2002 JEEP LIBERTY Engine removal

(3) There should be continuity. The ohmmeter
should register only a fraction of an ohm resistance.
High or infinite resistance indicates a damaged or
open antenna conductor. If OK, go to Test 3. If not
OK, isolate and test each of the individual antenna
conductor components. Replace only the faulty
antenna conductor component.
TEST 3
Test 3 checks the condition of the vehicle body
ground connection. To begin this test, proceed as fol-
lows:
(1) This test must be performed with the battery
positive cable disconnected from the battery. Discon-
nect and isolate both battery cables, negative cable
first.
(2) Reconnect the battery negative cable.
(3) Touch one ohmmeter test lead to a good clean
ground point on the vehicle fender. Touch the other
test lead to the battery negative terminal post. Check
the ohmmeter reading for continuity.
(4) There should be continuity. The ohmmeter
should register less than one ohm resistance. High or
infinite resistance indicates a loose, corroded, or
damaged connection between the battery negative
terminal and the vehicle body. If OK, go to Test 4. If
not OK, check the battery negative cable connection
to the vehicle body and the radio noise suppression
ground strap connections to the engine and the vehi-
cle body for being loose or corroded. Clean or tighten
these connections as required.
TEST 4
Test 4 checks the condition of the connection
between the antenna coaxial cable shield and the
vehicle body ground as follows:
(1) Disconnect and isolate the antenna coaxial
cable connector behind the right side kick panel.
(2) Touch one ohmmeter test lead to a good clean
ground point on the vehicle fender. Touch the other
test lead to the outer crimp on the antenna coaxial
cable connector. Check the ohmmeter reading for con-
tinuity.
(3) There should be continuity. The ohmmeter
should register less than one ohm resistance. High or
infinite resistance indicates a loose, corroded, or
damaged connection between the antenna body and
the vehicle body or between the antenna body and
the antenna coaxial cable shield. If not OK, clean the
antenna body to fender mating surfaces and tighten
the antenna cap nut to specifications.
(4) Check the resistance again with an ohmmeter.
If the resistance is still more then one ohm, replace
the faulty antenna body and cable.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the antenna mast.
(3) Remove cover (Fig. 3).
(4) Remove mounting nut.
(5) Remove bezel adapter.
(6) Remove right kick panel trim.
(7) Disconnect antenna body and cable from the
instrument panel cable. Attach a wire or string
(approximately 2 feet in length) to the cable to aid in
installation of the new cable.
(8) Remove the upper fender mounting bolts.
Loosen the two fender mounting bolts located near
the upper door hinge (Refer to 23 - BODY/EXTERI-
OR/FRONT FENDER - REMOVAL).
(9) Carefully pull fender out to access the antenna
body and cable. Pull cable up through the opening
with wire attached.
INSTALLATION
(1) Attached wire to new cable. Pull fender out and
insert cable into opening.
(2) Pull cable through hole in kick panel area
using the attached wire.
(3) Connect antenna body cable to the instrument
panel cable.
(4) Install right kick panel trim.
(5) Install bezel adapter.
(6) Install mounting nut. Tighten to 12 N´m (105
in. lbs.).
(7) Install cover.
Fig. 3 ANTENNA BODY AND CABLE
1 - ANTENNA MAST
2 - ANTENNA COVER
3 - ANTENNA BASE MOUNTING NUT
4 - ANTENNA BEZEL ADAPTER
5 - ANTENNA BODY AND CABLE
8A - 6 AUDIOKJ
ANTENNA BODY & CABLE (Continued)

ness routing and retention, connector pin-out infor-
mation and location views for the various wire
harness connectors, splices and grounds.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel center trim
panel.
(3) Remove the radio mounting screws (Fig. 7).
(4) Disconnect the antenna cable by pulling the
locking antenna connector away from the radio (Fig.
8).
(5) Disconnect the electrical harness connector(s).
(6) Remove radio from instrument panel.
INSTALLATION
(1) Connect the wire harness connector(s).
(2) Connect the antenna cable.
(3) Install the radio to the instrument panel.
(4) Install the radio mounting screws.
(5) Install the instrument panel center trim panel.
(6) Connect the battery negative cable.
RADIO NOISE SUPPRESSION
GROUND STRAP
DESCRIPTION
Radio noise suppression devices are factory-in-
stalled standard equipment on this vehicle. Radio
Frequency Interference (RFI) and ElectroMagnetic
Interference (EMI) can be produced by any on-board
or external source of electromagnetic energy. These
electromagnetic energy sources can radiate electro-
magnetic signals through the air, or conduct them
through the vehicle electrical system.
