2002 JEEP LIBERTY Termine

DIAGNOSIS AND TESTING - BATTERY CABLES
A voltage drop test will determine if there is exces-
sive resistance in the battery cable terminal connec-
tions or the battery cable. If excessive resistance is
found in the battery cable connections, the connec-
tion point should be disassembled, cleaned of all cor-
rosion or foreign material, then reassembled.
Following reassembly, check the voltage drop for the
battery cable connection and the battery cable again
to confirm repair.
When performing the voltage drop test, it is impor-
tant to remember that the voltage drop is giving an
indication of the resistance between the two points at
which the voltmeter probes are attached.EXAM-
PLE:When testing the resistance of the battery pos-
itive cable, touch the voltmeter leads to the battery
positive cable terminal clamp and to the battery pos-
itive cable eyelet terminal at the starter solenoid
B(+) terminal stud. If you probe the battery positive
terminal post and the battery positive cable eyelet
terminal at the starter solenoid B(+) terminal stud,
you are reading the combined voltage drop in the
battery positive cable terminal clamp-to-terminal
post connection and the battery positive cable.
VOLTAGE DROP TEST
The following operation will require a voltmeter
accurate to 1/10 (0.10) volt. Before performing this
test, be certain that the following procedures are
accomplished:
²The battery is fully-charged and load tested.
Refer to Standard Procedures for the proper battery
charging and load test procedures.
²Fully engage the parking brake.
²If the vehicle is equipped with an automatic
transmission, place the gearshift selector lever in the
Park position. If the vehicle is equipped with a man-
ual transmission, place the gearshift selector lever in
the Neutral position and block the clutch pedal in the
fully depressed position.
²Verify that all lamps and accessories are turned
off.
²To prevent the engine from starting, remove the
Automatic Shut Down (ASD) relay. The ASD relay is
located in the Power Distribution Center (PDC), in
the engine compartment. See the fuse and relay lay-
out label affixed to the underside of the PDC cover
for ASD relay identification and location.
(1) Connect the positive lead of the voltmeter to
the battery negative terminal post. Connect the neg-
ative lead of the voltmeter to the battery negative
cable terminal clamp (Fig. 19). Rotate and hold the
ignition switch in the Start position. Observe the
voltmeter. If voltage is detected, correct the poor con-
nection between the battery negative cable terminal
clamp and the battery negative terminal post.(2) Connect the positive lead of the voltmeter to
the battery positive terminal post. Connect the nega-
tive lead of the voltmeter to the battery positive cable
terminal clamp (Fig. 20). Rotate and hold the ignition
switch in the Start position. Observe the voltmeter. If
voltage is detected, correct the poor connection
between the battery positive cable terminal clamp
and the battery positive terminal post.
(3) Connect the voltmeter to measure between the
battery positive cable terminal clamp and the starter
solenoid B(+) terminal stud (Fig. 21). 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 positive cable eyelet terminal con-
Fig. 19 TEST BATTERY NEGATIVE CONNECTION
RESISTANCE - TYPICAL
1 - VOLTMETER
2 - BATTERY
Fig. 20 TEST BATTERY POSITIVE CONNECTION
RESISTANCE - TYPICAL
1 - VOLTMETER
2 - BATTERY
KJBATTERY SYSTEM 8F - 19
BATTERY CABLES (Continued)

SPECIAL TOOLS
BATTERY TEMPERATURE
SENSOR
DESCRIPTION
The Battery Temperature Sensor (BTS) is attached
to the battery tray located under the battery.
OPERATION
The BTS is used to determine the battery temper-
ature and control battery charging rate. This temper-
ature data, along with data from monitored line
voltage, is used by the PCM to vary the battery
charging rate. System voltage will be higher at colder
temperatures and is gradually reduced at warmer
temperatures.
The PCM sends 5 volts to the sensor and is
grounded through the sensor return line. As temper-
ature increases, resistance in the sensor decreases
and the detection voltage at the PCM increases.The BTS is also used for OBD II diagnostics. Cer-
tain faults and OBD II monitors are either enabled
or disabled, depending upon BTS input (for example,
disable purge and enable Leak Detection Pump
(LDP) and O2 sensor heater tests). Most OBD II
monitors are disabled below 20 degrees F.
