voltages caused
by the switching of any of the electrical components
or circuits in the vehicle.
DIAGNOSIS AND TESTING - BATTERY SYSTEM
The battery, starting, and charging systems in the
vehicle operate with one another and must be tested
as a complete system. In order for the engine to start
and the battery to maintain its charge properly, all of
the components that are used in these systems must
perform within specifications. It is important that
the battery, starting, and charging systems be thor-
oughly tested and inspected any time a battery needs
to be charged or replaced. The cause of abnormal bat-
tery discharge, overcharging or early battery failure
must be diagnosed and corrected before a battery is
replaced and before a vehicle is returned to service.
The service information for these systems has been
separated within this service manual to make it eas-
ier to locate the specific information you are seeking.
However, when attempting to diagnose any of these
systems, it is important that you keep their interde-
pendency in mind.
The diagnostic procedures used for the battery,
starting, and charging systems include the most
basic conventional diagnostic methods, to the more
sophisticated On-Board Diagnostics (OBD) built into
the Powertrain Control Module (PCM). Use of an
induction-type milliampere ammeter, a volt/ohmme-
ter, a battery charger, a carbon pile rheostat (load
tester) and a 12-volt test lamp may be required. All
OBD-sensed systems are monitored by the PCM.
Each monitored circuit is assigned a Diagnostic Trou-
ble Code (DTC). The PCM will store a DTC in elec-
tronic memory for any failure it detects. Refer to
Charging System for the proper charging system on-
board diagnostic test procedures.
MICRO 420 ELECTRICAL SYSTEM TESTER
The Micro 420 automotive battery tester is
designed to help the dealership technicians diagnose
a defective battery. Follow the instruction manual
supplied with the tester to properly diagnose a vehi-
cle. If the instruction manual is not available refer to
the standard procedure in this section, which
includes the directions for using the Micro 420 elec-
trical system tester.
8F - 2 BATTERY SYSTEMWJ

BATTERY SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
THE BATTERY STATE OF
CHARGE CANNOT BE
MAINTAINED.1. The battery has an
incorrect size or rating for
this vehicle.1. Refer to Battery System Specifications for the
proper specifications. Replace an incorrect
battery, as required.
2. The battery terminal
connections are loose or
corroded.2. Refer to Battery Cable for the proper cable
diagnosis and testing procedures. Clean and
tighten the battery terminal connections, as
required.
3. The electrical system
ignition-off draw is excessive.3. Refer to the IGNITION-OFF DRAW TEST
Standard Procedure for the proper test
procedures. Repair the faulty electrical system, as
required.
4. The battery is faulty. 4. Test the battery using the Micro 420 battery
tester. Refer to Standard Procedures for
additional test procedures. Replace the faulty
battery, as required.
5. The starting system is
faulty.5. Determine if the starting system is performing
to specifications. Refer to Starting System for the
proper starting system diagnosis and testing
procedures. Repair the faulty starting system, as
required.
6. The charging system is
faulty.6. Determine if the charging system is performing
to specifications using the Micro 420 battery.
Refer to Charging System for additional charging
system diagnosis and testing procedures. Repair
the faulty charging system, as required.
7. Electrical loads exceed the
output of the charging
system.7. Inspect the vehicle for aftermarket electrical
equipment which might cause excessive electrical
loads.
8. Slow driving or prolonged
idling with high-amperage
draw systems in use.8. Advise the vehicle operator, as required.
THE BATTERY WILL NOT
ACCEPT A CHARGE.1. The battery is faulty. 1. Test the battery using the Micro 420 battery
tester. Charge or replace the faulty battery, as
required.
ABNORMAL BATTERY DISCHARGING
Any of the following conditions can result in abnor-
mal battery discharging:
1. A faulty or incorrect charging system compo-
nent. Refer to Charging System for additional charg-
ing system diagnosis and testing procedures.
2. A faulty or incorrect battery. Use Micro 420 bat-
tery tester and refer to Battery System for additional
battery diagnosis and testing procedures.
3. A faulty circuit or component causing excessive
ignition-off draw.4. Electrical loads that exceed the output of the
charging system. This can be due to equipment
installed after manufacture, or repeated short trip
use.
5. A faulty or incorrect starting system component.
Refer to Starting System for the proper starting sys-
tem diagnosis and testing procedures.
6. Corroded or loose battery posts and/or terminal
clamps.
7. Slow driving speeds (heavy traffic conditions) or
prolonged idling, with high-amperage draw systems
in use.
8F - 4 BATTERY SYSTEMWJ
BATTERY SYSTEM (Continued)