When the audio system converts RFI or EMI to an
audible acoustic wave form, it is referred to as radio
noise. This undesirable radio noise is generally man-
ifested in the form of ªbuzzing,º ªhissing,º ªpopping,º
ªclicking,º ªcrackling,º and/or ªwhirringº sounds. In
most cases, RFI and EMI radio noise can be sup-
pressed using a combination of vehicle and compo-
nent grounding, filtering and shielding techniques.
This vehicle is equipped with factory-installed radio
noise suppression devices that were designed to min-
imize exposure to typical sources of RFI and EMI;
thereby, minimizing radio noise complaints.
Factory-installed radio noise suppression is accom-
plished primarily through circuitry or devices that
are integral to the factory-installed radios, audio
power amplifiers and other on-board electrical com-
ponents such as generators, wiper motors, blower
motors, and fuel pumps that have been found to be
potential sources of RFI or EMI. External radio noise
suppression devices that are used on this vehicle to
control RFI or EMI, and can be serviced, include the
following:
²Engine-to-body ground strap- This length of
braided ground strap has an eyelet terminal connec-
tor crimped to each end. One end is secured to the
engine cylinder head(s). The other is secured to the
plenum.
²Resistor-type spark plugs- This type of spark
plug has an internal resistor connected in series
between the spark plug terminal and the center elec-
trode to help reduce the production of electromag-
netic radiation that can result in radio noise.
Fig. 7 RADIO
Fig. 8 ANTENNA TO RADIO
1 - RADIO
2 - LOCKING ANTENNA CONNECTOR
3 - INSTRUMENT PANEL ANTENNA CABLE
KJAUDIO 8A - 9
RADIO (Continued)

OPERATION
There are two common strategies that can be used
to suppress Radio Frequency Interference (RFI) and
ElectroMagnetic Interference (EMI) radio noise. The
first suppression strategy involves preventing the
production of RFI and EMI electromagnetic signals
at their sources. The second suppression strategy
involves preventing the reception of RFI and EMI
electromagnetic signals by the audio system compo-
nents.
The use of braided ground straps in key locations
is part of the RFI and EMI prevention strategy.
These ground straps ensure adequate ground paths,
particularly for high current components such as
many of those found in the starting, charging, igni-
tion, engine control and transmission control sys-
tems. An insufficient ground path for any of these
high current components may result in radio noise
caused by induced voltages created as the high cur-
rent seeks alternative ground paths through compo-
nents or circuits intended for use by, or in close
proximity to the audio system components or circuits.
Preventing the reception of RFI and EMI is accom-
plished by ensuring that the audio system compo-
nents are correctly installed in the vehicle. Loose,
corroded or improperly soldered wire harness connec-
tions, improperly routed wiring and inadequate audio
system component grounding can all contribute to
the reception of RFI and EMI. A properly grounded
antenna body and radio chassis, as well as a shielded
antenna coaxial cable with clean and tight connec-
tions will each help reduce the potential for reception
of RFI and EMI.
REMOVAL
2.4L ENGINE
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the retaining bolt from the engine cyl-
inder head (Fig. 9).
(3) Remove the retaining nut from the plenum
(Fig. 10).
Fig. 9 GROUND STRAP TO ENGINE - 2.4L
1 - GROUND STRAP
2 - BOLT
Fig. 10 GROUND STRAP TO PLENUM - 2.4L
1 - PLENUM
2 - RETAINING NUT
3 - GROUND STRAP
8A - 10 AUDIOKJ
RADIO NOISE SUPPRESSION GROUND STRAP (Continued)

ELECTRONIC CONTROL MODULES
TABLE OF CONTENTS
page page
ELECTRONIC CONTROL MODULES
STANDARD PROCEDURE - PCM/SKIM
PROGRAMMING.......................1
BODY CONTROL MODULE
DESCRIPTION..........................2
OPERATION............................5
DIAGNOSIS AND TESTING - BODY CONTROL
MODULE.............................7
REMOVAL.............................7
INSTALLATION..........................7
COMMUNICATION
DESCRIPTION..........................8
OPERATION............................8
CONTROLLER ANTILOCK BRAKE
REMOVAL.............................10
INSTALLATION.........................10
DATA LINK CONNECTOR
DESCRIPTION - DATA LINK CONNECTOR....10
OPERATION - DATA LINK CONNECTOR......10
POWERTRAIN CONTROL MODULE
DESCRIPTION
DESCRIPTION - PCM..................11
DESCRIPTION - MODES OF OPERATION . . . 11
DESCRIPTION - 5 VOLT SUPPLIES.......13
DESCRIPTION - IGNITION CIRCUIT SENSE . 13DESCRIPTION - POWER GROUNDS......13
DESCRIPTION - SENSOR RETURN.......14
OPERATION
OPERATION - PCM....................14
OPERATION - 5 VOLT SUPPLIES.........15
OPERATION - IGNITION CIRCUIT SENSE . . . 15
REMOVAL.............................15
INSTALLATION.........................15
SENTRY KEY IMMOBILIZER MODULE
DESCRIPTION.........................15
OPERATION...........................16
REMOVAL.............................17
INSTALLATION.........................18
TRANSMISSION CONTROL MODULE
DESCRIPTION.........................18
OPERATION...........................18
STANDARD PROCEDURE - TCM QUICK
LEARN..............................21
HEATED SEAT MODULE
DESCRIPTION.........................21
OPERATION...........................21
DIAGNOSIS AND TESTING - HEATED SEAT
MODULE............................22
REMOVAL.............................24
INSTALLATION.........................24
ELECTRONIC CONTROL
MODULES
STANDARD PROCEDURE - PCM/SKIM
PROGRAMMING
NOTE: Before replacing the PCM for a failed driver,
control circuit, or ground circuit, be sure to check
the related component/circuit integrity for failures
not detected due to a double fault in the circuit.
