Wire JEEP GRAND CHEROKEE 2002 WJ / 2.G Service Manual

faults arenoterased if the battery is disconnected.
(Fig. 4)
REMOVAL
(1) Remove negative battery cable from the bat-
tery.
(2) Remove air cleaner housing,(Refer to 9 -
ENGINE/AIR INTAKE SYSTEM/AIR CLEANER
HOUSING - REMOVAL) OR (Refer to 9 - ENGINE/
AIR INTAKE SYSTEM/AIR CLEANER HOUSING -
REMOVAL).
(3) Release CAB harness connector and remove
connector (Fig. 5).
(4) Remove pump motor connector.
(5) Remove CAB mounting bolts (Fig. 6) and
remove the CAB from the HCU.
INSTALLATION
(1) Install the CAB onto the HCU and tighten
mounting bolts to 1.8 N´m (16 in. lbs.).
(2) Install pump motor connector.
(3) Install CAB harness connector and push down
connector release.
(4) Install air cleaner housing,(Refer to 9 -
ENGINE/AIR INTAKE SYSTEM/AIR CLEANER
HOUSING - INSTALLATION) OR (Refer to 9 -
ENGINE/AIR INTAKE SYSTEM/AIR CLEANER
HOUSING - INSTALLATION).
(5) Install negative battery cable to the battery.
DATA LINK CONNECTOR
DESCRIPTION - DATA LINK CONNECTOR
The data link connector (DLC) is located at the
lower edge of the instrument panel near the steering
column.
OPERATION - DATA LINK CONNECTOR
The 16±way DLC links the DRBIIItscan tool or
the Mopar Diagnostic System (MDS) with the Power-
train Control Module (PCM).
DOOR MODULE
DESCRIPTION
A door module is concealed behind the trim panel
of each front door (Fig. 7).The module on the driver
side is referred to as the Driver Door Module (DDM),
while the module on the passenger side is the Pas-
senger Door Module (PDM). Each door module
houses both the front power lock and power window
switches. In addition to the power window and power
lock switches for its own door, the DDM also houses
individual switches for each passenger door power
window, a power window lockout switch, the power
mirror switch, and the power foldaway mirror switch
for export vehicles.
The DDM and PDM each utilize integrated cir-
cuitry and information 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. The
PDM also receives inputs through an integral Radio
Fig. 5 CAB Connector Release
1 - CONNECTOR RELEASE
2 - CAB
Fig. 6 CAB Mounting Bolts
1 - MOUNTING BOLTS
WJELECTRONIC CONTROL MODULES 8E - 7
CONTROLLER ANTILOCK BRAKE (Continued)

Frequency (RF) Remote Keyless Entry (RKE)
receiver. The DDM and PDM control and integrate
many functions and features of the vehicle through
both hard wired outputs and messages over the PCI
data bus. The functions and features that the door
modules support or control include the following:
²Automatic Door Lock- The two door modules
provide an automatic door lock feature which locks
the doors when the vehicle is moving. This is a pro-
grammable feature.
²Automatic Door Unlock On Exit- The two
door modules provide an automatic door unlock on
exit feature. This feature will unlock all the doors if
they were locked via the automatic door lock feature
after the vehicle has stopped moving and the driver
door is opened. This is a programmable feature via
the EVIC.
²Customer Programmable Features- Each
door module provides support for certain customer
programmable features that are monitored on the
PCI bus.
²Cylinder Lock Switch Status- The DDM
monitors and transmits the status of the cylinder
lock switch on the driver side front door lock cylin-
der.
²Door Courtesy Lamp Control- Each door
module provides control of its own optional front
door-mounted courtesy lamp.
²Door Lock Inhibit- Each door module pro-
vides a door lock inhibit feature which prevents the
doors from being locked with a power lock switch ifthe key was left in the ignition and a front door is
open.
²Express-Down Window- The DDM provides
an express-down feature for the driver side front door
window only.
²Extended Window Operation- Both door
modules provide an extended power window opera-
tion feature that allows operation of the power win-
dows for 45 seconds following ignition Off or until a
front door is opened.
²Front Door Ajar Switch Status- Each door
module monitors and transmits the status of its own
front door ajar switch.
²Heated Mirrors- Each door module provides
control for its own optional heated outside rear view
mirror.
²Illuminated Entry- Each door module sup-
ports an illuminated entry feature through its own
optional front door-mounted courtesy lamp.
²Memory Mirrors- Each door module provides
control for its own optional memory outside rear view
mirror.
²Memory Switch- The DDM monitors the sta-
tus of the optional memory switch and controls the
illumination of the memory switch ªsetº Light Emit-
ting Diode (LED) indicator and illumination lamps.
²Memory System- The DDM transmits memory
set and recall messages based upon inputs from the
memory switch. If the optional RKE linked to mem-
ory feature is enabled, the DDM will also transmit
memory recall messages based upon memory
requests received from the Remote Keyless Entry
(RKE) system in the PDM. Certain memory system
features are programmable.
²Power Foldaway Mirrors - Export Only-
Each door module provides support for the optional
power foldaway outside mirrors. The DDM also
houses the control switch for this system.
²Power Lock Control- The DDM provides con-
trol for the driver side front door power lock motor,
while the PDM provides control for the power lock
motors of the three remaining doors and the liftgate.
²Power Lock Switch Status- Each door mod-
ule monitors and transmits the status of its own inte-
gral power lock switch.
²Power Window Control- Each door module
provides control for both the front and rear door
power window motors and the rear door power win-
dow switches on the same side of the vehicle.
²Power Window Switch Status- The DDM
monitors and transmits the status of its integral pas-
senger side front and rear power window switches.
²Remote Keyless Entry- The PDM monitors
and transmits the status of the Remote Keyless
Entry (RKE) system and provides support for the
RKE Lock (with the optional horn chirp and park
Fig. 7 Door Module
1 - FRONT DOOR TRIM PANEL
2 - SCREW (5)
3 - DOOR MODULE
8E - 8 ELECTRONIC CONTROL MODULESWJ
DOOR MODULE (Continued)

