engine DODGE NEON 1999 Service Repair Manual

MAXIMUM HEATER OUTPUT: TEST AND
ACTION
Engine coolant is provided to the heater system by
two 16 mm (5/8 inch inside diameter) heater hoses.
With engine idling at normal running temperature,
set the control to maximum heat, floor, and high
blower setting. Using a test thermometer, check the
air temperature coming from the floor outlets, refer
to Temperature Reference Table.
If the floor outlet air temperature is insufficient,
refer to Group 7, Cooling Systems for specifications.
Both heater hoses should be HOT to the touch (cool-
ant return hose should be slightly cooler than the
supply hose). If coolant return hose is much cooler
than the supply hose, locate and repair engine cool-
ant flow obstruction in heater system.
POSSIBLE LOCATIONS OR CAUSE OF
OBSTRUCTED COOLANT FLOW
(1) Pinched or kinked heater hoses.
(2) Improper heater hose routing.
(3) Plugged heater hoses or supply and return
ports at cooling system connections, refer to Group 7,
Cooling System.(4) Plugged heater core.
(5) Air locked heater core.
(6) If coolant flow is verified and outlet tempera-
ture is insufficient, a mechanical problem may exist.
POSSIBLE LOCATION OR CAUSE OF
INSUFFICIENT HEAT
(1) Obstructed cowl air intake.
(2) Obstructed heater system outlets.
(3) Blend-air door not functioning properly.
TEMPERATURE CONTROL
If temperature cannot be adjusted with the TEMP
lever on the control panel, the following could require
service:
(1) Blend-air door binding.
(2) Faulty blend-air door cable.
(3) Improper engine coolant temperature.
(4) Faulty Instrument Panel Control.
LOW PRESSURE CUT-OFF SWITCH
The work area must not be below 21ÉC (70ÉF) to
test the compressor clutch circuit.
(1) With gear selector in park or neutral and park
brake set, start engine and allow to idle.
(2) Raise hood and disconnect low pressure cut off
switch connector boot.
(3) Using a suitable jumper wire, jump across the
terminals inside wire connector boot.
(4) If the compressor clutch does not engage, the
cycling clutch switch, wiring, relay, or fuse can be
defective. Refer to Group 8W, Wiring Diagrams.
(5) If clutch engages, connect manifold gauge set.
Read low pressure gauge. At pressure above 97 kPa
(14 psi) and above, low pressure out off switch will
complete the clutch circuit. If the low pressure gauge
reads below 140 kPa (20 psi), the system is low on
refrigerant charge or empty due to a leak. Refer to
Service±Procedures, System Leak Checking in this
section.
(6) Install connector boot on switch and repeat
Step 3. If the clutch does not engage, replace the low
pressure cut off switch.
SYSTEM CHARGE LEVEL TEST
The procedure below should be used to check
and/or fill the refrigerant charge in the air condition-
ing system.
Fig. 11 Evaporator Probe Harness Connector
TEMPERATURE REFERENCE TABLE
Ambient Temp.Minimum
FloorOutlet
Temp.
Celsius Fahrenheit Celsius Fahrenheit
15.5É 60É 62.2É 144É
21.1É 70É 63.8É 147É
26.6É 80É 65.5É 150É
32.2É 90É 67.2É 153É
PLHEATING AND AIR CONDITIONING 24 - 11
DIAGNOSIS AND TESTING (Continued)

WARNING: AVOID BREATHING A/C REFRIGERANT
AND LUBRICANT VAPOR OR MIST. EXPOSURE MAY
IRRITATE EYES, NOSE AND THROAT. USE ONLY
APPROVED SERVICE EQUIPMENT MEETING SAE
REQUIREMENTS TO DISCHARGE R-134a SYSTEM.
IF ACCIDENTAL SYSTEM DISCHARGE OCCURS,
VENTILATE WORK AREA BEFORE RESUMING SER-
VICE.
R-134a SERVICE EQUIPMENT OR VEHICLE A/C
SYSTEM SHOULD NOT BE PRESSURE TESTED OR
LEAK TESTED WITH COMPRESSED AIR. MIXTURE
OF AIR and R-134a CAN BE COMBUSTIBLE AT ELE-
VATED PRESSURES. THESE MIXTURES ARE
POTENTIALLY DANGEROUS AND MAY RESULT IN
FIRE OR EXPLOSION CAUSING INJURY OR PROP-
ERTY DAMAGE.
