
(11) Connect the heater hoses.
(12) Fill cooling system.
FRESH AIR DOOR VACUUM MOTOR
REMOVAL
(1) Remove glove box and assist handle.
(2) Disconnect vacuum hose from the motor.
(3) Remove motor lever retaining clip.
(4) Remove motor attaching nuts and remove the
motor from the fresh air duct.
INSTALLATION
(1) Position motor on fresh air duct and install the
motor attaching nuts.
(2) Align motor lever with the air door lever and
install the lever retaining clip.
(3) Connect vacuum hose to the motor.
(4) Install glove box and assist handle.
FRESH AIR INTAKE DUCT
REVIEW WARNINGS AND CAUTIONS IN
THIS GROUP BEFORE PERFORMING THIS
OPERATION.
REMOVAL
(1) Drain coolant from the radiator.
(2) Disconnect heater hoses.
(3) Remove nuts attaching the heater housing
studs to the dash panel from inside the engine com-
partment.
(4) Disconnect speedometer cable.
(5) Remove glove box and assist handle.
(6) Tilt heater housing back and pull it rearward
and out from under the instrument panel.
(7) Disconnect vent cables.
(8) Remove windshield bracket bolts and lower
windshield.
(9) Remove fresh air intake grille from the cowl.
(10) Remove fresh air intake duct.
INSTALLATION
(1) Install fresh air intake duct.
(2) Install defroster nozzle and duct.
(3) Raise and secure the windshield.
(4) Install fresh air grille on the cowl.
(5) Install vent cables.
(6) Position heater housing on the dash panel. Be
sure all the housing studs extend through the dash
panel.
(7) Install seals on the blower motor and heater
core inlet and outlet tubes.
(8) Install nuts on the heater housing studs.
CAUTION: DO NOT over tighten the attaching nuts.
The housing could become distorted causing air
leaks and improper heater door operation. Tightenthe nuts alternately and evenly until 2 stud threads
are visible beyond each nut.
(9) Install glove box and assist handle.
(10) Connect speedometer cable.
(11) Connect heater hoses.
(12) Fill cooling system.
TEMPERATURE CONTROL THERMOSTAT
REMOVAL
(1) Remove mounting bolts and lower the evapora-
tor housing.
(2) Remove the attaching screws holding the top
and bottom housings together.
(3) Separate the housings.
(4) Remove the thermostat.
INSTALLATION
(1) Install temperature control thermostat. Insert
thermostat capillary tube into the evaporator coil a
minimum of 50 mm (2 inch).
CAUTION: Handle the tube with care to avoid bends
or kinks that could cause the thermostat to mal-
function.
(2) Assemble the housing and install the attaching
screws. DO NOT over tighten the attaching screws.
(3) Install the evaporator housing.
A/C CONDENSER
REVIEW WARNINGS AND CAUTIONS IN
THIS GROUP BEFORE PERFORMING THIS
OPERATION.
REMOVAL
(1) Recover refrigerant from A/C system.
(2) Drain the radiator.
(3) Remove fan shroud and radiator.
(4) Disconnect A/C line from the condenser.
(5) Remove condenser attaching screws and tilt the
bottom of the condenser toward the engine.Plug all
the condenser openings to prevent entry of dirt
or moisture.
(6) Working from under the vehicle, disconnect the
receiver-drier to-evaporator hose fitting from the re-
ceiver-drier.
(7) Remove condenser and receiver-drier as an as-
sembly.
(8) Remove receiver-drier from the condenser, if
necessary.
INSTALLATION
Add 30 ml (1 fluid oz.) of refrigerant oil to the A/C
system if the condenser is replaced.
(1) Attach receiver-drier to the condenser.
(2) Install condenser and connect A/C line to the
receiver-drier.
24 - 34 HEATING AND AIR CONDITIONINGJ