Most PCM driver/control circuit failures are caused
by internal component failures (i.e. relays and sole-
noids) and shorted circuits (i.e. pull-ups, drivers,
and switched circuits). These failures are difficult to
detect when a double fault has occurred and only
one DTC has been set.
When a PCM (JTEC) and the SKIM are replaced
at the same time, perform the following steps in
order:
(1) Program the new PCM (JTEC).(2) Program the new SKIM.
(3) Replace all ignition keys and program them to
the new SKIM.
PROGRAMMING THE PCM (JTEC)
The SKIS Secret Key is an ID code that is unique
to each SKIM. This code is programmed and stored
in the SKIM, the PCM, and the ignition key tran-
sponder chip(s). When replacing the PCM, it is nec-
essary to program the secret key into the new PCM
using the DRBIIItscan tool. Perform the following
steps to program the secret key into the PCM.
(1) Turn the ignition switch to the On position
(transmission in Park/Neutral).
(2) Use the DRBIIItand select THEFT ALARM,
SKIM, then MISCELLANEOUS.
(3) Select PCM REPLACED (GAS ENGINE).
(4) Enter secured access mode by entering the
vehicle four-digit PIN.
(5) Select ENTER to update PCM VIN.
KJELECTRONIC CONTROL MODULES 8E - 1

²Transmission convertor clutch circuit. Driven
through J1850 circuits.
OPERATION - 5 VOLT SUPPLIES
Primary 5±volt supply:
²supplies the required 5 volt power source to the
Crankshaft Position (CKP) sensor.
²supplies the required 5 volt power source to the
Camshaft Position (CMP) sensor.
²supplies a reference voltage for the Manifold
Absolute Pressure (MAP) sensor.
²supplies a reference voltage for the Throttle
Position Sensor (TPS) sensor.
Secondary 5±volt supply:
²supplies the required 5 volt power source to the
oil pressure sensor.
²supplies the required 5 volt power source for the
Vehicle Speed Sensor (VSS) (if equipped).
²supplies the 5 volt power source to the transmis-
sion pressure sensor (certain automatic transmis-
sions).
OPERATION - IGNITION CIRCUIT SENSE
The ignition circuit sense input tells the PCM the
ignition switch has energized the ignition circuit.
Battery voltage is also supplied to the PCM
through the ignition switch when the ignition is in
the RUN or START position. This is referred to as
the9ignition sense9circuit and is used to9wake up9
the PCM. Voltage on the ignition input can be as low
as 6 volts and the PCM will still function. Voltage is
supplied to this circuit to power the PCM's 8-volt reg-
ulator and to allow the PCM to perform fuel, ignition
and emissions control functions.
REMOVAL
USE THE DRB SCAN TOOL TO REPROGRAM
THE NEW POWERTRAIN CONTROL MODULE
(PCM) WITH THE VEHICLES ORIGINAL IDEN-
TIFICATION NUMBER (VIN) AND THE VEHI-
CLES ORIGINAL MILEAGE. IF THIS STEP IS
NOT DONE, A DIAGNOSTIC TROUBLE CODE
(DTC) MAY BE SET.
The PCM is located in the engine compartment
near the battery (Fig. 9).
To avoid possible voltage spike damage to the
PCM, ignition key must be off, and negative battery
cable must be disconnected before unplugging PCM
connectors.