lamp flash features), Unlock with the optional RKE
unlock, and Panic Mode functions. The optional RKE
features are programmable.
²Switch Illumination- Each door module pro-
vides control of the power window and power lock
switch illumination for the front and rear doors on
the same side of the vehicle. The DDM provides con-
trol of the power mirror switch illumination.
²Window Lockout- The DDM monitors and
transmits the status of its integral window lockout
switch to provide the power window lockout feature
and coordinate power window switch knob illumina-
tion.
The door modules are serviced only as complete
units. Many of the features in the vehicle controlled
or supported by the door modules are programmable
using either the Electronic Vehicle Information Cen-
ter (EVIC) user interface, or the DRBIIItscan tool. If
a door module is damaged or faulty, the entire door
module unit must be replaced.
OPERATION
The microprocessor-based DDM and PDM hard-
ware and software monitors integral and hard wired
external switch inputs as well as those resources it
shares with other electronic modules in the vehicle
through its communication over the PCI data bus
network. The internal programming and all of these
inputs allow the DDM or PDM microprocessor to
determine the tasks it needs to perform and their
priorities, as well as both the standard and optional
features that it should provide.
The DDM and PDM are powered by a fused bat-
tery circuit so that they can operate regardless of the
ignition switch position. The DDM and PDM cir-
cuitry is grounded to the chassis beneath the front
seat.
The DDM and PDM can be diagnosed using a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information.
HARD WIRED INPUTS
The hard wired inputs to the door modules include
the following:
²Door ajar switch sense
²Driver door key cylinder switch sense (DDM)
²Fused B(+)
²Ground
²Memory switch mux (DDM)
²Mirror horizontal position signal
²Mirror vertical position signal
²PCI bus
HARD WIRED OUTPUTS
The hard wired outputs of the door modules
include the following:
²Courtesy lamp driver
²Courtesy lamp ground
²Diagnostic out (DDM)
²Door/liftgate lock driver
²Door/liftgate unlock driver
²Door switch illumination (rear power window)
²Front window driver (down)
²Front window driver (up)
²Memory set indicator driver (DDM)
²Memory switch return (DDM)
²Mirror common driver
²Mirror heater ground
²Mirror heater 12V supply
²Rear window driver (down)
²Rear window driver (up)
²Mirror horizontal driver
²Mirror sensor ground
²Mirror vertical driver
²PCI bus
²Switch illumination driver (memory - DDM)
MESSAGING
The door modules use the following messages
received from other electronic modules over the PCI
data bus:
²Accessory Delay Control (PDM)
²Courtesy Lamp Status (BCM)
²Door Ajar Status/Rear Doors (BCM)
²Door Lock Status (DDM/PDM)
²Ignition Switch Position (BCM)
²Key-In Ignition Status (BCM)
²Programmable Features Preferences/Auto Lock/
Auto Unlock/RKE Unlock Sequence/RKE Link to
Memory (EVIC)
²Memory Recall (DDM)
²Rear Window Defogger Relay Status (BCM)
²Vehicle Speed (PCM)
The door modules provide the following messages
to other electronic modules over the PCI data bus:
²Cylinder Lock Switch Status (BCM)
²Door Ajar Status/Front Doors (BCM/DDM/PDM)
²Door Lock Status (DDM/PDM)
²Memory Recall (PDM/MHSM/MSM/Radio)
²Memory Set Switch Status (PDM/MHSM/MSM/
Radio)
²Panic Control (BCM)
²Power Window Switch Status (PDM)
²RKE Status (BCM/DDM)
²Window Lockout Switch Status (PDM)
WJELECTRONIC CONTROL MODULES 8E - 9
DOOR MODULE (Continued)