NOTE: The maximum amount of R-134a refrigerant
that the air conditioning system holds is 784 grams
(28 oz. or 1.57 lbs.)
It is recommended to use the gauges or reclaim/re-
cycle equipment.
(1) Use a manifold gauge and check the liquid line
pressure.
(2) Attach a clamp-on thermocouple (P.S.E. 66-324-
0014 or 80PK-1A) or equivalent to the liquid line
near the filter/drier.
(3) The vehicle must be in the following modes:
²Automatic transaxle in park or manual tran-
saxle in neutral.
²Engine at idle
²A/C controls set to outside air
²Panel mode
²A/C ON full cool
²Blower motor ON high speed
²Vehicle windows closed
(4) Operate system for a couple of minutes to allow
the system to stabilize.
(5) Observe filter/drier pressure and Liquid line
temperature. Using the Charge Determination Chart
(Fig. 12) determine where the system is currently
operating. If the system is not in the proper range,
reclaim all the refrigerant and recharge per A/C label
.
VACUUM CONTROL SYSTEM
Use an adjustable vacuum test set (Special Tool
C-3707) and a suitable vacuum pump to test the
heater-A/C vacuum control system. With a finger
placed over the end of the vacuum test hose probe
(Fig. 13), adjust the bleed valve on the test set gauge
to obtain a vacuum of exactly 27 kPa (8 in. Hg.).
Release and block the end of the probe several times
to verify that the vacuum reading returns to theexact 27 kPa (8 in. Hg.) setting. Otherwise, a false
reading will be obtained during testing.
ONE-WAY CHECK VALVE
(1) Disconnect the heater-A/C vacuum supply
(Black) tube in the engine compartment. This tube
passes through an opening in the dash panel.
(2) Remove the one-way vacuum check valve. The
valve is located on the (Black) vacuum supply hose at
the brake power booster.
(3) Connect the test set vacuum supply hose to the
heater side of the valve. When connected to this side
of the check valve, no vacuum should pass and the
test set gauge should return to the 27 kPa (8 in. Hg.)
setting. If OK, go to step Step 4. If not OK, replace
the faulty valve.
(4) Connect the test set vacuum supply hose to the
engine vacuum side of the valve. When connected to
this side of the check valve, vacuum should flow
through the valve without restriction. If not OK,
replace the faulty valve.
HEATER-A/C CONTROLS
The operation of the Circulation door can be
viewed by removing the blower motor and looking up
into the unit inlet. See Blower Motor Wheel and
Assembly removal and installation in this section for
service procedures.
(1) Connect the test set vacuum probe to the heat-
er-A/C vacuum supply (Black) hose in the engine
compartment. Position the test set gauge so that it
can be viewed from the passenger compartment.
(2) Start with the Mode control in the Panel posi-
tion and the Circulation control in the Ouside-air
position.
(3) Move the Circulation control to the Recircula-
tion position (the Circulation door should move into
the Recirculation position). After a short pause move
the Mode control to the Defrost position (the Circula-
tion door should move to the Outside-air position).
The test gauge should return to the calibrated set-
ting of 27 kPa (8in. Hg.) after each selection is made.
If the gauge cannot achieve the calibrated setting,
the vacuum circuit or a component has a leak.
(4) If the gauge achieves the calibrated setting but
the door does not move, there is either a pinched vac-
uum line or a failed actuator.
LOCATING VACUUM LEAKS
(1) Connect the test vacuum probe to the vehicles
(Black) supply hose. Position the vacuum test gauge
so it can be viewed from the passenger compartment.
(2) Place the Mode in the Panel position and the
Circulation control in the Recirculation position.
(3) Remove the instrument panel top cover.
(4) Remove the right side upper instrument panel
bezel.
24 - 12 HEATING AND AIR CONDITIONINGPL
DIAGNOSIS AND TESTING (Continued)

This A/C system does not have or use a sight glass to
check or charge the system.
WARNING: REVIEW SAFETY PRECAUTIONS AND
WARNINGS IN THIS GROUP BEFORE CHARGING
THE REFRIGERANT SYSTEM.
