torque JEEP LIBERTY 2002 KJ / 1.G Manual Online

CHARGING SYSTEM
TABLE OF CONTENTS
page page
CHARGING SYSTEM
DESCRIPTION.........................22
OPERATION...........................22
DIAGNOSIS AND TESTING - CHARGING
SYSTEM............................22
SPECIFICATIONS
TORQUE - EXCEPT DIESEL.............23
GENERATOR RATINGS - GAS ENGINES . . . 23
SPECIAL TOOLS.......................24
BATTERY TEMPERATURE SENSOR
DESCRIPTION.........................24
OPERATION...........................24
REMOVAL.............................24
INSTALLATION.........................24
GENERATOR
DESCRIPTION.........................25OPERATION...........................25
REMOVAL.............................25
INSTALLATION.........................26
GENERATOR DECOUPLER PULLEY
DESCRIPTION.........................26
OPERATION...........................27
DIAGNOSIS AND TESTING - GENERATOR
DECOUPLER.........................27
REMOVAL.............................27
INSTALLATION.........................30
VOLTAGE REGULATOR
DESCRIPTION.........................31
OPERATION...........................31
CHARGING SYSTEM
DESCRIPTION
The charging system consists of:
²Generator
²Electronic Voltage Regulator (EVR) circuitry
within the Powertrain Control Module (PCM)
²Ignition switch
²Battery (refer to 8, Battery for information)
²Battery temperature sensor
²Generator Lamp (if equipped)
²Check Gauges Lamp (if equipped)
²Wiring harness and connections (refer to 8, Wir-
ing for information)
OPERATION
The charging system is turned on and off with the
ignition switch. The system is on when the engine is
running and the ASD relay is energized. When the
ASD relay is on, voltage is supplied to the ASD relay
sense circuit at the PCM. This voltage is connected
through the PCM and supplied to one of the genera-
tor field terminals (Gen. Source +) at the back of the
generator.
The amount of DC current produced by the gener-
ator is controlled by the EVR (field control) circuitry
contained within the PCM. This circuitry is con-
nected in series with the second rotor field terminal
and ground.
A battery temperature sensor, located in the bat-
tery tray housing, is used to sense battery tempera-ture. This temperature data, along with data from
monitored line voltage, is used by the PCM to vary
the battery charging rate. This is done by cycling the
ground path to control the strength of the rotor mag-
netic field. The PCM then compensates and regulates
generator current output accordingly.
All vehicles are equipped with On-Board Diagnos-
tics (OBD). All OBD-sensed systems, including EVR
(field control) circuitry, are monitored by the PCM.
Each monitored circuit is assigned a Diagnostic Trou-
ble Code (DTC). The PCM will store a DTC in elec-
tronic memory for certain failures it detects. Refer to
Diagnostic Trouble Codes in; Powertrain Control
Module; Electronic Control Modules for more DTC
information.
The Check Gauges Lamp (if equipped) monitors:
charging system voltage,engine coolant tempera-
ture and engine oil pressure. If an extreme condition
is indicated, the lamp will be illuminated. This is
done as reminder to check the three gauges. The sig-
nal to activate the lamp is sent via the CCD bus cir-
cuits. The lamp is located on the instrument panel.
Refer to 8, Instrument Cluster for additional infor-
mation.
DIAGNOSIS AND TESTING - CHARGING
SYSTEM
The following procedures may be used to diagnose
the charging system if:
²the check gauges lamp (if equipped) is illumi-
nated with the engine running
8F - 22 CHARGING SYSTEMKJ

