2003 JEEP GRAND CHEROKEE tps

(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)

(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

The PCM uses the IAC motor to control idle speed
(along with timing) and to reach a desired MAP dur-
ing decel (keep engine from stalling).
The IAC motor has 4 wires with 4 circuits. Two of
the wires are for 12 volts and ground to supply elec-
trical current to the motor windings to operate the
stepper motor in one direction. The other 2 wires are
also for 12 volts and ground to supply electrical cur-
rent to operate the stepper motor in the opposite
direction.
To make the IAC go in the opposite direction, the
PCM just reverses polarity on both windings. If only
1 wire is open, the IAC can only be moved 1 step
(increment) in either direction. To keep the IAC
motor in position when no movement is needed, the
PCM will energize both windings at the same time.
This locks the IAC motor in place.
In the IAC motor system, the PCM will count
every step that the motor is moved. This allows the
PCM to determine the motor pintle position. If the
memory is cleared, the PCM no longer knows the
position of the pintle. So at the first key ON, the
PCM drives the IAC motor closed, regardless of
where it was before. This zeros the counter. From
this point the PCM will back out the IAC motor and
keep track of its position again.
When engine rpm is above idle speed, the IAC is
used for the following:
²Off-idle dashpot (throttle blade will close quickly
but idle speed will not stop quickly)
²Deceleration air flow control
²A/C compressor load control (also opens the pas-
sage slightly before the compressor is engaged so
that the engine rpm does not dip down when the
compressor engages)
²Power steering load control
The PCM can control polarity of the circuit to con-
trol direction of the stepper motor.
IAC Stepper Motor Program:The PCM is also
equipped with a memory program that records the
number of steps the IAC stepper motor most recently
advanced to during a certain set of parameters. For
example: The PCM was attempting to maintain a
1000 rpm target during a cold start-up cycle. The last
recorded number of steps for that may have been
125. That value would be recorded in the memory
cell so that the next time the PCM recognizes the
identical conditions, the PCM recalls that 125 steps
were required to maintain the target. This program
allows for greater customer satisfaction due to
greater control of engine idle.
Another function of the memory program, which
occurs when the power steering switch (if equipped),
or the A/C request circuit, requires that the IAC step-
per motor control engine rpm, is the recording of the
last targeted steps into the memory cell. The PCMcan anticipate A/C compressor loads. This is accom-
plished by delaying compressor operation for approx-
imately 0.5 seconds until the PCM moves the IAC
stepper motor to the recorded steps that were loaded
into the memory cell. Using this program helps elim-
inate idle-quality changes as loads change. Finally,
the PCM incorporates a9No-Load9engine speed lim-
iter of approximately 1800 - 2000 rpm, when it rec-
ognizes that the TPS is indicating an idle signal and
IAC motor cannot maintain engine idle.
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate.Never attempt to adjust the engine idle
speed using this screw.All idle speed functions are
controlled by the IAC motor through the PCM.
REMOVAL
REMOVAL - 4.0L
The IAC motor is located on the throttle body.
(1) Remove air duct and air resonator box at throt-
tle body.
(2) Disconnect electrical connector from IAC motor
(Fig. 40).
(3) Remove two mounting bolts (screws) (Fig. 26).
(4) Remove IAC motor from throttle body.
REMOVAL - 4.7L
(1) Remove air duct and air resonator box at throt-
tle body.
(2) Disconnect electrical connector from IAC motor
(Fig. 36).
(3) Remove two mounting bolts (screws) (Fig. 42).
(4) Remove IAC motor from throttle body.
Fig. 26 Mounting Bolts (Screws)ÐIAC
1 - IDLE AIR CONTROL MOTOR
2 - MOUNTING SCREWS
WJFUEL INJECTION 14 - 45
IDLE AIR CONTROL MOTOR (Continued)

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)

INSTALLATION
INSTALLATION - 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) Install sensor into intake manifold. Tighten
sensor to 28 N´m (20 ft. lbs.) torque.
(2) Connect electrical connector to sensor.
INSTALLATION - 4.7L
Threaded Type Sensor
(1) Install sensor (Fig. 28) into intake manifold.
Tighten sensor to 28 N´m (20 ft. lbs.) torque.
(2) Connect electrical connector to sensor.
Snap-In Type Sensor
(1) Check condition of sensor o-ring (Fig. 30).
(2) Clean sensor mounting hole in intake manifold.(3) Position sensor (Fig. 29) into intake manifold
and rotate clockwise until past release tab.
(4) Install electrical connector.
Fig. 28 IAT - 4.7L (THREADED TYPE)
1 - THROTTLE BODY
2 - TPS
3 - IAC MOTOR
4 - IAT SENSOR (THREADED TYPE)
5 - MOUNTING SCREWS
Fig. 29 IAT SENSOR - 4.7L (SNAP-IN TYPE)
1 - LEFT SIDE OF THROTTLE BODY
2 - ELEC. CONNECT.
3 - IAT SENSOR
4 - RELEASE TAB
Fig. 30 IAT SENSOR TAB / O-RING - 4.7L (SNAP-IN
TYPE)
1 - IAT SENSOR
2 - SENSOR O-RING
3 - RELEASE TAB
WJFUEL INJECTION 14 - 47
INTAKE AIR TEMPERATURE SENSOR (Continued)

