map sensor JEEP GRAND CHEROKEE 2003 WJ / 2.G Owner's Manual

NOTE: When installing oil pan gasket/windage tray,
start four pan bolts at each corner before tightening
oil pickup tube. This will keep pan gasket in align-
ment.
(3) Install oil pump pick-up tube using a new
O-ring. First tighten bolt at O-ring end of tube to 28
N´m (20 ft. lbs.). Tighten remain tube support fasten-
ers to 28 N´m (20 ft. lbs.).
(4) Install oil pan and tighten fasteners to 15 N´m
(11 ft. lbs.) (Fig. 95).
(5) Reconnect transmission oil cooler lines to oil
pan stud bolt.
(6) Install starter (Refer to 8 - ELECTRICAL/
STARTING/STARTER MOTOR - INSTALLATION).
(7) Install exhaust system Y-pipe.
(8) Install structural cover (Refer to 9 - ENGINE/
ENGINE BLOCK/STRUCTURAL COVER - INSTAL-
LATION).
(9) Lower vehicle.
(10) Fill engine with proper amount of oil (Refer to
LUBRICATION & MAINTENANCE/FLUID TYPES -
SPECIFICATIONS).
(11) Connect negative cable to battery.
OIL PRESSURE SENSOR/
SWITCH
DESCRIPTION
The 3±wire, solid-state engine oil pressure sensor
(sending unit) is located in an engine oil pressure
gallery.
OPERATION
The oil pressure sensor uses three circuits. They are:
²A 5±volt power supply from the Powertrain Con-
trol Module (PCM)
²A sensor ground through the PCM's sensor
return
²
A signal to the PCM relating to engine oil pressure
The oil pressure sensor has a 3±wire electrical
function very much like the Manifold Absolute Pres-
sure (MAP) sensor. Meaning different pressures
relate to different output voltages.
A 5±volt supply is sent to the sensor from the PCM
to power up the sensor. The sensor returns a voltage
signal back to the PCM relating to engine oil pres-
sure. This signal is then transferred (bussed) to the
instrument panel on either a CCD or PCI bus circuit
(depending on vehicle line) to operate the oil pressure
gauge and the check gauges lamp. Ground for the
sensor is provided by the PCM through a low-noise
sensor return.
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Raise vehicle on hoist.
(3) Remove front splash shield.
(4) Disconnect oil pressure sender wire (Fig. 96).
(5) Remove the pressure sender (Fig. 96).
INSTALLATION
(1) Install oil pressure sender.
(2) Connect oil pressure sender wire.
(3) Install front splash shield.
(4) Lower vehicle.
(5) Connect the negative battery cable.
Fig. 95 Oil Pan Tightening Sequence
Fig. 96 Oil Pressure Sending Unit
1 - BELT
2 - OIL PRESSURE SENSOR
3 - OIL FILTER
4 - ELEC. CONNECTOR
WJENGINE - 4.7L 9 - 133
OIL PAN (Continued)

INTAKE MANIFOLD
DESCRIPTION
The intake manifold is made of a composite mate-
rial and features long runners which maximizes low
end torque. The intake manifold uses single plane
sealing which consist of eight individual press in
place port gaskets to prevent leaks. Eight studs and
two bolts are used to fasten the intake to the head.
DIAGNOSIS AND TESTINGÐINTAKE
MANIFOLD LEAKAGE
An intake manifold air leak is characterized by
lower than normal manifold vacuum. Also, one or
more cylinders may not be functioning.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.
(1) Start the engine.
(2) Spray a small stream of water at the suspected
leak area.
(3) If a change in RPM is observed the area of the
suspected leak has been found.
(4) Repair as required.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove air cleaner housing and throttle body
resonator (Fig. 104).
(3) Disconnect throttle and speed control cables.
(4) Disconnect electrical connectors for the follow-
ing components:
²Manifold Absolute Pressure (MAP) Sensor
²Intake Air Temperature (IAT) Sensor
²Throttle Position (TPS) Sensor
²Coolant Temperature (CTS) Sensor
²Idle Air Control (IAC) Motor
(5) Disconnect vapor purge hose, brake booster
hose, speed control servo hose, positive crankcase
ventilation (PCV) hose.
