2002 JEEP LIBERTY Workshop Manual

DIAGNOSIS AND TESTING - AMPLIFIER
CHOKE AND RELAY
Any diagnosis of the Audio system should
begin with the use of the DRB diagnostic tool.
For information on the use of the DRB, refer to
the appropriate Diagnostic Service Manual.
The amplifier choke and relay is used to switch
power to the individual speaker amplifiers used with
the premium speaker package. The amplifier choke
and relay is serviced only as a unit. If all of the
speakers are inoperative the amplifier choke and
relay should be inspected. Before replacement, make
the following inspections of the amplifier choke and
relay circuits. For complete circuit diagrams, refer to
the appropriate wiring information. The wiring infor-
mation includes wiring diagrams, proper wire and
connector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
(1)
Check the fused B(+) fuse in the junction block. If
OK, go to Step 2. If not OK, replace the faulty fuse.
(2) Check for battery voltage at the fused B(+) fuse
in the junction block. If OK, go to Step 3. If not OK,
repair the open fused B(+) circuit to the battery as
required.
(3) Disconnect the instrument panel wire harness
connector from the amplifier choke and relay. Check
for battery voltage at the fused B(+) circuit cavity of
the instrument panel wire harness connector for the
amplifier choke and relay. If OK, go to Step 4. If not
OK, repair the open fused B(+) circuit to the junction
block fuse as required.
(4) Probe the ground circuit cavity of the instru-
ment panel wire harness connector for the amplifier
choke and relay. Check for continuity to a good
ground. There should be continuity. If OK, go to Step
5. If not OK, repair the open ground circuit to ground
as required.
(5) Turn the ignition switch to the RUN position
and turn the radio ON. Check for battery voltage at
the radio 12-volt output circuit cavity of the instru-
ment panel wire harness connector for the amplifier
choke and relay. If OK, go to Step 6. If not OK,
repair the open radio 12-volt output circuit to the
radio as required.
(6) Turn the radio and ignition switches to the
OFF position. Reconnect the instrument panel wire
harness connector to the amplifier choke and relay.
Check for battery voltage at the amplified speaker
(+) circuit cavity of the instrument panel wire har-
ness connector for the amplifier choke and relay.
There should be zero volts. Turn the ignition and
radio switches to the ON position. There should now
be battery voltage. If OK, repair the open amplified
speaker (+) circuits to the speaker-mounted amplifi-ers as required. If not OK, replace the faulty ampli-
fier choke and relay.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove knee blocker cover and knee blocker.
(3) Disconnect the electrical harness connector
from the amplifier choke and relay (Fig. 1).
(4) Remove mounting screws and amplifier choke
and relay.
INSTALLATION
(1) Install the amplifier choke and relay.
(2) Install the mounting screws.
(3) Connect the electrical harness connector.
(4) Install knee blocker cover and knee blocker.
(5) Connect the battery negative cable.
ANTENNA BODY & CABLE
DESCRIPTION
The antenna body and cable is secured below the
fender panel by the antenna cap nut through a
mounting hole in the side of the right front fender.
The primary coaxial antenna cable is then routed
beneath the fender sheet metal and through a entry
hole in the right cowl side panel into the interior of
the vehicle. Inside the vehicle, the primary coaxial
cable is connected to a secondary instrument panel
antenna coaxial cable with an in-line connector that
is located behind the right kick panel. The secondary
coaxial cable is then routed behind the instrument
panel to the back of the radio.
Fig. 1 RADIO CHOKE
1 - RADIO CHOKE
2 - MOUNTING SCREWS
8A - 4 AUDIOKJ
AMPLIFIER CHOKE AND RELAY (Continued)

