2002 JEEP GRAND CHEROKEE Air filter assembly

AIR INLET POINTER
63 Engine Intake Air Temperature
(in degrees F)-40 to
215
64 Vehicle speed in MPH 0 to 255
65 Engine RPM/100 -0 to 82
66 Engine Coolant Temp - 40 (in
degrees F)-40 to
215
67 Country Code 0 to 255
68 Not used 0 to 0
69 Not used 0 to 0
IR SENSOR POINTER
Pointer
NumberDESCRIPTION Value
Displayed
70 Thermistor temp (in degrees) -40 to
215
71 Left side sensor A/D (filtered) 0 to 255
72 Right side sensor A/D (filtered) 0 to 255
73 Left side temp (in degrees F) -40 to
140
74 Right side temp (in degrees F) -40 to
140
75 Not used 0 to 0
76 Not used 0 to 0
77 Not used 0 to 0
78 Not used 0 to 0
79 Not used 0 to 0
IDENTIFICATION POINTER
Pointer
NumberDESCRIPTION Value
Displayed
80 ROM bit pattern number (digits
1,2,3 & 4)0to
9999
81 ROM bit pattern number (digits
5,6,7 & 8)0to
9999
82 CAL bit pattern number (digits
1,2,3 & 4)0to
9999
83 CAL bit pattern number (digits
5,6,7 & 8)0to
9999
84 Not used 0 to 0
85 Not used 0 to 0
86 Not used 0 to 0
87 Not used 0 to 0
88 Not used 0 to 0
89 Not used 0 to 0
OUTPUT CIRCUIT/ACTUATOR TESTS
In the Output Circuit/Actuator Test mode, the out-
put circuits can be viewed, monitored, overridden,
and tested. If a failure occurs in an output circuit,
test the circuit by overriding the system. Test the
actuator through its full range of operation.
(1) To begin the Output Circuit/Actuator Tests you
must be in the Select Test mode.
(2) With a ª00º value displayed in the Test Selector
and no stick man, turn the rotary temperature con-
trol knob until the test number you are looking for
appears in the Test Selector display. See the Circuit
Testing charts for a listing of the test numbers, test
items, test types, system tested, and displayed val-
ues.
(3) To see the output value, depress the a/c or
recirc button. The values displayed will represent the
output from the AZC control module.
(4) To enter the actuator test, depress the a/c or
recirc button. Then, rotate the right temperature set
knob to the desired position.
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) Disconnect and isolate the battery negative
cable.
(2) Remove the center upper, and center lower
bezels from the instrument panel. Refer to Instru-
ment Panel System for the procedures.
(3) Remove the 4 screws that secure the a/c heater
control to the instrument panel (Fig. 13).
(4) Pull the a/c heater control assembly away from
the instrument panel far enough to access the con-
nections on the back of the control.
(5) Unplug the wire and/or vacuum harness con-
nectors from the back of the a/c heater control (Fig.
14).
(6) Remove the a/c heater control from the instru-
ment panel.
24 - 24 CONTROLSWJ
A/C HEATER CONTROL (Continued)

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) When installing individual tubes, insert tube
into core ensuring that tube O-ring is seated in core
and not pinched. Hold tube in seated position while
installing the round tube-to-core clamp (Fig. 14).
NOTE: The round tube-to-heater-core clamp should
be left loose enough to turn the tube in the core.
Position the core in the housing, and then tighten
the tube-to-heater-core clamp after orienting the
tubes to the molded HVAC housing.
(2) Lower the heater core into the HVAC housing.
(3) Install the mode door actuator, if removed from
housing for core removal.
(4) Position the retainers over the heater core
tubes. Install and tighten the screws that secure the
heater core and retainers to the HVAC housing.
Tighten the screws to 2.2 N´m (20 in. lbs.).NOTE: The grounding strap is to be attached to the
lower heater core tube retainer.
(5) Reinstall the HVAC housing to the vehicle.
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - INSTALLA-
TION)
RECEIVER / DRIER
DESCRIPTION
The receiver/drier is mounted in the engine com-
partment between the condenser and is part of the
liquid line assembly. The filter/drier cannot be
repaired, if the filter/drier is faulty, damaged, left
open to the atmosphere or contaminated the line
assembly must be replaced.
OPERATION
The filter-drier performs a filtering action to pre-
vent foreign material in the refrigerant from contam-
inating the expansion valve. A desiccant bag is
mounted inside the filter-drier canister to absorb any
Fig. 13 HEATER CORE AND TUBES - (Typical)
1 - ELECTRICAL CONNECTORS
2 - EXPANSION VALVE
3 - ELECTRIC ACTUATOR
4 - OUTLET TO DEFROSTER DUCTS
5 - ELECTRIC ACTUATOR
6 - FLOOR DUCT
7 - TO REAR PASSENGER FLOOR AIR DUCTS8 - FLOOR DUCT
9 - HEATER CORE AND TUBES
10 - HOUSING DRAIN
11 - BLOWER MOTOR RESISTOR/CONTROLLER
12 - BLOWER MOTOR
13 - GROUND STRAP
24 - 72 PLUMBINGWJ
HEATER CORE (Continued)

