2002 JEEP GRAND CHEROKEE throttle

STANDARD PROCEDURE
STANDARD PROCEDURE - TCM QUICK LEARN
The quick learn procedure requires the use of the
DRBIIItscan tool.
This program allows the electronic transmission
system to recalibrate itself. This will provide the
proper transmission operation. The quick learn pro-
cedure should be performed if any of the following
procedures are performed:
²Transmission Assembly Replacement
²Transmission Control Module Replacement
²Solenoid Pack Replacement
²Clutch Plate and/or Seal Replacement
²Valve Body Replacement or ReconditionTo perform the Quick Learn Procedure, the follow-
ing conditions must be met:
²The brakes must be applied
²The engine speed must be above 500 rpm
²The throttle angle (TPS) must be less than 3
degrees
²The shift lever position must stay in PARK until
prompted to shift to overdrive
²The shift lever position must stay in overdrive
after the Shift to Overdrive prompt until the DRBt
indicates the procedure is complete
²The calculated oil temperature must be above
60É and below 200É
8E - 22 ELECTRONIC CONTROL MODULESWJ
TRANSMISSION CONTROL MODULE (Continued)

OPERATION
Battery voltage is supplied to the 8 ignition coils
from the ASD relay. The Powertrain Control Module
(PCM) opens and closes each ignition coil ground cir-
cuit at a determined time for ignition coil operation.
Base ignition timing is not adjustable.By con-
trolling the coil ground circuit, the PCM is able to set
the base timing and adjust the ignition timing
advance. This is done to meet changing engine oper-
ating conditions.
The ignition coil is not oil filled. The windings are
embedded in an epoxy compound. This provides heat
and vibration resistance that allows the ignition coil
to be mounted on the engine.
Because of coil design, spark plug cables (second-
ary cables) are not used.
REMOVAL
An individual ignition coil is used for each spark
plug (Fig. 18). The coil fits into machined holes in the
cylinder head. A mounting stud/nut secures each coil
to the top of the intake manifold (Fig. 19). The bot-
tom of the coil is equipped with a rubber boot to seal
the spark plug to the coil. Inside each rubber boot is
a spring. The spring is used for a mechanical contact
between the coil and the top of the spark plug. These
rubber boots and springs are a permanent part of the
coil and are not serviced separately. An o-ring (Fig.
18) is used to seal the coil at the opening into the cyl-
inder head.
(1) Depending on which coil is being removed, the
throttle body air intake tube or intake box may need
to be removed to gain access to coil.
(2) Disconnect electrical connector (Fig. 19) from
coil by pushing downward on release lock on top of
connector and pull connector from coil.
(3) Clean area at base of coil with compressed air
before removal.
(4) Remove coil mounting nut from mounting stud
(Fig. 19).
(5) Carefully pull up coil from cylinder head open-
ing with a slight twisting action.
(6) Remove coil from vehicle.
INSTALLATION
(1) Using compressed air, blow out any dirt or con-
taminants from around top of spark plug.
(2) Check condition of coil o-ring and replace as
necessary. To aid in coil installation, apply silicone to
coil o-ring.
(3) Position ignition coil into cylinder head opening
and push onto spark plug. Do this while guiding coil
base over mounting stud.
(4) Install mounting stud nut and tighten to 8 N´m
(70 in. lbs.) torque.(5) Connect electrical connector to coil by snapping
into position.
(6) If necessary, install throttle body air tube or
box.
Fig. 18 Ignition CoilÐ4.7L V±8
1 - O-RING
2 - IGNITION COIL
3 - ELECTRICAL CONNECTOR
Fig. 19 Ignition Coil
1 - IGNITION COIL
2 - COIL ELECTRICAL CONNECTOR
3 - COIL MOUNTING STUD/NUT
8I - 12 IGNITION CONTROLWJ
IGNITION COIL (Continued)

The voltage signal produced by the knock sensor
increases with the amplitude of vibration. The PCM
receives the knock sensor voltage signal as an input.
If the signal rises above a predetermined level, the
PCM will store that value in memory and retard
ignition timing to reduce engine knock. If the knock
sensor voltage exceeds a preset value, the PCM
retards ignition timing for all cylinders. It is not a
selective cylinder retard.
The PCM ignores knock sensor input during engine
idle conditions. Once the engine speed exceeds a
specified value, knock retard is allowed.
Knock retard uses its own short term and long
term memory program.
Long term memory stores previous detonation
information in its battery-backed RAM. The maxi-
mum authority that long term memory has over tim-
ing retard can be calibrated.