²the voltmeter (if equipped) does not register
properly
²an undercharged or overcharged battery condi-
tion occurs.
Remember that an undercharged battery is often
caused by:
²accessories being left on with the engine not
running
²a faulty or improperly adjusted switch that
allows a lamp to stay on. Refer to Ignition-Off Draw
Test in 8, Battery for more information.
INSPECTION
The Powertrain Control Module (PCM) monitors
critical input and output circuits of the charging sys-
tem, making sure they are operational. A Diagnostic
Trouble Code (DTC) is assigned to each input and
output circuit monitored by the On-Board Diagnostic
(OBD) system. Some charging system circuits are
checked continuously, and some are checked only
under certain conditions.
Refer to Diagnostic Trouble Codes in; Powertrain
Control Module; Electronic Control Modules for more
DTC information. This will include a complete list of
DTC's including DTC's for the charging system.
To perform a complete test of the charging system,
refer to the appropriate Powertrain Diagnostic Proce-
dures service manual and the DRBtscan tool. Per-form the following inspections before attaching the
scan tool.
(1) Inspect the battery condition. Refer to 8, Bat-
tery for procedures.
(2) Inspect condition of battery cable terminals,
battery posts, connections at engine block, starter
solenoid and relay. They should be clean and tight.
Repair as required.
(3) Inspect all fuses in both the fuseblock and
Power Distribution Center (PDC) for tightness in
receptacles. They should be properly installed and
tight. Repair or replace as required.
(4) Inspect generator mounting bolts for tightness.
Replace or tighten bolts if required. Refer to the Gen-
erator Removal/Installation section of this group for
torque specifications.
(5) Inspect generator drive belt condition and ten-
sion. Tighten or replace belt as required. Refer to
Belt Tension Specifications in 7, Cooling System.
(6) Inspect automatic belt tensioner (if equipped).
Refer to 7, Cooling System for information.
(7) Inspect generator electrical connections at gen-
erator field, battery output, and ground terminal (if
equipped). Also check generator ground wire connec-
tion at engine (if equipped). They should all be clean
and tight. Repair as required.
SPECIFICATIONS
TORQUE - EXCEPT DIESEL
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Generator Horizontal Mounting Bolts - 3.7L 57 42 -
Generator Vertical Mounting Bolt - 3.7L 40 29 -
Generator Mounting Bolts - 2.4L 57 42 -
B+ Terminal Nut at Top of Generator 13 - 115
Generator Decoupler 110 81 -
GENERATOR RATINGS - GAS ENGINES
TYPE PART NUMBER RATED SAE AMPS ENGINES MINIMUM TEST AMPS
DENSO 56044530AB 124 2.4L 88
DENSO 56044532AB 136 2.4L 96
DENSO 56041693AA 136 3.7L 96
DENSO 56029914AA 160 3.7L 112
KJCHARGING SYSTEM 8F - 23
CHARGING SYSTEM (Continued)

INSTALLATION
Gasoline Powered Engines
(1) 2.4L Engine: Position generator to engine and
install 2 mounting bolts. Refer to torque specifica-
tions.
(2) 3.7L Engine: Position generator to engine and
install 3 mounting bolts. Tighten 2 horizontal mount-
ing bolts to specified torque. Tighten 1 verticle
mounting bolt to specified torque. Refer to torque
specifications.
(3) Snap field wire connector into rear of genera-
tor.
(4) Install B+ terminal and nut to generator
mounting stud. Refer to torque specifications.
(5) Snap plastic protective cover to B+ terminal.
CAUTION: Never force a belt over a pulley rim
using a screwdriver. The synthetic fiber of the belt
can be damaged.
CAUTION: When installing a serpentine accessory
drive belt, the belt MUST be routed correctly. The
water pump will be rotating in the wrong direction if
the belt is installed incorrectly, causing the engine
to overheat. Refer to belt routing label in engine
compartment, or refer to Belt Schematics in 7, Cool-
ing System.
(6) Install drive belt Refer to 7, Cooling System for
belt routing, belt adjustment and bolt tightening pro-
cedures.
(7) Install negative battery cable to battery.
GENERATOR DECOUPLER
PULLEY
DESCRIPTION
The generator decoupler is used only with
certain engines.The decoupler is used in place of
the standard generator drive pulley (Fig. 5).
Fig. 3 GENERATOR - 2.4L
1 - UPPER MOUNTING BOLT
2 - GENERTOR
3 - LOWER MOUNTING BOLT
Fig. 4 GENERATOR - 3.7L
1 - GENERATOR
2 - VERTICAL MOUNTING BOLT
3 - HORIZONTAL MOUNTING BOLTS
8F - 26 CHARGING SYSTEMKJ
GENERATOR (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)