(3) Install condenser attaching screws.
(4) Connect condenser A/C line.
(5) Install radiator and fan shroud.
(6) Fill coolant system (Refer to cooling for proper
procedure).
(7) Evacuate, charge and leak test the air condi-
tioning system.
RECEIVER-DRIER REPLACEMENT
REVIEW ALL WARNINGS AND CAUTIONS IN
THIS GROUP BEFORE PERFORMING THIS
OPERATION.
REMOVAL
(1) Recover refrigerant from A/C system.
(2) Disconnect A/C lines from the receiver-drier.
(3) Remove receiver-drier attaching screws and re-
move receiver-drier.
INSTALLATION
(1) Position receiver-drier in place and install re-
ceiver-drier attaching screws.
(2) Connect A/C lines to receiver-drier.
(3) Evacuate, charge and leak test the air condi-
tioning system.
EVAPORATOR AND HOUSING
REVIEW ALL WARNINGS AND CAUTIONS IN
THIS GROUP BEFORE PERFORMING THIS
OPERATION.
REMOVAL
(1) Recover refrigerant from A/C system.
(2) Disconnect A/C lines.
(3) Remove hose clamps and dash grommet retain-
ing screws.
(4) Remove the evaporator housing-to-instrument
panel attaching screws and the housing mounting
bracket screw (Fig. 3).
(5) Lower the evaporator housing and pull the
hoses and hose grommet through the dash opening.(6) Remove upper housing and remove evaporator.
The evaporator core, control switches, expansion
valve, blower motor and housing can be serviced af-
ter removing evaporator housing (Fig. 4).
INSTALLATION
Add 30 ml (1 fluid oz.) of refrigerant oil to the A/C
system if the evaporator is replaced.
(1) Install evaporator into housing and install up-
per housing.
(2) Push A/C hoses through the grommet openings
and install the hose grommet by pushing it toward
the engine compartment.
(3) Install hose grommet attaching screws.
(4) Raise evaporator housing and install the evap-
orator housing-to- instrument panel attaching
screws.
(5) Install A/C lines.
(6) Evacuate, charge and leak test the system.
EXPANSION VALVE
REVIEW WARNINGS AND CAUTIONS IN
THIS GROUP BEFORE PERFORMING THIS
OPERATION.
REMOVAL
(1) Recover refrigerant from A/C system.
(2) Remove evaporator housing
(3) Remove the insulation wrapped around the suc-
tion hose fitting, expansion valve and evaporator tub-
ing.
(4) Mark the capillary tube location on the evapo-
rator tubing.
(5) Disconnect inlet and outlet hose fittings, and
remove the capillary tube clamp.
(6) Disconnect and remove the expansion valve.
INSTALLATION
(1) Clean evaporator tubing to provide a positive
contact with the expansion valve capillary tube.
(2) Install expansion valve.
(3) Clamp the capillary tube at the marked loca-
tion on the evaporator tubing.
(4) Connect inlet and outlet hose fittings.The
capillary tube must be securely clamped and
have positive metal-to-metal contact with the
evaporator tubing.
(5) Wrap expansion valve, inlet hose fitting and
capillary tube with insulation.
(6) Install evaporator housing.
(7) Evacuate, charge and leak test the system.
A/C BLOWER MOTOR
It is not necessary to discharge the system to ser-
vice the blower motor. The evaporator housing need
only be lowered for access to the blower motor at-
taching screws.Fig. 3 Evaporator Housing
JHEATING AND AIR CONDITIONING 24 - 35

EMISSION CONTROL SYSTEMS
CONTENTS
page page
COMPONENT REMOVAL/INSTALLATION....... 7
EMISSION CONTROLS.................... 4GENERAL INFORMATION.................. 1
GENERAL INFORMATION
INDEX
page page
Catalytic Convertor......................... 1
DRB Scan Tool............................ 2
Exhaust Gas Recirculation (EGR) System........ 1Service Reminder Indicator (SRI) Lamp.......... 1
Vacuum Hose Routing Schematics............. 2
Vehicle Emission Control Information (VECI) Label . 1
Throughout this group, references are made to par-
ticular vehicle models by alphabetical designation
(XJ or YJ) or by the particular vehicle nameplate. A
chart showing a breakdown of alphabetical designa-
tions is included in the Introduction section at the
beginning of this manual.
Information on the air cleaner housing and the air
cleaner element can be found in Group 14, Fuel Sys-
tems.
CATALYTIC CONVERTOR
Refer to Group 11, Exhaust System and Intake
Manifold for information.
EXHAUST GAS RECIRCULATION (EGR) SYSTEM
An EGR system is not used with the 2.5L 4 cylin-
der or the 4.0L 6 cylinder engine on any XJ or YJ
model.
SERVICE REMINDER INDICATOR (SRI) LAMP
The instrument panel mounted SRI lamp was for-
merly referred to as the emission maintenance re-
minder (EMR) lamp. It isnot usedon any XJ or YJ
model for the 1995 model year.
VEHICLE EMISSION CONTROL INFORMATION
(VECI) LABEL
All vehicles are equipped with a combined VECI la-
bel. The label is located in the engine compartment
(Figs. 1 or 2). The label contains the following:
²Engine family and displacement
²Evaporative family
²Emission control system schematic²Certification application
²Engine timing specifications (if adjustable)
²Idle speeds (if adjustable)
²Spark plug and plug gap
The label also contains an engine vacuum sche-
matic. There are unique labels for vehicles built for
sale in the state of California and the country of
Canada. Canadian labels are written in both the En-
glish and French languages. These labels are perma-
nently attached and cannot be removed without
defacing information and destroying label.
The VECI label illustration (Fig. 3) is used as
an example only.Refer to the VECI label located in
the engine compartment (Figs. 1 or 2) for actual
emission information.
Fig. 1 VECI Label LocationÐXJ Models
JEMISSION CONTROL SYSTEMS 25 - 1

