throttle position sensor JEEP GRAND CHEROKEE 2003 WJ / 2.G Owner's Guide

(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)

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

(2) Remove two MAP sensor mounting bolts
(screws) (Fig. 31).
(3) While removing MAP sensor, slide the rubber
L-shaped fitting (Fig. 31) from the throttle body.
(4) Remove rubber L-shaped fitting from MAP sen-
sor.
REMOVAL - 4.7L
The MAP sensor is located on the front of the
intake manifold (Fig. 32). An o-ring seals the sensor
to the intake manifold.
(1) Disconnect electrical connector at sensor.
(2) Clean area around MAP sensor.
(3) Remove 2 sensor mounting bolts (Fig. 32).
(4) Remove MAP sensor from intake manifold.
INSTALLATION
INSTALLATION - 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) Install rubber L-shaped fitting to MAP sensor.
(2) Position sensor to throttle body while guiding
rubber fitting over throttle body vacuum nipple.
(3) Install MAP sensor mounting bolts (screws).
Tighten screws to 3 N´m (25 in. lbs.) torque.
(4) Install air cleanerduct/air box.
INSTALLATION - 4.7L
The MAP sensor is located on the front of the
intake manifold (Fig. 32). An o-ring seals the sensor
to the intake manifold.
(1) Clean MAP sensor mounting hole at intake
manifold.
(2) Check MAP sensor o-ring seal for cuts or tears.
(3) Position sensor into manifold.
(4) Install MAP sensor mounting bolts (screws).
Tighten screws to 3 N´m (25 in. lbs.) torque.
(5) Connect electrical connector.
O2S HEATER RELAY
DESCRIPTION
The 2 oxygen (O2) sensor heater relays (upstream
and downstream) are located in the Powertrain Dis-
tribution Center (PDC).
OPERATION
Engines equipped with the California (NAE) Emis-
sions Package usefour O2 sensors.
Two of the four sensor heater elements (upstream
sensors 1/1 and 2/1) are controlled by the upstream
heater relay through output signals from the Power-
train Control Module (PCM).
Fig. 31 Rubber L-Shaped FittingÐMAP Sensor-to-
Throttle BodyÐ4.0L Engine
1 - THROTTLE BODY
2 - MAP SENSOR
3 - RUBBER FITTING
4 - MOUNTING SCREWS (2)Fig. 32 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 - 49
MAP SENSOR (Continued)

THROTTLE BODY
DESCRIPTION
The throttle body is located on the intake manifold.
Fuel does not enter the intake manifold through the
throttle body. Fuel is sprayed into the manifold by
the fuel injectors.
OPERATION
Filtered air from the air cleaner enters the intake
manifold through the throttle body. The throttle body
contains an air control passage controlled by an Idle
Air Control (IAC) motor. The air control passage is
used to supply air for idle conditions. A throttle valve
(plate) is used to supply air for above idle conditions.
Certain sensors are attached to the throttle body.
The accelerator pedal cable, speed control cable and
transmission control cable (when equipped) are con-
nected to the throttle body linkage arm.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 PCM.
REMOVAL
REMOVAL - 4.0L
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 Powertrain Control Module (PCM).
(1) Remove air cleaner duct and air resonator box
at throttle body.
(2) Disconnect throttle body electrical connectors
at MAP sensor, IAC motor and TPS (Fig. 35).
Fig. 33 Oxygen Sensor LocationsÐ4.0L Engine
14 - 52 FUEL INJECTIONWJ
O2S SENSOR (Continued)

(3) Remove all control cables from throttle body
(lever) arm. Refer to Accelerator Pedal and Throttle
Cable.
(4) Remove four throttle body mounting bolts.
(5) Remove throttle body from intake manifold.
(6) Discard old throttle body-to-intake manifold
gasket.
REMOVAL - 4.7L
(1) Remove the air duct and air resonator box at
throttle body.
(2) Disconnect throttle body electrical connectors
at IAC motor and TPS (Fig. 36).
(3) Remove vacuum line at throttle body.
(4) Remove all control cables from throttle body
(lever) arm. Refer to Accelerator Pedal and Throttle
Cable.
(5) Remove three throttle body mounting bolts
(Fig. 36).
(6) Remove throttle body from intake manifold.
INSTALLATION
INSTALLATION - 4.0L
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 Powertrain Control Module (PCM).
(1) Clean the mating surfaces of the throttle body
and the intake manifold.
(2) Install new throttle body-to-intake manifold
gasket.
(3) Install throttle body to intake manifold.
(4) Install four mounting bolts. Tighten bolts to 11
N´m (100 in. lbs.) torque.
(5) Install control cables.
(6) Install electrical connectors.
(7) Install air duct and air box at throttle body.
Fig. 34 Oxygen Sensor LocationsÐ4.7L V-8 Engine
WJFUEL INJECTION 14 - 53
THROTTLE BODY (Continued)