DIAGNOSIS AND TESTING - DOOR MODULE
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.
The hard wired inputs to and outputs from the
Driver Door Module (DDM) or the Passenger Door
Module (PDM) may be diagnosed and tested using
conventional diagnostic tools and procedures. It is
suggested that the proper operation of the inopera-
tive power window motor, power door lock motor,
power liftgate lock motor, power mirror motors, or
heated mirror grid be confirmed using jumper wires
to bypass the door module. If the inoperative compo-
nent operates when the door module is bypassed,
check the circuits between the component and the
door module, as well as the fused B(+) and ground
circuits of the door module for shorts or opens.
These conventional diagnostic methods may not
prove conclusive in the diagnosis of the DDM or the
PDM. In order to obtain conclusive testing of these
modules, the Programmable Communications Inter-
face (PCI) data bus network and all of the modules
that provide inputs to or receive outputs from the
door modules must also be checked. The most reli-
able, efficient, and accurate means to diagnose the
DDM, the PDM, the PCI data bus network, and the
modules that provide inputs to or receive outputs
from the door modules requires the use of a DRBIIIt
scan tool and the appropriate diagnostic information.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the trim panel from the front door.
(Refer to 23 - BODY/DOOR - FRONT/TRIM PANEL -
REMOVAL).
(3) Remove the door module from the back of the
front door trim panel (Fig. 8).
(4) Remove the door module from the front door
trim panel.
INSTALLATION
(1) Position the door module onto the front door
trim panel.
(2) Install the door module to the back of the front
door trim panel (Fig. 8). Tighten the screws to 2.2
N´m (20 in. lbs.).
(3) Reinstall the trim panel onto the front door.
(Refer to 23 - BODY/DOOR - FRONT/TRIM PANEL -
INSTALLATION).
(4) Reconnect the battery negative cable.
MEMORY HEATED SEAT/
MIRROR MODULE
DESCRIPTION
There are two different modules that can be used
in the optional heated seat system. The Heated Seat
Module (HSM) is used on vehicles that are not
equipped with the optional Memory System. The
Memory Heated Seat Module (MHSM) is used on
vehicles that are equipped with the optional Memory
System and the optional heated seat system.Refer to
Memory Systemin Power Seat Systems for more
information on the memory system option.
The module is mounted on a bracket that is located
between the power seat track and the seat cushion
frame (Fig. 9). The HSM or MHSM is used to control
the heated seat system functions for both front seats.
The HSM or MHSM contains a central processing
unit that communicates with other modules on the
Fig. 8 Door Module Remove/Install
1 - FRONT DOOR TRIM PANEL
2 - SCREW (5)
3 - DOOR MODULE
8E - 10 ELECTRONIC CONTROL MODULESWJ
DOOR MODULE (Continued)

