Air flow JEEP GRAND CHEROKEE 2002 WJ / 2.G Owners Manual

REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Recover the refrigerant from the A/C system-
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - STANDARD PROCEDURE).
(3) Disconnect the the A/C lines from the expan-
sion valve. Cap or tape over the open A/C lines.
(4) Remove the lines from the expansion valve(Re-
fer to 24 - HEATING & AIR CONDITIONING/
PLUMBING/LIQUID LINE - REMOVAL), (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING/
LIQUID LINE - REMOVAL), (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/A/C
DISCHARGE LINE - REMOVAL) and (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/A/C
DISCHARGE LINE - REMOVAL).
(5) Remove the expansion valve retainer screw
from the expansion valve.
(6) Remove the expansion valve.
(7) Remove the expansion valve gasket.
INSTALLATION
(1) Install a NEW gasket and install the eapansion
valve to the evaporator.
(2) Install the expansion valve bolts and tighten to
11 N´m (100 in. lbs.).
(3) Install NEW seals on the A/C lines and install
the lines to the expansion valve(Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/A/C DIS-
CHARGE LINE - INSTALLATION), (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/A/C
DISCHARGE LINE - INSTALLATION), (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING/
LIQUID LINE - INSTALLATION) and (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/
LIQUID LINE - INSTALLATION).
(4) Evacuate the A/C system(Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE).
(5) Recharge the A/C system(Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - STAN-
DARD PROCEDURE).
(6) Connect the battery negative cable.
LIQUID LINE
REMOVAL
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) The liquid line is serviced as an integral part of
the receiver/drier assembly(Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/RECEIVER /
DRIER - REMOVAL) or (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING/RECEIVER /
DRIER - REMOVAL).
REMOVAL - 2.7L TURBO DIESEL
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) The liquid line is service as an integral part of
the receiver/drier assembly(Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/RECEIVER /
DRIER - REMOVAL).
INSTALLATION
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
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.
(1) The liquid line is serviced as an integral part of
the receiver/drier assembly(Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING/RECEIVER /
DRIER - INSTALLATION) or (Refer to 24 - HEAT-
24 - 66 PLUMBINGWJ
A/C EXPANSION VALVE (Continued)

ING & AIR CONDITIONING/PLUMBING/RE-
CEIVER / DRIER - INSTALLATION).
INSTALLATION - 2.7L TURBO DIESEL
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
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.
(1) The liquid line is serviced as an integral part of
the receiver/drier bottle assembly(Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/RE-
CEIVER / DRIER - INSTALLATION).
SUCTION LINE
REMOVAL
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) Disconnect and isolate the battery negative
cable.
(2) Recover the refrigerant from the refrigerant
system. (Refer to 24 - HEATING & AIR CONDI-
TIONING/PLUMBING - STANDARD PROCEDURE -
REFRIGERANT RECOVERY)
(3) Remove the retainer nut from the evaporator
connection (Fig. 8) or (Fig. 9).(4) Slide the suction line off the stud and liquid
line. Install plugs in, or tape over all the opened
refrigerant line fittings. Remove from clip.
(5) Remove the bolt that secures the suction line
fitting to compressor. Install plugs in, or tape over all
of the opened refrigerant line fittings.
(6) Remove the suction line assembly from the
vehicle.
Fig. 8 SUCTION LINE - I-6
1 - SUCTION LINE
2 - RECEIVER DRIER- LIQUID LINE
3 - H-BLOCK
Fig. 9 V-8 Suction Line
1 - SUCTION LINE TO H-BLOCK
2 - A/C COMPRESSOR
3 - SUCTION LINE TO COMPRESSOR
4 - RECEIVER DRIER ASSEMBLY
5 - H-BLOCK
WJPLUMBING 24 - 67
LIQUID LINE (Continued)

