2002 JEEP GRAND CHEROKEE check engine

INSTALLATION
INSTALLATION - RECIRCULATION DOOR
VACUUM ACTUATOR
(1) Install the recirculation door vacuum actuator
on the HVAC housing and tighten the mounting
screws to 2.2 N´m (20 in. lbs.).
(2) Engage the recirculation door actuating rod
with the recirculation door lever.
(3) Engage the recirculation door pivot connection
with the door pivot pin.
(4) Plug in the vacuum harness connector to the
recirculation door vacuum actuator.
(5) Install the instrument panel in the vehicle.
Refer to Instrument Panel System for the procedures.
INSTALLATION - RECIRCULATION DOOR
ELECTRIC ACTUATOR
(1) Install the recirculation door actuator on the
recirculation door housing and tighten the mounting
screws to 2.2 N´m (20 in. lbs.).
(2) Install the recirculation door housing on the
HVAC unit and tighten the mounting screws to 2.2
N´m (20 in. lbs.).
(3) Plug in the wire harness connector to the recir-
culation door actuator.
(4) Install the instrument panel in the vehicle.
Refer to Instrument Panel System for the procedures.
VACUUM CHECK VALVE
DESCRIPTION
Two vacuum check valves (non AZC only) are
installed on the vacuum supply system. One is on the
accessory vacuum supply line in the engine compart-
ment, near the vacuum tap on the engine intake
manifold. A second vacuum check valve is located on
the bottom of the HVAC unit behind the passenger
front floor duct on the black vacuum line. The vac-
uum check valves are designed to allow vacuum to
flow in only one direction through the accessory vac-
uum supply circuits.
OPERATION
The use of a vacuum check valve helps to maintain
the system vacuum needed to retain the selected A/C
Heater mode settings. The check valve will prevent
the engine from bleeding down system vacuum
through the intake manifold during extended heavy
engine load (low engine vacuum) operation.
The vacuum check valve cannot be repaired and, if
faulty or damaged, it must be replaced.
REMOVAL
(1) Unplug the HVAC vacuum supply line connec-
tor at the vacuum check valve near the engine intake
manifold vacuum adapter fitting.
(2) Note the orientation of the check valve in the
vacuum supply line for correct installation.
(3) Unplug the vacuum check valve from the vac-
uum supply line fittings.
INSTALLATION
(1) Plug in the vacuum check valve at the vacuum
supply line fittings, noting the orientation of the
check valve in the vacuum supply line for correct
installation.
(2) Plug in the HVAC vacuum supply line connec-
tor at the vacuum check valve near the engine intake
manifold vacuum adapter fitting.
VACUUM RESERVOIR
DESCRIPTION
The vacuum reservoir is mounted in the right front
of the vehicle behind the headlamp mounting module
(Fig. 22). The headlamp mounting module and head-
lamp assembly must be removed from the vehicle to
access the vacuum reservoir for service. Refer to
Lamps/Lighting for the procedures.
OPERATION
Engine vacuum is stored in the vacuum reservoir.
The stored vacuum is used to operate the vacuum-
Fig. 21 RECIRCULATION DOOR HOUSING
1 - RECIRCULATION DOOR HOUSING
2 - ATTACHING SCREWS
24 - 34 CONTROLSWJ
RECIRCULATION DOOR ACTUATOR (Continued)

NOTE: The blend door sub-assembly is attached to
the housing with 2 screws, and may be removed for
service (Fig. 19).
ASSEMBLY
(1) Place the top half of the HVAC housing on the
bottom half. Be certain that each of the door pivot
pins align with the pivot holes in the HVAC housing.
(2) Install the 10 screws that secure the two hous-
ing halves to each other. Tighten the HVAC housing
screws to 2.2 N´m (20 in. lbs.).
(3) Attach the wire harness electrical connector(s)
to the mounts on the lower case at the blower motor
end of the unit.
(4) Install the 5 clips that secure the two housing
halves to each other. Check doors for binding after
replacement, and after assembly of housing.
(5) Install the screw with plastic washer holding
the lever assembly to the upper case section.