(7) From inside vehicle, install clip holding cable
to dashpanel (Fig. 16).
(8) From inside vehicle, slide throttle cable core
wire into opening in top of pedal arm.
(9) Push cable retainer (clip) into pedal arm open-
ing until it snaps in place.
(10) Before starting engine, operate accelerator
pedal to check for any binding.
INSTALLATION - 4.7L
(1) Slide accelerator cable plastic mount into
bracket. Continue sliding until tab (Fig. 39) is
aligned to hole in mounting bracket.
(2) Route accelerator cable over top of cable cam.
(3) Connect cable end to throttle body bellcrank
pin (snaps on rearward).
(4) Slide rubber grommet away from plastic cable
housing.
(5) Install rubber grommet into dash panel until
seated.
(6) Push cable housing into rubber grommet and
through opening in dash panel.
(7) From inside vehicle, install clip holding cable
to dashpanel (Fig. 16).
(8) From inside vehicle, slide throttle cable core
wire into opening in top of pedal arm.(9) Push cable retainer (clip) into pedal arm open-
ing until it snaps in place.
(10) Snap cable into plenum routing clip.
(11) Install air box to throttle body.
(12) Before starting engine, operate accelerator
pedal to check for any binding.
THROTTLE POSITION SENSOR
DESCRIPTION
The 3±wire Throttle Position Sensor (TPS) is
mounted on the throttle body and is connected to the
throttle blade.
OPERATION
The TPS is a 3±wire variable resistor that provides
the Powertrain Control Module (PCM) with an input
signal (voltage) that represents the throttle blade
position of the throttle body. The sensor is connected
to the throttle blade shaft. As the position of the
throttle blade changes, the resistance (output volt-
age) of the TPS changes.
The PCM supplies approximately 5 volts to the
TPS. The TPS output voltage (input signal to the
PCM) represents the throttle blade position. The
PCM receives an input signal voltage from the TPS.
This will vary in an approximate range of from .26
volts at minimum throttle opening (idle), to 4.49 volts
at wide open throttle. Along with inputs from other
sensors, the PCM uses the TPS input to determine
current engine operating conditions. In response to
engine operating conditions, the PCM will adjust fuel
injector pulse width and ignition timing.
The PCM needs to identify the actions and position
of the throttle blade at all times. This information is
needed to assist in performing the following calcula-
tions:
²Ignition timing advance
²Fuel injection pulse-width
²Idle (learned value or minimum TPS)
²Off-idle (0.06 volt)
²Wide Open Throttle (WOT) open loop (2.608
volts above learned idle voltage)
²Deceleration fuel lean out
²Fuel cutoff during cranking at WOT (2.608 volts
above learned idle voltage)
²A/C WOT cutoff (certain automatic transmis-
sions only)
Fig. 39 Accelerator Cable Release TabÐ4.7L V-8
Engine
1 - ACCELERATOR CABLE
2 - PLASTIC CABLE MOUNT
3 - PRESS TAB FOR REMOVAL
4 - CABLE BRACKET
5 - SLIDE FOR REMOVAL
14 - 56 FUEL INJECTIONWJ
THROTTLE CONTROL CABLE (Continued)

REMOVAL
REMOVAL - 4.0L
The TPS is mounted to the throttle body.
(1) Disconnect TPS electrical connector (Fig. 40).
(2) Remove TPS mounting screws (Fig. 41).
(3) Remove TPS.
REMOVAL - 4.7L
The TPS is located on the throttle body.
(1) Remove air duct and air resonator box at throt-
tle body.
(2) Disconnect TPS electrical connector (Fig. 36).
(3) Remove two TPS mounting bolts (screws) (Fig.
42).
(4) Remove TPS from throttle body.
Fig. 40 TPS Electrical ConnectorÐ4.0L 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.
Fig. 41 TPS Mounting ScrewsÐ4.0L Engine
1 - MOUNTING SCREWS
2 - TPS
Fig. 42 TPS Mounting BoltsÐ4.7L V±8
1 - THROTTLE BODY
2 - TPS
3 - IAC MOTOR
4 - IAT SENSOR (THREADED TYPE)
5 - MOUNTING SCREWS
WJFUEL INJECTION 14 - 57
THROTTLE POSITION SENSOR (Continued)

