ignition JEEP LIBERTY 2002 KJ / 1.G Repair Manual

no continuity between terminals 87 and 30. If OK, go
to Step 2. If not OK, replace the faulty relay.
(2) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 60.7 to 80.3 ohms. If OK, go to
Step 3. If not OK, replace the faulty relay.
(3) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, see the Relay Circuit Test in this
group. If not OK, replace the faulty relay.
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
RELAY CIRCUIT TEST
(1) The relay common feed terminal cavity (30) is
connected to battery voltage and should be hot at all
times. If OK, go to Step 2. If not OK, repair the open
circuit to the PDC fuse as required.
(2) The relay normally closed terminal (87A) is
connected to terminal 30 in the de-energized position,
but is not used for this application. Go to Step 3.
(3) The relay normally open terminal (87) is con-
nected to the common feed terminal (30) in the ener-
gized position. This terminal supplies battery voltage
to the rear glass and outside rear view mirror heat-
ing grids and the defogger switch indicator lamp.
There should be continuity between the cavity for
relay terminal 87 and the rear window defogger relay
output circuit cavities of the rear glass heating grid
connector, both outside rear view mirror heating grid
connectors, and the defogger switch connector at all
times. If OK, go to Step 4. If not OK, repair the open
circuit(s) as required.(4) The coil ground terminal (85) is connected to
the electromagnet in the relay. This terminal is pro-
vided with ground by the instrument cluster rear
window defogger timer and logic circuitry to energize
the defogger relay. There should be continuity to
ground at the cavity for relay terminal 85 when the
defogger switch is turned On. However, with the
defogger relay removed, the defogger switch indicator
lamp will not light to show that the defogger system
is turned On. Be certain that you depress the defog-
ger switch at least twice to confirm that the system
is turned on during this test. If OK, go to Step 5. If
not OK, repair the open circuit to the HVAC control
head as required.
(5) The coil battery terminal (86) is connected to
the electromagnet in the relay. It is connected to
fused ignition switch output voltage and should be
hot when the ignition switch is in the run position.
Check for battery voltage at the cavity for relay ter-
minal 86 with the ignition switch in the run position.
If OK, see the diagnosis for Instrument Cluster in
this group. If not OK, repair the open circuit to the
fuse in the junction block as required.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the rear window defogger relay from
the junction block.
INSTALLATION
(1) Install the rear window defogger relay by align-
ing the relay terminals with the cavities in the junc-
tion block and pushing the relay firmly into place.
(2) Connect the battery negative cable.
(3) Test the relay operation.
Fig. 4 DEFOGGER RELAY- TERMINAL LEGEND
KJWINDOW DEFOGGER 8G - 7
REAR WINDOW DEFOGGER RELAY (Continued)

HEATED SEAT SYSTEM
TABLE OF CONTENTS
page page
HEATED SEAT SYSTEM
DESCRIPTION.........................10
OPERATION...........................10
DIAGNOSIS AND TESTING - HEATED SEAT
SYSTEM............................11
DRIVER SEAT HEATER SWITCH
DESCRIPTION.........................11
OPERATION...........................12
DIAGNOSIS AND TESTING - HEATED SEAT
SWITCH............................12
REMOVAL.............................13
INSTALLATION.........................13
HEATED SEAT ELEMENT
DESCRIPTION.........................13OPERATION...........................13
DIAGNOSIS AND TESTING - HEATED SEAT
ELEMENT...........................13
HEATED SEAT SENSOR
DIAGNOSIS AND TESTING - HEATED SEAT
SENSOR............................14
PASSENGER SEAT HEATER SWITCH
DESCRIPTION.........................14
OPERATION...........................14
DIAGNOSIS AND TESTING - HEATED SEAT
SWITCH............................14
REMOVAL.............................15
INSTALLATION.........................15
HEATED SEAT SYSTEM
DESCRIPTION
Individually controlled electrically heated front
seats are available on models that are also equipped
with the optional leather trim package. Vehicles with
this option can be visually identified by the two sep-
arate heated seat switches mounted on the outboard
seat cushion side shields. The heated seat system
allows the front seat driver and passenger to select
from two different levels of supplemental electrical
seat heating, or no seat heating to suit their individ-
ual comfort requirements. The heated seat system for
this vehicle includes the following major components:
²Heated Seat Switches- Two heated seat
switches are used per vehicle, including two Light-
Emitting Diode (LED) indicator lamps and an incan-
descent back lighting bulb for each switch. One
switch for the driver and one for the passenger front
seats. The switches are mounted on the outboard
seat cushion side shields.
