2002 JEEP LIBERTY Jb power

INSTALLATION
2.4L
The intake manifold air temperature (IAT) sensor
is installed into the intake manifold plenum at the
rear end of the intake manifold.
(1) Check condition of sensor o-ring.
(2) Clean sensor mounting hole in intake manifold.
(3) Position sensor into intake manifold and rotate
clockwise until past release tab.
(4) Install electrical connector.
3.7L
The intake manifold air temperature (IAT) sensor
is installed into the left side of intake manifold ple-
num (Fig. 16).
(1) Check condition of sensor o-ring.
(2) Clean sensor mounting hole in intake manifold.
(3) Position sensor into intake manifold and rotate
clockwise until past release tab (Fig. 16).
(4) Install electrical connector.
MAP SENSOR
DESCRIPTION
2.4L
The Manifold Absolute Pressure (MAP) sensor is
mounted into the rear of the intake manifold with 1
screw.
3.7L
The Manifold Absolute Pressure (MAP) sensor is
mounted into the front of the intake manifold with 2
screws.
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 a
very 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.
14 - 38 FUEL INJECTIONKJ
INTAKE AIR TEMPERATURE SENSOR (Continued)

INSTALLATION
2.4L
The Manifold Absolute Pressure (MAP) sensor is
mounted into the rear of the intake manifold. An
o-ring is used to seal the sensor to the intake mani-
fold (Fig. 19).
(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 screws. Tighten
screw to 3 N´m (25 in. lbs.) torque.
(5) Connect electrical connector.
3.7L
The Manifold Absolute Pressure (MAP) sensor is
mounted into the front of the intake manifold (Fig.
18). An o-ring is used to seal the sensor to the intake
manifold (Fig. 19).
(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.
OXYGEN SENSOR
DESCRIPTION
The Oxygen Sensors (O2S) are attached to, and
protrude into the vehicle exhaust system. Depending
on the engine or emission package, the vehicle may
use a total of either 2 or 4 sensors.
2.4L Engine:Two sensors are used: upstream
(referred to as 1/1) and downstream (referred to as
1/2). With this emission package, the upstream sen-
sor (1/1) is located just before the main catalytic con-
vertor. The downstream sensor (1/2) is located just
after the main catalytic convertor.
3.7L V-6 Engine:On this emissions package, 4
sensors are used: 2 upstream (referred to as 1/1 and
2/1) and 2 downstream (referred to as 1/2 and 2/2).
With this emission package, the right upstream sen-
sor (2/1) is located in the right exhaust downpipe just
before the mini-catalytic convertor. The left upstream
sensor (1/1) is located in the left exhaust downpipe
just before the mini-catalytic convertor. The right
downstream sensor (2/2) is located in the right
exhaust downpipe just after the mini-catalytic con-
vertor, and before the main catalytic convertor. The
left downstream sensor (1/2) is located in the left
exhaust downpipe just after the mini-catalytic con-
vertor, and before the main catalytic convertor.
OPERATION
An O2 sensor is a galvanic battery that provides
the PCM with a voltage signal (0-1 volt) inversely
proportional to the amount of oxygen in the exhaust.
In other words, if the oxygen content is low, the volt-
age output is high; if the oxygen content is high the
output voltage is low. The PCM uses this information
to adjust injector pulse-width to achieve the
14.7±to±1 air/fuel ratio necessary for proper engine
operation and to control emissions.
The O2 sensor must have a source of oxygen from
outside of the exhaust stream for comparison. Cur-
rent O2 sensors receive their fresh oxygen (outside
air) supply through the O2 sensor case housing.
Four wires (circuits) are used on each O2 sensor: a
12±volt feed circuit for the sensor heating element; a
ground circuit for the heater element; a low-noise
sensor return circuit to the PCM, and an input cir-
cuit from the sensor back to the PCM to detect sen-
sor operation.
Oxygen Sensor Heater Relay - 3.7L Engine:On
the 3.7L engine, 4 heated oxygen sensors are used. A
separate oxygen sensor relay is used to supply volt-
age to the sensors heating elements for only the 1/2
and 2/2 downstream sensors. Voltage for the other 2
sensor heating elements is supplied directly from the
Powertrain Control Module (PCM) through a Pulse
Width Module (PWM) method.
Pulse Width Module (PWM):Voltage to the O2
sensor heating elements is supplied directly from the
Powertrain Control Module (PCM) through two sepa-
rate Pulse Width Module (PWM) low side drivers.
PWM is used on both the upstream and downstream
O2 sensors on the 2.4L engine, and only on the 2
upstream sensors (1/1 and 2/1) on the 3.7L engine.
The main objective for a PWM driver is to avoid over-
heating of the O2 sensor heater element. With
exhaust temperatures increasing with time and
engine speed, it's not required to have a full-voltage
duty-cycle on the O2 heater elements.
To avoid the large simultaneous current surge
needed to operate all 4 sensors, power is delayed to
the 2 downstream heater elements by the PCM for
approximately 2 seconds.
Oxygen Sensor Heater Elements:
The O2 sensor uses a Positive Thermal Co-efficient
(PTC) heater element. As temperature increases,
resistance increases. At ambient temperatures
around 70ÉF, the resistance of the heating element is
approximately 4.5 ohms. As the sensor's temperature
increases, resistance in the heater element increases.
This allows the heater to maintain the optimum
operating temperature of approximately 930É-1100ÉF
(500É-600É C). Although the sensors operate the
same, there are physical differences, due to the envi-
14 - 40 FUEL INJECTIONKJ
MAP SENSOR (Continued)

