2003 JEEP GRAND CHEROKEE pack

(14) Remove the snap ring from the hub and
remove the clutch field coil (Fig. 22). Slide the clutch
field coil off of the hub.
INSTALLATION
INSTALLATION
(1) Install Viscous Heater to engine mounting
bracket.
(2) Install the Viscous Heater mounting bolts and
tighten to 33 N´m ( 25 ft. lbs.).
(3) Plug the wiring harness electrical connector to
the Viscous Heater clutch.
(4) Install heater hoses to the Viscous Heater con-
nections.
(5) Install heater hose clamps to Viscous Heater
connections.
(6) Install the engine accessory drive belt(Refer to
7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(7) Refill the engine cooling system(Refer to 7 -
COOLING/ENGINE - STANDARD PROCEDURE).
(8) Reconnect the battery negative cable.
(9) Operate vehicle and check for any coolant
leaks, repair as required.
INSTALLATION - VISCOUS HEATER CLUTCH
(1) Install the clutch field coil and snap ring.
(2) Install the screw and retainer on the clutch coil
lead wire harness on the viscous heater housing.
Tighten the screw to 2.2 N´m (20 in. lbs.)
(3) Align the rotor assembly squarely on the front
housing hub.
(4) Install the rotor bearing asembly with the
installer (Special Tool C-6871 or equalivent). Threadthe installer on the shaft, then turn the nut until the
rotor asembly is seated.
(5) Install the external front housing snap ring
with snap ring pliers. The bevel side of the snap ring
must be facing outward. Press the snap ring to make
sure it is properly seated in the groove.
CAUTION: If the snap ring is not fully seated in the
groove it will vibrate out, resulting in a clutch fail-
ure and severe damage to the front housing of the
compressor.
(6) Install the original clutch shims on the shaft.
(7) Install the clutch plate. Install the shaft hex
nut and tighten to 15±20 N´m (11±15 ft. lbs.).
(8) Check the clutch air gap with a feeler gauge
(Fig. 23). If the gap does not meet specification, add
or substract shims as required. The air gap specifica-
tion if 0.41 to 0.79 millimeters (0.016 to 0.031 inch-
es).
NOTE: The air gap is determined by the spacer
shims. When installing an original, or a new clutch
assembly, try the original shims first. When install-
ing a new clutch (and not having the old shims
available) use a 1.0, 0.50 and 0.13 millimeter (0.040,
0.020 and 0.005 inch) shim from the new clutch
hardware package that is provided with the new
clutch.
(9) Reinstall the viscous heater to the mounting
bracket. Tighten the mounting screws to 33 N´m (25
ft. lbs.).
(10) Reinstall the battery negative cable.
Fig. 22 CLUTCH FIELD COIL SNAP RING REMOVE-
typical
1 - COIL
2 - SNAP RING PLIERS
Fig. 23 CHECK CLUTCH AIR GAP-typical
1 - FEELER GAUGE
24 - 78 PLUMBINGWJ
VISCOUS HEATER (Continued)

EVAPORATIVE EMISSIONS
TABLE OF CONTENTS
page page
EVAPORATIVE EMISSIONS
DESCRIPTION
DESCRIPTION - EVAPORATION CONTROL
SYSTEM............................24
DESCRIPTION - CCV SYSTEM...........25
DESCRIPTION - PCV SYSTEM...........25
OPERATION
OPERATION - 4.0L CCV SYSTEM.........26
OPERATION - 4.7L PCV SYSTEM.........26
SPECIFICATIONS
TORQUE - EVAPORATION SYSTEM.......27
CCV HOSE
DIAGNOSIS AND TESTING - CCV SYSTEM -
4.0L................................28
REMOVAL - FIXED ORIFICE FITTING........28
INSTALLATION - FIXED ORIFICE FITTING....29
EVAP/PURGE SOLENOID
DESCRIPTION.........................29
OPERATION...........................29
REMOVAL.............................29
INSTALLATION.........................29
FUEL FILLER CAP
DESCRIPTION.........................29
OPERATION...........................29REMOVAL.............................29
LEAK DETECTION PUMP
DESCRIPTION.........................30
OPERATION...........................31
DIAGNOSIS AND TESTING - ENABLING
CONDITIONS TO RUN EVAP LEAK
DETECTION TEST.....................32
REMOVAL.............................35
INSTALLATION.........................35
ORVR
DESCRIPTION.........................37
OPERATION...........................37
P C V VA LV E
DIAGNOSIS AND TESTING - PCV VALVE/PCV
SYSTEM - 4.7L.......................37
REMOVAL - PCV VALVE - 4.7L.............39
INSTALLATION - PCV VALVE - 4.7L.........39
VACUUM LINES
DESCRIPTION.........................39
VAPOR CANISTER
DESCRIPTION.........................39
OPERATION...........................39
REMOVAL.............................40
INSTALLATION.........................40
EVAPORATIVE EMISSIONS
DESCRIPTION
DESCRIPTION - EVAPORATION CONTROL
SYSTEM
The evaporation control system prevents the emis-
sion of fuel tank vapors into the atmosphere. When
fuel evaporates in the fuel tank, the vapors pass
through the control valve, through the fuel manage-
ment valve, and through vent hoses and tubes to a
charcoal filled evaporative canister. The canister tem-
porarily holds the vapors. The Powertrain Control
Module (PCM) allows intake manifold vacuum todraw vapors into the combustion chambers during
certain operating conditions.
Gas powered engines use a duty cycle purge sys-
tem. The PCM controls vapor flow by operating the
duty cycle EVAP purge solenoid. Refer to Duty Cycle
EVAP Canister Purge Solenoid.
When equipped with certain emissions packages, a
Leak Detection Pump (LDP) will be used as part of
the evaporative system for OBD II requirements.
Also refer to Leak Detection Pump.
Vehicles powered with gasoline engines are also
equipped with ORVR (On-Board Refueling Vapor
Recovery). Refer to ORVR for additional information.
25 - 24 EVAPORATIVE EMISSIONSWJ

