2002 JEEP GRAND CHEROKEE Open loop

(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)

(4) Install screw attaching B-pillar lower trim to
B-pillar.
(5) Install screw attaching front of B-pillar lower
trim to floor.
(6) Install screw attaching front of quarter panel
trim to floor.
(7) Install front seat shoulder belt anchor bolt.
(8) Install front seat shoulder belt height adjust-
ment knob and turning loop.
(9) Install front door sill trim (Refer to 23 - BODY/
INTERIOR/DOOR SILL TRIM - INSTALLATION).
B-PILLAR UPPER TRIM
REMOVAL
(1) Remove shoulder belt height adjustment knob.
(2) Remove front seat belt turning loop.
(3) Remove the screw attaching lower B pillar
trim.
(4) Pull lower B pillar trim out far enough to
remove upper trim panel.
(5) Grasp upper B-pillar trim and pull outward to
detach from B-pillar (Fig. 2).
INSTALLATION
(1) Position trim panel on B-pillar (Fig. 2).
(2) Ensure trim panel covers inner edge of door
opening weatherstrip and press inward to seat.
(3) Install screw attaching lower B pillar trim
panel.
(4) Install front seat belt turning loop.
(5) Install shoulder belt height adjustment knob.
CARPETS AND FLOOR MATS
REMOVAL
REMOVAL - FRONT CARPET
(1) Remove door sill trim (Refer to 23 - BODY/IN-
TERIOR/DOOR SILL TRIM - REMOVAL).
(2) Remove the B-pillar lower trim, refer to (Refer
to 23 - BODY/INTERIOR/B-PILLAR LOWER TRIM -
REMOVAL).
(3) Remove front seats (Refer to 23 - BODY/
SEATS/SEAT - REMOVAL).
(4) Remove the rear seats lower cushions (Refer to
23 - BODY/SEATS/SEAT CUSHION - REMOVAL).
(5) Remove center floor console (Refer to 23 -
BODY/INTERIOR/FLOOR CONSOLE - REMOVAL).
(6) Remove any other interfering trim or molding.
(7) Lift carpet and mat from floor panel.
REMOVAL - CARGO AREA CARPET
(1) Lift tailgate.
(2) Fold rear seat cushions forward.
(3) Remove rear seat backs (Refer to 23 - BODY/
SEATS/REAR SEAT BACK - REMOVAL).
(4) Remove the rear shoulder belts (Refer to 8 -
ELECTRICAL/RESTRAINTS/REAR SEAT BELT &
RETRACTOR - REMOVAL).
(5) Remove the retractable security cargo cover
assembly.
(6) Remove the spare tire cover.
(7) Remove the rear cargo tie down footman loops.
The side mounted footman loops are retained by
screws. The floor footman loops are riveted (Fig. 3).
(8) Remove the C pillar trim (Refer to 23 - BODY/
INTERIOR/C-PILLAR TRIM - REMOVAL).
(9) Remove the CD changer, if equipped (Refer to 8
- ELECTRICAL/AUDIO/CD CHANGER - REMOV-
AL).
(10) Remove the Infinity amp, if equipped (Refer to
8 - ELECTRICAL/AUDIO/AMPLIFIER - REMOVAL).
(11) Lift the carpet.
INSTALLATION
INSTALLATION - FRONT CARPET
(1) Carefully lay the carpet and mat on the floor
panel. Align the carpet to allow installation of the
components fastened to the floor panel.
(2) Install the center console (Refer to 23 - BODY/
INTERIOR/FLOOR CONSOLE - INSTALLATION).
(3) Install the front seats (Refer to 23 - BODY/
SEATS/SEAT - INSTALLATION).
(4) Install the rear seat cushions (Refer to 23 -
BODY/SEATS/SEAT CUSHION - INSTALLATION).
Fig. 3 Cargo Area Carpet
1 - CARGO AREA CARPET
2 - RIVET
3 - CARGO TIE-DOWN LOOP
WJINTERIOR 23 - 71
B-PILLAR LOWER TRIM (Continued)

LIFTGATE OPENING UPPER
TRIM
REMOVAL
The upper liftgate opening trim is held on with
spring clips.
(1) Grasp the rear of the trim piece and pull down
and back to disengage clips (Fig. 12).
(2) Slide the trim piece to the rear to disengage
headliner locating hooks.
INSTALLATION
The liftgate upper opening trim piece is equipped
with headliner locating hooks (Fig. 13).
(1) Align the locating hooks with the slots in the
headliner.
(2) Engage the spring clips and press the liftgate
upper opening trim panel into place.
QUARTER TRIM PANEL
REMOVAL
(1) Move rear seat to cargo position.