Short term memory is allowed to retard timing up
to a preset amount under all operating conditions (as
long as rpm is above the minimum rpm) except at
Wide Open Throttle (WOT). The PCM, using short
term memory, can respond quickly to retard timing
when engine knock is detected. Short term memory
is lost any time the ignition key is turned off.
NOTE: Over or under tightening the sensor mount-
ing bolts will affect knock sensor performance, pos-
sibly causing improper spark control. Always use
the specified torque when installing the knock sen-
sors.
REMOVAL
4.7L High-Output Engine Only
The 2 knock sensors are bolted into the cylinder
block under the intake manifold (Fig. 22).
NOTE: The left sensor is identified by an identifica-
tion tag (LEFT). It is also identified by a larger bolt
head. The Powertrain Control Module (PCM) must
have and know the correct sensor left/right posi-
tions. Do not mix the sensor locations.
(1) Disconnect knock sensor dual pigtail harness
connector from engine wiring harness connector. This
connection is made near the right/rear of intake man-
ifold (Fig. 23).
(2) Remove intake manifold. Refer to Engine sec-
tion.
(3) Remove sensor mounting bolts (Fig. 22). Note
foam strip on bolt threads. This foam is used only to
retain the bolts to sensors for plant assembly. It is
not used as a sealant. Do not apply any adhesive,
sealant or thread locking compound to these bolts.
(4) Remove sensors from engine.
Fig. 22 KNOCK SENSOR LOCATION - 4.7L H.O.
1 - KNOCK SENSORS (2)
2 - MOUNTING BOLTS
3 - INTAKE MANIFOLD (CUTAWAY)
4 - PIGTAIL CONNECTOR
Fig. 23 KNOCK SENSOR ELEC. CONNECTOR - 4.7L
H.O.
1 - KNOCK SENSOR PIGTAIL HARNESS CONNECTOR
2 - ENGINE WIRING HARNESS
8I - 14 IGNITION CONTROLWJ
KNOCK SENSOR (Continued)

This vehicle also offers several customer program-
mable features, which allows the selection of several
optional electronic features to suit individual prefer-
ences. (Refer to 8 - ELECTRICAL/OVERHEAD CON-
SOLE/ELECTRONIC VEHICLE INFO CENTER -
DESCRIPTION). Customer programmable feature
options affecting the power door lock system include:
²Auto Door Locks- Automatically locks all of
the vehicle doors and the liftgate when the vehicle
reaches a speed of about 24 kilometers-per-hour (15
miles-per-hour) with 10% throttle tip-in.
²Auto Unlock on Exit- Automatically unlocks
all of the vehicle doors and the liftgate when the
driver side front door is opened, if the vehicle is
stopped and the transmission gear selector is in the
Park or Neutral positions. This feature is linked to
the Auto Door Locks feature, and will only occur one
time following each Auto Door Lock event.
The power lock system for this vehicle can also be
operated remotely using the standard equipment
Remote Keyless Entry (RKE) system radio frequency
transmitters. (Refer to 8 - ELECTRICAL/POWER
LOCKS - DESCRIPTION - REMOTE KEYLESS
ENTRY SYSTEM).
The components of the power lock system include:
²Driver Door Module (DDM)
²Passenger Door Module (PDM)
²PCI Bus Messages
²Power Lock Motors
Certain functions and features of the power lock
system rely upon resources shared with other elec-
tronic modules in the vehicle over the Programmable
Communications Interface (PCI) data bus network.
The PCI data bus network allows the sharing of sen-
sor information. This helps to reduce wire harness
complexity, internal controller hardware, and compo-
nent sensor current loads. At the same time, this sys-
tem provides increased reliability, enhanced
diagnostics, and allows the addition of many new fea-
ture capabilities. For proper diagnosis of these elec-
tronic modules or of the PCI data bus network, the
use of a DRBIIItscan tool and the appropriate diag-
nostic information are required.
The other electronic modules that may affect power
lock system operation are as follows:
²Body Control Module (BCM)- (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/BODY CONTROL/CENTRAL TIMER MOD-
ULE - DESCRIPTION).
²Electronic Vehicle Information Center
(EVIC)- (Refer to 8 - ELECTRICAL/OVERHEAD
CONSOLE/ELECTRONIC VEHICLE INFO CENTER
- DESCRIPTION).
²Powertrain Control Module (PCM)- (Refer
to 8 - ELECTRICAL/ELECTRONIC CONTROLMODULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION).