MAP SENSOR
DESCRIPTION
DESCRIPTION
On the 4.0L six-cylinder engine the MAP sensor is
mounted to the engine throttle body. On the 4.7L V-8
engine the MAP sensor is mounted to front of the
intake manifold.
DESCRIPTION - 4.7L
The MAP sensor is located on the front of the
intake manifold. An o-ring seals the sensor to the
intake manifold.
OPERATION
The MAP sensor is used as an input to the Power-
train Control Module (PCM). It contains a silicon
based sensing unit to provide data on the manifold
vacuum that draws the air/fuel mixture into the com-
bustion chamber. The PCM requires this information
to determine injector pulse width and spark advance.
When manifold absolute pressure (MAP) equals
Barometric pressure, the pulse width will be at max-
imum.
A 5 volt reference is supplied from the PCM and
returns a voltage signal to the PCM that reflects
manifold pressure. The zero pressure reading is 0.5V
and full scale is 4.5V. For a pressure swing of 0±15
psi, the voltage changes 4.0V. To operate the sensor,
it is supplied a regulated 4.8 to 5.1 volts. Ground is
provided through the low-noise, sensor return circuit
at the PCM.
The MAP sensor input is the number one contrib-
utor to fuel injector pulse width. The most important
function of the MAP sensor is to determine baromet-
ric pressure. The PCM needs to know if the vehicle is
at sea level or at a higher altitude, because the air
density changes with altitude. It will also help to cor-
rect for varying barometric pressure. Barometric
pressure and altitude have a direct inverse correla-
tion; as altitude goes up, barometric goes down. At
key-on, the PCM powers up and looks at MAP volt-
age, and based upon the voltage it sees, it knows the
current barometric pressure (relative to altitude).
Once the engine starts, the PCM looks at the voltage
again, continuously every 12 milliseconds, and com-
pares the current voltage to what it was at key-on.
The difference between current voltage and what it
was at key-on, is manifold vacuum.
During key-on (engine not running) the sensor
reads (updates) barometric pressure. A normal range
can be obtained by monitoring a known good sensor.
As the altitude increases, the air becomes thinner
(less oxygen). If a vehicle is started and driven to avery different altitude than where it was at key-on,
the barometric pressure needs to be updated. Any
time the PCM sees Wide Open Throttle (WOT), based
upon Throttle Position Sensor (TPS) angle and RPM,
it will update barometric pressure in the MAP mem-
ory cell. With periodic updates, the PCM can make
its calculations more effectively.
The PCM uses the MAP sensor input to aid in cal-
culating the following:
²Manifold pressure
²Barometric pressure
²Engine load
²Injector pulse-width
²Spark-advance programs
²Shift-point strategies (certain automatic trans-
missions only)
²Idle speed
²Decel fuel shutoff
The MAP sensor signal is provided from a single
piezoresistive element located in the center of a dia-
phragm. The element and diaphragm are both made
of silicone. As manifold pressure changes, the dia-
phragm moves causing the element to deflect, which
stresses the silicone. When silicone is exposed to
stress, its resistance changes. As manifold vacuum
increases, the MAP sensor input voltage decreases
proportionally. The sensor also contains electronics
that condition the signal and provide temperature
compensation.
The PCM recognizes a decrease in manifold pres-
sure by monitoring a decrease in voltage from the
reading stored in the barometric pressure memory
cell. The MAP sensor is a linear sensor; meaning as
pressure changes, voltage changes proportionately.
The range of voltage output from the sensor is usu-
ally between 4.6 volts at sea level to as low as 0.3
volts at 26 in. of Hg. Barometric pressure is the pres-
sure exerted by the atmosphere upon an object. At
sea level on a standard day, no storm, barometric
pressure is approximately 29.92 in Hg. For every 100
feet of altitude, barometric pressure drops .10 in. Hg.
If a storm goes through it can change barometric
pressure from what should be present for that alti-
tude. You should know what the average pressure
and corresponding barometric pressure is for your
area.
REMOVAL
REMOVAL - 4.0L
The MAP sensor is mounted to the side of the
throttle body (Fig. 40). An L-shaped rubber fitting is
used to connect the MAP sensor to throttle body (Fig.
31).
(1) Remove air cleaner duct and air resonator box
at throttle body.
14 - 48 FUEL INJECTIONWJ