REMOVAL - 2.7L TURBO DIESEL
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) Disconnect the negative battery cable.
(2) Recover the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT
RECOVERY)
(3) Remove the refrigerant line retaining fastener
from the H-Valve Block (Fig. 10). Remove the line
and gasket from the H-Valve block and cap or tape
over both ends.
(4) Remove the refrigerant line support bracket
bolt from the cylinder head cap.
(5) Remove the refrigerant line retaining fastener
from the compressor inlet fitting. Remove the line
and cap the compressor outlet tube to prevent con-
tamination of the system.
(6) Unclip and remove the suction line from the
vehicle.
INSTALLATION
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
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.
(1) Remove the tape or plugs from the suction line
block fitting and the manifold on the compressor.
Install the suction line block fitting to the manifold
on the compressor. Tighten the mounting bolt to 25.4
N´m (225 in. lbs.).
(2) Remove the tape or plugs from the refrigerant
line fittings on the evaporator outlet and the suction
line. Slide the suction line copnnection block over the
liquid line and evaporator stud. Tighten the retaining
nut to 28 N´m (250 in. lbs.).
(3) Connect the battery negative cable.
(4) Evacuate the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE)
(5) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)
Fig. 10 Suction-Discharge Lines- RHD (LHD-typical)
1 - SUCTION LINE
2 - H-BLOCK
3 - RECEIVER DRIER
4 - DISCHARGE LINE & SERVICE PORT
5 - A/C COMPRESSOR
6 - DISCHARGE LINE & CONDENSOR CONNECTION
24 - 68 PLUMBINGWJ
SUCTION LINE (Continued)

INSTALLATION - 2.7L TURBO DIESEL
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
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.
(1) Carefully position the suction line in the vehi-
cle.
(2) Remove the cap or tape and install the suction
line on the compressor. Be certain the sealing o-ring
is well lubricated with PAG oil and free of tears.
Torque the retaining fastener to 22 N´m (200 in. lbs.).
(3) Position and install the refrigerant line support
bracket bolt on the cylinder head cap. Torque the bolt
to 20 N´m (177 in. lbs.).
(4) Remove the cap or tape and install the suction
line on the H-Valve Block. Be certain the sealing
O-ring is well lubricated with PAG oil and free of
tears. Torque the retaining fastener to 28 N´m (21 ft.
lbs.).
(5) Install the tie-straps retaining the wire har-
ness on the suction line.
(6) Evacuate the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM EVACUATE)
(7) Charge the refrigerant system. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE - REFRIGERANT SYS-
TEM CHARGE)
(8) Connect the negative battery cable.
A/C EVAPORATOR
DESCRIPTION
The evaporator coil is located in the HVAC hous-
ing, under the instrument panel. The evaporator coil
is positioned in the HVAC housing so that all air that
enters the housing must pass over the fins of the
evaporator before it is distributed through the sys-
tem ducts and outlets. However, air passing over the
evaporator coil fins will only be conditioned when the
compressor is engaged and circulating refrigerant
through the evaporator coil tubes.
OPERATION
Refrigerant enters the evaporator from the orifice
tube as a low-temperature, low-pressure liquid. As
air flows over the fins of the evaporator, the humidity
in the air condenses on the fins, and the heat from
the air is absorbed by the refrigerant. Heat absorp-
tion causes the refrigerant to boil and vaporize. The
refrigerant becomes a low-pressure gas before it
leaves the evaporator.
The evaporator coil cannot be repaired and, if
faulty or damaged, it must be replaced.
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.
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) 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) Lift the evaporator coil unit out of the lower
half of the HVAC housing (Fig. 11).
WJPLUMBING 24 - 69
SUCTION LINE (Continued)

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
inspect all flexible hose refrigerant lines at least once
a year to make sure they are in good condition and
properly routed.
(1) Install the evaporator coil in the bottom half of
the HVAC housing. Be certain that the evaporator
foam insulator wrap is reinstalled.
(2) 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: If the evaporator is replaced, add 60 millili-
ters (2 fluid ounces) of refrigerant oil to the refrig-
erant system.
Fig. 11 HVAC HOUSING- CASE SEPARATED
1 - ELECTRICIAL CONNECTORS
2 - VACUUM ACTUATOR
3 - RECIRCULATION DOOR
4 - THERMAL EXPANSION VALVE
5 - BLOWER MOTOR RESISTOR/CONTROLLER
6 - BLOWER WHEEL
7 - EVAPORATOR AND TUBES
8 - FIN SENSOR PROBE9 - BLEND DOOR
10 - PIVOT SHAFT (MOTOR REMOVED)
11 - PANEL/OUTLET DOOR
12 - LOWER HOUSING
13 - VACUUM ACTUATORS
14 - UPPER HOUSING
15 - VACUUM HARNESS
24 - 70 PLUMBINGWJ
A/C EVAPORATOR (Continued)