Hard wired circuitry connects the power lock sys-
tem components to the electrical system of the vehi-
cle. 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 power lock sys-
tem components through the use of a combination of
soldered splices, splice block connectors, and many
different types of wire harness terminal connectors
and insulators. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
further details on wire harness routing and reten-
tion, as well as pin-out and location views for the
various wire harness connectors, splices and grounds.
DESCRIPTION - REMOTE KEYLESS ENTRY
SYSTEM
A Radio Frequency (RF) type Remote Keyless
Entry (RKE) system is standard factory-installed
equipment on this model. The RKE system allows
the use of a remote battery-powered radio transmit-
ter to control the power lock system. The RKE
receiver operates on non-switched battery current
through a fuse in the Power Distribution Center
(PDC), so that the system remains operational,
regardless of the ignition switch position.
In addition to Lock and Unlock buttons, the RKE
transmitters are also equipped with a Panic button.
If the Panic button on the RKE transmitter is
depressed, the horn will sound and the exterior lights
will flash on the vehicle for about three minutes, or
until the Panic button is depressed a second time, if
ignition is in the Off position. A vehicle speed of
about 24 kilometers-per-hour (15 miles-per-hour) will
also cancel the panic event.
The RKE system can also perform other functions
on this vehicle. If the vehicle is equipped with the
optional Vehicle Theft Security System (VTSS), the
RKE transmitter will arm the VTSS when the Lock
button is depressed, and disarm the VTSS when the
Unlock button is depressed. (Refer to 8 - ELECTRI-
CAL/VEHICLE THEFT SECURITY - DESCRIPTION
- VEHICLE THEFT SECURITY SYSTEM). If the
vehicle is equipped with the optional Memory Sys-
tem, each of the two numbered and color-coded RKE
transmitters can be used to recall the stored driver
side front seat position, both outside power rear view
mirror positions, and the radio station presets for the
two assigned drivers. (Refer to 8 - ELECTRICAL/
POWER SEATS - DESCRIPTION - MEMORY SYS-
TEM).
8N - 2 POWER LOCKSWJ
POWER LOCKS (Continued)

²The speed signal decreases at a rate of 10 mph
per second (indicates that the vehicle may have
decelerated at an extremely high rate)
Once the speed control has been disengaged,
depressing the RES/ACCEL switch (when speed is
greater than 30 mph) restores the vehicle to the tar-
get speed that was stored in the PCM.
While the speed control is engaged, the driver can
increase the vehicle speed by depressing the RES/AC-
CEL switch. The new target speed is stored in the
PCM when the RES/ACCEL is released. The PCM
also has a9tap-up9feature in which vehicle speed
increases at a rate of approximately 2 mph for each
momentary switch activation of the RES/ACCEL
switch.
A ªtap downº feature is used to decelerate without
disengaging the speed control system. To decelerate
from an existing recorded target speed, momentarily
depress the COAST switch. For each switch activa-
tion, speed will be lowered approximately 1 mph.
OVERSHOOT/UNDERSHOOT
If the vehicle operator repeatedly presses and
releases the SET button with their foot off of the
accelerator (referred to as a ªlift foot setº), the vehicle
may accelerate and exceed the desired set speed by
up to 5 mph (8 km/h). It may also decelerate to less
than the desired set speed, before finally achieving
the desired set speed.
The Speed Control System has an adaptive strat-
egy that compensates for vehicle-to-vehicle variations
in speed control cable lengths. When the speed con-
trol is set with the vehicle operators foot off of the
accelerator pedal, the speed control thinks there is
excessive speed control cable slack and adapts
accordingly. If the ªlift foot setsº are continually used,
a speed control overshoot/undershoot condition will
develop.
To ªunlearnº the overshoot/undershoot condition,
the vehicle operator has to press and release the set
button while maintaining the desired set speed using
the accelerator pedal (not decelerating or accelerat-
ing), and then turning the cruise control switch to
the OFF position (or press the CANCEL button if
equipped) after waiting 10 seconds. This procedure
must be performed approximately 10±15 times to
completely unlearn the overshoot/undershoot condi-
tion.DIAGNOSIS AND TESTING - ROAD TEST
Perform a vehicle road test to verify reports of
speed control system malfunction. The road test
should include attention to the speedometer. Speed-
ometer operation should be smooth and without flut-
ter at all speeds.