VACUUM ROUTING SCHEMATICÐ2.5L 4 CYLINDER ENGINE
VACUUM ROUTING SCHEMATICÐ4.0L 6 CYLINDER ENGINE
JEMISSION CONTROL SYSTEMS 25 - 3

EMISSION CONTROLS
INDEX
page page
Crankcase Ventilation System................. 5
EVAP (Evaporation) Control System............ 4
EVAP Canister............................ 4Fuel Tank Filler Tube Cap.................... 4
Oxygen (O2S) Sensor....................... 6
Pressure Relief/Rollover Valve................. 6
EVAP (EVAPORATION) CONTROL SYSTEM
GENERAL INFORMATION
The function of the EVAP control system is to pre-
vent the emissions of gasoline vapors from the fuel
tank into the atmosphere. When fuel evaporates in
the fuel tank, the vapors pass through vent hoses or
tubes to a carbon filled EVAP canister. They are tem-
porarily held in the canister until they can be drawn
into the intake manifold when the engine is running.
The EVAP canister is a feature on all models for
the storage of fuel vapors from the fuel tank.
The hoses used in this system are specially
manufactured. If replacement becomes neces-
sary, it is important to use only fuel resistant
hose.
EVAP CANISTER
A sealed, maintenance free, EVAP canister is used
on all vehicles. On XJ models, the EVAP canister is
located in the engine compartment on the passenger
side frame rail (Fig. 4). On YJ models, the EVAP can-
ister is located in the engine compartment on the
dash panel and below the brake master cylinder (Fig.
5). The EVAP canister is filled with granules of an
activated carbon mixture. Fuel vapors entering the
EVAP canister are absorbed by the charcoal granules.
CANISTER OPERATION
Vacuum is used to control and operate the
EVAP canister. No electrical circuitry is used to
control or operate the EVAP system.
The EVAP canister is equipped with a vacuum con-
trolled purge shutoff switch (orifice) (Figs. 4 or 5)
that controls canister purge operation. The switch is
open when manifold vacuum is applied to it. When
the engine is operating, the EVAP canister purge
function draws fresh air through the top of the can-
ister. This causes the stored vapors to be drawn out
of the canister and into the airstream in the air
cleaner snorkel (Fig. 6).
The air cleaner contains a venturi in the air
cleaner cover used as a purge line vacuum source
(Fig. 6). The venturi effect increases the speed of the
intake air flowing by the slots in the venturi wall.
This creates a low pressure area around the slots.
When the purge shutoff switch is open, vapors from
the canister are drawn through slots and into the air-
stream flowing through the venturi (Fig. 7). The va-
pors pass through the intake manifold into the
engine combustion chambers where they are con-
sumed during engine combustion.
FUEL TANK FILLER TUBE CAP
The fuel tank filler tube cap (fuel tank cap) incor-
porates a two-way pressure/relief valve that is closed
to atmosphere during normal operating conditions.Fig. 4 EVAP Canister LocationÐXJ Models
Fig. 5 EVAP Canister LocationÐYJ Models
25 - 4 EMISSION CONTROL SYSTEMSJ