(6) Install the mode door actuator on the left side
of the housing.
INSTALLATION
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN PLUMBING BEFORE PERFORMING THE
FOLLOWING OPERATION. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - WARNING) (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
CAUTION)Any kinks or sharp bends in the refrigerant plumb-
ing will reduce the capacity of the entire air condi-
tioning system. Kinks and sharp bends reduce the
flow of refrigerant in the system. A good rule for the
flexible hose refrigerant lines is to keep the radius of
all bends at least ten times the diameter of the hose.
In addition, the flexible hose refrigerant lines should
be routed so they are at least 80 millimeters (3
inches) from the exhaust manifold.
High pressures are produced in the refrigerant sys-
tem when the air conditioning compressor is operat-
ing. Extreme care must be exercised to make sure
that each of the refrigerant system connections is
pressure-tight and leak free. It is a good practice to
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.
(1) Position the HVAC housing to the dash panel.
Be certain that the evaporator condensate drain tube
and the housing mounting studs are inserted into
their correct mounting holes.
(2) Install the HVAC housing mounting nuts to the
studs on the passenger compartment side of the dash
panel. Tighten the nuts to 4.5 N´m (40 in. lbs.).
(3) Connect the HVAC housing wire harness con-
nectors.
(4) Reinstall the rear floor heat ducts to the center
floor heat duct outlets.
(5) Install and tighten the nuts onto the HVAC
housing mounting studs on the engine compartment
side of the dash panel. Tighten the nuts to 7 N´m (60
in. lbs.).
(6) Reinstall the PCM to the passenger side dash
panel in the engine compartment. Refer to Electronic
Control Modules for the procedures.
(7) Reinstall the coolant reserve/overflow bottle to
the passenger side inner fender shield. Refer to Cool-
ing for the procedures.
(8) If the vehicle is equipped with the manual tem-
perature control system, connect the HVAC system
vacuum supply line connector to the tee fitting near
the heater core tubes.
(9) Unclamp/unplug the heater core hoses and
tubes. Connect the heater hoses to the heater core
tubes and fill the engine cooling system. Refer to
Cooling for the procedures.
(10) Unplug or remove the tape from the suction
line and the evaporator outlet tube fittings. Connect
the suction line to the evaporator outlet tube.
Tighten retaining nut to 28 N´m (250 in. lbs.).
(11) Unplug or remove the tape from the liquid
line and the evaporator inlet tube fittings. Connect
the liquid line to the evaporator inlet tube. Tighten
retaining nut to 28 N´m (250 in. lbs.).
(12) Evacuate the refrigerant system. (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
Fig. 19 BLEND DOOR SUB-ASSEMBLY (AZC)
1 - PASSENGER SIDE BLEND DOOR
2 - BLEND DOOR SUB-ASSEMBLY
3 - DOOR PIVOT SHAFT BUSHING
4 - DOOR SHAFT LEVER
5 - DRIVER SIDE BLEND DOOR
WJDISTRIBUTION 24 - 45
HVAC HOUSING (Continued)

STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE)
(13) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)
(14) Install the instrument panel in the vehicle(Re-
fer to 23 - BODY/INSTRUMENT PANEL - INSTAL-
LATION).
(15) Connect the battery negative cable.
(16) Start the engine and check for proper opera-
tion of the heating and air conditioning systems.
BLEND DOOR
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Remove and disassemble the HVAC housing.
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL)
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - DISASSEMBLY)
(2) Remove evaporator from lower case to ease
access to plastic door shaft bushing.
(3) Pinch the retention tabs holding the blend door
pivot shaft to the case. The 3 plastic tabs, located on
the inside of the case, are part of the shaft retainer.
(4) Remove door(s).
INSTALLATION
(1) Install the blend door(s) by snapping the pivot
shaft into the HVAC case.
(2) Install the evaporator in the lower case.