REMOVAL
The battery temperature sensor is located under
the vehicle battery (Fig. 1) and is attached to a
mounting hole on battery tray.
(1) Remove battery. Refer to 8, Battery for proce-
dures.
(2) Disconnect sensor pigtail harness from engine
wire harness electrical connector.
(3) Pry sensor straight up from battery tray
mounting hole.
INSTALLATION
The battery temperature sensor is located under
vehicle battery and is attached to a mounting hole on
battery tray.
(1) Feed pigtail harness through hole in top of bat-
tery tray and press sensor into top of battery tray.
(2) Connect pigtail harness.
(3) Install battery. Refer to 8, Battery for proce-
dures.
GENERATOR DECOUPLER TOOL #8433
GENERATOR DECOUPLER TOOL #8823
Fig. 1 BATTERY TEMPERATURE SENSOR
1 - BATTERY TEMPERATURE SENSOR
2 - BATTERY TRAY
3 - ELECTRICAL CONNECTOR
8F - 24 CHARGING SYSTEMKJ
CHARGING SYSTEM (Continued)

OPERATION
The generator decoupler is used only with
certain engines.The decoupler (Fig. 5). is a one-
way clutch designed to help reduce belt tension fluc-
tuation, vibration, reduce fatigue loads, improve belt
life, reduce hubloads on components, and reduce
noise. Dry operation is used (no grease or lubricants).
The decoupler is not temperature sensitive and also
has a low sensitivity to electrical load. The decoupler
is a non-serviceable item and is to be replaced as an
assembly.
DIAGNOSIS AND TESTING - GENERATOR DECOUPLER
CONDITION POSSIBLE CAUSES CORRECTION
Does not drive generator (generator not charging) Internal failure Replace decoupler
Noise coming from decoupler Internal failure Replace decoupler
REMOVAL
The generator decoupler is used only with
certain engines.
Two different type generator decoupler pulleys are
used. One can be identified by the use of machined
splines (Fig. 6). The other can be identified by a hex
opening (Fig. 7) and will not use splines.
Different special tools are required to service each
different decoupler. Refer to following procedure.
INA Decoupler
(1) Disconnect negative battery cable.
(2) Remove generator and accessory drive belt.
Refer to Generator Removal.
(3) Position Special Tool #8823 (VM.1048) into
decoupler (Fig. 8).
(4) Determine if end of generator shaft is hex
shaped (Fig. 9) or is splined (Fig. 10). If hex is used,
insert a 10MM deep socket into tool #8823 (VM.1048)
(Fig. 11). If splined, insert a 5/16º 6-point hex driver,
or a 10MM 12-point triple square driver into tool
#8823 (VM.1048) (Fig. 12).
(5) The generator shaft uses conventional right-
hand threads to attach decoupler. To break decoupler
loose from generator threads, rotate end of tool clock-
wise (Fig. 11) or, (Fig. 12).(6) After breaking loose with tool, unthread decou-
pler by hand from generator.
Fig. 5 GENERATOR DECOUPLER PULLEY
(TYPICAL)
Fig. 6 GENERATOR DECOUPLER PULLEY (INA)
1 - GENERATOR
2 - DECOUPLER (INA)
3 - MACHINED SPLINES
KJCHARGING SYSTEM 8F - 27
GENERATOR DECOUPLER PULLEY (Continued)

INSTALLATION
INA Decoupler
(1) Thread decoupler pulley onto generator shaft
by hand (right-hand threads).
(2) Position Special Tool #8823 (VM.1048) into
decoupler (Fig. 8).
(3) Determine if end of generator shaft is hex
shaped (Fig. 9) or is splined (Fig. 10). If hex is used,
insert a 10MM deep socket into tool #8823 (VM.1048)
(Fig. 15). If splined, insert a 5/16º 6-point hex driver,
or a 10MM 12-point triple square driver into tool
#8823 (VM.1048) (Fig. 16).
(4)Do not use an adjustable, ratcheting ªclick
typeº torque wrench. Most ªclick typeº
wrenches will only allow torque to be applied
in a clockwise rotation. Use a dial-type or
beam-type wrench.Tighten in counter-clockwise
rotation (Fig. 15) or, (Fig. 16). Refer to torque speci-
fications.
(5) Install accessory drive belt, and generator.
Refer to Generator Installation.
(6) Connect negative battery cable.