STARTING SYSTEM
TABLE OF CONTENTS
page page
STARTING SYSTEM
DESCRIPTION.........................32
OPERATION...........................32
DIAGNOSIS AND TESTING - STARTING
SYSTEM............................33
INSPECTION - STARTING SYSTEM.........37
SPECIFICATIONS
TORQUE - GAS POWERED.............38
STARTER MOTOR - GAS POWERED......39
STARTER MOTOR
DIAGNOSIS AND TESTING - STARTER
MOTOR .............................39REMOVAL.............................39
INSTALLATION.........................41
STARTER MOTOR RELAY
DESCRIPTION.........................41
OPERATION...........................42
DIAGNOSIS AND TESTING -
STARTER RELAY......................42
REMOVAL.............................43
INSTALLATION.........................43
STARTING SYSTEM
DESCRIPTION
The starting system consists of:
²Starter relay
²Starter motor (including an integral starter sole-
noid)
Other components to be considered as part of start-
ing system are:
²Battery
²Battery cables
²Ignition switch and key lock cylinder
²Clutch pedal position switch (manual transmis-
sion)
²Park/neutral position switch (automatic trans-
mission)
²Wire harnesses and connections.
The Battery, Starting, and Charging systems oper-
ate in conjunction with one another, and must be
tested as a complete system. For correct operation of
starting/charging systems, all components used in
these 3 systems must perform within specifications.
When attempting to diagnose any of these systems, it
is important that you keep their interdependency in
mind.
The diagnostic procedures used in each of these
groups include the most basic conventional diagnostic
methods, to the more sophisticated On-Board Diag-
nostics (OBD) built into the Powertrain Control Mod-
ule (PCM). Use of an induction-type milliampere
ammeter, volt/ohmmeter, battery charger, carbon pile
rheostat (load tester), and 12-volt test lamp may be
required.Certain starting system components are monitored
by the PCM and may produce a Diagnostic Trouble
Code (DTC). Refer to Emission Control. See Diagnos-
tic Trouble Codes for additional information and a
list of codes.
OPERATION
The starting system components form two separate
circuits. A high-amperage feed circuit that feeds the
starter motor between 150 and 350 amperes (700
amperes - diesel engine), and a low-amperage control
circuit that operates on less than 20 amperes. The
high-amperage feed circuit components include the
battery, the battery cables, the contact disc portion of
the starter solenoid, and the starter motor. The low-
amperage control circuit components include the igni-
tion switch, the clutch pedal position switch (manual
transmission), the park/neutral position switch (auto-
matic transmission), the starter relay, the electro-
magnetic windings of the starter solenoid, and the
connecting wire harness components.
If the vehicle is equipped with a manual transmis-
sion, it has a clutch pedal position switch installed in
series between the ignition switch and the coil bat-
tery terminal of the starter relay. This normally open
switch prevents the starter relay from being ener-
gized when the ignition switch is turned to the
momentary Start position, unless the clutch pedal is
depressed. This feature prevents starter motor oper-
ation while the clutch disc and the flywheel are
engaged. The starter relay coil ground terminal is
always grounded on vehicles with a manual trans-
mission.
8F - 32 STARTING SYSTEMKJ

If the vehicle is equipped with an automatic trans-
mission, battery voltage is supplied through the low-
amperage control circuit to the coil battery terminal
of the starter relay when the ignition switch is
turned to the momentary Start position. The park/
neutral position switch is installed in series between
the starter relay coil ground terminal and ground.
This normally open switch prevents the starter relay
from being energized and the starter motor from
operating unless the automatic transmission gear
selector is in the Neutral or Park positions.
When the starter relay coil is energized, the nor-
mally open relay contacts close. The relay contacts
connect the relay common feed terminal to the relay
normally open terminal. The closed relay contacts
energize the starter solenoid coil windings.
The energized solenoid pull-in coil pulls in the sole-
noid plunger. The solenoid plunger pulls the shift
lever in the starter motor. This engages the starter
overrunning clutch and pinion gear with the starter
ring gear on the manual transmission flywheel or on
the automatic transmission torque converter or
torque converter drive plate.
As the solenoid plunger reaches the end of its
travel, the solenoid contact disc completes the high-
amperage starter feed circuit and energizes the sole-
noid plunger hold-in coil. Current now flows betweenthe solenoid battery terminal and the starter motor,
energizing the starter.
Once the engine starts, the overrunning clutch pro-
tects the starter motor from damage by allowing the
starter pinion gear to spin faster than the pinion
shaft. When the driver releases the ignition switch to
the On position, the starter relay coil is de-energized.
This causes the relay contacts to open. When the
relay contacts open, the starter solenoid plunger
hold-in coil is de-energized.
When the solenoid plunger hold-in coil is de-ener-
gized, the solenoid plunger return spring returns the
plunger to its relaxed position. This causes the con-
tact disc to open the starter feed circuit, and the shift
lever to disengage the overrunning clutch and pinion
gear from the starter ring gear.
DIAGNOSIS AND TESTING - STARTING
SYSTEM
The battery, starting, and charging systems oper-
ate in conjunction with one another, and must be
tested as a complete system. For correct starting/
charging system operation, all of the components
involved in these 3 systems must perform within
specifications.
Starting System Diagnosis
CONDITION POSSIBLE CAUSE CORRECTION
STARTER FAILS TO
OPERATE.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 relay faulty. 3. Refer to Starter Relay in Diagnosis and Testing.
Replace starter relay if required.
4. Ignition switch faulty. 4. Refer to Ignition Switch and Key Lock Cylinder.
Replace ignition switch if required.
5. Clutch pedal position
switch faulty.5. Refer to Clutch Pedal Position Switch.
6. Park/Neutral position
switch faulty or
misadjusted.6. Refer to Park/Neutral Position Switch. Replace
park/neutral position switch if required.
7. Starter solenoid faulty. 7. Refer to Starter Motor. Replace starter motor assembly
if required.
8. Starter motor faulty. 8. If all other starting system components and circuits test
OK, replace starter motor.
KJSTARTING SYSTEM 8F - 33
STARTING SYSTEM (Continued)

