1995 JEEP CHEROKEE Compressor

²The PCM opens the ground circuit to the A/C
clutch relay to disengage the A/C compressor clutch.
This will be done for approximately 15 seconds (if the
air conditioning system is operating).
If the vehicle has a manual transmission, the up-
shift lamp is operated by the PCM.
IGNITION SWITCH OFF MODE
When ignition switch is turned to OFF position,
the PCM stops operating the injectors, ignition coil,
ASD relay and fuel pump relay.
THROTTLE BODY
Filtered air from the air cleaner enters the intake
manifold through the throttle body (Fig. 29). Fuel
does not enter the intake manifold through the throt-
tle body. Fuel is sprayed into the manifold by the fuel
injectors. The throttle body is mounted on the intake
manifold. It contains an air control passage (Fig. 30)
controlled by an Idle Air Control (IAC) motor. The air
control passage is used to supply air for idle condi-
tions. A throttle valve (plate) is used to supply air for
above idle conditions.
The throttle position sensor (TPS) and idle air con-
trol (IAC) motor are attached to the throttle body.
The accelerator pedal cable, speed control cable and
transmission control cable (when equipped) are con-
nected to the throttle arm.
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate.Never attempt to adjust the engine idle
speed using this screw.All idle speed functions are
controlled by the PCM.
FUEL RAIL
The fuel rail supplies fuel to the injectors and is
mounted to the intake manifold (Fig. 31). The fuel
pressure regulator is attached to the rail and the fuel
pressure test port is integral with the rail. The fuel
rail is not repairable.
FUEL PRESSURE REGULATOR
The fuel pressure regulator (Fig. 32) is a mechani-
cal device that is not controlled by the powertrain
control module (PCM).
Fig. 29 Throttle BodyÐTypical
Fig. 30 Idle Air Control Passage
Fig. 31 Fuel RailÐTypical
Fig. 32 Fuel Pressure RegulatorÐTypical
JFUEL SYSTEM COMPONENT DESCRIPTION/SYSTEM OPERATION 14 - 33

MULTI-PORT FUEL INJECTION (MFI)ÐGENERAL DIAGNOSIS
INDEX
page page
Automatic Shutdown (ASD) Relay Testing....... 46
Camshaft Position Sensor Test............... 46
Crankshaft Position Sensor Test.............. 47
Diagnostic Trouble Code (DTC)............... 54
DRB Scan Tool........................... 54
Engine Coolant Temperature Sensor Test....... 46
Extended Idle Switch Test................... 48
Fuel Injector Test......................... 51
Fuel Pump Relay Testing................... 47
Fuel System Pressure Test.................. 51
General Information....................... 35
Idle Air Control Motor Test................... 49
Intake Manifold Air Temperature Sensor Test..... 46Manifold Absolute Pressure (Map) Sensor Test . . . 47
On-Board Diagnostics (OBD)................. 51
Oxygen Sensor (O2S) Heating Element Test..... 48
Pcm System Schematics.................... 41
Powertrain Control Module (PCM) 60-Way
Connector............................. 40
RelaysÐOperation/Testing.................. 50
Starter Motor Relay Test.................... 51
Throttle Position Sensor (TPS) Test............ 48
Torque Converter Clutch Relay Test............ 48
Vehicle Speed Sensor Test.................. 48
Visual Inspection.......................... 35
GENERAL INFORMATION
All 2.5L 4-cylinder and 4.0L 6-cylinder engines are
equipped with sequential Multi-Port Fuel Injection
(MFI). The MFI system provides precise air/fuel ra-
tios for all driving conditions.
VISUAL INSPECTION
A visual inspection for loose, disconnected, or incor-
rectly routed wires and hoses should be made. This
should be done before attempting to diagnose or ser-
vice the fuel injection system. A visual check will
help spot these faults and save unnecessary test and
diagnostic time. A thorough visual inspection will in-
clude the following checks:
(1) Verify that the 60-way connector is fully in-
serted into the connector of the powertrain control
module (PCM) (Figs. 1 or 2). Verify that the connec-
tor mounting bolt is tightened to 4 Nzm (35 in. lbs.)
torque.(2) Inspect the battery cable connections. Be sure
they are clean and tight.
(3) Inspect fuel pump relay and air conditioning
compressor clutch relay (if equipped). Inspect ASD
relay and radiator fan relay (if equipped) connec-
tions. Inspect starter motor relay connections. In-
spect relays for signs of physical damage and
corrosion. The relays are installed in the power dis-
tribution center (PDC) (Figs. 3 or 4).
(4) Inspect ignition coil connections. Verify that coil
secondary cable is firmly connected to coil (Figs. 5 or
6).
(5) Verify that distributor cap is correctly attached
to distributor. Be sure that spark plug cables are
firmly connected to the distributor cap and the spark
plugs in their correct firing order. Be sure that coil
cable is firmly connected to distributor cap and coil.
Be sure that camshaft position sensor wire connector
is firmly connected to harness connector (Figs. 7 or
8). Inspect spark plug condition. Refer to Group 8D,
Fig. 1 PCMÐYJ Models
Fig. 2 PCMÐXJ Models
JFUEL SYSTEM GENERAL DIAGNOSIS 14 - 35