moisture which may have netered and become
trapped within the refrigerant system. In addition,
during periods of high demand air conditioner opera-
tion, the filter-drier acts as a reservoir to store sur-
plus refrigerant. Refrigerant enters the filter-drier as
a high-pressure, low-temperature liquid.
REMOVAL
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 refrigerant
system(Refer to 24 - HEATING & AIR CONDITION-
ING/PLUMBING - STANDARD PROCEDURE).
(2) Remove the battery and the battery tray(Refer
to 8 - ELECTRICAL/BATTERY SYSTEM/BATTERY -
REMOVAL) and (Refer to 8 - ELECTRICAL/BAT-
TERY SYSTEM/TRAY - REMOVAL).
(3) Remove the screw from the receiver/drier
bracket (Fig. 15) or (Fig. 16).
(4) Remove the retaining nut from the evaporator
connection and then slide the suction line off the
stud and liquid line.
(5) Remove the receiver/drier bracket from the
stud and disconnect the liquid line from the evapora-tor inlet. Install plugs in or tape over all of the evap-
orator connection openings and opened refrigerant
line fittings.
(6) Disconnect the liquid line from the condenser
outlet. Install plugs in, or tape over all of the opened
refrigerant line fittings.
(7) Remove liquid line assembly.
INSTALLATION
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)
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
Fig. 14 HEATER CORE, TUBES, AND O-RINGS
1 - HEATER CORE TUBES
2 - TUBE-TO-CORE CLAMPS
3 - SCREWS
4 - O-RINGS
5 - HEATER CORE
Fig. 15 COMPRESSOR AND A/C LINES - V8
1 - DISCHARGE LINE
2 - A/C COMPRESSOR
3 - SUCTION LINE
4 - A/C/ CONDENSOR
5 - DISCHARGE LINE TO CONDENSOR
6 - A/C PRESSURE TRANSDUCER SWITCH
7 - A/C/ SERVICE PORT
8 - RECEIVER DRIER
WJPLUMBING 24 - 73
RECEIVER / DRIER (Continued)

OPERATION
The main purpose of the LDP is to pressurize the
fuel system for leak checking. It closes the EVAP sys-
tem vent to atmospheric pressure so the system can
be pressurized for leak testing. The diaphragm is
powered by engine vacuum. It pumps air into the
EVAP system to develop a pressure of about 7.59
H2O (1/4) psi. A reed switch in the LDP allows the
PCM to monitor the position of the LDP diaphragm.
The PCM uses the reed switch input to monitor how
fast the LDP is pumping air into the EVAP system.
This allows detection of leaks and blockage. The LDP
assembly consists of several parts (Fig. 12). The sole-
noid is controlled by the PCM, and it connects the
upper pump cavity to either engine vacuum or atmo-
spheric pressure. A vent valve closes the EVAP sys-
tem to atmosphere, sealing the system during leak
testing. The pump section of the LDP consists of a
diaphragm that moves up and down to bring air in
through the air filter and inlet check valve, and
pump it out through an outlet check valve into the
EVAP system. The diaphragm is pulled up by engine
vacuum, and pushed down by spring pressure, as the
LDP solenoid turns on and off. The LDP also has a
magnetic reed switch to signal diaphragm position to
the PCM. When the diaphragm is down, the switch is
closed, which sends a 12 V (system voltage) signal to
the PCM. When the diaphragm is up, the switch is
open, and there is no voltage sent to the PCM. This
allows the PCM to monitor LDP pumping action as it
turns the LDP solenoid on and off.
LDP AT REST (NOT POWERED)
When the LDP is at rest (no electrical/vacuum) the
diaphragm is allowed to drop down if the internal
(EVAP system) pressure is not greater than the
return spring. The LDP solenoid blocks the engine
vacuum port and opens the atmospheric pressure
port connected through the EVAP system air filter.
The vent valve is held open by the diaphragm. This
allows the canister to see atmospheric pressure (Fig.
13).
DIAPHRAGM UPWARD MOVEMENT
When the PCM energizes the LDP solenoid, the
solenoid blocks the atmospheric port leading through
the EVAP air filter and at the same time opens the
engine vacuum port to the pump cavity above the
diaphragm. The diaphragm moves upward when vac-
uum above the diaphragm exceeds spring force. This
upward movement closes the vent valve. It also
causes low pressure below the diaphragm, unseating
the inlet check valve and allowing air in from the
EVAP air filter. When the diaphragm completes its
upward movement, the LDP reed switch turns from
closed to open (Fig. 14).
DIAPHRAGM DOWNWARD MOVEMENT
Based on reed switch input, the PCM de-energizes
the LDP solenoid, causing it to block the vacuum
port, and open the atmospheric port. This connects
the upper pump cavity to atmosphere through the
EVAP air filter. The spring is now able to push the
diaphragm down. The downward movement of the
diaphragm closes the inlet check valve and opens the
outlet check valve pumping air into the evaporative
system. The LDP reed switch turns from open to
closed, allowing the PCM to monitor LDP pumping
(diaphragm up/down) activity (Fig. 15). During the
pumping mode, the diaphragm will not move down
far enough to open the vent valve. The pumping cycle
is repeated as the solenoid is turned on and off.
When the evaporative system begins to pressurize,
the pressure on the bottom of the diaphragm will
begin to oppose the spring pressure, slowing the
pumping action. The PCM watches the time from
when the solenoid is de-energized, until the dia-
phragm drops down far enough for the reed switch to
Fig. 12 EVAP LEAK DETECTION SYSTEM
COMPONENTS
1 - Reed Switch
2 - Solenoid
3 - Spring
4 - Pump Cavity
5 - Diaphragm
6 - Inlet Check Valve
7 - Vent Valve
8 - From Air Filter
9 - To Canister
10 - Outlet Check Valve
11 - Engine Vacuum
WJEVAPORATIVE EMISSIONS 25 - 31
LEAK DETECTION PUMP (Continued)