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)

Clutch Pedal Position Switch
²If vehicle is equipped with a manual transmis-
sion, visually inspect clutch pedal position switch for
indications of physical damage and loose or corroded
wire harness connections. Clean corroded connections
as required. Refer toClutch Hydraulic Linkagefor
clutch pedal position switch service procedures.
Park/Neutral Position Switch
²If vehicle is equipped with an automatic trans-
mission, visually inspect park/neutral position switch
for indications of physical damage and loose or cor-
roded wire harness connections. Clean corroded con-
nections as required. Refer toPark/Neutral
Position Switchfor park/neutral position switch
service procedures.
Starter Relay
²Visually inspect starter relay for indications of
physical damage and loose or corroded wire harness
connections. Clean corroded connections as required.
Refer toStarter Relayfor starter relay service pro-
cedures.
Starter Motor
²Visually inspect starter motor for indications of
physical damage and loose or corroded wire harness
connections. Clean corroded connections as required.
If problem being diagnosed involves improper starter
engagement, disengagement or noise complaints,
starter motor should be removed. With starter motor
removed, inspect starter pinion and ring gears for
damaged or missing teeth. Replace faulty compo-
nents as required. Refer toStarter Motorfor
removal/installation procedures.
Starter Solenoid
²Visually inspect starter solenoid for indications
of physical damage and loose or corroded wire har-
ness connections. Clean corroded connections as
required. Refer toStarter Motorfor starter solenoid
service procedures.
Wiring
²Visually inspect starting system wire harnesses
for indications of physical damage. Repair or replace
any faulty wiring, as required. Refer toWiring Dia-
gramsfor repair or connector and terminal service
procedures.
SPECIFICATIONS
TORQUE - GAS POWERED
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Starter Solenoid Battery
Cable Nut11 - 100
Starter Mounting Bolts -
2.4L54 40 -
Starter Mounting Bolts
-3.7L54 40 -
Starter Heat Shield
Mounting Bolts6-55
8F - 38 STARTING SYSTEMKJ
STARTING SYSTEM (Continued)

INSTALLATION
2.4L 4±Cylinder
(1) Position starter into bellhousing and install 2
bolts. Refer to torque specifications.
(2) Install battery cable and nut to stud on starter
solenoid. Refer to torque specifications.
(3) Install solenoid wire connector to solenoid ter-
minal.
(4) Lower vehicle.
(5) Connect negative battery cable.
3.7L V-6
(1) Position front of starter towards rear of vehicle
with solenoid position rotated until it is located below
starter. Install starter by passing it between exhaust
pipe and transmission bellhousing.
(2) Position starter into bellhousing and install 2
bolts. Refer to torque specifications.
(3) Install battery cable and nut to stud on starter
solenoid. Refer to torque specifications.
(4) Install solenoid wire connector to solenoid ter-
minal.
(5) Position starter heat shield and install nut at
front of starter.
(6) Install 2 starter heat shield bolts at side of
starter.
(7) Install front propeller shaft.
(8) Install 2 flange bolts securing left exhaust
downpipe to crossover pipe.
(9) Lower vehicle.
(10) Connect negative battery cable.
STARTER MOTOR RELAY
DESCRIPTION
The starter relay is an electromechanical device
that switches battery current to the pull-in coil of the
starter solenoid when ignition switch is turned to
Start position. The starter relay is located in the
Power Distribution Center (PDC) in the engine com-
partment. See PDC cover for relay identification and
location.
The starter relay is a International Standards
Organization (ISO) relay. Relays conforming to ISO
specifications have common physical dimensions, cur-
rent capacities, terminal patterns, and terminal func-
tions.
The starter relay cannot be repaired or adjusted
and, if faulty or damaged, it must be replaced.
Fig. 11 STARTER ELECTRICAL CONNECTORS -
2.4L/3.7L
1 - BATERY CABLE NUT
2 - BATTERY CABLE
3 - SOLENOID CONNECTOR
4 - HEAT SHIELD
Fig. 12 STARTER - 3.7L
1-STARTER
2 - MOUNTING BOLTS (2)
KJSTARTING SYSTEM 8F - 41
STARTER MOTOR (Continued)