Fig. 102 Measuring Clearance Over Rotors
1 - STRAIGHT EDGE
2 - FEELER GAUGE
Fig. 103 Oil Pump and Primary Timing Chain
Tensioner Tightening Sequence
Fig. 104 Throttle Body Resonator
1 - THROTTLE BODY RESONATOR
2 - BOLT
3 - BOLT
9 - 136 ENGINE - 4.7LWJ
OIL PUMP (Continued)

(7) Connect throttle cable and speed control cable
to throttle body.
(8) Install fuel rail (Refer to 14 - FUEL SYSTEM/
FUEL DELIVERY/FUEL RAIL - INSTALLATION).
(9) Install ignition coil towers (Refer to 8 - ELEC-
TRICAL/IGNITION CONTROL/IGNITION COIL -
INSTALLATION).
(10) Install coolant temperature sensor (Refer to 7
- COOLING/ENGINE/ENGINE COOLANT TEMP
SENSOR - INSTALLATION).
(11) Connect electrical connectors for the following
components:
²Manifold Absolute Pressure (MAP) Sensor
²Intake Air Temperature (IAT) Sensor
²Throttle Position (TPS) Sensor
²Coolant Temperature (CTS) Sensor
²Idle Air Control (IAC) Motor
²Ignition coil towers
²Fuel injectors
(12) Install top oil dipstick tube retaining bolt and
ground strap.
(13) Install right side engine lifting stud.
(14) Install generator including electrical connec-
tions (Refer to 8 - ELECTRICAL/CHARGING/GEN-
ERATOR - INSTALLATION).
(15) Connect Vapor purge hose, Brake booster
hose, Speed control servo hose, Positive crankcase
ventilation (PCV) hose.
(16) Install air conditioning compressor including
electrical connections.
(17) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(18) Install accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(19) Install cowl to hood seal (Refer to 23 - BODY/
WEATHERSTRIP/SEALS/COWL WEATHERSTRIP -
INSTALLATION).
(20) Install air cleaner housing and throttle body
resonator. Tighten resonator bolts 4.5 N´m (40 in.
lbs.).
(21) Connect negative cable to battery.
EXHAUST MANIFOLD - LEFT
DESCRIPTION
The exhaust manifolds are log style with a pat-
ented flow enhancing design to maximize perfor-
mance. The exhaust manifolds are made of high
silicon molybdenum cast iron. A perforated core
graphite exhaust manifold gasket is used to improve
sealing to the cylinder head. The exhaust manifolds
are covered by a three layer laminated heat shield
for thermal protection and noise reduction. The heat
shields are fastened with a torque prevailing nutthat is backed off slightly to allow for the thermal
expansion of the exhaust manifold.
REMOVAL
(1) Disconnect negative cable for battery.
(2) Hoist vehicle.
(3) Disconnect exhaust pipe at manifold.
(4) Lower vehicle.
(5) Remove air cleaner housing and tube.
(6) Remove the front two exhaust heat shield
retaining fasteners. Raise vehicle and remove the
fasteners at rear of heat shield.
(7) Remove heat shield (Fig. 107).
(8) Lower vehicle and remove the upper exhaust
manifold retaining bolts (Fig. 107).
(9) Raise vehicle and remove the lower exhaust
manifold retaining bolts (Fig. 107).
(10) Remove exhaust manifold and gasket (Fig.
107). Manifold is removed from below the engine
compartment.
CLEANING
(1) Clean the exhaust manifold using a suitable
cleaning solvent, then allow to air dry.
(2) Clean all gasket residue from the manifold
mating surface.
INSPECTION
(1) Inspect the exhaust manifold for cracks in the
mating surface and at every mounting bolt hole.
(2) Using a straight edge and a feeler gauge, check
the mating surface for warp and twist.