Litens Decoupler
(1) Thread decoupler pulley onto generator shaft
by hand (right-hand threads).
(2) Position Special Tool 8433 (Fig. 13) into decou-
pler. Align tool to hex end of generator shaft.
(3)Do not use an adjustable, ratcheting ªclick
typeº torque wrench. Most ªclick typeº
wrenches will only allow torque to be applied
in a clockwise rotation. Use a dial-type orbeam-type wrench.Tighten in counter-clockwise
rotation (Fig. 17). Refer to torque specifications.
(4) Install accessory drive belt, and generator.
Refer to Generator Installation.
(5) Connect negative battery cable.
Fig. 15 DECOUPLER INSTALLATION (INA-HEX)
1 - 10MM DEEP SOCKET
2 - TOOL # 8823 (VM.1048)
Fig. 16 DECOUPLER INSTALLATION (INA SPLINED)
1 - DRIVER
2 - TOOL # 8823 (VM.1048)
Fig. 17 DECOUPLER INSTALLATION (Litens)
8F - 30 CHARGING SYSTEMKJ
GENERATOR DECOUPLER PULLEY (Continued)

VOLTAGE REGULATOR
DESCRIPTION
The Electronic Voltage Regulator (EVR) is not a
separate component. It is actually a voltage regulat-
ing circuit located within the Powertrain Control
Module (PCM). The EVR is not serviced separately. If
replacement is necessary, the PCM must be replaced.
OPERATION
The amount of DC current produced by the gener-
ator is controlled by EVR circuitry contained within
the Powertrain Control Module (PCM). This circuitry
is connected in series with the generators second
rotor field terminal and its ground.
Voltage is regulated by cycling the ground path to
control the strength of the rotor magnetic field. TheEVR circuitry monitors system line voltage (B+) and
battery temperature (refer to Battery Temperature
Sensor for more information). It then determines a
target charging voltage. If sensed battery voltage is
0.5 volts or lower than the target voltage, the PCM
grounds the field winding until sensed battery volt-
age is 0.5 volts above target voltage. A circuit in the
PCM cycles the ground side of the generator field up
to 100 times per second (100Hz), but has the capabil-
ity to ground the field control wire 100% of the time
(full field) to achieve the target voltage. If the charg-
ing rate cannot be monitored (limp-in), a duty cycle
of 25% is used by the PCM in order to have some
generator output. Also refer to Charging Operation
for additional information.
KJCHARGING SYSTEM 8F - 31

Starting System Diagnosis
CONDITION POSSIBLE CAUSE CORRECTION
STARTER ENGAGES,
FAILS TO TURN
ENGINE.1. Battery discharged or
faulty.1. Refer to Battery. Charge or replace battery if required.
2. Starting circuit wiring
faulty.2. Refer to 8, Wiring Diagrams. Test and repair starter
feed and/or control circuits if required.
3. Starter motor faulty. 3. If all other starting system components and circuits test
OK, replace starter motor assembly.
4. Engine seized. 4. Refer to Engine Diagnosis in the Diagnosis and Testing
section of 9, Engine.
STARTER ENGAGES,
SPINS OUT BEFORE
ENGINE STARTS.1. Starter ring gear faulty. 1. Refer to Starter Motor Removal and Installation.
Remove starter motor to inspect starter ring gear.
Replace starter ring gear if required.
2. Starter motor faulty. 2. If all other starting system components and circuits test
OK, replace starter motor assembly.
STARTER DOES NOT
DISENGAGE.1. Starter motor
improperly installed.1. Refer to Starter Motor Removal and Installation.
Tighten starter mounting hardware to correct torque
specifications.
2. Starter relay faulty. 2. Refer to Starter Relay Diagnosis and Testing. Replace
starter relay if required.
3. Ignition switch faulty. 3. Refer to Ignition Switch and Key Lock Cylinder.
Replace ignition switch if required.
4. Starter motor faulty. 4. If all other starting system components and circuits test
OK, replace starter motor.
INSPECTION
For complete starter wiring circuit diagrams, refer
to 8, Wiring Diagrams. Before removing any unit
from starting system for repair or diagnosis, perform
the following inspections:
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO 8, PASSIVE RESTRAINT SYS-
TEMS, BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, OR INSTRUMENT
PANEL COMPONENT DIAGNOSIS OR SERVICE.