IGNITION CONTROL
TABLE OF CONTENTS
page page
IGNITION CONTROL
DESCRIPTION..........................1
OPERATION............................1
SPECIFICATIONS
SPECIFICATIONS - IGNITION TIMING.......2
ENGINE FIRING ORDER - 2.4L 4-CYLINDER . 2
ENGINE FIRING ORDER - 3.7L V-6.........2
IGNITION COIL RESISTANCE - 2.4L........2
IGNITION COIL RESISTANCE - 3.7L V-6.....3
SPARK PLUGS........................3
SPARK PLUG CABLE RESISTANCE - 2.4L . . . 3
TORQUE - IGNITION SYSTEM............3
AUTO SHUT DOWN RELAY
DESCRIPTION - PCM OUTPUT.............4
OPERATION
OPERATION - ASD SENSE - PCM INPUT....4
OPERATION - PCM OUTPUT.............4
DIAGNOSIS AND TESTING - ASD AND FUEL
PUMP RELAYS........................4
REMOVAL.............................5
INSTALLATION..........................5
CAMSHAFT POSITION SENSOR
DESCRIPTION
DESCRIPTION - 2.4L....................5
DESCRIPTION-3.7L.....................6
OPERATION
OPERATION - 2.4L.....................6OPERATION - 3.7L.....................6
REMOVAL.............................7
INSTALLATION..........................8
IGNITION COIL
DESCRIPTION..........................9
OPERATION............................9
REMOVAL.............................10
INSTALLATION.........................10
KNOCK SENSOR
DESCRIPTION.........................11
OPERATION...........................11
REMOVAL.............................12
INSTALLATION.........................12
SPARK PLUG
DESCRIPTION.........................12
OPERATION...........................12
DIAGNOSIS AND TESTING - SPARK PLUG
CONDITIONS.........................13
REMOVAL.............................15
CLEANING SPARK PLUGS................15
INSTALLATION.........................15
IGNITION COIL CAPACITOR
DESCRIPTION.........................16
OPERATION...........................16
REMOVAL.............................16
INSTALLATION.........................16
IGNITION CONTROL
DESCRIPTION
The ignition system consists of:
²Spark Plugs
²Ignition Coil(s)
²Powertrain Control Module (PCM)
²Crankshaft Position Sensor
²2 Knock Sensors (3.7L only)
²Camshaft Position Sensor
²The MAP, TPS, IAC and ECT also have an effect
on the control of the ignition system.
OPERATION
2.4L
A common ignition coil divided into 2 halves is
used. Secondary, high-tension spark plug cables are
also used. One half of the coil fires two spark plugs
simultaneously (one plug is the cylinder under com-pression, and the other plug is the cylinder on the
exhaust stroke). Coil half number one fires cylinders
1 and 4. Coil half number two fires cylinders 2 and 3.
The PCM determines which of the coils to charge and
fire at the correct time.
The Auto Shutdown (ASD) relay provides battery
voltage to the ignition coil. The PCM provides a
ground contact (circuit) for energizing the coil. When
the PCM breaks the contact, the energy in the coil
primary transfers to the secondary causing a spark.
The PCM will de-energize the ASD relay if it does
not receive inputs from either the crankshaft or cam-
shaft position sensors.
A distributor is not used with the 2.4L engine.
3.7L
The 3.7L V6 engine uses a separate ignition coil for
each cylinder. The one-piece coil bolts directly to the
cylinder head. Rubber boots seal the secondary ter-
minal ends of the coils to the top of all 6 spark plugs.
A separate electrical connector is used for each coil.
KJIGNITION CONTROL 8I - 1