(1) Disconnect negative battery cable at battery.
(2) Remove cover over electrical connectors. Cover
snaps onto PCM.
(3) Carefully unplug the three 32±way connectors
from PCM.
(4) Remove three PCM mounting bolts and remove
PCM from vehicle.
INSTALLATION
USE THE DRB SCAN TOOL TO REPROGRAM
THE NEW POWERTRAIN CONTROL MODULE
(PCM) WITH THE VEHICLES ORIGINAL IDEN-
TIFICATION NUMBER (VIN) AND THE VEHI-
CLES ORIGINAL MILEAGE. IF THIS STEP IS
NOT DONE, A DIAGNOSTIC TROUBLE CODE
(DTC) MAY BE SET.
(1) Install PCM and 3 mounting bolts to vehicle.
(2) Tighten bolts. Refer to torque specifications.
(3) Check pin connectors in the PCM and the three
32±way connectors for corrosion or damage. Also, the
pin heights in connectors should all be same. Repair
as necessary before installing connectors.
(4) Install three 32±way connectors.
(5) Install cover over electrical connectors. Cover
snaps onto PCM.
(6) Install battery cable.
(7) Use the DRB scan tool to reprogram new PCM
with vehicles original Identification Number (VIN)
and original vehicle mileage.
SENTRY KEY IMMOBILIZER
MODULE
DESCRIPTION
The Sentry Key Immobilizer Module (SKIM) is the
primary component of the Sentry Key Immobilizer
System (SKIS) (Fig. 10). The SKIM is located on the
right side of the steering column, below the ignition
Fig. 9 PCM REMOVE/INSTALL
1 - PCM
2 - MOUNTING BOLTS (3)
3 - 32-WAY CONNECTORS
KJELECTRONIC CONTROL MODULES 8E - 15
POWERTRAIN CONTROL MODULE (Continued)

ENGINE SYSTEMS
TABLE OF CONTENTS
page page
BATTERY SYSTEM......................... 1
CHARGING SYSTEM....................... 22STARTING SYSTEM....................... 32
BATTERY SYSTEM
TABLE OF CONTENTS
page page
BATTERY SYSTEM
DESCRIPTION..........................1
OPERATION............................2
DIAGNOSIS AND TESTING - BATTERY
SYSTEM.............................2
CLEANING.............................5
INSPECTION...........................6
SPECIFICATIONS........................6
SPECIAL TOOLS........................7
BATTERY
DESCRIPTION..........................7
DIAGNOSIS AND TESTING - BATTERY.......8
STANDARD PROCEDURE
STANDARD PROCEDURE - BATTERY
CHARGING...........................8
STANDARD PROCEDURE - BUILT-IN
INDICATOR TEST.....................10
STANDARD PROCEDURE - HYDROMETER
TEST...............................11
STANDARD PROCEDURE - OPEN-CIRCUIT
VOLTAGE TEST.......................12
STANDARD PROCEDURE - LOAD TEST....12
STANDARD PROCEDURE - IGNITION-OFF
DRAW TEST.........................14STANDARD PROCEDURE - USING
MIDTRONICS ELECTRICAL TESTER.......15
REMOVAL.............................16
INSTALLATION.........................16
BATTERY HOLDDOWN
DESCRIPTION.........................17
OPERATION...........................17
REMOVAL.............................17
INSTALLATION.........................17
BATTERY CABLES
DESCRIPTION.........................18
OPERATION...........................18
DIAGNOSIS AND TESTING - BATTERY
CABLES............................19
THERMAL GUARD
DESCRIPTION.........................20
OPERATION...........................20
REMOVAL.............................20
INSTALLATION.........................20
BATTERY TRAY
DESCRIPTION.........................21
OPERATION...........................21
REMOVAL.............................21
INSTALLATION.........................21
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 Cable- The battery cables connect the
battery terminal posts to the vehicle electrical sys-
tem.
²Battery Holddown- The battery holddown
hardware secures the battery in the battery tray in
the engine compartment.
KJENGINE SYSTEMS 8F - 1

nection at the starter solenoid B(+) terminal stud.
Repeat the test. If the reading is still above 0.2 volt,
replace the faulty battery positive cable.
(4) Connect the voltmeter to measure between the
battery negative cable terminal clamp and a good
clean ground on the engine block (Fig. 22). Rotate
and hold the ignition switch in the Start position.
Observe the voltmeter. If the reading is above 0.2
volt, clean and tighten the battery negative cable
eyelet terminal connection to the engine block.