(3) Reassemble the HVAC housing and install in
the vehicle. (Refer to 24 - HEATING & AIR CONDI-
TIONING/DISTRIBUTION/HVAC HOUSING -
ASSEMBLY) (Refer to 24 - HEATING & AIR CON-
DITIONING/DISTRIBUTION/HVAC HOUSING -
INSTALLATION)NOTE: The blend door sub-assembly is attached to
the housing with 2 screws, and may be removed for
service (Fig. 20).
MODE DOOR
REMOVAL
REMOVAL - PANEL OUTLET DOOR
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Remove and disassemble the HVAC housing.
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL)
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - DISASSEMBLY)
Fig. 20 BLEND DOOR SUB-ASSEMBLY
1 - PASSENGER SIDE BLEND DOOR
2 - BLEND DOOR SUB-ASSEMBLY
3 - DOOR PIVOT SHAFT BUSHING
4 - DOOR SHAFT LEVER
5 - DRIVER SIDE BLEND DOOR
24 - 46 DISTRIBUTIONWJ
HVAC HOUSING (Continued)

(a) If the refrigerant system fails to reach the
specified vacuum, the system has a leak that must
be corrected. (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING - DIAGNOSIS AND
TESTING - REFRIGERANT SYSTEM LEAKS)
(b) If the refrigerant system maintains the spec-
ified vacuum for five minutes, restart the vacuum
pump, open the suction and discharge valves and
evacuate the system for an additional ten minutes.
(3) Close all of the valves, and turn off the charg-
ing station vacuum pump.
(4) The refrigerant system is now ready to be
charged with R-134a refrigerant. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)
STANDARD PROCEDURE - REFRIGERANT
SYSTEM CHARGE
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
After the refrigerant system has been tested for
leaks and evacuated, a refrigerant charge can be
injected into the system. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - SPECIFICA-
TIONS - CHARGE CAPACITY)
A R-134a refrigerant recovery/recycling/charging
station that meets SAE Standard J2210 must be
used to charge the refrigerant system with R-134a
refrigerant. Refer to the operating instructions sup-
plied by the equipment manufacturer for proper care
and use of this equipment.
PARTIAL CHARGE METHOD
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
The partial charge method is used to add a partial
charge to a refrigerant system that is low on refrig-
erant. To perform this procedure the evaporator inlet
and outlet tube temperatures are measured. The
temperature difference is measured with a tempera-
ture meter with one or two clamp-on thermocouple
probes. The difference between the evaporator inlet
and outlet tube temperatures will determine the
amount of refrigerant needed.Before adding a partial refrigerant charge, check
for refrigerant system leaks. (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING - DIAGNOSIS
AND TESTING - REFRIGERANT SYSTEM LEAKS)
If a leak is found, make the necessary repairs before
attempting a full or partial refrigerant charge.
(1) Attach a manifold gauge set to the refrigerant
system service ports.
(2) Attach the two clamp-on thermocouple probes
to the inlet and outlet tubes of the evaporator coil.
²If a single thermocouple probe is used, attach
the probe to the evaporator inlet tube just before the
collar of the refrigerant line connector fitting. The
probe must make contact with the bottom surface of
the evaporator inlet tube.
²If dual thermocouple probes are used, attach
probe 1 to the evaporator inlet tube, and probe 2 to
the evaporator outlet tube. Attach both probes to the
evaporator tubes just before the collar of the refrig-
erant line connector fittings. The probes must make
contact with the bottom surfaces of the evaporator
inlet and outlet tubes.
(3) Open all of the windows or doors of the passen-
ger compartment.
(4) Set the A/C button on the A/C Heater controls
to the on position, the temperature control knob in
the full cool position, select Recirculation Mode, and
place the blower motor switch in the highest speed
position.
(5) Start the engine and hold the engine idle speed
at 1,000 rpm. Allow the engine to warm up to normal
operating temperature.
(6) The compressor clutch may cycle, depending
upon ambient temperature, humidity, and the refrig-
erant system charge level.
(7) Hold the engine idle speed at 1,000 rpm.
(8) Allow three to five minutes for the refrigerant
system to stabilize, then record the temperatures of
the evaporator inlet and outlet tubes.