WARNING: THE EXHAUST MANIFOLD, EXHAUST
PIPES AND CATALYTIC CONVERTER BECOME
VERY HOT DURING ENGINE OPERATION. ALLOW
ENGINE TO COOL BEFORE REMOVING OXYGEN
SENSOR.
(1) Raise and support vehicle.
(2) Disconnect wire connector from O2S sensor.
CAUTION: When disconnecting sensor electrical
connector, do not pull directly on wire going into
sensor.
(3) Remove O2S sensor with an oxygen sensor
removal and installation tool.
(4) Clean threads in exhaust pipe using appropri-
ate tap.
INSTALLATION
Threads of new oxygen sensors are factory coated
with anti-seize compound to aid in removal.DO
NOT add any additional anti-seize compound to
threads of a new oxygen sensor.
(1) Install O2S sensor. Tighten to 30 N´m (22 ft.
lbs.) torque.
(2) Connect O2S sensor wire connector.
(3) Lower vehicle.
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
2.4L
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 tube at throttle body.
(2) Disconnect throttle body electrical connectors
at IAC motor and TPS.
(3) Remove all control cables from throttle body
(lever) arm. Refer to the Accelerator Pedal and Throt-
tle Cable section for removal/installation procedures.
(4) Disconnect necessary vacuum lines at throttle
body.
(5) Remove 3 throttle body mounting bolts (Fig.
23).
(6) Remove throttle body from intake manifold.
(7) Check condition of old throttle body-to-intake
manifold o-ring.
3.7L
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 tube at throttle body.
(2) Disconnect throttle body electrical connectors
at IAC motor and TPS.
Fig. 23 THROTTLE BODY MOUNTING BOLTS - 2.4L
1 - THROTTLE BODY
2 - IGNITION COIL
3 - MOUNTING BOLTS (3)
KJFUEL INJECTION 14 - 43
OXYGEN SENSOR (Continued)

THROTTLE POSITION SENSOR
DESCRIPTION
The 3±wire Throttle Position Sensor (TPS) is
mounted on the throttle body and is connected to the
throttle blade shaft.
OPERATION
The 3±wire TPS 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 output voltage 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)
REMOVAL
2.4L
The Throttle Position Sensor (TPS) is mounted to
the throttle body (Fig. 31).
(1) Disconnect TPS electrical connector.
(2) Remove 2 TPS mounting screws.
(3) Remove TPS.
Fig. 31 TPS/IAC MOTOR - 2.4L
1 - THROTTLE POSITION SENSOR (TPS)
2 - MOUNTING SCREWS
3 - IDLE AIR CONTROL MOTOR (IAC)
4 - MOUNTING SCREWS
KJFUEL INJECTION 14 - 47

STEERING
TABLE OF CONTENTS
page page
STEERING
DESCRIPTION..........................1
OPERATION............................1
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - POWER
STEERING SYSTEM....................1DIAGNOSIS AND TESTING - POWER
STEERING FLOW AND PRESSURE........3
COLUMN...............................5
GEAR.................................13
LINKAGE..............................16
PUMP.................................17
STEERING
DESCRIPTION
Power steering systems consist of:
²Steering column & Intermediate Shaft
²Rack and pinion steering gear
²Belt driven hydraulic steering pump
²Pump pressure, supply and return hoses
²Oil Cooler
OPERATION
The steering column intermediate shaft attaches
the steering column to the gear pinion. The rotation
of the pinion moves the gear rack from side-to-side.
This lateral action of the rack pushes and pulls the
tie rods to change the direction of the front wheels.
Power assist is provided by an engine mounted
hydraulic pump. The pump supplies hydraulic fluid
to the steering gear. All vehicles are equipped with
an oil cooler.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - POWER STEERING SYSTEM
STEERING NOISE
There is some noise in all power steering systems. One of the most common is a hissing sound evident at a
standstill/parking, or when the steering is at the end of it's travel. Hiss is a high frequency noise similar to that
of a water tap being closed slowly. The noise is present in all valves that have a high velocity fluid passing through
an orifice. There is no relationship between this noise and steering performance.
CONDITION POSSIBLE CAUSES CORRECTION
OBJECTIONAL HISS OR
WHISTLE1. Steering intermediate shaft to dash panel
seal.1. Check and repair seal at dash
panel.
2. Noisy valve in power steering gear. 2. Replace steering gear.
1. Gear mounting bolts loose. 1. Tighten bolts to specification.
2. Loose or damaged suspension
components.2. Inspect and repair suspension.
3. Internal gear noise. 3. Replace steering gear.
4. Loose or damaged intermediate shaft or
column.4. Inspect and repair or replace.
MOAN Pressure hose in contact with other
components.Reposition hose.
CHIRP OR SQUEAL 1. Loose belt. 1. Adjust or replace.
KJSTEERING 19 - 1

