Crank sensor wiring JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual

INSTALLATION
(1) Install the MHSM,HSM into the bracket.
(2) Position the heated seat module and mounting
bracket onto the power seat track.
(3) Reconnect the power seat wiring harness con-
nectors to the heated seat module.
(4) Install the driver side front bucket seat onto
the power seat track unit (Refer to 23 - BODY/
SEATS/SEAT TRACK ADJUSTER - INSTALLA-
TION).
(5) Reconnect the battery negative cable.
NOTE: If the vehicle is equipped with the optional
Memory System, following installation, it will be
necessary to initialize the Memory Heated Seat
Module (MHSM). In order to function properly, the
MHSM must ªlearnº the sensor values of each of
the power seat motor position transducers in each
of the adjuster hard stop positions. This is done by
performing the ªReset Guard Bandº procedure
using a DRBIIITscan tool and the proper Diagnostic
Procedures manual.
WARNING: THE ªRESET GUARD BANDº PROCE-
DURE WILL CAUSE THE DRIVER SIDE FRONT
SEAT TO AUTOMATICALLY ADJUST TO EACH OF
ITS TRAVEL LIMITS. BE CERTAIN THAT NO ONE IS
SEATED IN THE VEHICLE AND THAT THERE IS
NOTHING IN THE VEHICLE THAT WILL OBSTRUCT
SEAT MOVEMENT. FAILURE TO OBSERVE THIS
WARNING COULD RESULT IN PERSONAL INJURIES
AND/OR VEHICLE DAMAGE.
POWERTRAIN CONTROL
MODULE
DESCRIPTION
DESCRIPTION - PCM
The Powertrain Control Module (PCM) is located
in the engine compartment (Fig. 11). The PCM is
referred to as JTEC.
MODES OF OPERATION
As input signals to the Powertrain Control Module
(PCM) change, the PCM adjusts its response to the
output devices. For example, the PCM must calculate
different injector pulse width and ignition timing for
idle than it does for wide open throttle (WOT).
The PCM will operate in two different modes:
Open Loop and Closed Loop.
During Open Loop modes, the PCM receives input
signals and responds only according to preset PCMprogramming. Input from the oxygen (O2S) sensors
is not monitored during Open Loop modes.
During Closed Loop modes, the PCM will monitor
the oxygen (O2S) sensors input. This input indicates
to the PCM whether or not the calculated injector
pulse width results in the ideal air-fuel ratio. This
ratio is 14.7 parts air-to-1 part fuel. By monitoring
the exhaust oxygen content through the O2S sensor,
the PCM can fine tune the injector pulse width. This
is done to achieve optimum fuel economy combined
with low emission engine performance.
The fuel injection system has the following modes
of operation:
²Ignition switch ON
²Engine start-up (crank)
²Engine warm-up
²Idle
²Cruise
²Acceleration
²Deceleration
²Wide open throttle (WOT)
²Ignition switch OFF
The ignition switch On, engine start-up (crank),
engine warm-up, acceleration, deceleration and wide
open throttle modes are Open Loop modes. The idle
and cruise modes, (with the engine at operating tem-
perature) are Closed Loop modes.
IGNITION SWITCH (KEY-ON) MODE
This is an Open Loop mode. When the fuel system
is activated by the ignition switch, the following
actions occur:
Fig. 11 PCM Location
1 - PCM
2 - COOLANT TANK
8E - 12 ELECTRONIC CONTROL MODULESWJ
MEMORY HEATED SEAT/MIRROR MODULE (Continued)

²Front Check Valve- The front washer system
check valve is integral to the wye fitting located in
the washer plumbing between the cowl plenum
washer hose and the front washer nozzles, and is
concealed beneath the cowl plenum cover/grille panel
at the base of the windshield.
²Front Washer Nozzle- Two fluidic front
washer nozzles are secured with integral snap fea-
tures to dedicated openings in the cowl plenum cover/
grille panel located near the base of the windshield.
²Front Washer Plumbing- The plumbing for
the front washer system consists of rubber hoses and
molded plastic fittings. The plumbing is routed along
the left side of the engine compartment from the
washer reservoir, and through the dash panel into
the cowl plenum to the front washer nozzle fittings
beneath the cowl plenum cover/grille panel.