²If a single probe is used, record the temperature
of the evaporator inlet tube. Then remove the probe
from the inlet tube and attach it to the evaporator
outlet tube just before the collar of the refrigerant
line connector fitting. The probe must make contact
with the bottom surface of the evaporator outlet tube.
Allow the thermocouple and meter time to stabilize,
then record the temperature of the evaporator outlet
tube. Subtract the inlet tube temperature reading
from the outlet tube temperature reading.
²If dual probes are used, record the temperatures
of both the evaporator inlet and outlet tubes. Then
subtract the inlet tube temperature reading from the
outlet tube temperature reading.
(9) If the measured temperature differential is
higher than 22É C to 26É C (40É F to 47É F), add 0.4
kilograms (14 ounces) of refrigerant.
24 - 56 PLUMBINGWJ
PLUMBING (Continued)

The high pressure relief valve vents only enough
refrigerant to reduce the system pressure, and then
re-seats itself. The majority of the refrigerant is con-
served in the system. If the valve vents refrigerant, it
does not mean that the valve is faulty.
The high pressure relief valve is a factory-cali-
brated unit. The valve cannot be adjusted or
repaired, and must not be removed or otherwise dis-
turbed. The valve is only serviced as a part of the
compressor assembly.
DIAGNOSIS AND TESTING - COMPRESSOR
NOISE
When investigating an air conditioning related
noise, you must first know the conditions under
which the noise occurs. These conditions include:
weather, vehicle speed, transmission in gear or neu-
tral, engine speed, engine temperature, and any
other special conditions. Noises that develop during
air conditioning operation can often be misleading.
For example: What sounds like a failed front bearing
or connecting rod, may be caused by loose bolts, nuts,
mounting brackets, or a loose compressor clutch
assembly.
Drive belts are speed sensitive. At different engine
speeds and depending upon belt tension, belts can
develop noises that are mistaken for a compressor
noise. Improper belt tension can cause a misleading
noise when the compressor clutch is engaged, which
may not occur when the compressor clutch is disen-
gaged. Check the serpentine drive belt condition and
tension as described in Cooling before beginning this
procedure.
(1) Select a quiet area for testing. Duplicate the
complaint conditions as much as possible. Switch the
compressor on and off several times to clearly iden-
tify the compressor noise. Listen to the compressor
while the clutch is engaged and disengaged. Probe
the compressor with an engine stethoscope or a long
screwdriver with the handle held to your ear to bet-
ter localize the source of the noise.
(2) Loosen all of the compressor mounting hard-
ware and retighten. Tighten the compressor clutch
mounting nut. Be certain that the clutch coil is
mounted securely to the compressor, and that the
clutch plate and pulley are properly aligned and have
the correct air gap. (Refer to 24 - HEATING & AIR
CONDITIONING/CONTROLS/A/C COMPRESSOR
CLUTCH - INSTALLATION)
(3) To duplicate a high-ambient temperature condi-
tion (high head pressure), restrict the air flow
through the condenser. Install a manifold gauge set
to be certain that the discharge pressure does not
exceed 2760 kPa (400 psi).
(4) Check the refrigerant system plumbing for
incorrect routing, rubbing or interference, which cancause unusual noises. Also check the refrigerant lines
for kinks or sharp bends that will restrict refrigerant
flow, which can cause noises. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAU-
TION - REFRIGERANT HOSES/LINES/TUBES
PRECAUTIONS)
(5) If the noise is from opening and closing of the
high pressure relief valve, reclaim, evacuate, and
recharge the refrigerant system. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE - REFRIGERANT RECOVERY)
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE - REFRIG-
ERANT SYSTEM EVACUATE) (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)If the high pressure relief valve still
does not seat properly, replace the a/c compressor.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/A/C COMPRESSOR - REMOVAL)
(6) If the noise is from liquid slugging on the suc-
tion line, check the refrigerant oil level and the
refrigerant system charge. (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/REFRIGER-
ANT OIL - STANDARD PROCEDURE) (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
SPECIFICATIONS - CHARGE CAPACITY).
(7) If the noise continues, replace the compressor
and repeat Step 1.