HEATER CORE
DESCRIPTION
The heater core is located in the HVAC housing,
under the instrument panel. It is a heat exchanger
made of rows of tubes and fins.
OPERATION
Engine coolant is circulated through heater hoses
to the heater core at all times. As the coolant flows
through the heater core, heat removed from the
engine is transferred to the heater core fins and
tubes. Air directed through the heater core picks up
the heat from the heater core fins. The temperature
control door allows control of the heater output air
temperature by controlling how much of the air flow-
ing through the HVAC housing is directed through
the heater core. The blower motor speed controls the
volume of air flowing through the HVAC housing.
The heater core cannot be repaired and, if faulty or
damaged, it must be replaced. Refer to Cooling for
more information on the engine cooling system, the
engine coolant and the heater hoses.
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.
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) Remove the HVAC housing from the vehicle.
(Refer to 24 - HEATING & AIR CONDITIONING/
DISTRIBUTION/HVAC HOUSING - REMOVAL)
(2) Remove the foam gasket surrounding the core
tubes.
NOTE: Notice the orientation of the irregularly
shaped gasket on the tubes. The gasket must be
placed correctly to ensure proper sealing against
the body during reinstallation.(3)
Remove the screws and retainers that secure the
heater core and tubes to the HVAC housing (Fig. 12).
(4) Remove the mode door actuator if necessary,
for clearance to remove the core.
(5) Lift the heater core straight up and out of the
HVAC housing (Fig. 13).
(6) When replacing individual tubes, loosen and
remove the round tube-to-core clamp, and pull tube
from core.
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
Fig. 12 HEATER CORE, TUBES, AND RETAINERS
1 - TUBE-TO-CORE CLAMPS
2 - GROUND STRAP
3 - HVAC HOUSING
4 - TUBE RETAINERS AND SCREWS
5 - HEATER CORE
WJPLUMBING 24 - 71

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)

(M)Malfunction Indicator Lamp (MIL) illuminated during engine operation if this DTC was recorded
(depending if required by CARB and/or EPA). MIL is displayed as an engine icon on instrument panel.
(G)Generator lamp illuminated
Generic Scan
Tool P-CodeDRB Scan Tool Display Brief Description of DTC
P0406 EGR Position Sensor Volts Too High EGR position sensor input above the acceptable voltage
range.
P0412 Secondary Air Solenoid Circuit An open or shorted condition detected in the secondary
air (air switching/aspirator) solenoid control circuit.
P0420 (M) 1/1 Catalytic Converter Efficiency Catalyst 1/1 efficiency below required level.
P0432 (M) 1/2 Catalytic Converter Efficiency Catalyst 2/1 efficiency below required level.
P0441 (M) Evap Purge Flow Monitor Insufficient or excessive vapor flow detected during
evaporative emission system operation.
P0442 (M) Evap Leak Monitor Medium Leak
DetectedA small leak has been detected in the evaporative
system.
P0443 (M) Evap Purge Solenoid Circuit An open or shorted condition detected in the EVAP purge
solenoid control circuit.
P0455 (M) Evap Leak Monitor Large Leak
DetectedA large leak has been detected in the evaporative system.
P0456 (M) Evap Leak Monitor Small Leak
DetectedLeak has been detected in the evaporative system.
P0460 Fuel Level Unit No Change Over
MilesDuring low fuel
P0460 Fuel Level Unit No Change Over
MilesFuel level sending unit voltage does not change for more
than 40 miles.
PO061 Fuel Level Unit No Change Over
Time
P0462 Fuel Level Sending Unit Volts Too
LowFuel level sensor input below acceptable voltage.
P0462 (M) Fuel Level Sending Unit Volts Too
LowOpen circuit between PCM and fuel gauge sending unit.
P0463 Fuel Level Sending Unit Volts Too
HighFuel level sensor input above acceptable voltage.
P0463 (M) Fuel Level Sending Unit Volts Too
HighCircuit shorted to voltage between PCM and fuel gauge
sending unit.
P0500 (M) No Vehicle Speed Sensor Signal No vehicle speed sensor signal detected during road load
conditions.
P0500 (M) No Vehicle Speed Sensor Signal A vehicle speed signal was not detected.
P0505 (M) Idle Air Control Motor Circuits
P0508 (M) IAC Motor Sense Circuit Low
P0509 (M) IAC Motor Sense Circuit High
P0521 Oil Pressure Switch Rationality
P0522 Oil Pressure Voltage Too Low Oil pressure sending unit (sensor) voltage input below the
minimum acceptable voltage.
P0523 Oil Pressure Voltage Too High Oil pressure sending unit (sensor) voltage input above the
maximum acceptable voltage.
P0524 Oil Pressure Too Low Engine oil pressure is low. Engine power derated.
25 - 8 EMISSIONS CONTROLWJ
EMISSIONS CONTROL (Continued)