(6) Column shift vehicles, install the shift cable
grommet on the shift lever.
(7) Install and tighten the toe plate to floor pan
bolts/nuts to 21.5 Nzm (192 in. lbs.) torque (Fig. 5).
(8) Install the lower portion of the instrument
panel, refer to Group 8E, Instrument Panel.
(9) Install steering wheel on column, refer to Steer-
ing Wheel-Installation.
(10) Connect the negative (ground) cable to the
battery.
NON-TILT STEERING COLUMN
DISASSEMBLYÐCOLUMN OR CONSOLE SHIFT
Steering column removal from the vehicle is not
necessary for;
²Lockplate cover
²Lockplate
²Steering shaft retaining ring
²Canceling cam
²Turn signal switch
²Upper bearing preload spring
²Ignition key/lock cylinder service
The steering column must be removed from
the vehicle to service any other component.
(1) If the column is removed for service, fabricate a
support fixture to clamp it in a vise (Fig. 1).
(2) Remove the steering wheel. Refer to the re-
moval procedure.
(3) Remove the lockplate cover.
WARNING: THE LOCKPLATE RETAINS A VERY
STRONG, SPRING FORCE. DO NOT ATTEMPT TOREMOVE THE STEERING SHAFT RETAINING SNAP
RING WITHOUT USING LOCKPLATE COMPRESSOR
C-4156.
(4) Compress the lockplate with Compressor
C-4156 and release the steering shaft retaining snap
ring (Fig. 2).
(5) Remove the lockplate compressor tool and the
retaining snap ring. Discard the snap ring.
CAUTION: When the steering shaft retaining snap
ring is removed, the steering shaft is no longer re-
tained within the column.
(6) Remove the lockplate, canceling cam, upper
bearing preload spring, and the thrust washer from
the steering column/shaft (Fig. 3).
(7) Remove the hazard warning switch knob. Press
the knob inward and remove it from the column by
turning it counterclockwise.
(8) Remove the turn signal/wiper/cruise control
stalk by pulling it out straight from the column.
Wiper must be in the off position.
(9) Disconnect the turn signal wire harness con-
nector from the bracket.
CAUTION: Wrap tape around the turn signal
switch wire harness connector (Fig. 4) to prevent it
from becoming entangled during removal.
(10) Remove the turn signal switch retaining
screws (Fig. 5), dimmer switch actuator arm, to re-
move the switch. Guide the switch straight up and
out of the steering column.
Fig. 1 Steering Column Support Fixture
Fig. 2 Retaining Snap Ring Removal
19 - 60 STEERINGJ

(6) Position the turn signal switch and wire har-
ness in the cylinder housing. Fold the wires against
the connector. Route the connector down through the
steering column jacket.
(7) Install the windshield wiper wire harness and
switch. Route the wire harness down through steer-
ing column jacket.
(8) Align the turn signal switch in the housing and
secure the switch with the attaching screws. Tighten
the screws to 4 Nzm (35 in. lbs.) torque.
(9) Install the dimmer switch actuator arm.
Tighten the attaching screws to 4 Nzm (35 in. lbs.)
torque.
(10) If equipped, install the cruise control wire har-
ness. Install the turn signal stalk by pushing it
straight into the column.
(11) Position the thrust washer, the upper bearing
preload spring and the canceling cam on the steering
shaft (Fig. 18).
(12) Place the turn signal switch in the neutral
(OFF) position and install the hazard warning switch
knob.
(13) Position the lockplate on the steering shaft.
Install a replacement lockplate retaining snap ring
on the sleeve of the Lock Plate Compressor C-4156.
Install the tool on the steering shaft (Fig. 19).
(14) Compress the lockplate with the compressor
tool and position the retaining snap ring in the steer-
ing shaft groove.
(15) Ensure that the retaining snap ring is com-
pletely seated in the groove before removing the tool.
Remove the tool and install the lockplate cover.(16) Install the steering wheel. Refer to the instal-
lation procedure. Tighten the steering wheel retain-
ing nut to 34 Nzm (25 ft. lbs.) torque.
(17) If removed, install the steering column in the
vehicle. Refer to the installation procedure.
(18) If disconnected, connect the battery negative
cable and, if equipped, reset the clock
Fig. 17 Key/Lock Cylinder InstallationFig. 18 Canceling Cam Position
Fig. 19 Lockplate Snap Ring Installation
JSTEERING 19 - 65