FAILURE TO TAKE THE PROPER PRECAUTIONS
COULD RESULT IN ACCIDENTAL AIRBAG DEPLOY-
MENT AND POSSIBLE PERSONAL INJURY.
²Battery- Visually inspect battery for indica-
tions of physical damage and loose or corroded cable
connections. Determine state-of-charge and cranking
capacity of battery. Charge or replace battery if
required. Refer toBatteryin 8, Battery.Note: If
equipped with diesel engine, a dual battery sys-
tem may be used, and both batteries must be
inspected.
²Ignition Switch- Visually inspect ignition
switch for indications of physical damage and loose
or corroded wire harness connections. Refer toIgni-
tion Switch and Key Lock Cylinder.²Clutch Pedal Position Switch- If equipped
with manual transmission, visually inspect clutch
pedal position switch for indications of physical dam-
age and loose or corroded wire harness connections.
Refer toClutch Pedal Position Switchin 6,
Clutch.
²Park/Neutral Position Switch- If equipped
with automatic transmission, visually inspect park/
neutral position switch for indications of physical
damage and loose or corroded wire harness connec-
tions. Refer toPark/Neutral Position Switchin
21, Transmission.
²Starter Relay- Visually inspect starter relay
for indications of physical damage and loose or cor-
roded wire harness connections.
²Starter Motor- Visually inspect starter motor
for indications of physical damage and loose or cor-
roded wire harness connections.
²Starter Solenoid- Visually inspect starter sole-
noid for indications of physical damage and loose or
corroded wire harness connections.
²Wiring- Visually inspect wire harnesses for
damage. Repair or replace any faulty wiring, as
required. Refer to 8, Wiring Diagrams.
8F - 34 STARTING SYSTEMKJ
STARTING SYSTEM (Continued)

TESTING
COLD CRANKING TEST
For complete starter wiring circuit diagrams, refer
to 8, Wiring Diagrams. The battery must be fully-
charged and load-tested before proceeding. Refer to
Batteryin 8, Battery.
(1) Connect volt-ampere tester to battery terminals
(Fig. 1). See instructions provided by manufacturer of
volt-ampere tester being used.Note: Certain diesel
equipped models use dual batteries. If equipped
with dual battery system, tester should be con-
nected to battery on left side of vehicle only.
Also, tester current reading must be taken from
positive battery cable lead that connects to
starter motor.
(2) Fully engage parking brake.
(3) If equipped with manual transmission, place
gearshift selector lever in Neutral position and block
clutch pedal in fully depressed position. If equipped
with automatic transmission, place gearshift selector
lever in Park position.
(4) Verify that all lamps and accessories are
turned off.
(5) To prevent a gasoline engine from starting,
remove Automatic ShutDown (ASD) relay. To prevent
a diesel engine from starting, remove Fuel Pump
Relay. These relays are located in Power Distribution
Center (PDC). Refer to label on PDC cover for relay
location.
WARNING: IF EQUIPPED WITH DIESEL ENGINE,
ATTEMPT TO START ENGINE A FEW TIMES
BEFORE PROCEEDING WITH FOLLOWING STEP.(6) Rotate and hold ignition switch in Start posi-
tion. Note cranking voltage and current (amperage)
draw readings shown on volt-ampere tester.
(a) If voltage reads below 9.6 volts, refer to
Starter Motorin Diagnosis and Testing. If starter
motor is OK, refer toEngine Diagnosisin 9,
Engine for further testing of engine. If starter
motor is not OK, replace faulty starter motor.
(b) If voltage reads above 9.6 volts and current
(amperage) draw reads below specifications, refer
toFeed Circuit Testin this section.
(c) If voltage reads 12.5 volts or greater and
starter motor does not turn, refer toControl Cir-
cuit Testingin this section.
(d) If voltage reads 12.5 volts or greater and
starter motor turns very slowly, refer toFeed Cir-
cuit Testin this section.
NOTE: A cold engine will increase starter current
(amperage) draw reading, and reduce battery volt-
age reading.
FEED CIRCUIT TEST
The starter feed circuit test (voltage drop method)
will determine if there is excessive resistance in
high-amperage feed circuit. For complete starter wir-
ing circuit diagrams, refer 8, Wiring Diagrams.