Flutter in the speedometer indicates a problem
which might cause surging in the speed control sys-
tem. The cause of any speedometer problems should
be corrected before proceeding. Refer to Group 8J,
Instrument Cluster for speedometer diagnosis.
If a road test verifies a system problem and the
speedometer operates properly, check for:
²A Diagnostic Trouble Code (DTC). If a DTC
exists, conduct tests per the Powertrain Diagnostic
Procedures service manual.
²A misadjusted brake (stop) lamp switch. This
could also cause an intermittent problem.
²Loose, damaged or corroded electrical connec-
tions at the servo. Corrosion should be removed from
electrical terminals and a light coating of Mopar
MultiPurpose Grease, or equivalent, applied.
²Leaking vacuum reservoir.
²Loose or leaking vacuum hoses or connections.
²Defective one-way vacuum check valve.
²Secure attachment of both ends of the speed con-
trol servo cable.
²Smooth operation of throttle linkage and throttle
body air valve.
²Failed speed control servo. Do the servo vacuum
test.
CAUTION: When test probing for voltage or conti-
nuity at electrical connectors, care must be taken
not to damage connector, terminals or seals. If
these components are damaged, intermittent or
complete system failure may occur.
8P - 2 SPEED CONTROLWJ
SPEED CONTROL (Continued)

SPECIFICATIONS
TORQUE - SPEED CONTROL
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Servo Mounting Bracket-to-
Servo Nuts8.5 75
Servo Mounting Bracket-to-
Body Nuts28 6 250 50
Switch Module Mounting
Screws.6-1 6-9
Vacuum Reservoir Mounting
Bolts325
CABLE
DESCRIPTION
The speed control servo cable is connected between
the speed control vacuum servo diaphragm and the
throttle body control linkage.
OPERATION
This cable causes the throttle control linkage to
open or close the throttle valve in response to move-
ment of the vacuum servo diaphragm.
REMOVAL
REMOVAL - 4.0L
(1) Disconnect negative battery cable at battery.
(2) Remove air box housing from throttle body.
(3) Using finger pressure only, remove speed con-
trol cable connector at throttle body bellcrank pin by
pushing connector off bellcrank pin towards drivers
side of vehicle (Fig. 1).DO NOT try to pull con-
nector off perpendicular to the bellcrank pin.
Connector will be broken.
(4) Remove cable from cable guide at top of valve
cover.
(5) Squeeze 2 release tabs (Fig. 1) on sides of cable
at bracket and push cable out of bracket.
(6) Remove servo cable from servo. Refer to Speed
Control Servo Removal/Installation.
REMOVAL - 4.7L
(1) Disconnect negative battery cable at battery.
(2) Remove air box housing from throttle body.
The accelerator cable must be partially removed to
gain access to speed control cable.(3) Using finger pressure only, disconnect accelera-
tor cable connector at throttle body bellcrank pin by
pushing connector off bellcrank pin towards front of
vehicle (Fig. 2).DO NOT try to pull connector off
perpendicular to the bellcrank pin. Connector
will be broken.
Fig. 1 Speed Control Cable at Bell CrankÐ4.0L
Engine
1 - ACCELERATOR CABLE
2 - OFF
3 - OFF
4 - THROTTLE BODY BELLCRANK
5 - SPEED CONTROL CABLE
6 - RELEASE TABS
7 - BRACKET
WJSPEED CONTROL 8P - 3
SPEED CONTROL (Continued)

(4) Lift accelerator cable from top of cable cam
(Fig. 2).
(5) Press tab (Fig. 3) to release plastic cable mount
from bracket.Press on tab only enough to
release cable from bracket. If tab is pressed too
much, it will be broken.Slide plastic mount (Fig.
3) towards passenger side of vehicle to remove cable
from bracket.
(6) Using finger pressure only, disconnect speed
control cable connector at throttle body bellcrank pin
by pushing connector off bellcrank pin towards front
of vehicle (Fig. 2).DO NOT try to pull connector
off perpendicular to the bellcrank pin. Connec-
tor will be broken.
(7) Slide speed control cable plastic mount towards
passenger side of vehicle to remove cable from
bracket (Fig. 4).
(8) Remove servo cable from servo. Refer to Speed
Control Servo Removal/Installation.
INSTALLATION
INSTALLATION - 4.0L
(1) Install end of cable to speed control servo.
Refer to Speed Control Servo Removal/Installation.
(2) Install cable into mounting bracket (snaps in).
(3) Install speed control cable connector at throttle
body bellcrank pin (snaps on).
(4) Connect negative battery cable at battery.