(2) If equipped, remove sunshade cover.
(3) Open liftgate.
(4) Remove upper and lower liftgate opening trim
panels (Refer to 23 - BODY/INTERIOR/LIFTGATE
OPENING UPPER TRIM - REMOVAL).
(5) Remove D-pillar upper trim (Refer to 23 -
BODY/INTERIOR/D-PILLAR TRIM - REMOVAL).
(6) Remove storage bin (right side only) (Refer to
23 - BODY/INTERIOR/REAR STORAGE BOX -
REMOVAL).
(7) Remove C-pillar upper trim panel (Refer to 23 -
BODY/INTERIOR/C-PILLAR TRIM - REMOVAL).
(8) Remove mounting screws.
(9) Pull quarter trim panel forward and disengage
connectors for CD player and power outlet, if
equipped.
(10) Pull quarter trim panel extension in the rear
door opening upward.
(11) Remove rear quarter trim panel.
INSTALLATION
(1) Position quarter trim panel, engage connectors
for CD player and power outlet, if equipped, and
align screw holes.
(2) Install quarter trim panel.
(3) Install C-pillar upper trim panel (Refer to 23 -
BODY/INTERIOR/C-PILLAR TRIM - INSTALLA-
TION).
(4) Install storage bin (Refer to 23 - BODY/INTE-
RIOR/REAR STORAGE BOX - INSTALLATION).
(5) Install D-pillar upper trim panel (Refer to 23 -
BODY/INTERIOR/D-PILLAR TRIM - INSTALLA-
TION).
(6) Install upper and lower liftgate opening trim
panels (Refer to 23 - BODY/INTERIOR/LIFTGATE
OPENING UPPER TRIM - INSTALLATION).
(7) If equipped, install sunshade cover.
(8) Install cargo loops.
(9) Move the rear seat to the upright position.
REAR STORAGE BOX
REMOVAL
(1) Open the storage bin lid and remove screws on
each side of the lid hinge.
(2) Pull upward sharply on the bottom of the bin
to disengage hooks.
(3) Raise bin and move inboard to disengage the
quarter trim panel.
Fig. 12 Upper Liftgate Opening Trim
1 - UPPER LIFTGATE OPENING TRIM
Fig. 13 Headliner Locating Hooks
1 - UPPER LIFTGATE OPENING TRIM
2 - HEADLINER
WJINTERIOR 23 - 79

DESCRIPTION - TASK MANAGER
The PCM is responsible for efficiently coordinating
the operation of all the emissions-related compo-
nents. The PCM is also responsible for determining if
the diagnostic systems are operating properly. The
software designed to carry out these responsibilities
is referred to as the 'Task Manager'.
DESCRIPTION - MONITORED SYSTEMS
There are new electronic circuit monitors that
check fuel, emission, engine and ignition perfor-
mance. These monitors use information from various
sensor circuits to indicate the overall operation of the
fuel, engine, ignition and emission systems and thus
the emissions performance of the vehicle.
The fuel, engine, ignition and emission systems
monitors do not indicate a specific component prob-
lem. They do indicate that there is an implied prob-
lem within one of the systems and that a specific
problem must be diagnosed.
If any of these monitors detect a problem affecting
vehicle emissions, the Malfunction Indicator Lamp
(MIL) will be illuminated. These monitors generate
Diagnostic Trouble Codes that can be displayed with
the MIL or a scan tool.
The following is a list of the system monitors:
²Misfire Monitor
²Fuel System Monitor
²Oxygen Sensor Monitor
²Oxygen Sensor Heater Monitor
²Catalyst Monitor
²Leak Detection Pump Monitor (if equipped)
All these system monitors require two consecutive
trips with the malfunction present to set a fault.
Refer to the appropriate Powertrain Diagnos-
tics Procedures manual for diagnostic proce-
dures.
The following is an operation and description of
each system monitor:
OXYGEN SENSOR (O2S) MONITOR
Effective control of exhaust emissions is achieved
by an oxygen feedback system. The most important
element of the feedback system is the O2S. The O2S
is located in the exhaust path. Once it reaches oper-
ating temperature 300É to 350ÉC (572É to 662ÉF), the
sensor generates a voltage that is inversely propor-
tional to the amount of oxygen in the exhaust. The
information obtained by the sensor is used to calcu-
late the fuel injector pulse width. This maintains a
14.7 to 1 Air Fuel (A/F) ratio. At this mixture ratio,
the catalyst works best to remove hydrocarbons (HC),
carbon monoxide (CO) and nitrogen oxide (NOx) from
the exhaust.