AVOID BREATHING A/C REFRIGERANT AND
LUBRICANT VAPOR OR MIST. EXPOSURE MAY
IRRITATE EYES, NOSE AND THROAT. USE ONLY
APPROVED SERVICE EQUIPMENT MEETING SAE
REQUIREMENTS TO DISCHARGE R-134a SYSTEM.
IF ACCIDENTAL SYSTEM DISCHARGE OCCURS,
VENTILATE WORK AREA BEFORE RESUMING SER-
VICE.
R-134a SERVICE EQUIPMENT OR VEHICLE A/C
SYSTEM SHOULD NOT BE PRESSURE TESTED OR
LEAK TESTED WITH COMPRESSED AIR. MIXTURE
OF AIR and R-134a CAN BE COMBUSTIBLE AT ELE-
VATED PRESSURES. THESE MIXTURES ARE
POTENTIALLY DANGEROUS AND MAY RESULT IN
FIRE OR EXPLOSION CAUSING INJURY OR PROP-
ERTY DAMAGE.
CAUTION: Do not overcharge refrigerant system,
as excessive compressor head pressure can cause
noise and system failure.
After the system has been tested for leaks and
evacuated, a refrigerant (R-134a) charge can be
injected into the system.
NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.
(1) If using a separate vacuum pump close all
valves before disconnecting pump. Connect manifold
gauge set to the A/C service ports (Fig. 14).
NOTE: The air conditioning system in this vehicle
holds 784 grams (28 oz. or 1.57 lbs.) of R-134a
refrigerant.
(2) Measure refrigerant (refer to capacities). Refer
to the instructions provided with the equipment
being used.
(3) Verify engine is shut off. Open the suction and
discharge valves. Open the charge valve to allow the
refrigerant to flow into the system. When the trans-
fer of refrigerant has stopped, close the suction and
discharge valve.
(4) If all of the charge did not transfer from the
dispensing device, put vehicle controls into the fol-
lowing mode:
²Automatic transaxle in park or manual tran-
saxle in neutral²Engine idling at 700 rpm
²A/C control set in 100 percent outside air
²Panel mode
²Blower motor ON high speed
²Vehicle windows closed
If the A/C compressor does not engage, test the
compressor clutch control circuit and correct any fail-
ure. Refer to Group 8W, Wiring Diagrams.
(5) Open the suction valve to allow the remaining
refrigerant to transfer to the system.
WARNING: TAKE CARE NOT TO OPEN THE DIS-
CHARGE (HIGH-PRESSURE) VALVE AT THIS TIME.
(6) Close all valves and test the A/C system perfor-
mance.
(7) Disconnect the charging station or manifold
gauge set. Install the service port caps.
EVACUATING REFRIGERANT SYSTEM
NOTE: Special effort must be used to prevent mois-
ture from entering the A/C system oil. Moisture in
the oil is very difficult to remove and will cause a
reliability problem with the compressor.
If a compressor designed to use R-134a refrigerant
is left open to the atmosphere for an extended period
of time. It is recommended that the refrigerant oil be
drained and replaced with new oil or a new compres-
sor be used. This will eliminate the possibility of con-
taminating the refrigerant system.
If the refrigerant system has been open to the
atmosphere, it must be evacuated before the system
can be filled. Moisture and air mixed with the refrig-
erant will raise the compressor head pressure above
acceptable operating levels. This will reduce the per-
formance of the air conditioner and damage the com-
pressor. Moisture will boil at near room temperature
when exposed to vacuum. To evacuate the refrigerant
system:
NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.
(1) Connect a suitable charging station, refrigerant
recovery machine, and a manifold gauge set with
vacuum pump (Fig. 15).
(2) Open the suction and discharge valves and
start the vacuum pump. The vacuum pump should
run a minimum of 45 minutes prior to charge to
eliminate all moisture in system. When the suction
gauge reads -88 kPa (- 26 in. Hg) vacuum or greater
for 45 minutes, close all valves and turn off vacuum
pump. If the system fails to reach specified vacuum,
PLHEATING AND AIR CONDITIONING 24 - 15
SERVICE PROCEDURES (Continued)

SERVICING REFRIGERANT OIL LEVEL
CAUTION: The refrigerant oil used in a R-134a A/C
system is unique. Use only oils which were
designed to work with R-134a refrigerant. The oil
designated for this vehicle is ND8 PAG (polyalka-
lene glycol).