²Heated Seat Module- also referred to as the
Seat Heat Interface Module (SHIM), this module con-
tains the solid state electronic control and diagnostic
logic circuitry for the heated seat system. One heated
seat module is used per vehicle and is mounted
under the left front seat cushion. Refer to the Elec-
tronic Control Modules section of the service manual
for heated seat module information.
²Heated Seat Elements- Four heated seat ele-
ments are used per vehicle, one for each front seat
back and one for each front seat cushion. The ele-
ments are integral to the individual front seat andseat back cushions and cannot be removed from the
cushions, once installed at the factory.
²Heated Seat Sensors- Two heated seat sen-
sors are used per vehicle, one for each front seat. The
sensors are integral to the individual front seat heat-
ing elements.
Following are general descriptions of the major
components in the heated seat system. See the own-
er's manual in the vehicle glove box for more infor-
mation on the features, use and operation of the
heated seat system. Refer toWiring Diagramsfor
the location of complete heated seat system wiring
diagrams.
OPERATION
The heated seat module receives fused battery cur-
rent through fuse #29 in the Junction Block (JB)
when the ignition switch is in the ªONº position. The
heated seat switches receive battery current through
fuse #25 in the Junction Block also, when the igni-
tion switch is in the ªONº position. The heated seat
module shares a common ground circuit with each of
the heated seat elements. The heated seat elements
will only operate when the surface temperature of
the seat cushion is below the designed temperature
set points of the system.
The heated seat system will also be turned off
automatically whenever the ignition switch is turned
to any position except On. If the ignition switch is
turned to the Off position while a heated seat is
turned ON, the heated seat will remain Off after the
ignition switch is turned back ªONº until a heated
seat switch is depressed again.
8G - 10 HEATED SEAT SYSTEMKJ

OPERATION
There are three positions that can be selected with
each of the heated seat switches: Off, Low, and High.
When the front of the switch rocker is fully
depressed, the High position is selected and the high
position LED indicator illuminates. When the rear of
the switch rocker is fully depressed, the Low position
is selected and the low position LED indicator illumi-
nates. When the switch rocker is depressed a second
time in either direction, Off is selected and both LED
indicators are extinguished.
Both switches provide separate resistor multi-
plexed hard wire inputs to the Heated Seat Module
to indicate the selected switch position. The heated
seat module monitors the switch inputs and responds
to the heated seat switch status messages by control-
ling the output to the seat heater elements of the
selected seat. The Low heat position set point is
about 36É C (97É F), and the High heat position set
point is about 41É C (105É F).
DIAGNOSIS AND TESTING - HEATED SEAT
SWITCH
If a heated seat fails to heat and one or both of the
indicator lamps on a heated seat switch flash, refer
toHeated Seat System Diagnosis and Testingin
this section for flashing LED failure identification.
Refer toWiring Diagramsfor complete heated seat
system wiring diagrams.
(1) If the problem being diagnosed involves a
heated seat switch indicator lamp that remains illu-
minated after the heated seat has been turned Off,refer toDiagnosis and Testing the Heated Seat
Modulein the Electronic Control Modules section for
heated seat module diagnosis and testing procedures.