The O2S is also the main sensing element for the
Catalyst and Fuel Monitors.The O2S can fail in any or all of the following
manners:
²slow response rate
²reduced output voltage
²dynamic shift
²shorted or open circuits
Response rate is the time required for the sensor to
switch from lean to rich once it is exposed to a richer
than optimum A/F mixture or vice versa. As the sen-
sor starts malfunctioning, it could take longer to
detect the changes in the oxygen content of the
exhaust gas.
The output voltage of the O2S ranges from 0 to 1
volt. A good sensor can easily generate any output
voltage in this range as it is exposed to different con-
centrations of oxygen. To detect a shift in the A/F
mixture (lean or rich), the output voltage has to
change beyond a threshold value. A malfunctioning
sensor could have difficulty changing beyond the
threshold value.
OXYGEN SENSOR HEATER MONITOR
If there is an oxygen sensor (O2S) shorted to volt-
age DTC, as well as a O2S heater DTC, the O2S
fault MUST be repaired first. Before checking the
O2S fault, verify that the heater circuit is operating
correctly.
Effective control of exhaust emissions is achieved
by an oxygen feedback system. The most important
element of the feedback system is the O2S. The O2S
is located in the exhaust path. Once it reaches oper-
ating temperature 300É to 350ÉC (572 É to 662ÉF), the
sensor generates a voltage that is inversely propor-
tional to the amount of oxygen in the exhaust. The
information obtained by the sensor is used to calcu-
late the fuel injector pulse width. This maintains a
14.7 to 1 Air Fuel (A/F) ratio. At this mixture ratio,
the catalyst works best to remove hydrocarbons (HC),
carbon monoxide (CO) and nitrogen oxide (NOx) from
the exhaust.
The voltage readings taken from the O2S sensor
are very temperature sensitive. The readings are not
accurate below 300ÉC. Heating of the O2S sensor is
done to allow the engine controller to shift to closed
loop control as soon as possible. The heating element
used to heat the O2S sensor must be tested to ensure
that it is heating the sensor properly.
The O2S sensor circuit is monitored for a drop in
voltage. The sensor output is used to test the heater
by isolating the effect of the heater element on the
O2S sensor output voltage from the other effects.
LEAK DETECTION PUMP MONITOR (IF EQUIPPED)
The leak detection assembly incorporates two pri-
mary functions: it must detect a leak in the evapora-
WJEMISSIONS CONTROL 25 - 17
EMISSIONS CONTROL (Continued)

an associated limp in will take two trips to illumi-
nate the MIL.
Refer to the Diagnostic Trouble Codes Description
Charts in this section and the appropriate Power-
train Diagnostic Procedure Manual for diagnostic
procedures.
DESCRIPTION - NON-MONITORED CIRCUITS
The PCM does not monitor the following circuits,
systems and conditions that could have malfunctions
causing driveability problems. The PCM might not
store diagnostic trouble codes for these conditions.
However, problems with these systems may cause the
PCM to store diagnostic trouble codes for other sys-
tems or components. For example, a fuel pressure
problem will not register a fault directly, but could
cause a rich/lean condition or misfire. This could
cause the PCM to store an oxygen sensor or misfire
diagnostic trouble code
FUEL PRESSURE
The fuel pressure regulator controls fuel system
pressure. The PCM cannot detect a clogged fuel
pump inlet filter, clogged in-line fuel filter, or a
pinched fuel supply or return line. However, these
could result in a rich or lean condition causing the
PCM to store an oxygen sensor or fuel system diag-
nostic trouble code.
SECONDARY IGNITION CIRCUIT
The PCM cannot detect an inoperative ignition coil,
fouled or worn spark plugs, ignition cross firing, or
open spark plug cables.
CYLINDER COMPRESSION
The PCM cannot detect uneven, low, or high engine
cylinder compression.
EXHAUST SYSTEM
The PCM cannot detect a plugged, restricted or
leaking exhaust system, although it may set a fuel
system fault.
FUEL INJECTOR MECHANICAL MALFUNCTIONS
The PCM cannot determine if a fuel injector is
clogged, the needle is sticking or if the wrong injectoris installed. However, these could result in a rich or
lean condition causing the PCM to store a diagnostic
trouble code for either misfire, an oxygen sensor, or
the fuel system.
EXCESSIVE OIL CONSUMPTION
Although the PCM monitors engine exhaust oxygen
content when the system is in closed loop, it cannot
determine excessive oil consumption.
THROTTLE BODY AIRFLOW
The PCM cannot detect a clogged or restricted air
cleaner inlet or filter element.
VACUUM ASSIST
The PCM cannot detect leaks or restrictions in the
vacuum circuits of vacuum assisted engine control
system devices. However, these could cause the PCM
to store a MAP sensor diagnostic trouble code and
cause a high idle condition.