²Front Washer Pump/Motor- The front washer
pump/motor unit is located in a dedicated hole on the
lower outboard side of the washer reservoir, behind
the inner fender liner ahead of the left front wheel.
The front washer pump is located ahead of and below
the rear washer pump.
²Front Wiper Arm- The two front wiper arms
are secured with nuts to the threaded studs on the
ends of the two wiper pivot shafts, which extend
through the cowl plenum cover/grille panel located
near the base of the windshield.
²Front Wiper Blade- The two front wiper
blades are secured to the two front wiper arms with
an integral latch, and are parked on the glass near
the bottom of the windshield when the front wiper
system is not in operation.
²Front Wiper Module- The front wiper pivot
shafts are the only visible components of the front
wiper module. The remainder of the module is con-
cealed within the cowl plenum beneath the cowl ple-
num cover/grille panel. The front wiper module
includes the module bracket, four rubber-isolated
wiper module mounts, the front wiper motor, the
wiper motor crank arm, the two wiper drive links,
and the two front wiper pivots.
²Rain Sensor Module- Models equipped with
the optional automatic wiper feature have a Rain
Sensor Module (RSM) located behind a trim cover on
a bracket bonded to the inside surface of the wind-
shield glass, just above the inside rear view mirror
mounting button.
²Right Multi-Function Switch- The right
(wiper) multi-function switch is secured to the right
side of the multi-function switch mounting housing
near the top of the steering column, just below the
steering wheel. Only the control stalk for the right
multi-function switch is visible, while the remainder
of the switch is concealed beneath the steering col-
umn shrouds. The right multi-function switch con-tains all of the switches and control circuitry for both
the front and rear wiper and washer systems.
²Washer Fluid Level Switch- The washer fluid
level switch is located in a dedicated hole near the
center of the forward surface of the washer reservoir,
behind the left front wheel house splash shield.
²Washer Reservoir- The washer reservoir is
concealed between the left inner fender shield and
the left outer fender panel, behind the inner fender
liner and ahead of the left front wheel. The washer
reservoir filler neck is the only visible portion of the
reservoir, and it is accessed from the left front corner
of the engine compartment.
²Wiper High-Low Relay- The wiper high-low
relay is an International Standards Organization
(ISO) micro relay located in the Power Distribution
Center (PDC) in the engine compartment near the
battery.
²Wiper On-Off Relay- The wiper on-off relay is
an International Standards Organization (ISO) micro
relay located in the Power Distribution Center (PDC)
in the engine compartment near the battery.
Hard wired circuitry connects the front wiper and
washer system components to the electrical system of
the vehicle. These hard wired circuits are integral to
several wire harnesses, which are routed throughout
the vehicle and retained by many different methods.
These circuits may be connected to each other, to the
vehicle electrical system and to the front wiper and
washer system components through the use of a com-
bination of soldered splices, splice block connectors,
and many different types of wire harness terminal
connectors and insulators. Refer to the appropriate
wiring information. The wiring information includes
wiring diagrams, proper wire and connector repair
procedures, further details on wire harness routing
and retention, as well as pin-out and location views
for the various wire harness connectors, splices and
grounds.
OPERATING MODES
The components of the front wiper and washer sys-
tem are designed to work in concert to provide the
following operating modes:
²Automatic Wiper- In models equipped with
the optional automatic wiper feature, the internal
circuitry of both the right (wiper) multi-function
switch, the rain sensor module, and the BCM work
in concert to provide an automatic wiper mode with
five sensitivity selections. The BCM tells the Rain
Sensor Module (RSM) when the automatic wiper
mode is selected and the manually selected sensitiv-
ity level, then the rain sensor module tells the BCM
each time enough water droplets have accumulated
within the wipe pattern on the windshield to require
front wiper operation. The BCM then automatically
WJFRONT WIPERS/WASHERS 8R - 3
FRONT WIPERS/WASHERS (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)

The sensor is a hall effect device combined with an
internal magnet. It is also sensitive to steel within a
certain distance from it.