Recovery/recycling equipment will measure the
lubricant being removed. This is the amount of lubri-
cant to be added back to the system. If a new com-
pressor is being installed, drain lubricant from old
compressor, measure the amount drained and discard
old lubricant. Drain the lubricant from the new com-
pressor into a clean container. Return the amount of
lubricant measured from the old compressor, plus the
amount reclaimed from the system back into the new
compressor.
(1) Discharge refrigerant system using recovery/re-
cycling equipment if charge is present.
(2) Disconnect refrigerant lines from A/C compres-
sor. Cap the open lines to prevent moisture from
entering system.
(3) Remove compressor from vehicle.
(4) From suction port on top of compressor, drain
lubricant from compressor.
(5) Add system capacity minus the capacity of
components that have not been replaced. Refer to the
Lubricant Capacity Chart. Add lubricant through the
suction port on compressor. This is not to exceed 200
ml (6.75 oz.) in total.
(6) Install compressor and connect refrigerant
lines. Then evacuate and charge refrigerant system.
SYSTEM LEAK CHECKING
WARNING: R-134a SERVICE EQUIPMENT OR VEHI-
CLE A/C SYSTEM SHOULD NOT BE PRESSURE
TESTED OR LEAK TESTED WITH COMPRESSED
AIR. MIXTURE OF AIR and R-134a CAN BE COM-
BUSTIBLE AT ELEVATED PRESSURES. THESE MIX-
TURES ARE POTENTIALLY DANGEROUS AND MAY
RESULT IN FIRE OR EXPLOSION CAUSING INJURY
OR PROPERTY DAMAGE.
AVOID BREATHING A/C REFRIGERANT AND
LUBRICANT VAPOR OR MIST. EXPOSURE MAY
IRRITATE EYES, NOSE AND THROAT. USE ONLY
APPROVED SERVICE EQUIPMENT MEETING SAE
REQUIREMENTS TO DISCHARGE R-134a SYSTEM.
IF ACCIDENTAL SYSTEM DISCHARGE OCCURS,
VENTILATE WORK AREA BEFORE RESUMING SER-
VICE.
If the A/C system is not cooling properly, determine
if the refrigerant system is fully charged with
R-134a. This is accomplished by performing a system
Charge Level-Check or Fill. If while performing thistest A/C liquid line pressure is less than 345 kPa (50
psi) proceed to Empty Refrigerant System Leak Test.
If liquid line pressure is greater than 345 kPa (50
psi) proceed to low refrigerant level leak test. If the
refrigerant system is empty or low in refrigerant
charge, a leak at any line fitting or component seal is
likely. A review of the fittings, lines and components
for oily residue is an indication of the leak location.
To detect a leak in the refrigerant system, perform
one of the following procedures as indicated by the
symptoms.
EMPTY REFRIGERANT SYSTEM LEAK TEST
(1) Evacuate the refrigerant system to the lowest
degree of vacuum possible (approx. 28 in Hg.). Deter-
mine if the system holds a vacuum for 15 minutes. If
vacuum is held, a leak is probably not present. If sys-
tem will not maintain vacuum level, proceed with
this procedure.
(2) Prepare a .284 Kg. (10 oz.) refrigerant charge
to be injected into the system.
(3) Connect and dispense .284 Kg. (10 oz.) of
refrigerant into the evacuated refrigerant system.
(4) Proceed to Step 2 of Low Refrigerant Level
Leak Test.
LOW REFRIGERANT LEVEL LEAK TEST
(1) Determine if there is any (R-134a) refrigerant
in the system.
(2) Position the vehicle in a wind free work area.
This will aid in detecting small leaks.
(3) Bring the refrigerant system up to operating
temperature and pressure. This is done by allowing
the engine to run for five minutes with the system
set to the following:
²Transaxle in Park
²Engine Idling at 700 rpm
²A/C Controls Set in 100 percent outside air
²Blower switch in the high A/C position
²A/C in the ON position
²Open all windows
CAUTION: A leak detector designed for R-12 refrig-
erant (only) will not detect leaks in a R-134a refrig-
erant system.