CLEANING
The following information details the recommended
cleaning procedures for the battery and related com-
ponents. In addition to the maintenance schedules
found in this service manual and the owner's man-
ual, it is recommended that these procedures be per-
formed any time the battery or related components
must be removed for vehicle service.
(1) Clean the battery cable terminal clamps of all
corrosion. Remove any corrosion using a wire brush
or a post and terminal cleaning tool, and a sodium
bicarbonate (baking soda) and warm water cleaning
solution (Fig. 1).
(2) Clean the battery tray and battery holddown
hardware of all corrosion. Remove any corrosion
using a wire brush and a sodium bicarbonate (baking
soda) and warm water cleaning solution. Paint any
exposed bare metal.
(3) If the removed battery is to be reinstalled,
clean the outside of the battery case and the top
cover with a sodium bicarbonate (baking soda) and
warm water cleaning solution using a stiff bristle
parts cleaning brush to remove any acid film (Fig. 2).
Rinse the battery with clean water. Ensure that the
cleaning solution does not enter the battery cells
through the vent holes. If the battery is being
replaced, refer to Battery System Specifications for
the factory-installed battery specifications. Confirm
that the replacement battery is the correct size and
has the correct ratings for the vehicle.(4) Clean any corrosion from the battery terminal
posts with a wire brush or a post and terminal
cleaner, and a sodium bicarbonate (baking soda) and
warm water cleaning solution (Fig. 3).
Fig. 1 Clean Battery Cable Terminal Clamp - Typical
1 - TERMINAL BRUSH
2 - BATTERY CABLE
Fig. 2 Clean Battery - Typical
1 - CLEANING BRUSH
2 - WARM WATER AND BAKING SODA SOLUTION
3 - BATTERY
Fig. 3 Clean Battery Terminal Post - Typical
1 - TERMINAL BRUSH
2 - BATTERY CABLE
3 - BATTERY
WJBATTERY SYSTEM 8F - 5
BATTERY SYSTEM (Continued)

SPECIAL TOOLS
BATTERY
DESCRIPTION
A large capacity, low-maintenance storage battery
(Fig. 4) is standard factory-installed equipment on
this model. Male post type terminals made of a soft
lead material protrude from the top of the molded
plastic battery case to provide the means for connect-
ing the battery to the vehicle electrical system. The
battery positive terminal post is visibly larger in
diameter than the negative terminal post, for easy
identification. The lettersPOSandNEGare also
molded into the top of the battery case adjacent to
their respective positive and negative terminal posts
for additional identification confirmation. Refer to
Battery Cablesin the index of this service manual
for the location of more information on the battery
cables that connect the battery to the vehicle electri-
cal system.
This battery is designed to provide a safe, efficient
and reliable means of storing electrical energy in a
chemical form. This means of energy storage allows
the battery to produce the electrical energy required
to operate the engine starting system, as well as to
operate many of the other vehicle accessory systems
for limited durations while the engine and/or the
charging system are not operating. The battery is
made up of six individual cells that are connected in
series. Each cell contains positively charged plate
groups that are connected with lead straps to thepositive terminal post, and negatively charged plate
groups that are connected with lead straps to the
negative terminal post. Each plate consists of a stiff
mesh framework or grid coated with lead dioxide
(positive plate) or sponge lead (negative plate). Insu-
lators or plate separators made of a non-conductive
material are inserted between the positive and nega-
tive plates to prevent them from contacting or short-
ing against one another. These dissimilar metal
plates are submerged in a sulfuric acid and water
solution called an electrolyte.
Some factory-installed batteries have a built-in test
indicator (hydrometer). The color visible in the sight
glass of the indicator will reveal the battery condi-
tion. For more information on the use of the built-in
test indicator, refer toStandard Procedures The
factory-installed low-maintenance battery has
removable battery cell caps.Distilled water can
be added to this battery. The battery is not sealed
and has vent holes in the cell caps. The chemical
composition of the metal coated plates within the
low-maintenance battery reduces battery gassing and
water loss, at normal charge and discharge rates.
Therefore, the battery should not require additional
water in normal service. If the electrolyte level in
this battery does become low, distilled water must be
added. However, rapid loss of electrolyte can be
caused by an overcharging condition. Be certain to
MICRO 420 BATTERY AND CHARGING SYSTEM
TESTER
Fig. 4 Low-Maintenance Battery - Typical
1 - POSITIVE POST
2 - VENT
3 - CELL CAP
4 - TEST INDICATOR
5 - CELL CAP
6 - VENT
7 - NEGATIVE POST
8 - GREEN BALL
9 - ELECTROLYTE LEVEL
10 - PLATE GROUPS
11 - LOW-MAINTENANCE BATTERY
WJBATTERY SYSTEM 8F - 7
BATTERY SYSTEM (Continued)