If not, go to Step 2
(2) Remove the heated seat switch (Refer to 8 -
ELECTRICAL/HEATED SEATS/DRIVER HEATED
SEAT SWITCH - REMOVAL). Check for continuity
between the ground circuit cavity #5 of the heated
seat switch connector and a good ground. There
should be continuity. If OK, go to Step 3. If not OK,
repair the open ground circuit as required.
(3) Turn the ignition switch to the ON position.
Check for battery voltage at the fused ignition switch
output circuit cavity #1 of the heated seat switch con-
nector. If OK, go to Step 4. If not OK, repair the open
fused ignition switch output circuit as required.
(4) Check the continuity between pin #1 and pin
#3 of the heated seat switch (Fig. 2). If the readings
do not correspond to those in the Heated Seat Switch
Continuity table below, replace the heated seat
switch. If OK, and the heated seat system is still not
operating properly refer toDiagnosis and Testing
the Heated Seat Module.
NOTE: ANY RESISTANCE VALUES (OHMSV) GIVEN
IN THE FOLLOWING TEXT ARE SUPPLIED USING
THE AUTOMATIC RANGE GENERATED BY A
FLUKETAUTOMOTIVE METER. IF ANOTHER TYPE
OF MEASURING DEVICE IS USED, THE VALUES
GENERATED MAY NOT BE THE SAME AS THE
RESULTS SHOWN HERE, OR MAY HAVE TO BE
CONVERTED TO THE RANGE USED HERE.
Fig. 1 KJ POWER / HEATED SEAT
Fig. 2 Heated Seat Switches
8G - 12 HEATED SEAT SYSTEMKJ
DRIVER SEAT HEATER SWITCH (Continued)

(2) Remove the heated seat switch (Refer to 8 -
ELECTRICAL/HEATED SEATS/DRIVER HEATED
SEAT SWITCH - REMOVAL). Check for continuity
between the ground circuit cavity #5 of the heated
seat switch connector and a good ground. There
should be continuity. If OK, go to Step 3. If not OK,
repair the open ground circuit as required.
(3) Turn the ignition switch to the ON position.
Check for battery voltage at the fused ignition switch
output circuit cavity #1 of the heated seat switch con-
nector. If OK, go to Step 4. If not OK, repair the open
fused ignition switch output circuit as required.
(4) Check the continuity between pin #1 and pin
#3 of the heated seat switch (Fig. 4). If the readings
do not correspond to those in the Heated Seat Switch
Continuity table below, replace the heated seat
switch. If OK, and the heated seat system is still not
operating properly refer toDiagnosis and Testing
the Heated Seat Module.NOTE: ANY RESISTANCE VALUES (OHMSV) GIVEN
IN THE FOLLOWING TEXT ARE SUPPLIED USING
THE AUTOMATIC RANGE GENERATED BY A
FLUKETAUTOMOTIVE METER. IF ANOTHER TYPE
OF MEASURING DEVICE IS USED, THE VALUES
GENERATED MAY NOT BE THE SAME AS THE
RESULTS SHOWN HERE, OR MAY HAVE TO BE
CONVERTED TO THE RANGE USED HERE.
HEATED SEAT SWITCH CONTINUITY
CONTINUITY
BETWEENSWITCH
POSITIONOHMS
READING +/±
10%
PIN 1 AND 3 OFF 2.2 K (2200)
OHMS
PIN 1 AND 3 LO .415 K (415)
OHMS
PIN 1 AND 3 HI 33 OHMS
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the appropriate seat cushion side
shield (Refer to 23 - BODY/SEATS/SEAT CUSHION
SIDE COVERS - REMOVAL).
(3) Disconnect the heated seat switch electrical
connector. Depress the locking tab and pull straight
apart.
(4) Working from the underside of the switch, gen-
tly rock the switch back and forth out of its mounting
location.
INSTALLATION
(1) Gently rock the switch back and forth in to its
mounting location.
(2) Connect the heated seat switch electrical con-
nector.