PCM SYSTEM GROUND
The PCM cannot determine a poor system ground.
However, one or more diagnostic trouble codes may
be generated as a result of this condition. The mod-
ule should be mounted to the body at all times, also
during diagnostic.
PCM CONNECTOR ENGAGEMENT
The PCM may not be able to determine spread or
damaged connector pins. However, it might store
diagnostic trouble codes as a result of spread connec-
tor pins.
DESCRIPTION - HIGH AND LOW LIMITS
The PCM compares input signal voltages from each
input device with established high and low limits for
the device. If the input voltage is not within limits
and other criteria are met, the PCM stores a diagnos-
tic trouble code in memory. Other diagnostic trouble
code criteria might include engine RPM limits or
input voltages from other sensors or switches that
must be present before verifying a diagnostic trouble
code condition.
DESCRIPTION - LOAD VALUE
ENGINE IDLE/NEUTRAL 2500 RPM/NEUTRAL
All Engines 2% to 8% of Maximum Load 9% to 17% of Maximum Load
25 - 20 EMISSIONS CONTROLWJ
EMISSIONS CONTROL (Continued)

INSTALLATION - FIXED ORIFICE FITTING
When installing fixed orifice fitting, be sure loca-
tions of fixed orifice fitting and air inlet fitting (Fig.
9) have not been inadvertently exchanged. The fixed
orifice fitting is light grey in color and is located at
rearof valve cover. The air inlet fitting is black in
color and is located atfrontof valve cover.
(1) Connect fitting to CCV breather tube.
(2) Return fixed orifice fitting to valve cover grom-
met.
EVAP/PURGE SOLENOID
DESCRIPTION
The duty cycle EVAP canister purge solenoid (DCP)
regulates the rate of vapor flow from the EVAP can-
ister to the intake manifold. The Powertrain Control
Module (PCM) operates the solenoid.
OPERATION
During the cold start warm-up period and the hot
start time delay, the PCM does not energize the sole-
noid. When de-energized, no vapors are purged. The
PCM de-energizes the solenoid during open loop oper-
ation.
The engine enters closed loop operation after it
reaches a specified temperature and the time delay
ends. During closed loop operation, the PCM cycles
(energizes and de-energizes) the solenoid 5 or 10
times per second, depending upon operating condi-
tions. The PCM varies the vapor flow rate by chang-
ing solenoid pulse width. Pulse width is the amount
of time that the solenoid is energized. The PCM
adjusts solenoid pulse width based on engine operat-
ing condition.
REMOVAL
The duty cycle evaporative (EVAP) canister purge
solenoid is located in the engine compartment near
the brake master cylinder (Fig. 10).
(1) Disconnect electrical connector at solenoid.
(2) Disconnect vacuum lines at solenoid.
(3) Lift solenoid slot (Fig. 10) from mounting
bracket for removal.
INSTALLATION
(1) Position solenoid slot to mounting bracket.
(2) Connect vacuum lines to solenoid. Be sure vac-
uum lines are firmly connected and not leaking or
damaged. If leaking, a Diagnostic Trouble Code
(DTC) may be set with certain emission packages.
(3) Connect electrical connector to solenoid.
FUEL FILLER CAP
DESCRIPTION
The plastic fuel tank filler tube cap is threaded
onto the end of the fuel fill tube. Certain models are
equipped with a 1/4 turn cap.
OPERATION
The loss of any fuel or vapor out of fuel filler tube
is prevented by the use of a pressure-vacuum fuel fill
cap. Relief valves inside the cap will release fuel tank
pressure at predetermined pressures. Fuel tank vac-
uum will also be released at predetermined values.
This cap must be replaced by a similar unit if
replacement is necessary. This is in order for the sys-
tem to remain effective.
CAUTION: Remove fill cap before servicing any fuel
system component to relieve tank pressure. If
equipped with a California emissions package and a
Leak Detection Pump (LDP), the cap must be tight-
ened securely. If cap is left loose, a Diagnostic
Trouble Code (DTC) may be set.
REMOVAL
If replacement of the 1/4 turn fuel tank filler tube
cap is necessary, it must be replaced with an identi-
cal cap to be sure of correct system operation.
Fig. 10 EVAP/PURGE SOLENOID LOCATION
1 - BRAKE MASTER CYLINDER
2 - EVAP SOLENOID
3 - SLOT
4 - ELEC. CONNEC.
5 - VACUUM LINE CONNEC.
6 - TEST PORT
WJEVAPORATIVE EMISSIONS 25 - 29
CCV HOSE (Continued)