(3) Inspect the manifold to exhaust pipe mating
surface for cracks, gouges, or other damage that
would prevent sealing.
INSTALLATION
(1) Install exhaust manifold and gasket from below
engine compartment.
(2) Install lower exhaust manifold fasteners (Fig.
107). DO NOT tighten until all fasteners are in
place.
(3) Lower vehicle and install upper exhaust mani-
fold fasteners (Fig. 107). Tighten all manifold bolts
starting at center and working outward to 25 N´m
(18 ft. lbs.).
CAUTION: Over tightening heat shield fasteners,
may cause shield to distort and/or crack.
(4) Install exhaust manifold heat shield (Fig. 107).
Tighten fasteners to 8 N´m (72 in. lbs.), then loosen
45 degrees.
(5) Install air cleaner housing and tube.
(6) Connect exhaust pipe to manifold.
(7) Connect negative cable to battery.
9 - 138 ENGINE - 4.7LWJ
INTAKE MANIFOLD (Continued)

CAUTION: The left and right fuel rails are replaced
as an assembly. Do not attempt to separate rail
halves at connector tube (Fig. 22). Due to design of
tube, it does not use any clamps. Never attempt to
install a clamping device of any kind to tube. When
removing fuel rail assembly for any reason, be care-
ful not to bend or kink tube.
(1) Remove fuel tank filler tube cap.
(2) Perform Fuel System Pressure Release Proce-
dure.
(3) Remove negative battery cable at battery.
(4) Remove air duct at throttle body air box.
(5) Remove air box at throttle body.
(6) Remove wiring at rear of generator.
(7) Disconnect fuel line latch clip and fuel line at
fuel rail. A special tool will be necessary for fuel line
disconnection. Refer to Quick-Connect Fittings.
(8) Remove vacuum lines at throttle body.(9) Disconnect electrical connectors at all 8 fuel
injectors. To remove connector refer to (Fig. 23). Push
red colored slider away from injector (1). While push-
ing slider, depress tab (2) and remove connector (3)
from injector. The factory fuel injection wiring har-
ness is numerically tagged (INJ 1, INJ 2, etc.) for
injector position identification. If harness is not
tagged, note wiring location before removal.
(10) Disconnect electrical connectors at throttle
body.
(11) Disconnect electrical connectors at MAP and
IAT sensors.
Fig. 21 Fuel Injector Rail/Fuel DamperÐ4.0L Engine
1 - INJ. #1
2 - INJ. #2
3 - INJ. #3
4 - INJ. #4
5 - INJ. #5
6 - INJ. #6
7 - FUEL INJECTOR RAIL
8 - FUEL DAMPER
9 - PRESSURE TEST PORT CAP
10 - MOUNTING BOLTS (4)
11 - QUICK-CONNECT FITTING
Fig. 22 FUEL INJECTOR RAIL - 4.7L V-8 EN
1 - MOUNTING BOLTS (4)
2 - INJ.#7
3 - INJ.#5
4 - QUICK-CONNECT FITTING
5 - INJ.#3
6 - FUEL INJECTOR RAIL
7 - INJ.#1
8 - CONNECTOR TUBE
9 - INJ.#2
10 - INJ.#4
11 - INJ.#6
12 - INJ.#8
13 - PRESSURE TEST PORT CAP
14 - 16 FUEL DELIVERYWJ
FUEL RAIL (Continued)

(9) Disconnect speed control cable at throttle body
(if equipped). Refer to Speed Control Cable.
(10) Disconnect automatic transmission cable at
throttle body (if equipped).
(11) Remove cable routing bracket at intake mani-
fold.
(12) Clean dirt/debris from each fuel injector at
intake manifold.
(13) Remove fuel rail mounting nuts/bolts (Fig.
24).
(14) Remove fuel rail by gently rocking until all
fuel injectors have cleared machined holes at intake
manifold.
(15) If fuel injectors are to be removed, refer to
Fuel Injector Removal/Installation.
INSTALLATION
INSTALLATION - 4.7L
(1) If fuel injectors are to be installed, refer to Fuel
Injector Removal/Installation.