Programmable Communications Interface (PCI) data
bus network.
For diagnosis of the HSM, MHSM or the PCI data
bus, a DRBIIItscan tool and the proper Diagnostic
Procedures manual are recommended. The HSM or
MHSM cannot be repaired and, if faulty or damaged,
it must be replaced.
OPERATION
The MSM receives hard wired inputs from the
power seat switch and the potentiometers on each of
the driver side power seat motors. The MSM receives
messages over the PCI data bus from the Driver
Door Module (DDM) (memory switch status), the
Powertrain Control Module (PCM) (vehicle speed sta-
tus), and the Body Control Module (seat belt switch
status).The MSM will prevent the seat memory recall
function from being initiated if the driver side seat
belt is buckled, if the transmission gear selector lever
is not in the Park or Neutral positions, or if the vehi-
cle is moving.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - HEATED SEAT
MODULE
Visually inspect the related wiring harness connec-
tors. Look for broken, bent, pushed out, or corroded
terminals. If any of the above conditions are present,
repair as necessary. If not, use a DRBIIItscan tool
and the proper Diagnostic Procedures Manual to test
the HSM or MHSM. For complete circuit diagrams,
refer toPower Seat Premium I/IIIin Wiring Dia-
grams.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the driver side front bucket seat from
the power seat track unit. Refer toBucket Seat
Track Adjusterin Body for the procedure.
(3) Lift the heated seat module off of the power
seat track and disconnect the power seat wire har-
ness connectors (Fig. 10).
(4) Remove the module from the bracket.
Fig. 9 Heated Seat Module Remove/Install
1 - NUT (4)
2 - SEAT CUSHION FRAME
3 - POWER SEAT TRACK
4 - STUD (4)
5 - MODULE
6 - BRACKET
Fig. 10 Heated Seat Module Remove/Install
1 - NUT (4)
2 - SEAT CUSHION FRAME
3 - POWER SEAT TRACK
4 - STUD (4)
5 - MODULE
6 - BRACKET
WJELECTRONIC CONTROL MODULES 8E - 11
MEMORY HEATED SEAT/MIRROR MODULE (Continued)

DESCRIPTION - POWER GROUNDS
The Powertrain Control Module (PCM) has 2 main
grounds. Both of these grounds are referred to as
power grounds. All of the high-current, noisy, electri-
cal devices are connected to these grounds as well as
all of the sensor returns. The sensor return comes
into the sensor return circuit, passes through noise
suppression, and is then connected to the power
ground.
The power ground is used to control ground cir-
cuits for the following PCM loads:
²Generator field winding
²Fuel injectors
²Ignition coil(s)
²Certain relays/solenoids
²Certain sensors
DESCRIPTION - SENSOR RETURN
The Sensor Return circuits are internal to the Pow-
ertrain Control Module (PCM).
Sensor Return provides a low±noise ground refer-
ence for all engine control system sensors. Refer to
Power Grounds for more information.
OPERATION
OPERATION - PCM
(1) Also refer to Modes of Operation.
The PCM operates the fuel system. The PCM is a
pre-programmed, triple microprocessor digital com-
puter. It regulates ignition timing, air-fuel ratio,
emission control devices, charging system, certain
transmission features, speed control, air conditioning
compressor clutch engagement and idle speed. The
PCM can adapt its programming to meet changing
operating conditions.
The PCM receives input signals from various
switches and sensors. Based on these inputs, the
PCM regulates various engine and vehicle operations
through different system components. These compo-
nents are referred to as Powertrain Control Module
(PCM) Outputs. The sensors and switches that pro-
vide inputs to the PCM are considered Powertrain
Control Module (PCM) Inputs.
The PCM adjusts ignition timing based upon
inputs it receives from sensors that react to: engine
rpm, manifold absolute pressure, engine coolant tem-
perature, throttle position, transmission gear selec-
tion (automatic transmission), vehicle speed and the
brake switch.
The PCM adjusts idle speed based on inputs it
receives from sensors that react to: throttle position,
vehicle speed, transmission gear selection, engine
coolant temperature and from inputs it receives from
the air conditioning clutch switch and brake switch.Based on inputs that it receives, the PCM adjusts
ignition coil dwell. The PCM also adjusts the gener-
ator charge rate through control of the generator
field and provides speed control operation.
NOTE: PCM Inputs:
²A/C request
²Auto shutdown (ASD) sense
²Battery temperature
²Battery voltage
²Brake switch
²J1850 bus circuits
²Camshaft position sensor signal
²Crankshaft position sensor
²Data link connections for DRB scan tool
²Engine coolant temperature sensor
²Five volts (primary)
²Five volts (secondary)
²Fuel level
²Generator (battery voltage) output
²Ignition circuit sense (ignition switch in on/off/
crank/run position)
²Intake manifold air temperature sensor
²Leak detection pump (switch) sense (if equipped)
²Manifold absolute pressure (MAP) sensor
²Oil pressure
²Overdrive/override switch
²Oxygen sensors
²Park/neutral switch (auto. trans. only)
²Power ground
²Sensor return
²Signal ground
²Speed control multiplexed single wire input
²Throttle position sensor
²Transmission governor pressure sensor
²Transmission temperature sensor
²Vehicle speed (from ABS module)
NOTE: PCM Outputs:
²A/C clutch relay
²Auto shutdown (ASD) relay
²J1850 (+/-) circuits for: speedometer, voltmeter,
fuel gauge, oil pressure gauge/lamp, engine temp.
gauge and speed control warn. lamp
²Data link connection for DRBIIItscan tool
²EGR valve control solenoid (if equipped)
²EVAP canister purge solenoid
²Fuel injectors
²Fuel pump relay
²Generator field driver (-)
²Generator field driver (+)
²Generator lamp (if equipped)
²Idle air control (IAC) motor
²Ignition coil
²Leak detection pump
WJELECTRONIC CONTROL MODULES 8E - 15
POWERTRAIN CONTROL MODULE (Continued)