(3) Install the appropriate seat cushion side shield.
Refer to the Body section of the service manual for
the procedure.
(4) Connect the negative battery cable.
Fig. 4 Heated Seat Switches
KJHEATED SEAT SYSTEM 8G - 15
PASSENGER SEAT HEATER SWITCH (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

Because of coil design, spark plug cables (second-
ary cables) are not used. A distributor is not used
with the 3.7L engine.
Two knock sensors (one for each cylinder bank) are
used to help control spark knock.
The Auto Shutdown (ASD) relay provides battery
voltage to each ignition coil. The Powertrain Control
Module (PCM) provides a ground contact (circuit) for
energizing each coil. When the PCM breaks the con-
tact, 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 camshaft position sensors.
SPECIFICATIONS
SPECIFICATIONS - IGNITION TIMING
Ignition timing is not adjustable on any
engine.
ENGINE FIRING ORDER - 2.4L 4-CYLINDER1-3-4-2
ENGINE FIRING ORDER - 3.7L V-61-6-5-4-3-2
IGNITION COIL RESISTANCE - 2.4L
Engine Coil ManufacturePrimary Resistance at
21ÉC-27ÉC (70ÉF-80ÉF)Secondary Resistance at
21ÉC-27ÉC (70ÉF-80ÉF)
2.4L Toyodenso or Diamond 0.51 to 0.61 Ohms 11,500 to 13,500 Ohms
Fig. 1 IGNITION COIL - 2.4L
8I - 2 IGNITION CONTROLKJ
IGNITION CONTROL (Continued)

IGNITION COIL RESISTANCE - 3.7L V-6
PRIMARY RESISTANCE
21-27ÉC (70-80ÉF)SECONDARY
RESISTANCE 21-27ÉC
(70-80ÉF)
0.6 - 0.9 Ohms 6,000 - 9,000 Ohms
SPARK PLUGS
ENGINE PLUG TYPE ELECTRODE GAP
2.4L RE14MCC5 (Champion #) 1.24 to 1.37 mm (0.048 to 0.053 in.)
3.7L V-6 2FR6F - 11G (NGK #) 1.1 mm (0.042 in.)
SPARK PLUG CABLE RESISTANCE - 2.4L
MINIMUM MAXIMUM
250 Ohms Per Inch 1000 Ohms Per Inch
3000 Ohms Per Foot 12,000 Ohms Per Foot
TORQUE - IGNITION SYSTEM
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Camshaft Position Sensor-2.4L 23 21 205
Camshaft Position Sensor±3.7L 12 - 106
Crankshaft Position Sensor Bolt-2.4L 12 - 106
Crankshaft Position Sensor Nut/Bolt-3.7L 23 21 205
* Knock Sensor Bolt - 3.7L * 20 * 15
Ignition Coil Mounting Bolts - 2.4L 11 - 105
Ignition Coil Mounting Nuts - 3.7L 8 - 70
Ignition Coil Capacitor Nuts- 3.7L 8 - 70
** Spark Plugs - 2.4L ** 15 ** 11 -
Spark Plugs - 3.7L 27 20 -
* Do not apply any sealant, thread-locker or adhesive to
bolts. Poor sensor performance may result.
** Torque critical tapered design. Do not exceed 15 ft. lbs.
KJIGNITION CONTROL 8I - 3
IGNITION CONTROL (Continued)

AUTO SHUT DOWN RELAY
DESCRIPTION - PCM OUTPUT
The 5±pin, 12±volt, Automatic Shutdown (ASD)
relay is located in the Power Distribution Center
(PDC). Refer to label on PDC cover for relay location.
OPERATION
OPERATION - ASD SENSE - PCM INPUT
A 12 volt signal at this input indicates to the PCM
that the ASD has been activated. The relay is used to
connect the oxygen sensor heater elements, oxygen
sensor heater relay, ignition coil and fuel injectors to
12 volt + power supply.