REMOVAL
REMOVAL
The compressor may be removed and repositioned
without disconnecting the refrigerant lines or dis-
charging the refrigerant system. Discharging is not
necessary if servicing the compressor clutch or clutch
coil, the engine, the cylinder head, or the generator.
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNING) (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - CAUTION)
(1) Recover the refrigerant from the system. (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMB-
ING - STANDARD PROCEDURE - REFRIGERANT
RECOVERY)
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the serpentine drive belt. Refer to
Cooling for the procedures.
(4) Unplug the compressor clutch coil wire harness
connector.
24 - 58 PLUMBINGWJ
A/C COMPRESSOR (Continued)

REFRIGERANT
DESCRIPTION
The refrigerant used in this air conditioning sys-
tem is a HydroFluoroCarbon (HFC), type R-134a.
Unlike R-12, which is a ChloroFluoroCarbon (CFC),
R-134a refrigerant does not contain ozone-depleting
chlorine. R-134a refrigerant is a non-toxic, non-flam-
mable, clear, and colorless liquefied gas.
Even though R-134a does not contain chlorine, it
must be reclaimed and recycled just like CFC-type
refrigerants. This is because R-134a is a greenhouse
gas and can contribute to global warming.
OPERATION
R-134a refrigerant is not compatible with R-12
refrigerant in an air conditioning system. Even a
small amount of R-12 added to an R-134a refrigerant
system will cause compressor failure, refrigerant oil
sludge or poor air conditioning system performance.
In addition, the PolyAlkylene Glycol (PAG) synthetic
refrigerant oils used in an R-134a refrigerant system
are not compatible with the mineral-based refriger-
ant oils used in an R-12 refrigerant system.
R-134a refrigerant system service ports, service
tool couplers and refrigerant dispensing bottles have
all been designed with unique fittings to ensure that
an R-134a system is not accidentally contaminated
with the wrong refrigerant (R-12). There are also
labels posted in the engine compartment of the vehi-
cle and on the compressor identifying to service tech-
nicians that the air conditioning system is equipped
with R-134a.
REFRIGERANT OIL
DESCRIPTION
The refrigerant oil used in R-134a refrigerant sys-
tems is a synthetic-based, PolyAlkylene Glycol (PAG),
wax-free lubricant. Mineral-based R-12 refrigerant
oils are not compatible with PAG oils, and should
never be introduced to an R-134a refrigerant system.
There are different PAG oils available, and each
contains a different additive package. The 10PA17
compressor used in this vehicle is designed to use an
ND8 PAG refrigerant oil. Use only refrigerant oil of
this same type to service the refrigerant system.
OPERATION
After performing any refrigerant recovery or recy-
cling operation, always replenish the refrigerant sys-
tem with the same amount of the recommended
refrigerant oil as was removed. Too little refrigerant
oil can cause compressor damage, and too much can
reduce air conditioning system performance.PAG refrigerant oil is much more hygroscopic than
mineral oil, and will absorb any moisture it comes
into contact with, even moisture in the air. The PAG
oil container should always be kept tightly capped
until it is ready to be used. After use, recap the oil
container immediately to prevent moisture contami-
nation.
STANDARD PROCEDURE - REFRIGERANT OIL
LEVEL
When an air conditioning system is assembled at
the factory, all components except the compressor are
refrigerant oil free. After the refrigerant system has
been charged and operated, the refrigerant oil in the
compressor is dispersed throughout the refrigerant
system. The accumulator, evaporator, condenser, and
compressor will each retain a significant amount of
the needed refrigerant oil.
It is important to have the correct amount of oil in
the refrigerant system. This ensures proper lubrica-
tion of the compressor. Too little oil will result in
damage to the compressor. Too much oil will reduce
the cooling capacity of the air conditioning system.
It will not be necessary to check the oil level in the
compressor or to add oil, unless there has been an oil
loss. An oil loss may occur due to a rupture or leak
from a refrigerant line, a connector fitting, a compo-
nent, or a component seal. If a leak occurs, add 30
milliliters (1 fluid ounce) of refrigerant oil to the
refrigerant system after the repair has been made.