(4) Shut off the vehicle and wait 2 to 7 minutes.
Then use an Electronic Leak Detector that is
designed to detect R-134a type refrigerant and search
for leaks. Fittings, lines, or components that appear
to be oily usually indicates a refrigerant leak. To
inspect the evaporator core for leaks, insert the leak
detector probe into the drain tube opening or a heat
duct. A R-134a dye is available to aid in leak detec-
tion, use only Chrysler approved refrigerant dye.
PLHEATING AND AIR CONDITIONING 24 - 17
SERVICE PROCEDURES (Continued)

(4) Remove two resistor block retaining screws.
The screw threads attaching the resistor block are
not full length. It is necessary to gently pry out the
resistor block while turning the screws counterclock-
wise enabling the threads to engages.
(5) Remove resistor block from vehicle.
INSTALLATION
For installation, reverse the above procedures.
BLOWER MOTOR WHEEL
The blower motor wheel is only serviced with the
blower motor. The wheel and the motor are balanced
as an assembly. If the blower motor wheel requires
replacement, the blower motor must also be replaced.
Refer to blower motor for replacement procedure.
COMPRESSOR
CAUTION: Add only new lubricant when system
requires additional lubricant. Do not use old
reclaimed lubricant.
REMOVAL
The A/C compressor may be unbolted and reposi-
tioned without discharging the refrigerant system.
Discharging is not necessary if removing the com-
pressor clutch/coil assembly, engine, cylinder head, or
alternator.
WARNING: REFRIGERANT PRESSURES REMAIN
HIGH EVEN THOUGH THE ENGINE MAY BE
TURNED OFF. DO NOT TWIST OR KINK THE
REFRIGERANT LINES WHEN REMOVING A FULLY
CHARGED COMPRESSOR. SAFETY GLASSES
MUST BE WORN.
(1) Disconnect battery negative cable.
(2) Loosen and remove drive belts, refer to Group
7, Engine Cooling.
(3) Using a R-134a refrigerant recovery machine,
remove the refrigerant from A/C system. If the com-
pressor is being replaced.
(4) Disconnect compressor clutch wire lead.
(5) Remove refrigerant lines from compressor, if
necessary.
(6) If system is left open place plug/cap over open
lines.
(7) Remove compressor attaching bolt.
(8) Remove compressor. If refrigerant lines were
not removed, lift compressor/clutch assembly and tie
it to a suitable component.
INSTALLATION
For installation, reverse the above procedures.
COMPRESSOR CLUTCH/COIL ASSEMBLY
Compressor assembly must be removed from mount-
ing. Although, refrigerant discharge is not necessary.
REMOVAL
(1) Remove the compressor shaft bolt (Fig. 20). A
band type oil filter removal tool can be placed around
the clutch plate to aid in bolt removal.
(2) Tap the clutch plate with a plastic hammer and
remove clutch plate and shim(s) (Fig. 21).
NOTE: Use care not to lose any of the shim(s).
CAUTION: Do not use screwdrivers between the
clutch plate assembly and pulley to remove front
plate as this may damage the front plate assembly.
Fig. 20 Compressor Shaft Bolt and Clutch Plate
Fig. 21 Clutch Plate and Shim(s)
PLHEATING AND AIR CONDITIONING 24 - 19
REMOVAL AND INSTALLATION (Continued)

(4) Install pulley assembly retaining snap ring
(bevel side outward) with Snap Ring Pliers. Press the
snap ring to make sure it is properly seated in the
groove.
(5) If the original front plate assembly and pulley
assembly are to be reused, the old shim(s) can be
used. If not, place a trial stack of shims, 2.54 mm
(0.10 in.) thick, on the shaft against the shoulder.
(6) Install front plate assembly onto shaft.
(7) If installing a new front plate and/or pulley
assembly, the gap between front plate and pulley face
must be checked. Use the following procedure:
(a) Attach a dial indicator to front plate so that
movement of the plate can be measured.
(b) With the dial indicator zeroed on the front
plate, energize the clutch and record the amount of
movement.