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)

set a temporary fault without turning on the MIL
and continue the leak portion of the test. However,
the PCM will assume that the system is already
pressurized and skip the rapid pump cycles.
Always diagnose leaks, if possible, before discon-
necting connections. Disconnecting connections may
mask a leak condition.
Keep in mind that if the purge solenoid seat is
leaking, it could go undetected since the leak would
end up in the intake manifold. Disconnect the purge
solenoid at the manifold when leak checking. In addi-
tion, a pinched hose fault (P1486) could set if the
purge solenoid does not purge the fuel system prop-
erly (blocked seat). The purge solenoid must vent the
fuel system prior to the LDP system test. If the
purge solenoid cannot properly vent the system the
LDP cannot properly complete the test for P1486 and
this fault can set due to pressure being in the EVAP
system during the test sequence.
Multiple actuation's of the DRB IIItLeak Detec-
tion Pump (LDP) Monitor Test can hide a 0.020 leak
because of excess vapor generation. Additionally, any
source for additional vapor generation can hide a
small leak in the EVAP system. Excess vapor gener-
ation can delay the fall of the LDP diaphragm thus
hiding the small leak. An example of this condition
could be bringing a cold vehicle into a warm shop for
testing or high ambient temperatures.
Fully plugged and partially plugged underhood
vacuum lines have been known to set MIL condi-
tions. P1494 and P0456 can be set for this reason.
Always, thoroughly, check plumbing for pinches or
blockage before condemning components.
TEST EQUIPMENT The Evaporative Emission
Leak Detector (EELD) Miller Special Tool 8404 is
capable of visually detecting leaks in the evaporative
system and will take the place of the ultrasonic leak
detector 6917A. The EELD utilizes shop air and a
smoke generator to visually detect leaks down to
0.020 or smaller. The food grade oil used to make the
smoke includes an UV trace dye that will leave tell-
tale signs of the leak under a black light. This is
helpful when components have to be removed to
determine the exact leak location. For detailed test
instructions, follow the operators manual packaged
with the EELD.
NOTE: Be sure that the PCM has the latest software
update. Reprogram as indicated by any applicable
Technical Service Bulletin. After LDP repairs are
completed, verify the repair by running the DRB IIIT
Leak Detection Pump (LDP) Monitor Test as
described in Technical Service Bulletin 18-12-99.REMOVAL
The Leak Detection Pump (LDP) is located under
the left quarter panel behind the left/rear wheel (Fig.
16). It is attached to a two-piece support bracket
(Fig. 17). The LDP and LDP filter are replaced (ser-
viced) as one unit.
(1) Remove stone shield behind left/rear wheel
(Fig. 18). Drill out plastic rivets for removal.
(2) Remove 3 LDP mounting bolts (Fig. 19).
(3) Remove support bracket brace bolt (Fig. 17).
(4) Loosen, but do not remove 2 support bracket
nuts at frame rail (Fig. 19).
(5) To separate and lower front section of two-piece
support bracket, remove 3 attaching bolts on bottom
of support bracket (Fig. 17). While lowering support
bracket, disconnect LDP wiring clip (Fig. 20).
(6) Disconnect electrical connector at LDP (Fig.
20).
(7) Carefully remove vapor/vacuum lines at LDP
(Fig. 20).
(8) Remove LDP.
INSTALLATION
The LDP is located in the left quarter panel behind
the left/rear wheel. It is attached to a two-piece sup-
port bracket (Fig. 17). The LDP and LDP filter are
replaced (serviced) as one unit.
(1) Position LDP and carefully install vapor/vac-
uum lines to LDP and LDP filter.The vapor/vac-
uum lines and hoses must be firmly connected.
Fig. 16 LOCATION, LDP / EVAP CANISTER
1 - LEAK DETECTION PUMP
2 - EVAP CANISTER
WJEVAPORATIVE EMISSIONS 25 - 35
LEAK DETECTION PUMP (Continued)