This input is used only to sense that the ASD relay
is energized. If the Powertrain Control Module
(PCM) does not see 12 volts at this input when the
ASD should be activated, it will set a Diagnostic
Trouble Code (DTC).
OPERATION - PCM OUTPUT
The ASD relay supplies battery voltage (12+ volts)
to the fuel injectors and ignition coil(s). With certain
emissions packages it also supplies 12±volts to the
oxygen sensor heating elements and the oxygen sen-
sor heater relay.
The ground circuit for the coil within the ASD
relay is controlled by the Powertrain Control Module
(PCM). The PCM operates the ASD relay by switch-
ing its ground circuit on and off.
The ASD relay will be shut±down, meaning the
12±volt power supply to the ASD relay will be de-ac-
tivated by the PCM if the ignition key is left in the
ON position. This is if the engine has not been run-
ning for approximately 1.8 seconds.
DIAGNOSIS AND TESTING - ASD AND FUEL
PUMP RELAYS
The following description of operation and
tests apply only to the Automatic Shutdown
(ASD) and fuel pump relays. The terminals on the
bottom of each relay are numbered. Two different
types of relays may be used, (Fig. 2) or (Fig. 3).
²Terminal number 30 is connected to battery volt-
age. For both the ASD and fuel pump relays, termi-
nal 30 is connected to battery voltage at all times.
²The PCM grounds the coil side of the relay
through terminal number 85.
²Terminal number 86 supplies voltage to the coil
side of the relay.
²When the PCM de-energizes the ASD and fuel
pump relays, terminal number 87A connects to termi-
nal 30. This is the Off position. In the off position,voltage is not supplied to the rest of the circuit. Ter-
minal 87A is the center terminal on the relay.
²When the PCM energizes the ASD and fuel
pump relays, terminal 87 connects to terminal 30.
This is the On position. Terminal 87 supplies voltage
to the rest of the circuit.
The following procedure applies to the ASD and
fuel pump relays.
(1) Remove relay from connector before testing.
(2) With the relay removed from the vehicle, use
an ohmmeter to check the resistance between termi-
nals 85 and 86. The resistance should be 75 ohms +/-
5 ohms.
(3) Connect the ohmmeter between terminals 30
and 87A. The ohmmeter should show continuity
between terminals 30 and 87A.
Fig. 2 TYPE 1 RELAY (ISO MICRO RELAY)
Fig. 3 ASD AND FUEL PUMP RELAY TERMINALSÐ
TYPE 2
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
8I - 4 IGNITION CONTROLKJ

(4) Connect the ohmmeter between terminals 87
and 30. The ohmmeter should not show continuity at
this time.
(5) Connect one end of a jumper wire (16 gauge or
smaller) to relay terminal 85. Connect the other end
of the jumper wire to the ground side of a 12 volt
power source.
(6) Connect one end of another jumper wire (16
gauge or smaller) to the power side of the 12 volt
power source.Do not attach the other end of the
jumper wire to the relay at this time.
WARNING: DO NOT ALLOW OHMMETER TO CON-
TACT TERMINALS 85 OR 86 DURING THIS TEST.
DAMAGE TO OHMMETER MAY RESULT.
(7) Attach the other end of the jumper wire to
relay terminal 86. This activates the relay. The ohm-
meter should now show continuity between relay ter-
minals 87 and 30. The ohmmeter should not show
continuity between relay terminals 87A and 30.
(8) Disconnect jumper wires.
(9) Replace the relay if it did not pass the continu-
ity and resistance tests. If the relay passed the tests,
it operates properly. Check the remainder of the ASD
and fuel pump relay circuits. Refer to 8, Wiring Dia-
grams.
REMOVAL
The ASD relay is located in the Power Distribution
Center (PDC) (Fig. 4). Refer to label on PDC cover
for relay location.(1) Remove PDC cover.