(c) The readings should be 0.35 to 0.65 mm
(0.014 to 0.026 in.). If proper reading is not
obtained, add or subtract shims until desired read-
ing is obtained.
(8) Install compressor shaft bolt. Tighten to 17.5
62 N´m (155620 in. lbs.) torque.
NOTE: Shims may compress after tightening shaft
nut. Check air gap in four or more places to verify if
air gap is still correct. Spin pulley for final check.
CLUTCH BREAK-IN
After new clutch installation, cycle the A/C clutch
20 times (5 seconds on and 5 seconds off). During
this procedure, set the system to the A/C mode,
engine rpm at 1500 - 2000, and high blower speed.
This procedure (burnishing) will seat the opposing
friction surfaces and provide a higher clutch torque
capability.
CONDENSATION DRAIN TUBE
REMOVAL
(1) Raise vehicle.
(2) Locate rubber drain tube on right side of dash
panel (Fig. 25).
(3) Squeeze clamp and remove drain tube.
INSTALLATION
To install, reverse the preceding operation. Check
the drain tube nipple on the heater-A/C housing for
any obstructions.
CONDENSER
The condenser is located in front of the engine
radiator. It has no serviceable parts. If damaged or
leaking, the condenser assembly must be replaced.WARNING: THE REFRIGERANT MUST BE
REMOVED FROM THE SYSTEM BEFORE REMOV-
ING THE CONDENSER.
REMOVAL
(1) Using a R-134a refrigerant recovery machine,
remove the refrigerant from the A/C system.
(2) Remove battery support strut.
(3) Remove refrigerant lines from condenser.
(4) Remove upper radiator mounts.
(5) Remove condenser to radiator mounting
screws.
(6) Tilt radiator back and remove condenser.
INSTALLATION
For installation, reverse the above procedures.
DISCHARGE LINE
WARNING: THE REFRIGERANT SYSTEM MUST BE
RECOVERED BEFORE SERVICING ANY PART OF
THE REFRIGERANT SYSTEM.
REMOVAL
(1) Using a R-134a refrigerant recovery machine,
remove the refrigerant from A/C system.
(2) From the top side of the vehicle, remove line at
compressor (Fig. 26).
(3) From the bottom side of the vehicle, remove
line at condenser.
INSTALLATION
For installation, reverse the above procedures.
EVAPORATOR
This vehicle uses an aluminum plate and fin style
evaporator. It is located in the Evaporator/Blower
module.
Fig. 25 Condensate Water Drain Tube ± Typical
PLHEATING AND AIR CONDITIONING 24 - 21
REMOVAL AND INSTALLATION (Continued)

(2) If previous probe was removed from top hole,
use a small plastic stick and make a new hole. Make
the hole 1/4 inch above or below the original hole in
the evaporator core.
(3) Insert new probe into hole between evaporator
fins.
(4) Reinstall rubber grommet into evaporator
probe access hole.
EXPANSION VALVE
WARNING: THE REFRIGERATION SYSTEM MUST
BE COMPLETELY EMPTY BEFORE PROCEEDING
WITH THIS OPERATION.
REMOVAL
(1) Remove the boot-type wire connector from the
pressure cut-off switch.
(2) Remove the center bolt of refrigerant line
plumbing sealing plate (Fig. 31).
(3) Carefully pull the refrigerant line-sealing plate
assembly from the expansion valve towards front of
vehicle. Do not scratch the expansion valve sealing
surfaces with pilot tubes.
(4) Cover the openings on A/C line-sealing plate
assembly to prevent contamination.
(5) Remove two screws securing the expansion
valve to the evaporator sealing plate.
(6) Carefully remove valve.
INSTALLATION
(1) Remove and replace the aluminum gasket on
the evaporator sealing plate.
(2) Carefully hold the expansion valve to the evap-
orator sealing plate so not to scratch the sealing sur-
face. Install two screws and tighten to 1163 N´m
(100630 in. lbs.).
(3) Remove and replace the aluminum gasket on
the refrigerant line- sealing plate assembly.(4) Carefully hold the refrigerant line-sealing plate
assembly to the expansion valve. Install bolt and
tighten to 2363 N´m (200630 in. lbs.).
(5) Connect wires to low pressure cut-off switch.
(6) Evacuate and recharge system.