OPERATION
The antenna body and cable connects the antenna
mast to the radio. The radio antenna is an electro-
magnetic circuit component used to capture radio fre-
quency signals that are broadcast by local
commercial radio stations in both the Amplitude
Modulating (AM) and Frequency Modulating (FM)
frequency ranges. These electromagnetic radio fre-
quency signals induce small electrical modulations
into the antenna as they move past the mast. The
antenna body transfers the weak electromagnetic
radio waves induced into the rigid antenna mast into
the center conductor of the flexible primary antenna
coaxial cable. The braided outer shield of the
antenna coaxial cable is grounded through both the
antenna body and the radio chassis, effectively
shielding the radio waves as they are conducted to
the radio. The radio then tunes and amplifies the
weak radio signals into stronger electrical signals in
order to operate the audio system speakers.
DIAGNOSIS AND TESTING - ANTENNA BODY
AND CABLE
The following four tests are used to diagnose the
antenna with an ohmmeter:
²Test 1- Mast to ground test
²Test 2- Tip-of-mast to tip-of-conductor test
²Test 3- Body ground to battery ground test
²Test 4- Body ground to antenna coaxial cable
shield test.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, 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 ohmmeter test lead connections for each test
are shown in the illustration (Fig. 2).
NOTE: This model has a two-piece antenna coaxial
cable. Tests 2 and 4 must be conducted in two
steps to isolate an antenna cable problem. First,
test the primary antenna cable (integral to the
antenna body and cable) from the coaxial cable
connector behind the right side kick panel to the
antenna body. Then, test the secondary antennacable (instrument panel antenna cable) from the
coaxial cable connector behind the right side kick
panel to the coaxial cable connector at the radio.
TEST 1
Test 1 determines if the antenna mast is insulated
from ground. Proceed as follows:
(1) Disconnect and isolate the antenna coaxial
cable connector behind the right side kick panel.
(2) Touch one ohmmeter test lead to the tip of the
antenna mast. Touch the other test lead to known
ground. Check the ohmmeter reading for continuity.
(3) There should be no continuity. If OK, go to Test
2. If not OK, replace the faulty antenna body and
cable.
TEST 2
Test 2 checks the antenna conductor components
for an open circuit. This test should be performed
first on the entire antenna circuit, from the antenna
mast to the center conductor of the coaxial cable con-
nector at the radio. If an open circuit is detected,
each of the three antenna conductor components
(antenna mast, antenna body and cable, instrument
panel antenna cable) should be isolated and tested
individually to locate the exact component that is the
source of the open circuit. To begin this test, proceed
as follows:
(1) Disconnect the instrument panel antenna cable
coaxial connector from the back of the radio.
(2) Touch one ohmmeter test lead to the tip of the
antenna mast. Touch the other test lead to the center
conductor pin of the instrument panel antenna cable
coaxial connector for the radio. Check the ohmmeter
reading for continuity.
Fig. 2 Antenna Tests - Typical
KJAUDIO 8A - 5
ANTENNA BODY & CABLE (Continued)

(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)

(8) Install antenna mast.
(9) Tighten fender mounting bolts near door hinge
area.
(10) Install and tighten the upper fender mounting
bolts (Refer to 23 - BODY/EXTERIOR/FRONT
FENDER - INSTALLATION).
(11) Connect the battery negative cable.
CD CHANGER
DESCRIPTION
A factory-installed Compact Disc (CD) changer fea-
turing a six-CD magazine is an available option on
this model. The CD changer is mounted in the cargo
area of the passenger compartment on the right rear
quarter panel.
The controls on the radio receiver operate the CD
changer through messages sent over the Programma-
ble Communications Interface (PCI) data bus net-
work. For diagnosis of the messaging functions of the
radio receiver and the CD changer, or of the PCI data
bus, a DRB scan tool and the proper Diagnostic Pro-
cedures manual are required.
The CD changer can only be serviced by an autho-
rized radio repair station. See the latest Warranty
Policies and Procedures manual for a current listing
of authorized radio repair stations. Refer to the
appropriate wiring information. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
OPERATION
The CD changer will only operate when the igni-
tion switch is in the On or Accessory positions, and
the radio is turned on. The six-CD magazine may be
ejected with the ignition in the Off position. For more
information on the features, loading procedures and
radio control functions for the operation of the CD
changer, refer to the owner's manual.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the right rear quarter trim panel.
(Refer to 23 - BODY/INTERIOR/QUARTER TRIM
PANEL - REMOVAL).
(3) Disconnect the electrical wire harness connec-
tor (Fig. 4).
(4) Remove the mounting nuts.
(5) Remove the CD Changer from the vehicle.
INSTALLATION
(1) Install the CD Changer to the vehicle.
(2) Install the mounting nuts. Tighten to 11.8 N´m
(104 in. lbs.).
(3) Connect the wire harness connector.
(4) Install the right rear quarter trim panel (Refer
to 23 - BODY/INTERIOR/QUARTER TRIM PANEL -
INSTALLATION).
(5) Connect the battery negative cable.
INSTRUMENT PANEL
ANTENNA CABLE
REMOVAL
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, 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) Disconnect and isolate the battery negative
cable.
Fig. 4 CD CHANGER
1 - CD CHANGER
2 - WIRE HARNESS CONNECTOR
3 - MOUNTING NUT
KJAUDIO 8A - 7
ANTENNA BODY & CABLE (Continued)