Refrigerant oil loss will be evident at the leak point
by the presence of a wet, shiny surface around the
leak.
Refrigerant oil must be added when a accumulator,
evaporator coil, or condenser are replaced. See the
Refrigerant Oil Capacities chart. When a compressor
is replaced, the refrigerant oil must be drained from
the old compressor and measured. Drain all of the
refrigerant oil from the new compressor, then fill the
new compressor with the same amount of refrigerant
oil that was drained out of the old compressor.
Refrigerant Oil Capacities
Component ml fl oz
A/C System 130 4.40
Receiver Drier 70 2.37
Condenser 10 0.34
Evaporator 50 1.69
Compressordrain and measure
the oil from the old
compressor - see
text.
WJPLUMBING 24 - 75

(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)

EMISSIONS CONTROL
TABLE OF CONTENTS
page page
EMISSIONS CONTROL
DESCRIPTION
DESCRIPTION - EMISSION CONTROL
SYSTEM.............................1
DESCRIPTION - STATE DISPLAY TEST
MODE...............................2
DESCRIPTION - CIRCUIT ACTUATION TEST
MODE...............................2
DESCRIPTION - DIAGNOSTIC TROUBLE
CODES..............................2DESCRIPTION - TASK MANAGER.........17
DESCRIPTION - MONITORED SYSTEMS . . . 17
DESCRIPTION - TRIP DEFINITION........19
DESCRIPTION - COMPONENT MONITORS . . 19
DESCRIPTION - NON-MONITORED
CIRCUITS...........................20
DESCRIPTION - HIGH AND LOW LIMITS . . . 20
DESCRIPTION - LOAD VALUE...........20
OPERATION - TASK MANAGER............21
EVAPORATIVE EMISSIONS................24
EMISSIONS CONTROL
DESCRIPTION
DESCRIPTION - EMISSION CONTROL SYSTEM
The Powertrain Control Module (PCM) monitors
many different circuits in the fuel injection, ignition,
emission and engine systems. If the PCM senses a prob-
lem with a monitored circuit often enough to indicate an
actual problem, it stores a Diagnostic Trouble Code
(DTC) in the PCM's memory. If the code applies to a
non-emissions related component or system, and the
problem is repaired or ceases to exist, the PCM cancels
the code after 40 warm-up cycles. Diagnostic trouble
codes that affect vehicle emissions illuminate the Mal-
function Indicator (check engine) Lamp. Refer to Mal-
function Indicator Lamp in this section.
Certain criteria must be met before the PCM
stores a DTC in memory. The criteria may be a spe-
cific range of engine RPM, engine temperature,
and/or input voltage to the PCM.
The PCM might not store a DTC for a monitored cir-
cuit even though a malfunction has occurred. This may
happen because one of the DTC criteria for the circuit
has not been met.For example
,assume the diagnostic
trouble code criteria requires the PCM to monitor the
circuit only when the engine operates between 750 and
2000 RPM. Suppose the sensor's output circuit shorts to
ground when engine operates above 2400 RPM (result-
ing in 0 volt input to the PCM). Because the condition
happens at an engine speed above the maximum thresh-
old (2000 rpm), the PCM will not store a DTC.
There are several operating conditions for which
the PCM monitors and sets DTC's. Refer to Moni-
tored Systems, Components, and Non-Monitored Cir-
cuits in this section.Technicians must retrieve stored DTC's by connect-
ing the DRB scan tool (or an equivalent scan tool) to
the 16±way data link connector (Fig. 1).
NOTE: Various diagnostic procedures may actually
cause a diagnostic monitor to set a DTC. For
instance, pulling a spark plug wire to perform a
spark test may set the misfire code. When a repair
is completed and verified, connect the DRB scan
tool to the 16±way data link connector to erase all
DTC's and extinguish the MIL (check engine lamp).Fig. 1 Data Link (Diagnostic) Connector Location
1 - INSTRUMENT PANEL LOWER/LEFT EDGE
2 - DATA LINK CONNECTOR
WJEMISSIONS CONTROL 25 - 1