LOOSE STEERING AND VEHICLE LEAD
CONDITION POSSIBLE CAUSE CORRECTION
EXCESSIVE PLAY IN STEERING
WHEEL1. Worn or loose suspension or
steering components.1. Inspect and repair as necessary.
2. Worn or loose wheel bearings. 2. Inspect and replace bearings.
3. Steering gear mounting. 3. Tighten / replace gear mounting
bolts/ isolators to specification.
4. Gear out of adjustment. 4. Replace gear.
5. Worn or loose steering
intermediate shaft.5. Inspect and replace as
necessary.
VEHICLE PULLS, DRIFTS OR
LEADS TO ONE SIDE.1. Tire Pressure. 1. Adjust tire pressure.
2. Radial tire lead. 2. Rotate tires.
3. Brakes dragging. 3. Repair as necessary.
4. Wheel alignment. 4. Align front end.
DIAGNOSIS AND TESTING - POWER STEERING
FLOW AND PRESSURE
The following procedure is used to test the opera-
tion of the power steering system on the vehicle. This
test will provide the gallons per minute (GPM) or
flow rate of the power steering pump along with the
maximum relief pressure. Perform test any time a
power steering system problem is present. This test
will determine if the power steering pump or power
steering gear is not functioning properly. The follow-
ing pressure and flow test is performed using Power
Steering Analyzer Tool kit 6815 and (Fig. 1) Adapter
Kit 6893.
FLOW AND PRESSURE TEST
(1) Check the power steering belt to ensure it is in
good condition and adjusted properly.
(2) Connect pressure gauge hose from the Power
Steering Analyzer to Tube 6844.
(3) Connect Adapter 6826 to Power Steering Ana-
lyzer test valve end.
(4) Disconnect the high pressure hose from the
power steering pump.
(5) Connect the tube to the pump hose fitting.
(6) Connect the power steering hose from the
steering gear to the adapter.
(7) Open the test valve completely.
(8) Start engine and let idle long enough to circu-
late power steering fluid through flow/pressure test
gauge and to get air out of the fluid. Then shut off
engine.
(9) Check fluid level, add fluid as necessary. Start
engine again and let idle.
(10) Check for air bubbles, Evacuate if necessary
(11) Gauge should read below 862 kPa (125 psi), if
above, inspect the hoses for restrictions and repair as
necessary. The initial pressure reading should be in
the range of 345-552 kPa (50-80 psi).
(12) Increase the engine speed to 1500 RPM and
read the flow meter. If the flow rate (GPM) is below
specification, (refer to pump specification chart for
GPM) the pump should be replaced.
CAUTION: The following test procedure involves
testing maximum pump pressure output and flow
control valve operation. Do not leave valve closed
for more than three seconds as the pump could be
damaged.
Fig. 1 Analyzer With Tube and Adapter
1 - TUBE
2 - ADAPTER FITTINGS
3 - ANALYZER
4 - GAUGE HOSE
KJSTEERING 19 - 3
STEERING (Continued)