On 4.0L 6-cylinder engines, the flywheel/drive
plate has 3 sets of four notches at its outer edge (Fig.
19).
The notches cause a pulse to be generated when
they pass under the sensor. The pulses are the input
to the PCM. For each engine revolution there are 3
sets of four pulses generated.
The trailing edge of the fourth notch, which causes
the pulse, is four degrees before top dead center
(TDC) of the corresponding piston.
The engine will not operate if the PCM does not
receive a crankshaft position sensor input.
OPERATION - 4.7L
Engine speed and crankshaft position are provided
through the crankshaft position sensor. The sensor
generates pulses that are the input sent to the pow-
ertrain control module (PCM). The PCM interprets
the sensor input to determine the crankshaft posi-
tion. The PCM then uses this position, along with
other inputs, to determine injector sequence and igni-
tion timing.
The sensor is a hall effect device combined with an
internal magnet. It is also sensitive to steel within a
certain distance from it.On the 4.7L V±8 engine, a tonewheel is bolted to
the engine crankshaft (Fig. 20). This tonewheel has
sets of notches at its outer edge (Fig. 20).
The notches cause a pulse to be generated when
they pass under the sensor. The pulses are the input
to the PCM.
REMOVAL
REMOVAL - 4.0L
The Crankshaft Position (CKP) sensor is mounted
to the transmission bellhousing at the left/rear side
of the engine block (Fig. 21). The sensoris adjust-
ableand is attached with one bolt. A wire shield/
router is attached to the sensor (Fig. 21).
(1) Disconnect sensor pigtail harness (3±way con-
nector) from main engine wiring harness.
(2) Remove sensor mounting bolt.
(3) Remove wire shield and sensor.
REMOVAL - 4.7L
The Crankshaft Position (CKP) sensor is bolted to
the side of the engine cylinder block above the
starter motor (Fig. 22). It is positioned into a
machined hole at the side of the engine block.
(1) Remove starter motor. Refer to Starter Remov-
al/Installation.
Fig. 19 CKP Sensor OperationÐ4.0L 6-Cyl. Engine
1 - CRANKSHAFT POSITION SENSOR
2 - FLYWHEEL
3 - FLYWHEEL NOTCHES
Fig. 20 CKP Sensor Operation and TonewheelÐ4.7L
V±8 Engine
1 - TONEWHEEL
2 - NOTCHES
3 - CRANKSHAFT POSITION SENSOR
4 - CRANKSHAFT
WJFUEL INJECTION 14 - 41
CRANKSHAFT POSITION SENSOR (Continued)

(5) Push sensor against flywheel/drive plate. With
sensor pushed against flywheel/drive plate, tighten
mounting bolt to 7 N´m (60 in. lbs.) torque.
(6) Route sensor wiring harness into wire shield.
(7) Connect sensor pigtail harness electrical con-
nector to main wiring harness.
INSTALLATION - 4.7L
(1) Clean out machined hole in engine block.
(2) Apply a small amount of engine oil to sensor
o-ring.
(3) Install sensor into engine block with a slight
rocking action. Do not twist sensor into position as
damage to o-ring may result.
CAUTION: Before tightening sensor mounting bolt,
be sure sensor is completely flush to cylinder
block. If sensor is not flush, damage to sensor
mounting tang may result.
(4) Install mounting bolt and tighten to 28 N´m
(21 ft. lbs.) torque.
(5) Connect electrical connector to sensor.
(6) Install starter motor. Refer to Starter Removal/
Installation.
FUEL INJECTOR
DESCRIPTION
A separate fuel injector (Fig. 24) is used for each
individual cylinder.
OPERATION
OPERATION
The fuel injectors are electrical solenoids. The
injector contains a pintle that closes off an orifice at
the nozzle end. When electric current is supplied to
the injector, the armature and needle move a short
distance against a spring, allowing fuel to flow out
the orifice. Because the fuel is under high pressure, a
fine spray is developed in the shape of a pencil
stream. The spraying action atomizes the fuel, add-
ing it to the air entering the combustion chamber.