(M)Malfunction Indicator Lamp (MIL) illuminated during engine operation if this DTC was recorded
(depending if required by CARB and/or EPA). MIL is displayed as an engine icon on instrument panel.
(G)Generator lamp illuminated
Generic Scan
Tool P-CodeDRB Scan Tool Display Brief Description of DTC
P1291 (M) No Temperature Rise Seen From
Intake Air HeatersProblem detected in intake manifold air heating system.
P1292 CNG Pressure Sensor Voltage Too
HighCompressed natural gas pressure sensor reading above
acceptable voltage.
P1293 CNG Pressure Sensor Voltage Too
LowCompressed natural gas pressure sensor reading below
acceptable voltage.
P1294 (M) Target Idle Not Reached Target RPM not achieved during drive idle condition.
Possible vacuum leak or IAC (AIS) lost steps.
P1295 (M) No 5 Volts to TP Sensor Loss of a 5 volt feed to the Throttle Position Sensor has
been detected.
P1295 (M) Accelerator Position Sensor (APPS)
Supply Voltage Too LowAPPS supply voltage input below the minimum
acceptable voltage.
P1296 No 5 Volts to MAP Sensor Loss of a 5 volt feed to the MAP Sensor has been
detected.
P1297 (M) No Change in MAP From Start To
RunNo difference is recognized between the MAP reading at
engine idle and the stored barometric pressure reading.
P1298 Lean Operation at Wide Open
ThrottleA prolonged lean condition is detected during Wide Open
Throttle
P1299 Vacuum Leak Found (IAC Fully
Seated)MAP Sensor signal does not correlate to Throttle Position
Sensor signal. Possible vacuum leak.
P1388 Auto Shutdown Relay Control Circuit An open or shorted condition detected in the ASD or CNG
shutoff relay control ckt.
P1388 Auto Shutdown Relay Control Circuit An open or shorted condition detected in the auto
shutdown relay circuit.
P1389 No ASD Relay Output Voltage At
PCMNo Z1 or Z2 voltage sensed when the auto shutdown
relay is energized.
P1389 (M) No ASD Relay Output Voltage at
PCMAn open condition detected In the ASD relay output
circuit.
P1390 Timing Belt Skipped 1 Tooth or More Relationship between Cam and Crank signals not correct
P1391 (M) Intermittent Loss of CMP or CKP Loss of the Cam Position Sensor or Crank Position
sensor has occurred. For PL 2.0L
P1398 (M) Mis-Fire Adaptive Numerator at Limit PCM is unable to learn the Crank Sensor's signal in
preparation for Misfire Diagnostics. Probable defective
Crank Sensor
P1399 Wait To Start Lamp Cicuit An open or shorted condition detected in the Wait to Start
Lamp circuit.
P1403 No 5V to EGR Sensor Loss of 5v feed to the EGR position sensor.
P01475 Aux 5 Volt Supply Voltage High Sensor supply voltage for ECM sensors is too high.
P1476 Too Little Secondary Air Insufficient flow of secondary air injection detected during
aspirator test (was P0411)
P1477 Too Much Secondary Air Excessive flow of secondary air injection detected during
aspirator test (was P0411).
25 - 12 EMISSIONS CONTROLWJ
EMISSIONS CONTROL (Continued)