(2) Apply a small amount of engine oil to each fuel
injector o-ring. This will help in fuel rail installation.
(3) Position fuel rail/fuel injector assembly to
machined injector openings in cylinder head.
(4) Guide each injector into cylinder head. Be care-
ful not to tear injector o-rings.(5) Pushrightside of fuel rail down until fuel
injectors have bottomed on cylinder head shoulder.
Pushleftfuel rail down until injectors have bot-
tomed on cylinder head shoulder.
(6) Install 4 fuel rail mounting bolts and tighten to
27 N´m (20 ft. lbs.).
(7) Install ignition coils. Refer to Ignition Coil
Removal/Installation.
(8) Connect electrical connectors to throttle body.
(9) Connect electrical connectors to MAP and IAT
sensors.
(10) Connect electrical connectors at all fuel injec-
tors. To install connector, refer to (Fig. 23). Push con-
nector onto injector (1) and then push and lock red
colored slider (2). Verify connector is locked to injec-
tor by lightly tugging on connector.
(11) Connect vacuum lines to throttle body.
(12) Connect fuel line latch clip and fuel line to
fuel rail. Refer to Quick-Connect Fittings.
(13) Connect wiring to rear of generator.
(14) Install air box to throttle body.
(15) Install air duct to air box.
(16) Connect battery cable to battery.
(17) Start engine and check for leaks.
INSTALLATION - 4.0L
(1) If fuel injectors are to be installed, refer to Fuel
Injector Removal/Installation.
(2) Clean each injector bore at intake manifold.
(3) Apply a small amount of clean engine oil to
each injector o-ring. This will aid in installation.
(4) Position tips of all fuel injectors into the corre-
sponding injector bore in intake manifold. Seat injec-
tors into manifold.
(5) Install and tighten fuel rail mounting bolts to
11  3 N´m (100  25 in. lbs.) torque.
(6) Connect electrical connectors at all fuel injec-
tors. To install connector, refer to (Fig. 25). Push con-
nector onto injector (1) and then push and lock red
colored slider (2). Verify connector is locked to injec-
tor by lightly tugging on connector.
(7) Connect fuel line and fuel line latch clip to fuel
rail. Refer Quick-Connect Fittings.
(8) Install protective cap to pressure test port fit-
ting (if equipped).
(9) Install cable routing bracket to intake mani-
fold.
(10) Connect throttle cable at throttle body.
(11) Connect speed control cable at throttle body (if
equipped).
(12) Connect automatic transmission cable at
throttle body (if equipped).
(13) Install oxygen sensor wiring clip nuts to fuel
rail mounting studs (certain emissions packages
only).
Fig. 25 Remove/Install Injector ConnectorÐ4.0L
Engine
14 - 18 FUEL DELIVERYWJ
FUEL RAIL (Continued)

FUEL INJECTION
TABLE OF CONTENTS
page page
FUEL INJECTION
DIAGNOSIS AND TESTING
VISUAL INSPECTION..................32
SPECIFICATIONS
TORQUE - FUEL INJECTION.............39
ACCELERATOR PEDAL
REMOVAL.............................39
INSTALLATION.........................39
CRANKSHAFT POSITION SENSOR
DESCRIPTION
DESCRIPTION - 4.0L...................40
DESCRIPTION - 4.7L...................40
OPERATION
OPERATION - 4.0L....................40
OPERATION - 4.7L....................41
REMOVAL
REMOVAL - 4.0L......................41
REMOVAL - 4.7L......................41
INSTALLATION
INSTALLATION - 4.0L..................42
INSTALLATION - 4.7L..................43
FUEL INJECTOR
DESCRIPTION.........................43
OPERATION
OPERATION.........................43
OPERATION - PCM OUTPUT............43
DIAGNOSIS AND TESTING - FUEL INJECTOR . 44
REMOVAL.............................44
INSTALLATION.........................44
FUEL PUMP RELAY
DESCRIPTION.........................44