INSTALLATION
INSTALLATION - 4.0L
The TPS is mounted to the throttle body.
The throttle shaft end of throttle body slides into a
socket in the TPS (Fig. 43). The TPS must be
installed so that it can be rotated a few degrees. (If
sensor will not rotate, install sensor with throttle
shaft on other side of socket tangs). The TPS will be
under slight tension when rotated.
(1) Install TPS and retaining screws.
(2) Tighten screws to 7 N´m (60 in. lbs.) torque.
(3) Connect TPS electrical connector to TPS.
(4) Manually operate throttle (by hand) to check
for any TPS binding before starting engine.
INSTALLATION - 4.7L
The throttle shaft end of throttle body slides into a
socket in TPS (Fig. 44). The TPS must be installed so
that it can be rotated a few degrees. If sensor will
not rotate, install sensor with throttle shaft on other
side of socket tangs. The TPS will be under slight
tension when rotated.
(1) Install TPS and two retaining bolts.
(2) Tighten bolts to 7 N´m (60 in. lbs.) torque.
(3) Manually operate throttle control lever by hand
to check for any binding of TPS.
(4) Connect TPS electrical connector to TPS.
(5) Install air duct/air box to throttle body.
Fig. 43 Throttle Position Sensor InstallationÐ4.0L
Engine
1 - TANGS
2 - THROTTLE SHAFT
3 - THROTTLE BODY
4 - TPS
Fig. 44 TPS InstallationÐ4.7L
1 - THROTTLE BODY
2 - LOCATING TANGS
3 - THROTTLE POSITION SENSOR
4 - SOCKET
5 - THROTTLE SHAFT
14 - 58 FUEL INJECTIONWJ
THROTTLE POSITION SENSOR (Continued)

STANDARD PROCEDURE - FLUID AND
FILTER REPLACEMENT................71
STANDARD PROCEDURE - TRANSMISSION
FILL................................72
FRONT CLUTCH
DESCRIPTION.........................73
OPERATION...........................74
DISASSEMBLY.........................74
INSPECTION..........................74
ASSEMBLY............................74
FRONT SERVO
DESCRIPTION.........................77
OPERATION...........................77
DISASSEMBLY.........................77
CLEANING............................77
INSPECTION..........................77
ASSEMBLY............................77
GEARSHIFT CABLE
DIAGNOSIS AND TESTING - GEARSHIFT
CABLE..............................78
REMOVAL.............................78
INSTALLATION.........................79
ADJUSTMENTS - GEARSHIFT CABLE.......79
OIL PUMP
DESCRIPTION.........................80
OPERATION...........................80
STANDARD PROCEDURE - OIL PUMP
VOLUME CHECK......................81
DISASSEMBLY.........................81
CLEANING............................83
INSPECTION..........................83
ASSEMBLY............................83
OUTPUT SHAFT FRONT BEARING
REMOVAL.............................85
INSTALLATION.........................85
OUTPUT SHAFT REAR BEARING
REMOVAL.............................85
INSTALLATION.........................85
OVERDRIVE CLUTCH
DESCRIPTION.........................86
OPERATION...........................86
OVERDRIVE OFF SWITCH
DESCRIPTION.........................86
OPERATION...........................86
DIAGNOSIS AND TESTING - OVERDRIVE
ELECTRICAL CONTROLS...............87
OVERDRIVE UNIT
REMOVAL.............................87
DISASSEMBLY.........................88
CLEANING............................95
INSPECTION..........................95
ASSEMBLY............................95
INSTALLATION........................104
OVERRUNNING CLUTCH CAM/OVERDRIVE
PISTON RETAINER
DESCRIPTION........................105
OPERATION..........................105DISASSEMBLY........................106
CLEANING...........................106
INSPECTION.........................106
ASSEMBLY...........................106
PARK LOCK CABLE
REMOVAL............................108
INSTALLATION........................108
PARK/NEUTRAL POSITION SWITCH
DIAGNOSIS AND TESTING - PARK/NEUTRAL
POSITION SWITCH...................109
REMOVAL............................109
INSTALLATION........................109
PISTONS
DESCRIPTION........................110
OPERATION..........................110
PLANETARY GEARTRAIN/OUTPUT SHAFT
DESCRIPTION........................112
OPERATION..........................112
DISASSEMBLY........................112
INSPECTION..........................113
ASSEMBLY...........................113
REAR CLUTCH
DESCRIPTION........................118
OPERATION..........................118
DISASSEMBLY........................119
CLEANING...........................119
INSPECTION.........................120
ASSEMBLY...........................120
REAR SERVO
DESCRIPTION........................122
OPERATION..........................122
DISASSEMBLY........................122
CLEANING...........................122
ASSEMBLY...........................123
SHIFT MECHANISM
DESCRIPTION........................123
OPERATION..........................123
REMOVAL............................123
INSTALLATION........................125
SOLENOID
DESCRIPTION........................125
OPERATION..........................126
SPEED SENSOR
DESCRIPTION........................126
OPERATION..........................126
THROTTLE VALVE CABLE
DESCRIPTION........................126
ADJUSTMENTS - TRANSMISSION THROTTLE
VALVE CABLE.......................126
TORQUE CONVERTER
DESCRIPTION........................128
OPERATION..........................132
REMOVAL............................133
INSTALLATION........................133
TORQUE CONVERTER DRAINBACK VALVE
DESCRIPTION........................134
OPERATION..........................134
21 - 2 AUTOMATIC TRANSMISSION - 42REWJ