(5) Before starting engine, operate accelerator
pedal to check for any binding.
INSTALLATION - 4.7L
(1) Install end of cable to speed control servo.
Refer to Speed Control Servo Removal/Installation.
(2) Slide speed control cable plastic mount into
bracket.
(3) Install speed control cable connector onto throt-
tle body bellcrank pin (snaps on).
(4) Slide accelerator cable plastic mount into
bracket. Continue sliding until tab (Fig. 3) is aligned
to hole in mounting bracket.
(5) Route accelerator cable over top of cable cam
(Fig. 2).
(6) Install accelerator cable connector onto throttle
body bellcrank pin (snaps on).
(7) Install air box housing to throttle body.
Fig. 2 Cable Connectors at Bell CrankÐ4.7L V-8
Engine
1 - THROTTLE BODY
2 - SPEED CONTROL CABLE CONNECTOR
3 - OFF
4 - OFF
5 - ACCELERATOR CABLE CONNECTOR
6 - CABLE CAM
7 - BELLCRANK
Fig. 3 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
8P - 4 SPEED CONTROLWJ
CABLE (Continued)

(8) Connect negative battery cable at battery.
(9) Before starting engine, operate accelerator
pedal to check for any binding.
SERVO
DESCRIPTION
The servo unit consists of a solenoid valve body,
and a vacuum chamber. The solenoid valve body con-
tains three solenoids:
²Vacuum
²Vent
²Dump
The vacuum chamber contains a diaphragm with a
cable attached to control the throttle linkage.
OPERATION
The Powertrain Control Module (PCM) controls the
solenoid valve body. The solenoid valve body controls
the application and release of vacuum to the dia-
phragm of the vacuum servo. The servo unit cannot
be repaired and is serviced only as a complete assem-
bly.
Power is supplied to the servo's by the PCM
through the brake switch. The PCM controls the
ground path for the vacuum and vent solenoids.The dump solenoid is energized anytime it receives
power. If power to the dump solenoid is interrupted,
the solenoid dumps vacuum in the servo. This pro-
vides a safety backup to the vent and vacuum sole-
noids.
The vacuum and vent solenoids must be grounded
at the PCM to operate. When the PCM grounds the
vacuum servo solenoid, the solenoid allows vacuum
to enter the servo and pull open the throttle plate
using the cable. When the PCM breaks the ground,
the solenoid closes and no more vacuum is allowed to
enter the servo. The PCM also operates the vent sole-
noid via ground. The vent solenoid opens and closes a
passage to bleed or hold vacuum in the servo as
required.
The PCM duty cycles the vacuum and vent sole-
noids to maintain the set speed, or to accelerate and
decelerate the vehicle. To increase throttle opening,
the PCM grounds the vacuum and vent solenoids. To
decrease throttle opening, the PCM removes the
grounds from the vacuum and vent solenoids. When
the brake is released, if vehicle speed exceeds 30
mph to resume, 35 mph to set, and the RES/ACCEL
switch has been depressed, ground for the vent and
vacuum circuits is restored.
REMOVAL
The speed control servo is attached to a bracket.
The bracket and servo assembly are located below
the battery tray.
(1) Disconnect negative battery cable at battery.
(2) Disconnect positive battery cable at battery.
(3) Remove air cleaner housing at top of throttle
body and disconnect servo cable at throttle body.
Refer to Servo Cable Removal/Installation.
(4) Remove battery from battery tray.
(5) Disconnect wiring at battery tray.
(6) Disconnect positive battery cable at Power Dis-
tribution Center (PDC).
(7) Loosen PDC at battery tray.
(8) Remove 4 battery tray bolts. One of these bolts
attaches to speed control bracket flange that sup-
ports battery tray. While removing battery tray, dis-
connect battery temperature sensor electrical
connector at sensor.
(9) Disconnect vacuum line at servo vacuum hose
fitting (Fig. 5) .
(10) Disconnect electrical connector at servo (Fig.
5) .
If servo and mounting bracket are being removed
as one assembly, remove two mounting nuts (Fig. 5) .
These are located above right-front tire. Remove
inner fender clips and pry inner fender back slightly
to gain access to mounting nuts.
Fig. 4 Speed Control Cable at BracketÐ4.7L V-8
Engine
1 - PLASTIC CABLE MOUNT
2 - SPEED CONTROL CABLE
3 - BRACKET
4 - SLIDE FOR REMOVAL
WJSPEED CONTROL 8P - 5
CABLE (Continued)