OPERATION...........................44
IDLE AIR CONTROL MOTOR
DESCRIPTION.........................44
OPERATION...........................44
REMOVAL
REMOVAL - 4.0L......................45
REMOVAL - 4.7L......................45
INSTALLATION
INSTALLATION - 4.0L..................46
INSTALLATION - 4.7L..................46
INTAKE AIR TEMPERATURE SENSOR
DESCRIPTION.........................46
OPERATION...........................46
REMOVAL
REMOVAL - 4.0L......................46
REMOVAL - 4.7L......................46
INSTALLATION
INSTALLATION - 4.0L..................47INSTALLATION - 4.7L..................47
MAP SENSOR
DESCRIPTION
DESCRIPTION........................48
DESCRIPTION - 4.7L...................48
OPERATION...........................48
REMOVAL
REMOVAL - 4.0L......................48
REMOVAL - 4.7L......................49
INSTALLATION
INSTALLATION - 4.0L..................49
INSTALLATION - 4.7L..................49
O2S HEATER RELAY
DESCRIPTION.........................49
OPERATION...........................49
REMOVAL.............................50
INSTALLATION.........................50
O2S SENSOR
DESCRIPTION.........................50
OPERATION...........................50
REMOVAL.............................51
INSTALLATION.........................51
THROTTLE BODY
DESCRIPTION.........................52
OPERATION...........................52
REMOVAL
REMOVAL - 4.0L......................52
REMOVAL - 4.7L......................53
INSTALLATION
INSTALLATION - 4.0L..................53
INSTALLATION - 4.7L..................54
THROTTLE CONTROL CABLE
REMOVAL
REMOVAL - 4.0L......................54
REMOVAL - 4.7L......................55
INSTALLATION
INSTALLATION ± 4.0L..................55
INSTALLATION - 4.7L..................56
THROTTLE POSITION SENSOR
DESCRIPTION.........................56
OPERATION...........................56
REMOVAL
REMOVAL - 4.0L......................57
REMOVAL - 4.7L......................57
INSTALLATION
INSTALLATION - 4.0L..................58
INSTALLATION - 4.7L..................58
WJFUEL INJECTION 14 - 31

(8) Inspect system body grounds for loose or dirty
connections. Refer to Group 8, Wiring for ground
locations.
(9) Verify crankcase ventilation (CCV) operation.
Refer to Emission Control System for additional
information.
(10) Inspect all fuel line quick-connect fittings for
damage or leaks.
(11) Verify hose connections to all ports of vacuum
fittings on intake manifold, and for emission system
are tight and not leaking.
(12) Inspect accelerator cable, transmission throt-
tle cable (if equipped) and speed control cable connec-
tions (if equipped). Check their connections to
throttle body linkage for any binding or restrictions.
(13) Verify vacuum booster hose is firmly con-
nected to fitting on intake manifold. Also check con-
nection to brake vacuum booster.(14) Inspect air cleaner inlet and air cleaner ele-
ment for dirt or restrictions.
(15) Inspect radiator grille area, radiator fins and
air conditioning condenser for restrictions.
(16) 4.0L Engine: Verify MAP, Intake Manifold Air
Temperature (IAT) sensor, TPS and Idle Air Control
(IAC) motor connectors are firmly connected (Fig. 9).
Be sure throttle body mounting bolts (Fig. 9)are
tight.
(17) 4.7L Engine: Verify Intake Manifold Air Tem-
perature (IAT) sensor, TPS and Idle Air Control (IAC)
motor connectors are firmly connected (Fig. 10). Be
sure throttle body mounting bolts (Fig. 10)are tight.
Fig. 8 Crankshaft Position SensorÐ4.7L V-8 Engine
1 - CRANKSHAFT POSITION SENSOR
2-STARTER
3 - ELEC. CONNECTOR
Fig. 9 IAT, MAP, IAC, TPS Sensor LocationsÐ4.0L
Engine
1 - MOUNTING BOLTS (4)
2 - THROTTLE BODY
3 - IAC MOTOR
4 - ELEC. CONN.