Repeat the test. If the reading is still above 0.2 volt,
replace the faulty battery negative cable.THERMAL GUARD
DESCRIPTION
A flexible plastic bubble-wrap style thermal guard
(Fig. 23) slides over the battery case to enclose the
sides of the battery. The thermal guard consists of a
heavy black plastic outer skin and two lighter plies of
plastic that have been formed into a sheet with hun-
dreds of small air pockets entrapped between them.
The resulting material is very similar to the bubble-
wrap used to protect items in many parcel packaging
and shipping applications.
OPERATION
The thermal guard protects the battery from
engine compartment temperature extremes. The tem-
perature of the battery can affect battery perfor-
mance. The air trapped between the plastic plies of
the thermal guard create a dead air space, which
helps to insulate the sides of the battery case from
the air temperature found in the surrounding engine
compartment.
REMOVAL
(1) Remove the battery and the battery thermal
guard from the battery tray as a unit. Refer to Bat-
tery Removal for the proper battery removal proce-
dures.
(2) Carefully and evenly slide the battery thermal
guard up off of the battery case (Fig. 24).
INSTALLATION
(1) Clean and inspect the battery thermal guard.
Refer to Battery System Cleaning for the proper
cleaning procedures, and refer to Battery System
Inspection for the proper inspection procedures.
Fig. 21 TEST BATTERY POSITIVE CABLE
RESISTANCE - TYPICAL
1 - BATTERY
2 - VOLTMETER
3 - STARTER MOTOR
Fig. 22 TEST GROUND CIRCUIT RESISTANCE -
TYPICAL
1 - VOLTMETER
2 - BATTERY
3 - ENGINE GROUND
Fig. 23 Battery Thermal guard
1 - THERMAL GUARD
2 - BATTERY
8F - 20 BATTERY SYSTEMKJ
BATTERY CABLES (Continued)

(2) Carefully and evenly slide the battery thermal
guard down over the battery case.
(3) Install the battery and the battery thermal
guard into the battery tray as a unit. Refer to Bat-
tery Installation for the proper battery installation
procedures.
BATTERY TRAY
DESCRIPTION
The battery is placed in a molded plastic tray
located in the left front corner of the engine compart-
ment (Fig. 25). The battery hold down hardware is
contained within the battery tray. A hole in the bot-
tom of the battery tray is fitted with a battery tem-
perature sensor. Refer to Charging System for more
information on the battery temperature sensor. Refer
to Battery Hold down for more information on hold
down hardware.
OPERATION
The battery tray provides a secure mounting loca-
tion and supports the battery. On some vehicles, the
battery tray also provides the anchor point/s for the
battery holddown hardware. The battery tray and
the battery holddown hardware combine to secure
and stabilize the battery in the engine compartment,
which prevents battery movement during vehicle
operation. Unrestrained battery movement during
vehicle operation could result in damage to the vehi-
cle, the battery, or both.
REMOVAL
(1) Remove the battery from the battery tray
(Refer to 8 - ELECTRICAL/BATTERY SYSTEM/BAT-
TERY - REMOVAL).
(2) Unlatch and remove the PDC from the battery
tray.
(3) Remove the battery temperature sensor from
the battery tray (Refer to 8 - ELECTRICAL/CHARG-
ING/BATTERY TEMPERATURE SENSOR -
REMOVAL).
(4) Remove the three nuts that secure the battery
tray to the weld studs on the front extension of the
left front wheelhouse inner panel (Fig. 25).
(5) Remove the battery tray from the vehicle.
INSTALLATION
(1) Clean and inspect the battery tray (Refer to 8 -
ELECTRICAL/BATTERY SYSTEM - CLEANING).
(2) Position the battery tray onto the weld studs
on the front extension of the left front wheelhouse
inner panel.
(3) Install the battery temperature sensor onto the
battery tray (Refer to 8 - ELECTRICAL/CHARGING/
BATTERY TEMPERATURE SENSOR - INSTALLA-
TION).
(4) Install and tighten the three nuts that secure
the battery tray to the weld studs on the front exten-
sion of the left front wheelhouse inner panel. Tighten
the nuts to 5 N´m (45 in. lbs.).
(5) Install the PDC on the battery tray.
(6) Install the battery onto the battery tray (Refer
to 8 - ELECTRICAL/BATTERY SYSTEM/BATTERY -
INSTALLATION).
Fig. 24 Battery thermal guard
1 - THERMAL GUARD
2 - BATTERY
Fig. 25 Battery Tray Location
1 - Battery Tray
2 - Battery Tray Retaining Nuts
KJBATTERY SYSTEM 8F - 21
THERMAL GUARD (Continued)