The top (fuel entry) end of the injector (Fig. 24) is
attached into an opening on the fuel rail.
The nozzle (outlet) ends of the injectors are posi-
tioned into openings in the intake manifold just
above the intake valve ports of the cylinder head.
The engine wiring harness connector for each fuel
injector is equipped with an attached numerical tag
(INJ 1, INJ 2 etc.). This is used to identify each fuel
injector.
The injectors are electrically energized, individu-
ally and in a sequential order by the Powertrain Con-
trol Module (PCM). The PCM will adjust injector
pulse width by switching the ground path to each
individual injector on and off. Injector pulse width is
the period of time that the injector is energized. The
PCM will adjust injector pulse width based on vari-
ous inputs it receives.
Battery voltage is supplied to the injectors through
the ASD relay.
The PCM determines injector pulse width based on
various inputs.
OPERATION - PCM OUTPUT
The nozzle ends of the injectors are positioned into
openings in the intake manifold just above the intake
valve ports of the cylinder head. The engine wiring
harness connector for each fuel injector is equipped
with an attached numerical tag (INJ 1, INJ 2 etc.).
This is used to identify each fuel injector with its
respective cylinder number.
The injectors are energized individually in a
sequential order by the Powertrain Control Module
(PCM). The PCM will adjust injector pulse width by
switching the ground path to each individual injector
on and off. Injector pulse width is the period of time
that the injector is energized. The PCM will adjust
injector pulse width based on various inputs it
receives.
Battery voltage (12 volts +) is supplied to the injec-
tors through the ASD relay. The ASD relay will shut-
down the 12 volt power source to the fuel injectors if
the PCM senses the ignition is on, but the engine is
not running. This occurs after the engine has not
been running for approximately 1.8 seconds.
Fig. 24 Fuel InjectorÐ4.0L/4.7L Engines
1 - FUEL INJECTOR
2 - NOZZLE
3 - TOP (FUEL ENTRY)
WJFUEL INJECTION 14 - 43
CRANKSHAFT POSITION SENSOR (Continued)

PRESSURE TEST
Overdrive clutch Fourth gear only Pressure should be 469-496 kPa (68-72 psi) with
closed throttle and increase to 620-896 kPa (90-130
psi) at 1/2 to 3/4 throttle.
Line pressure (at
accumulator)Closed throttle 372-414 kPa (54-60 psi).
Front servo Third or Fourth gear only No more than 21 kPa (3 psi) lower than line pressure.
Rear servo 1 range No more than 21 kPa (3 psi) lower than line pressure.
R range 1103 kPa (160 psi) at idle, builds to 1862 kPa (270 psi)
at 1600 rpm.
Governor D range closed throttle Pressure should respond smoothly to changes in mph
and return to 0-7 kPa (0-1.5 psi) when stopped with
transmission in D, 1, 2. Pressure above 7 kPa (1.5 psi)
at stand still will prevent transmission from
downshifting.
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Fitting, cooler line at trans 18 13 -
Bolt, torque convertor 31 - 270
Bolt, clevis bracket to crossmember 47 35 -
Bolt, clevis bracket to rear support 68 50 -
Bolt, driveplate to crankshaft 75 55 -
Plug, front band reaction 17 13 -
Locknut, front band adj. 34 25 -
Switch, park/neutral 34 25 -
Bolt, fluid pan 17 13 -
Screws, fluid filter 4 - 35
Bolt, oil pump 20 15 -
Bolt, overrunning clutch cam 17 13 -
Bolt, O/D to trans. 34 25 -
Bolt, O/D piston retainer 17 13 -
Plug, pressure test port 14 10 -
Bolt, reaction shaft support 20 15 -
Locknut, rear band 41 30 -
Bolt, speedometer adapter 11 - 100
Screw, vehicle speed sensor 2.5 - 21
Bolt, valve body to case 12 - 100
Sensor, trans speed 27 20 -
Screw, solenoid wiring connector 4 - 35
Screw, solenoid to transfer plate 4 - 35
21 - 56 AUTOMATIC TRANSMISSION - 42REWJ
AUTOMATIC TRANSMISSION - 42RE (Continued)