5 - TPS
6 - MAP SENSOR
7 - ELEC. CONN.
8 - IAT SENSOR
9 - ELEC. CONN.
14 - 34 FUEL INJECTIONWJ
FUEL INJECTION (Continued)

(18) 4.0L Engine: Verify wire harness connector is
firmly connected to Engine Coolant Temperature
(ECT) sensor (Fig. 11).(19) 4.7L Engine: Verify MAP and Engine Coolant
Temperature (ECT) sensor electrical connectors are
firmly connected to sensors (Fig. 12).
(20) Verify fuel injector wire harness connectors
are firmly connected to injectors in correct order.
Each harness connector is numerically tagged with
injector number (INJ 1, INJ 2 etc.) of its correspond-
ing fuel injector and cylinder number.
(21) Raise and support vehicle.
(22) Verify all oxygen sensor wire connectors are
firmly connected to sensors. Inspect sensors and con-
nectors for damage (Fig. 13)or (Fig. 14).
Fig. 10 IAT, IAC, TPS Sensor LocationsÐ4.7L V-8
Engine
1 - MOUNTING BOLTS (3)
2 - THROTTLE BODY
3 - IAT SENSOR CONNECTOR
4 - IAC MOTOR CONNECTOR
5 - TPS CONNECTOR
Fig. 11 ECT Sensor LocationÐ4.0L Engine
1 - THERMOSTAT HOUSING
2 - ENGINE COOLANT TEMPERATURE SENSOR
3 - ELECTRICAL CONNECTOR
Fig. 12 MAP and ECT Sensor LocationsÐ4.7L V-8
Engine
1 - ECT SENSOR
2 - MOUNTING BOLTS (2)
3 - MAP SENSOR
4 - INTAKE MANIFOLD
WJFUEL INJECTION 14 - 35
FUEL INJECTION (Continued)

SPECIFICATIONS
TORQUE - FUEL INJECTION
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Air Cleaner Housing Mount. Nuts 10 93
Air Cleaner Air Duct Clamps 4 35
Air Cleaner Resonator Bolts 4 35
Engine Coolant Temperature SensorÐ4.0L Engine 11 96
Engine Coolant Temperature SensorÐ4.7L Engine 11 96
Fuel Hose Clamps 1 10
IAC Motor-To-Throttle Body BoltsÐ4.0L Engine 7860
IAC Motor-To-Throttle Body BoltsÐ4.7L Engine 7 60
Intake Manifold Air Temp. SensorÐ4.0L Engine 28 20
Intake Manifold Air Temp. SensorÐ4.7L Engine 28 20
MAP Sensor Mounting ScrewsÐ4.0L Engine 3 25
MAP Sensor Mounting ScrewsÐ4.7L Engine 3 25
Oxygen SensorÐAll Engines 30 22
PCM-to-Mounting Bracket Screws 3 25
PCM-to-Mounting Bracket Screws 9 80
Radiator Cooling Fan Relay Bolts 3 25
Throttle Body Mounting BoltsÐ4.0L Engine 11 100
Throttle Body Mounting BoltsÐ4.7L Engine 12 105
TPS Mounting ScrewsÐ4.0L Engine 7 60
TPS Mounting ScrewsÐ4.7L Engine 7 60
ACCELERATOR PEDAL
REMOVAL
The accelerator pedal is connected to the throttle
body linkage by the throttle cable. The cable is pro-
tected by a plastic sheathing and is connected to the
throttle body linkage by a ball socket. It is connected
to the accelerator pedal arm by a plastic retainer
(clip) (Fig. 16). This retainer (clip) snaps into the top
of the accelerator pedal arm. A retainer clip (Fig. 16)
is also used to fasten cable to dash panel.
CAUTION: Be careful not to damage or kink the
cable core wire (within the cable sheathing) while
servicing accelerator pedal or throttle cable.
(1) From inside vehicle, hold up accelerator pedal.
Remove plastic cable retainer (clip) and throttle cable
core wire from upper end of pedal arm. Plastic cable
retainer (clip) snaps into pedal arm.