GEAR
TABLE OF CONTENTS
page page
GEAR
DESCRIPTION.........................13
OPERATION...........................13
REMOVAL
REMOVAL - 4WD......................13
REMOVAL - 2WD......................14
INSTALLATION
INSTALLATION - 4WD..................14INSTALLATION - 2WD..................14
SPECIFICATIONS
TORQUE CHART......................15
SPECIAL TOOLS
OUTER TIE ROD END REMOVAL TOOL....15
GEAR
DESCRIPTION
A rack and pinion steering gear (Fig. 1) is made up
of two main components, the pinon shaft and the
rack. The gear cannot be adjusted or internally ser-
viced. If a malfunction or a fluid leak occurs, the gear
must be replaced as an assembly.
OPERATION
The steering column intermediate shaft is attached
to the gear pinion. The rotation of the pinion moves
the gear rack from side-to-side. This lateral action of
the rack pushes and pulls the tie rods, which are
connected to the steering knuckles to change the
direction of the front wheels.
REMOVAL
REMOVAL - 4WD
(1) Siphon the power steering fluid from the power
steering reservoir.
(2) Lock the steering wheel to prevent spinning of
the clockspring.
(3) Raise and support the vehicle.
(4) Remove the skid plate from under the front
end to gain access to the gear (Refer to 13 - FRAME
& BUMPERS/FRAME/FRONT SKID PLATE -
REMOVAL).
(5) Remove the front tire and wheel assemblies.
NOTE: Mark the alignment adjusting cams for eas-
ier installation.
(6) Remove the lower control arms. (Refer to 2 -
SUSPENSION/FRONT/LOWER CONTROL ARM -
REMOVAL).
(7) Remove the front axle. (Refer to 3 - DIFFER-
ENTIAL & DRIVELINE/FRONT AXLE - REMOV-
AL).
(8) Remove the tie rod end nuts.
(9) Separate tie rod ends from the knuckles with
Puller C-3894-A.
(10) Remove the intermediate shaft lower coupler
bolt and slide the coupler off the gear (Fig. 2).
(11) Remove power steering pressure hose bracket
(Fig. 3).
(12) Remove the power steering lines from the
gear (Fig. 2).
(13) Remove the mounting bolts from the gear to
the front cradle (Fig. 3).
(14) Remove the steering gear from the vehicle.
Fig. 1 Rack & Pinion Steering Gear
1 - TIE ROD - INNER
2 - TIE ROD - INNER
3 - TIE ROD END - OUTER LH
4 - BOOTS
5 - TIE ROD END - OUTER RH
KJGEAR 19 - 13

REMOVAL - 2WD
(1) Siphon the power steering fluid from the power
steering reservoir.
(2) Lock the steering wheel to prevent spinning of
the clockspring.
(3) Raise and support the vehicle.
(4) Remove the skid plate from under the front
end to gain access to the gear(Refer to 13 - FRAME
& BUMPERS/FRAME/FRONT SKID PLATE -
REMOVAL).
(5) Remove the tire and wheel assembly.
NOTE: Mark the alignment adjusting cams and tie
rod end jam nuts on the steering gear for easier
installation.
(6) Remove the tie rod end nuts.
(7) Separate tie rod ends from the knuckles with
Puller C-3894-A.
(8) Remove the lower intermediate shaft coupler
bolt and slide the coupler off the gear (Fig. 2).(9) Remove power steering pressure hose bracket
(Fig. 3).
(10) Remove the power steering lines from the
gear (Fig. 2).
(11) Remove the mounting bolts from the gear to
the front cradle (Fig. 3).
(12) Remove the steering gear from the vehicle.
INSTALLATION
INSTALLATION - 4WD
(1) Transfer the tie rod ends to the new steering
gear (if needed).
(2) Install the steering gear to the vehicle.
(3) Install the gear mounting bolts to the front cra-
dle. (Fig. 3). Tighten the gear mounting bolts to 162
N´m (120 ft.lbs.)
(4) Install the power steering lines to the gear
(Fig. 2).
(5) Install the power steering pressure hose
bracket (Fig. 3).
(6) Install the lower coupler bolt and slide the cou-
pler on to the gear (Fig. 2).
(7) Install the tie rod end to the knuckle and
tighten the nuts.
(8) Install the front axle. (Refer to 3 - DIFFEREN-
TIAL & DRIVELINE/FRONT AXLE - INSTALLA-
TION).
(9) Install the lower control arms. (Refer to 2 -
SUSPENSION/FRONT/LOWER CONTROL ARM -
INSTALLATION).
(10) Install the tire and wheel assembly. (Refer to
22 - TIRES/WHEELS/WHEELS - STANDARD PRO-
CEDURE).
(11) Install the skid plate (Refer to 13 - FRAME &
BUMPERS/FRAME/FRONT SKID PLATE - INSTAL-
LATION).
(12) Lower the vehicle.
(13) Unlock the steering wheel.
(14) Fill the power steering fluid (Refer to 19 -
STEERING/PUMP - STANDARD PROCEDURE).
(15) Reset the toe and center the steering wheel
(Refer to 2 - SUSPENSION/WHEEL ALIGNMENT -
STANDARD PROCEDURE).
INSTALLATION - 2WD
(1) Transfer the outer tie rod ends to the new
steering gear (if needed).
(2) Install the steering gear to the vehicle.
(3) Install the gear mounting bolts to the front cra-
dle. (Fig. 3). Tighten the gear mounting bolts to 162
N´m (120 ft.lbs.)
(4) Install the power steering lines to the gear
(Fig. 2).
Fig. 2 COUPLER BOLT
Fig. 3 RACK & PINION
19 - 14 GEARKJ
GEAR (Continued)