The relief valve used in fuel filler caps of all models
is calibrated at a pressure of 10 kPa (1.5 psi) or a
vacuum of 6 kPa (1.8 in. Hg). When the pressure or
vacuum is relieved, the valve returns to the normally
closed position.
CAUTION: The fuel filler cap must be removed prior
to disconnecting any fuel system component.
CRANKCASE VENTILATION SYSTEM
All 2.5L 4 cylinder and 4.0L 6 cylinder engines are
equipped with a Crankcase Ventilation (CCV) system(Figs. 8 or 9). The CCV system performs the same
function as a conventional PCV system, but does not
use a vacuum controlled valve.
On 4.0L 6 cylinder engines, a molded vacuum tube
connects manifold vacuum to top of cylinder head
(valve) cover at dash panel end. The vacuum tube
contains a fixed orifice of a calibrated size. It meters
the amount of crankcase vapors drawn out of the en-
gine.
On 2.5L 4 cylinder engines, a fitting on drivers side
of cylinder head (valve) cover contains the metered
orifice. It is connected to manifold vacuum.
A fresh air supply hose from the air cleaner is con-
nected to front of cylinder head cover on 4.0L en-
gines. It is connected to rear of cover on 2.5L
engines.
When the engine is operating, fresh air enters the
engine and mixes with crankcase vapors. Manifold
vacuum draws the vapor/air mixture through the
fixed orifice and into the intake manifold. The vapors
are then consumed during combustion.
Fig. 6 EVAP SystemÐTypical
Fig. 7 Air Cleaner VenturiÐTypical
Fig. 8 CCV SystemÐ2.5L EngineÐTypical
Fig. 9 CCV SystemÐ4.0L EngineÐTypical
JEMISSION CONTROL SYSTEMS 25 - 5

COMPONENT REMOVAL/INSTALLATION
INDEX
page page
Air Cleaner Element........................ 7
Coolant Temperature Sensor.................. 7
EVAP Canister............................ 7
Fuel Tank Filler Tube Cap.................... 7Oxygen (O2S) Sensor....................... 7
Powertrain Control Module (PCM).............. 7
Pressure Relief/Rollover Valve................. 7
AIR CLEANER ELEMENT
For removal and installation procedures of both the
air cleaner housing and the air cleaner element, refer
to the Group 14, Fuel System.
COOLANT TEMPERATURE SENSOR
For description, operation, diagnosis and removal/
installation procedures of the engine coolant temper-
ature sensor, refer to Group 14, Fuel Systems.
EVAP CANISTER
On XJ models, the EVAP canister is located in the
engine compartment on the passenger side frame rail
(Fig. 1). On YJ models, the EVAP canister is located
in the engine compartment on the dash panel and be-
low the brake master cylinder (Fig. 2).
REMOVAL/INSTALLATION
(1) Disconnect the vacuum lines at the EVAP can-
ister. Note location of lines before removal.(2) Remove canister retaining strap bolt.
(3) Remove canister from vehicle.
Reverse the procedure for installation.
FUEL TANK FILLER TUBE CAP
If replacement of the fuel filler tube cap (fuel tank
cap) is necessary, it must be replaced with aniden-
tical capto be sure of correct system operation.
OXYGEN (O2S) SENSOR
For description, operation, diagnosis and removal/
installation procedures of the O2S sensor, refer to
Group 14, Fuel Systems.
POWERTRAIN CONTROL MODULE (PCM)
For removal and installation procedures, refer to
Group 14, Fuel Systems.
PRESSURE RELIEF/ROLLOVER VALVE
For removal and installation procedures, refer to
the Fuel Tank section of Group 14, Fuel Systems.
Fig. 1 EVAP CanisterÐXJ Models
Fig. 2 EVAP CanisterÐYJ Models
JEMISSION CONTROL SYSTEMS 25 - 7

FOREWORD
The information contained in this service manual has been prepared for the professional automotive tech-
nician involved in daily repair operations. This manual does not cover theory of operation, which is addressed
in service training material. Information describing the operation and use of standard and optional equipment
is included in the Owner 's Manual provided with the vehicle.
Information in this manual is divided into groups. These groups contain general information, diagnosis,
testing, adjustments, removal, installation, disassembly, and assembly procedures for the components. To as-
sist in locating a group title page, use the Group Tab Locator on the following page. The solid bar after the
group title is aligned to a solid tab on the first page of each group. The first page of the group has a contents
section that lists major topics within the group. If you are not sure which Group contains the information you
need, look up the Component/System in the alphabetical index located in the rear of this manual.
A Service Manual Comment form is included at the rear of this manual. Use the form to provide Chrysler
Corporation with your comments and suggestions.
Tightening torques are provided as a specific value throughout this manual. This value represents the
midpoint of the acceptable engineering torque range for a given fastener application. These torque values are
intended for use in service assembly and installation procedures using the correct OEM fasteners. When re-
placing fasteners, always use the same type (part number) fastener as removed.
Chrysler Corporation reserves the right to change testing procedures, specifications, diagnosis, repair
methods, or vehicle wiring at any time without prior notice or incurring obligation.
NOTE: The acronyms, terminology and nomenclature used to identify emissions related components in
this manual may have changed from prior publications. These new terms are in compliance with S.A.E.
recommended practice J1930.
NEXT PAGE©