(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)

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)

(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)

STANDARD PROCEDURE - IGNITION-OFF
DRAW TEST
The term Ignition-Off Draw (IOD) identifies a nor-
mal condition where power is being drained from the
battery with the ignition switch in the Off position. A
normal vehicle electrical system will draw from five
to thirty-five milliamperes (0.005 to 0.035 ampere)
with the ignition switch in the Off position, and all
non-ignition controlled circuits in proper working
order. Up to thirty-five milliamperes are needed to
enable the memory functions for the Powertrain Con-
trol Module (PCM), digital clock, electronically tuned
radio, and other modules which may vary with the
vehicle equipment.
A vehicle that has not been operated for approxi-
mately twenty days, may discharge the battery to an
inadequate level. When a vehicle will not be used for
twenty days or more (stored), remove the IOD fuse
from the Power Distribution Center (PDC). This will
reduce battery discharging.Excessive IOD can be caused by:
²Electrical items left on.
²Faulty or improperly adjusted switches.
²Faulty or shorted electronic modules and compo-
nents.
²An internally shorted generator.
²Intermittent shorts in the wiring.
If the IOD is over thirty-five milliamperes, the
problem must be found and corrected before replac-
ing a battery. In most cases, the battery can be
charged and returned to service after the excessive
IOD condition has been corrected.
(1) Verify that all electrical accessories are off.
Turn off all lamps, remove the ignition key, and close
all doors. If the vehicle is equipped with an illumi-
nated entry system or an electronically tuned radio,
allow the electronic timer function of these systems
to automatically shut off (time out). This may take
up to three minutes. See the Electronic Module Igni-
tion-Off Draw Table for more information.
ELECTRONIC MODULE IGNITION-OFF DRAW (IOD) TABLE
ModuleTime Out?
(If Yes, Interval And Wake-Up Input)IODIOD After Time
Out
Radio No1to3
milliamperesN/A
Audio Power
AmplifierNoup to 1
milliampereN/A
Body Control Module
(BCM)No5.90
milliamperes
(max.)N/A
Powertrain Control
Module (PCM)No 0.95 milliampere N/A
Transmission Control
Module (TCM) 4.7L
w/45RFEYES (20 minutes, ignition on) 130 milliamperes 0.64 milliampere
ElectroMechanical
Instrument Cluster
(EMIC)No 0.44 milliampere N/A
Combination Flasher No 0.08 milliampere N/A
(2) Determine that the underhood lamp is operat-
ing properly, then disconnect the lamp wire harness
connector or remove the lamp bulb.
(3) Disconnect the battery negative cable.
(4) Set an electronic digital multi-meter to its
highest amperage scale. Connect the multi-meter
between the disconnected battery negative cable ter-
minal clamp and the battery negative terminal post.
Make sure that the doors remain closed so that the
illuminated entry system is not activated. The multi-
meter amperage reading may remain high for up tothree minutes, or may not give any reading at all
while set in the highest amperage scale, depending
upon the electrical equipment in the vehicle. The
multi-meter leads must be securely clamped to the
battery negative cable terminal clamp and the bat-
tery negative terminal post. If continuity between the
battery negative terminal post and the negative cable
terminal clamp is lost during any part of the IOD
test, the electronic timer function will be activated
and all of the tests will have to be repeated.
WJBATTERY SYSTEM 8F - 13
BATTERY (Continued)