When performing these tests, it is important to
remember that voltage drop is giving an indication of
resistance between two points at which voltmeter
probes are attached.
Example:When testing resistance of positive bat-
tery cable, touch voltmeter leads to positive battery
cable clamp and cable connector at starter solenoid.
If you probe positive battery terminal post and cable
connector at starter solenoid, you are reading com-
bined voltage drop in positive battery cable clamp-to-
terminal post connection and positive battery cable.
The following operation will require a voltmeter
accurate to 1/10 (0.10) volt. Before performing tests,
be certain that following procedures are accom-
plished:
²Battery is fully-charged and load-tested. Refer to
Batteryin 8, Battery.
²Fully engage parking brake.
²If equipped with manual transmission, place
gearshift selector lever in Neutral position and block
clutch pedal in fully depressed position. If equipped
with automatic transmission, place gearshift selector
lever in Park position.
²Verify that all lamps and accessories are turned
off.
²To prevent a gasoline engine from starting,
remove Automatic ShutDown (ASD) relay. To prevent
a diesel engine from starting, remove Fuel Pump
Relay. These relays are located in Power Distribution
Fig. 1 Volts-Amps Tester Connections - Typical
1 - POSITIVE CLAMP
2 - NEGATIVE CLAMP
3 - INDUCTION AMMETER CLAMP
KJSTARTING SYSTEM 8F - 35
STARTING SYSTEM (Continued)

equipped models use dual batteries. If equipped
with dual battery system, this procedure must
be performed on driver side battery only.
(6) If equipped with dual battery system (certain
diesel equipped models), connect positive lead of volt-
meter to positive battery cable clamp on battery
located on left side of vehicle. Connect negative lead
of voltmeter to positive battery terminal post on bat-
tery located on right side of vehicle. Rotate and hold
ignition switch in Start position. Observe voltmeter.
If reading is above 0.2 volt, clean and tighten battery
cables at both batteries. Repeat test. If reading is
still above 0.2 volt, replace faulty positive battery
cable.If resistance tests detect no feed circuit problems,
refer toStarter Motorin the Diagnosis and Testing.
CONTROL CIRCUIT TESTING
The starter control circuit components should be
tested in the order in which they are listed, as fol-
lows:
²Starter Relay- Refer toStarter RelayDiag-
nosis and Testing.
²Starter Solenoid- Refer toStarter Motor
Diagnosis and Testing.
²Ignition Switch- Refer toIgnition Switch
and Key Lock Cylinder
²Clutch Pedal Position Switch- If equipped
with manual transmission, refer toClutch Pedal
Position Switchin 6, Clutch.
²Park/Neutral Position Switch- If equipped
with automatic transmission, refer toPark/Neutral
Position Switchin 21, Transmission.
²Wire harnesses and connections- Refer to 8,
Wiring Diagrams.
INSPECTION - STARTING SYSTEM
The following starting system components should
be carefully inspected whenever any starting system
problem is encountered.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR AIRBAG SYSTEM
CAPACITOR TO DISCHARGE BEFORE PERFORM-
ING FURTHER DIAGNOSIS OR SERVICE. THIS IS
THE ONLY SURE WAY TO DISABLE AIRBAG SYS-
TEM. FAILURE TO TAKE PROPER PRECAUTIONS
COULD RESULT IN ACCIDENTAL AIRBAG DEPLOY-
MENT AND POSSIBLE PERSONAL INJURY.
Battery
²Visually inspect battery for indications of physi-
cal damage and loose or corroded cable connections.
Determine state-of-charge and cranking capacity of
battery. Charge or replace battery, if required. Refer
toBatteryfor battery cleaning and inspection proce-
dures.
Ignition Switch
²Visually inspect ignition switch for indications of
physical damage and loose or corroded wire harness
connections. Clean corroded connections as required.
Refer toWiring Diagrams. Refer toIgnition
Switch and Key Lock Cylinderfor ignition switch
service procedures.
Fig. 5 Test Ground Circuit Resistance - Typical
1 - VOLTMETER
2 - BATTERY
3 - ENGINE GROUND
Fig. 6 Test Starter Ground - Typical
1 - STARTER MOTOR
2 - BATTERY
3 - VOLTMETER
KJSTARTING SYSTEM 8F - 37
STARTING SYSTEM (Continued)