(7) After expansion valve is installed, system is
charged, and leaks have been checked, repeat A/C
performance check.
A/C FILTER/DRIER
The filter/drier is mounted in a rubber grommet on
the right side of the engine compartment. The refrig-
erant must be recovered from the A/C system before
replacing the filter/drier assembly.
WARNING: THE REFRIGERATION SYSTEM MUST
BE COMPLETELY RECOVERED BEFORE PRO-
CEEDING WITH THIS OPERATION.
REMOVAL
(1) Disconnect liquid line from filter/drier.
(2) Disconnect liquid line on suction line assembly
from filter/drier.
(3) Pull filter/drier out of rubber grommet.
INSTALLATION
For installation, reverse the above procedures.
HIGH PRESSURE CUT OUT SWITCH
WARNING: THE REFRIGERANT MUST BE
REMOVED FROM THE SYSTEM BEFORE REMOV-
ING THE HIGH PRESSURE CUT OUT SWITCH.
REMOVAL
(1) Disconnect wiring connector at the switch (Fig.
32).
(2) Remove internal snap ring.
Fig. 30 Evaporator Probe LocationFig. 31 Expansion Valve
PLHEATING AND AIR CONDITIONING 24 - 23
REMOVAL AND INSTALLATION (Continued)

(3) Pull switch out of manifold.
INSTALLATION
For installation, reverse the above procedures.
HIGH PRESSURE RELIEF VALVE
WARNING: AVOID BREATHING A/C REFRIGERANT
AND LUBRICANT VAPOR OR MIST. EXPOSURE MAY
IRRITATE EYES, NOSE AND THROAT. USE ONLY
APPROVED SERVICE EQUIPMENT MEETING SAE
REQUIREMENTS TO DISCHARGE R-134a SYSTEM.
IF ACCIDENTAL SYSTEM DISCHARGE OCCURS,
VENTILATE WORK AREA BEFORE RESUMING SER-
VICE.
R-134a SERVICE EQUIPMENT OR VEHICLE A/C
SYSTEM SHOULD NOT BE PRESSURE TESTED OR
LEAK TESTED WITH COMPRESSED AIR. MIXTURE
OF AIR and R-134a CAN BE COMBUSTIBLE AT ELE-
VATED PRESSURES. THESE MIXTURES ARE
POTENTIALLY DANGEROUS AND MAY RESULT IN
FIRE OR EXPLOSION CAUSING INJURY OR PROP-
ERTY DAMAGE.
REMOVAL
(1) Using a R-134a refrigerant recovery machine,
remove the refrigerant from A/C system.
(2) Rotate the high pressure relief valve counter-
clockwise and separate relief valve from the vehicle
(Fig. 32).
INSTALLATION
For installation, reverse the above procedures
using a new O-ring seal. Evacuate and charge the
refrigerant system.
HEATER CORE
Refer to Air Distribution Recondition of this section
for heater core removal procedure.
HEATER HOSES
CAUTION: When removing hoses from heater core
inlet or outlet nipples DO NOT exert excess pres-
sure. The heater core may become damaged and
leak engine coolant.
NOTE: Review Cooling System Precautions before
proceeding with this operation.
REMOVAL
(1) Drain engine cooling system. Refer to Group 7,
Cooling System.
(2) Remove clamp at end of heater hose to be
removed.
(3) RHD vehicles, heater hoses at the heater core
connection have quick connects (Fig. 33). The quick
connect consist of two pieces; a quick connect and
insert. The quick connect is removed by compressing
the insert with a pliers, pull quick connect free of
insert/nipple. Carefully compressed insert pulling the
quick connect from connector nipple. The insert will
remain on the connector nipple as the quick connect
is removed.
(4) Remove the heater hose clamp from the heater
hose at the block and remove hose.
INSTALLATION
NOTE: The insert should be remove from the con-
nector nipple and place it in side of the quick con-
nect.
For installation, reverse the above procedures.
Fig. 33 Heater Hose Quick Connect
Fig. 32 High Pressure Relief Valve Location
24 - 24 HEATING AND AIR CONDITIONINGPL
REMOVAL AND INSTALLATION (Continued)

(3) Using a refrigerant recovery machine, remove
the refrigerant from the A/C system, if equipped.