tive system and seal the evaporative system so the
leak detection test can be run.
The primary components within the assembly are:
A three port solenoid that activates both of the func-
tions listed above; a pump which contains a switch,
two check valves and a spring/diaphragm, a canister
vent valve (CVV) seal which contains a spring loaded
vent seal valve.
Immediately after a cold start, between predeter-
mined temperature thresholds limits, the three port
solenoid is briefly energized. This initializes the
pump by drawing air into the pump cavity and also
closes the vent seal. During non test conditions the
vent seal is held open by the pump diaphragm
assembly which pushes it open at the full travel posi-
tion. The vent seal will remain closed while the
pump is cycling due to the reed switch triggering of
the three port solenoid that prevents the diaphragm
assembly from reaching full travel. After the brief
initialization period, the solenoid is de-energized
allowing atmospheric pressure to enter the pump
cavity, thus permitting the spring to drive the dia-
phragm which forces air out of the pump cavity and
into the vent system. When the solenoid is energized
and de energized, the cycle is repeated creating flow
in typical diaphragm pump fashion. The pump is con-
trolled in 2 modes:
Pump Mode:The pump is cycled at a fixed rate to
achieve a rapid pressure build in order to shorten the
overall test length.
Test Mode:The solenoid is energized with a fixed
duration pulse. Subsequent fixed pulses occur when
the diaphragm reaches the Switch closure point.
The spring in the pump is set so that the system
will achieve an equalized pressure of about 7.5º
water. The cycle rate of pump strokes is quite rapid
as the system begins to pump up to this pressure. As
the pressure increases, the cycle rate starts to drop
off. If there is no leak in the system, the pump would
eventually stop pumping at the equalized pressure. If
there is a leak, it will continue to pump at a rate rep-
resentative of the flow characteristic of the size of the
leak. From this information we can determine if the
leak is larger than the required detection limit (cur-
rently set at .040º orifice by CARB). If a leak is
revealed during the leak test portion of the test, the
test is terminated at the end of the test mode and no
further system checks will be performed.
After passing the leak detection phase of the test,
system pressure is maintained by turning on the
LDP's solenoid until the purge system is activated.
Purge activation in effect creates a leak. The cycle
rate is again interrogated and when it increases due
to the flow through the purge system, the leak check
portion of the diagnostic is complete.The canister vent valve will unseal the system
after completion of the test sequence as the pump
diaphragm assembly moves to the full travel position.
Evaporative system functionality will be verified by
using the stricter evap purge flow monitor. At an
appropriate warm idle the LDP will be energized to
seal the canister vent. The purge flow will be clocked
up from some small value in an attempt to see a
shift in the 02 control system. If fuel vapor, indicated
by a shift in the 02 control, is present the test is
passed. If not, it is assumed that the purge system is
not functioning in some respect. The LDP is again
turned off and the test is ended.
MISFIRE MONITOR
Excessive engine misfire results in increased cata-
lyst temperature and causes an increase in HC emis-
sions. Severe misfires could cause catalyst damage.
To prevent catalytic convertor damage, the PCM
monitors engine misfire.
The Powertrain Control Module (PCM) monitors
for misfire during most engine operating conditions
(positive torque) by looking at changes in the crank-
shaft speed. If a misfire occurs the speed of the
crankshaft will vary more than normal.
FUEL SYSTEM MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide. The catalyst works best
when the Air Fuel (A/F) ratio is at or near the opti-
mum of 14.7 to 1.
The PCM is programmed to maintain the optimum
air/fuel ratio of 14.7 to 1. This is done by making
short term corrections in the fuel injector pulse width
based on the O2S sensor output. The programmed
memory acts as a self calibration tool that the engine
controller uses to compensate for variations in engine
specifications, sensor tolerances and engine fatigue
over the life span of the engine. By monitoring the
actual fuel-air ratio with the O2S sensor (short term)
and multiplying that with the program long-term
(adaptive) memory and comparing that to the limit,
it can be determined whether it will pass an emis-
sions test. If a malfunction occurs such that the PCM
cannot maintain the optimum A/F ratio, then the
MIL will be illuminated.
CATALYST MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide.
Normal vehicle miles or engine misfire can cause a
catalyst to decay. This can increase vehicle emissions
25 - 18 EMISSIONS CONTROLWJ
EMISSIONS CONTROL (Continued)