(2) Remove the instrument panel (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL ASSEMBLY - REMOVAL).
(3) Disconnect the antenna cable from radio by
pulling the locking antenna connector away from
radio (Fig. 5).
(4) Disengage each of the retainers that secure the
cable to the instrument panel (Fig. 6).
(5) Remove the cable from the instrument panel.
INSTALLATION
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, 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 instrument panel antenna cable
onto the instrument panel.
(2) Engage each of the retainers that secure the
cable to the back side of the instrument panel.
(3) Connect cable to radio.
(4) Install instrument panel (Refer to 23 - BODY/
INSTRUMENT PANEL/INSTRUMENT PANEL
ASSEMBLY - INSTALLATION).
(5) Connect the battery negative cable.
RADIO
DESCRIPTION
Available factory-installed radio receivers for this
model include an AM/FM/cassette with CD changer
control feature (RBB sales code), an AM/FM/cassette/
CD/graphic equalizer with CD changer control fea-
ture (RBP sales code), or an AM/FM/CD/ with CD
changer control feature (RBK sales code). All factory-
installed radio receivers can communicate on the
Programmable Communications Interface (PCI) data
bus network. All factory-installed receivers are stereo
Electronically Tuned Radios (ETR) and include an
electronic digital clock function.
These radio receivers can only be serviced by an
authorized radio repair station. See the latest War-
ranty Policies and Procedures manual for a current
listing of authorized radio repair stations.
OPERATION
The radio receiver operates on ignition switched
battery current that is available only when the igni-
tion switch is in the On or Accessory positions. The
electronic digital clock function of the radio operates
on fused battery current supplied through the IOD
fuse, regardless of the ignition switch position.
For more information on the features, setting pro-
cedures, and control functions for each of the avail-
able factory-installed radio receivers, refer to the
owner's manual. For complete circuit diagrams, refer
to the appropriate wiring information. The wiring
information includes wiring diagrams, proper wire
and connector repair procedures, details of wire har-
Fig. 5 ANTENNA TO RADIO
1 - RADIO
2 - LOCKING ANTENNA CONNECTOR
3 - INSTRUMENT PANEL ANTENNA CABLE
Fig. 6 INSTRUMENT PANEL ANTENNA CABLE
1 - INSTRUMENT PANEL ANTENNA CABLE
2 - ANTENNA BODY AND CABLE
8A - 8 AUDIOKJ
INSTRUMENT PANEL ANTENNA 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)

3.7L ENGINE
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the retaining bolts from the engine cyl-
inder heads (Fig. 11).
(3) Remove the retaining nut from the plenum
(Fig. 12).
INSTALLATION
2.4L ENGINE
(1) Install the retaining nut and ground strap to
the plenum. Tighten to 12 N´m (106 in. lbs.).(2) Install the retaining bolt and ground strap to
the engine cylinder head. Tighten to 12 N´m (106 in.
lbs.).
(3) Connect the battery negative cable.
3.7L ENGINE
(1) Install the retaining nut and ground strap to
the plenum. Tighten to 12 N´m (106 in. lbs.).
(2) Install the retaining bolts and ground strap to
the engine cylinder heads. Tighten to 12 N´m (106 in.
lbs.).
(3) Connect the battery negative cable.
REMOTE SWITCHES
DESCRIPTION
A remote radio control switch option is available on
some models. Two rocker-type switches are mounted
on the back (instrument panel side) of the steering
wheel spokes (Fig. 13). The switch on the left spoke
is the seek switch and has seek up, seek down, and
preset station advance functions. The switch on the
right spoke is the volume control switch and has vol-
ume up, and volume down functions. The switch on
the right spoke also includes a ªmodeº control that
allows the driver to sequentially select AM radio, FM
radio, cassette player, CD player or CD changer (if
equipped).
Fig. 11 GROUND STRAP TO ENGINE - 3.7L
1 - GROUND STRAP
2 - RETAINING BOLTS
Fig. 12 GROUND STRAP TO PLENUM - 3.7L
1 - PLENUM
2 - RETAINING NUT
3 - GROUND STRAP
Fig. 13 Remote Radio Switch Operational View
1 - PRESET SEEK
2 - SEEK UP
3 - VOLUME UP
4 - MODE
5 - VOLUME DOWN
6 - SEEK DOWN
KJAUDIO 8A - 11
RADIO NOISE SUPPRESSION GROUND STRAP (Continued)