(4) Remove suction line at expansion valve. Place a
piece of tape over open refrigerant line to prevent
moisture and/or dirt from entering the line.
(5) Remove expansion valve from evaporator. Place
a piece of tape over open evaporator fitting to pre-
vent moisture and/or dirt from entering the evapora-
tor.
(6) Remove rubber drain tube extension from con-
densation drain tube.
(7) Remove three retaining nuts located in the
engine compartment, on the dash panel (Fig. 41).
(8) Remove the right side retaining screw (Fig. 42).
(9) Remove remaining nut located on dash panel
stud.
(10) Disconnect the blue five way connector from
the plenum. Module wiring harness must be removed
with module.
(11) Remove assembly from the vehicle.
INSTALLATION
For installation, reverse the above procedures.
DISASSEMBLY AND ASSEMBLY
AIR DISTRIBUTION MODULE ± RECONDITION
Use this procedure if any or all of the following
items require service:
²Heater core
²Temperature door
²Mode door
²Heat/Defrost door
²Assembly housing
The unit housing must be removed from the vehi-
cle before beginning with this procedure. Refer to
Unit Housing in this section for removal procedure.
DISASSEMBLE
For RHD vehicles, the Unit Housing does not sep-
arate. It is a one piece unit and must be replaced as
a whole.
(1) Remove the clips and screws that hold the Air
Distribution Module to the Evaporator/Blower Mod-
ule. Then separate the two units (Fig. 43).
(2) Remove the panel opening foam seal, demister
opening foam seal, and heater core tube foam seals
from unit.
(3) Remove the retaining clips and screws that
hold the upper and lower housings together (Fig. 44).
(4) Place the unit in the upside down position.
Then separate the two halves of the module (Fig. 45).
(5) Lift the heater core out of the case (Fig. 46).
(6) Press tab in at base of temperature door and
release door from lever (Fig. 47). Then remove the
door.
Fig. 41 Dash Panel Studs
Fig. 42 Retaining Screws
Fig. 43 Air Distribution and Evaporator/Blower
Module Separation
24 - 28 HEATING AND AIR CONDITIONINGPL
REMOVAL AND INSTALLATION (Continued)

EMISSION CONTROL SYSTEMS
CONTENTS
page page
EVAPORATIVE EMISSION CONTROLS........ 11
EXHAUST GAS RECIRCULATION (EGR)
SYSTEM.............................. 18ON-BOARD DIAGNOSTICS.................. 1
ON-BOARD DIAGNOSTICS
INDEX
page page
GENERAL INFORMATION
SYSTEM DESCRIPTION................... 1
DESCRIPTION AND OPERATION
CIRCUIT ACTUATION TEST MODE........... 2
COMPONENT MONITORS.................. 9
DIAGNOSTIC TROUBLE CODES............. 2
HIGH AND LOW LIMITS................... 10LOAD VALUE........................... 10
MALFUNCTION INDICATOR LAMP (MIL)....... 1
MONITORED SYSTEMS.................... 6
NON-MONITORED CIRCUITS............... 9
STATE DISPLAY TEST MODE............... 2
TRIP DEFINITION........................ 9
GENERAL INFORMATION
SYSTEM DESCRIPTION
The Powertrain Control Module (PCM) monitors
many different circuits in the fuel injection, ignition,
emission and engine systems. If the PCM senses a
problem 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 warmup
cycles. Diagnostic trouble codes that affect vehicle
emissions illuminate the Malfunction Indicator Lamp
(MIL). Refer to Malfunction 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
circuit 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'soutput circuit shorts to ground when engine operates
above 2400 RPM (resulting in 0 volt input to the
PCM). Because the condition happens at an engine
speed above the maximum threshold (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.
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, use the DRB scan tool to
erase all DTC's and extinguish the MIL.
Technicians can display stored DTC's by using the
DRB scan tool. Refer to Diagnostic Trouble Codes in
this section. For DTC information, refer to charts in
this section.
DESCRIPTION AND OPERATION
MALFUNCTION INDICATOR LAMP (MIL)
As a functional test, the Malfunction Indicator
Lamp (MIL) illuminates at key-on before engine
PLEMISSION CONTROL SYSTEMS 25 - 1