(2) Remove relay from PDC.
(3) Check condition of relay terminals and PDC
connector terminals for damage or corrosion. Repair
if necessary before installing relay.
(4) Check for pin height (pin height should be the
same for all terminals within the PDC connector).
Repair if necessary before installing relay.
INSTALLATION
The ASD relay is located in the Power Distribution
Center (PDC). Refer to label on PDC cover for relay
location.
(1) Install relay to PDC.
(2) Install cover to PDC.
CAMSHAFT POSITION
SENSOR
DESCRIPTION
DESCRIPTION - 2.4L
The Camshaft Position Sensor (CMP) on the 2.4L
4±cylinder engine is bolted to the right-front side of
the cylinder head (Fig. 5).
Fig. 4 POWER DISTRIBUTION CENTER (PDC)
1 - BATTERY
2 - PDC
3 - PDC COVER
Fig. 5 CMP LOCATION - 2.4L
1 - CMP SENSOR
2 - ELECTRICAL CONNECTOR
3-
4 - SLOTTED HOLES
5 - MOUNTING BOLTS (2)
KJIGNITION CONTROL 8I - 5
AUTO SHUT DOWN RELAY (Continued)

DESCRIPTION-3.7L
The Camshaft Position Sensor (CMP) on the 3.7L
6±cylinder engine is bolted to the right-front side of
the right cylinder head (Fig. 6).
OPERATION
OPERATION - 2.4L
The Camshaft Position Sensor (CMP) sensor con-
tains a hall effect device referred to as a sync signal
generator. A rotating target wheel (tonewheel) for the
CMP is located behind the exhaust valve-camshaft
drive gear (Fig. 7). The target wheel is equipped with
a cutout (notch) around 180 degrees of the wheel.
The CMP detects this cutout every 180 degrees of
camshaft gear rotation. Its signal is used in conjunc-
tion with the Crankshaft Position Sensor (CKP) to
differentiate between fuel injection and spark events.
It is also used to synchronize the fuel injectors with
their respective cylinders.
When the leading edge of the target wheel cutout
enters the tip of the CMP, the interruption of mag-
netic field causes the voltage to switch high, result-
ing in a sync signal of approximately 5 volts.
When the trailing edge of the target wheel cutout
leaves the tip of the CMP, the change of the magnetic
field causes the sync signal voltage to switch low to 0
volts.
OPERATION - 3.7L
The Camshaft Position Sensor (CMP) sensor con-
tains a hall effect device referred to as a sync signal
generator. A rotating target wheel (tonewheel) for the
CMP is located at the front of the camshaft for the
right cylinder head (Fig. 8). This sync signal genera-
tor detects notches located on a tonewheel. As the
tonewheel rotates, the notches pass through the sync
signal generator. The signal from the CMP sensor is
used in conjunction with the Crankshaft Position
Sensor (CKP) to differentiate between fuel injection
and spark events. It is also used to synchronize the
fuel injectors with their respective cylinders.
When the leading edge of the tonewheel notch
enters the tip of the CMP, the interruption of mag-
netic field causes the voltage to switch high, result-
ing in a sync signal of approximately 5 volts.
When the trailing edge of the tonewheel notch
leaves then tip of the CMP, the change of the mag-
netic field causes the sync signal voltage to switch
low to 0 volts.
Fig. 6 CAMSHAFT POSITION SENSOR - 3.7L
1 - RIGHT/FRONT OF RIGHT CYLINDER HEAD
2 - CMP MOUNTING BOLT
3 - CMP LOCATION
Fig. 7 CMP FACE AT TARGET WHEEL-2.4L
1 - CAMSHAFT DRIVE GEAR
2 - TARGETWHEEL (TONEWHEEL)
3 - FACE OF CMP SENSOR
4 - CUTOUT (NOTCH)
8I - 6 IGNITION CONTROLKJ
CAMSHAFT POSITION SENSOR (Continued)