(2) Disconnect and isolate the battery negative
cable. Connect the battery charger leads. Some bat-
tery chargers are equipped with polarity-sensing cir-
cuitry. This circuitry protects the battery charger and
the battery from being damaged if they are improp-
erly connected. If the battery state-of-charge is too
low for the polarity-sensing circuitry to detect, the
battery charger will not operate. This makes it
appear that the battery will not accept charging cur-
rent. See the instructions provided by the manufac-
turer of the battery charger for details on how to
bypass the polarity-sensing circuitry.
(3) Battery chargers vary in the amount of voltage
and current they provide. The amount of time
required for a battery to accept measurable charging
current at various voltages is shown in the Charge
Rate Table. If the charging current is still not mea-
surable at the end of the charging time, the battery
is faulty and must be replaced. If the charging cur-
rent is measurable during the charging time, the bat-
tery may be good and the charging should be
completed in the normal manner.
CHARGE RATE TABLE
Voltage Hours
16.0 volts maximum up to 4 hours
14.0 to 15.9 volts up to 8 hours
13.9 volts or less up to 16 hours
CHARGING TIME REQUIRED
The time required to charge a battery will vary,
depending upon the following factors:
²Battery Capacity- A completely discharged
heavy-duty battery requires twice the charging time
of a small capacity battery.
²Temperature- A longer time will be needed to
charge a battery at -18É C (0É F) than at 27É C (80É
F). When a fast battery charger is connected to a cold
battery, the current accepted by the battery will bevery low at first. As the battery warms, it will accept
a higher charging current rate (amperage).
²Charger Capacity- A battery charger that
supplies only five amperes will require a longer
charging time. A battery charger that supplies
twenty amperes or more will require a shorter charg-
ing time.
²State-Of-Charge- A completely discharged bat-
tery requires more charging time than a partially
discharged battery. Electrolyte is nearly pure water
in a completely discharged battery. At first, the
charging current (amperage) will be low. As the bat-
tery charges, the specific gravity of the electrolyte
will gradually rise.
The Battery Charging Time Table gives an indica-
tion of the time required to charge a typical battery
at room temperature based upon the battery state-of-
charge and the charger capacity.
BATTERY CHARGING TIME TABLE
Charging
Amperage5 Amps10
Amps20 Amps
Open Circuit
VoltageHours Charging @ 21É C (70É
F)
12.25 to 12.49 6 hours 3 hours 1.5
hours
12.00 to 12.24 10 hours 5 hours 2.5
hours
10.00 to 11.99 14 hours 7 hours 3.5
hours
Below 10.00 18 hours 9 hours 4.5
hours
STANDARD PROCEDURE - USING MICRO 420
ELECTRICAL TESTER
Always use the Micro 420 Instruction Manual that
was supplied with the tester as a reference. If the
Instruction Manual is not available the following pro-
cedure can be used:
WARNING: ALWAYS WEAR APPROPRIATE EYE
PROTECTION AND USE EXTREME CAUTION WHEN
WORKING WITH BATTERIES.
BATTERY TESTING
(1) If testing the battery OUT-OF-VEHICLE, clean
the battery terminals with a wire brush before test-
ing. If the battery is equipped with side post termi-
nals, install and tighten the supplied lead terminal
stud adapters. Do not use steel bolts. Failure to prop-
erly install the stud adapters, or using stud adapters
that are dirty or worn-out may result in false test
readings.
Fig. 5 Voltmeter - Typical
8F - 10 BATTERY SYSTEMWJ
BATTERY (Continued)

REMOVAL
(1) Turn the ignition switch to the Off position. Be
certain that all electrical accessories are turned off.
(2) Loosen the battery negative cable terminal
clamp pinch-bolt hex nut.
(3) Disconnect the battery negative cable terminal
clamp from the battery negative terminal post. If
necessary, use a battery terminal puller to remove
the terminal clamp from the battery post (Fig. 12).
(4) Loosen the battery positive cable terminal
clamp pinch-bolt hex nut.
(5) Disconnect the battery positive cable terminal
clamp from the battery positive terminal post. If nec-
essary, use a battery terminal puller to remove the
terminal clamp from the battery post.
(6) Remove the battery hold down from the bat-
tery. Refer toBattery Hold Downin this section of
the service manual for the procedure.
WARNING: WEAR A SUITABLE PAIR OF RUBBER
GLOVES (NOT THE HOUSEHOLD TYPE) WHEN
REMOVING A BATTERY BY HAND. SAFETY
GLASSES SHOULD ALSO BE WORN. IF THE BAT-
TERY IS CRACKED OR LEAKING, THE ELECTRO-
LYTE CAN BURN THE SKIN AND EYES.
(7) Remove the battery from the battery tray.
INSTALLATION
(1) Clean and inspect the battery. Refer to the pro-
cedures in this section.
(2) Position the battery onto the battery tray as a
unit. Ensure that the battery positive and negative
terminal posts are correctly positioned. The battery
cable terminal clamps must reach the correct battery
terminal post without stretching the cables (Fig. 13)
or (Fig. 14).
(3) Reinstall the battery hold downs onto the bat-
tery. Refer toBattery Hold DownsCAUTION: Be certain that the battery cable terminal
clamps are connected to the correct battery termi-
nal posts. Reverse battery polarity may damage
electrical components of the vehicle.
(4) Clean the battery cable terminal clamps and
the battery terminal posts.
Fig. 12 Remove Battery Cable Terminal Clamp -
Typical
1 - BATTERY
2 - BATTERY TERMINAL PULLER
Fig. 13 Battery Cables - 4.0L Engine
1 - BATTERY POSITIVE CABLE
2 - BATTERY NEGATIVE CABLE
3 - CLIPS
Fig. 14 Battery Cables - 4.7L Engine
1 - BATTERY POSITIVE CABLE
2 - BATTERY NEGATIVE CABLE
3 - CLIPS
WJBATTERY SYSTEM 8F - 15
BATTERY (Continued)