(2) Remove accelerator pedal bracket nuts. Remove
accelerator pedal assembly.
INSTALLATION
The accelerator pedal is connected to the throttle
body linkage by the throttle cable. The cable is pro-
tected by a plastic sheathing and is connected to the
throttle body linkage by a ball socket. It is connected
to the accelerator pedal arm by a plastic retainer
(clip) (Fig. 16) . This retainer (clip) snaps into the top
of the accelerator pedal arm. A retainer clip (Fig. 16)
is also used to fasten cable to dash panel.
(1) Place accelerator pedal assembly over studs
protruding from floor pan. Tighten mounting nuts to
12 N´m   2 N´m (105 in. lbs.   20 in. lbs.) torque.
(2) Slide throttle cable into opening in top of pedal
arm. Push plastic cable retainer (clip) into pedal arm
opening until it snaps into place.
(3) Before starting engine, operate accelerator
pedal to check for any binding.
WJFUEL INJECTION 14 - 39

INSTALLATION
INSTALLATION - 4.0L
The IAC motor is located on the throttle body.
(1) Install IAC motor to throttle body.
(2) Install and tighten two mounting bolts (screws)
to 7 N´m (60 in. lbs.) torque.
(3) Install electrical connector.
(4) Install air cleaner duct/air box to throttle body.
INSTALLATION - 4.7L
(1) Install IAC motor to throttle body.
(2) Install and tighten two mounting bolts (screws)
to 7 N´m (60 in. lbs.) torque.
(3) Install electrical connector.
(4) Install air duct/air box to throttle body.
INTAKE AIR TEMPERATURE
SENSOR
DESCRIPTION
The 2±wire Intake Manifold Air Temperature (IAT)
sensor is installed in the intake manifold with the
sensor element extending into the air stream.
The IAT sensor is a two-wire Negative Thermal
Coefficient (NTC) sensor. Meaning, as intake mani-
fold temperature increases, resistance (voltage) in the
sensor decreases. As temperature decreases, resis-
tance (voltage) in the sensor increases.
OPERATION
The IAT sensor provides an input voltage to the
Powertrain Control Module (PCM) indicating the
density of the air entering the intake manifold based
upon intake manifold temperature. At key-on, a
5±volt power circuit is supplied to the sensor from
the PCM. The sensor is grounded at the PCM
through a low-noise, sensor-return circuit.
The PCM uses this input to calculate the following:
²Injector pulse-width
²Adjustment of spark timing (to help prevent
spark knock with high intake manifold air-charge
temperatures)
The resistance values of the IAT sensor is the same
as for the Engine Coolant Temperature (ECT) sensor.
REMOVAL
REMOVAL - 4.0L
The Intake Manifold Air Temperature (IAT) sensor
is installed into the intake manifold plenum near the
front of the throttle body (Fig. 27).
(1) Disconnect electrical connector from sensor.
(2) Remove sensor from intake manifold.
REMOVAL - 4.7L
The Intake Manifold Air Temperature (IAT) sensor
is located on the left side of the intake manifold.
Threaded Type Sensor
(1) Disconnect electrical connector from sensor.
(2) Remove sensor from intake manifold (Fig. 28).
Snap-In Type Sensor
(1) Disconnect electrical connector from IAT sen-
sor.
(2) Clean dirt from intake manifold at sensor base.
(3) Gently lift on small plastic release tab (Fig. 30)
or (Fig. 29) and rotate sensor about 1/4 turn counter-
clockwise for removal.
(4) Check condition of sensor o-ring.
Fig. 27 Intake Manifold Air Sensor LocationÐ4.0L
Engine
1 - MOUNTING BOLTS (4)
2 - THROTTLE BODY
3 - IAC MOTOR
4 - ELEC. CONN.
5 - TPS
6 - MAP SENSOR
7 - ELEC. CONN.
8 - IAT SENSOR
9 - ELEC. CONN.
14 - 46 FUEL INJECTIONWJ
IDLE AIR CONTROL MOTOR (Continued)