TILT STEERING COLUMN
DISASSEMBLY
(1) Remove the steering column from the vehicle, if
necessary. Refer to the removal procedure.
(2) If the column is removed for service, fabricate a
support fixture to clamp it in a vise (Fig. 1).
(3) If the steering column has not been removed
from the vehicle, place the front wheels in the
straight-ahead position. Disconnect the battery nega-
tive cable.
(4) Protect the painted areas on the steering col-
umn.
(5) Remove the steering wheel. Refer to the re-
moval procedure.
(6) Column shift: Remove the gear selector lever
retaining pin and the lever from the housing.
(7) Remove the lockplate cover. Use two small pry
bars to pry the cover off the lockplate.
WARNING: THE LOCKPLATE RETAINS A VERY
STRONG, SPRING FORCE. DO NOT ATTEMPT TO
REMOVE THE STEERING SHAFT RETAINING SNAP
RING WITHOUT USING LOCKPLATE COMPRESSOR
C-4156.
(8) Compress the lockplate with Lock Plate Com-
pressor C-4156 and release the steering shaft retain-
ing snap ring (Fig. 2).
(9) Remove the lockplate compressor tool and the
retaining snap ring. Discard the snap ring.
(10) Remove the lockplate, canceling cam, upper
bearing preload spring, and the thrust washer from
the steering column/shaft.(11) Remove the hazard warning switch knob.
Press the knob inward and remove it from the steer-
ing column by turning it counterclockwise.
(12) If the steering column is the column shift
type, remove the two retaining screws and the gear
selector indicator cover.
(13) If the steering column is the column shift
type, remove the gear selector indicator lamp bracket
retaining screw. Do not remove the lamp and bracket
at this time.
(14) Remove the tilt-release lever.
(15) Disconnect the turn signal wire harness con-
nector from the bracket located at the lower end of
the steering column (Fig. 3).
CAUTION: Wrap tape around the turn signal switch
wire harness connector to prevent it from becoming
entangled during removal.
(16) Remove the plastic protector from the wire
harness.
(17) Remove the turn signal switch retaining
screws (Fig. 4), dimmer switch actuator arm, to re-
move the switch. Guide the switch straight up and
out of the steering column.
(18) Remove the windshield wiper switch wire har-
ness and all the other wire harnesses located within
the steering column.
(19) Insert the ignition switch key into the key/lock
cylinder. Turn the key to the ON position.
CAUTION: Do not attempt to remove the key warn-
ing buzzer switch and contacts separately. If sepa-
rated, the contacts can detach and drop into the
steering column.
Fig. 1 Steering Column Support Fixture
Fig. 2 Lockplate Snap Ring Removal
19 - 66 STEERINGJ

(36) If equipped, install the cruise control wire har-
ness. Install the turn signal stalk by pushing it
straight into the column.
(37) Insert the hazard warning knob in the hazard
warning switch and press it inward. Align and install
the turn signal switch retaining screws. Ensure that
the turn signal switch is properly seated before tight-
ening the screws. Tighten the screws to 4 Nzm (33 in.
lbs.) torque. Thread the hazard warning switch knob
into the switch and pull the knob outward.
(38) Install and seat the upper bearing race in the
key/lock cylinder housing.
(39) Install the upper bearing preload spring, the
canceling cam and the lockplate.
(40) Install a replacement lockplate retaining snap
ring on the sleeve of the Lock Plate Compressor
C-4156. Install the tool on the steering shaft (Fig.
24).
(41) Compress the lockplate with the compressor
tool and position the retaining snap ring in the steer-
ing shaft groove.
(42) Remove the compressor tool. Ensure that the
retaining ring is completely seated in the groove be-
fore removing the tool.
(43) Position the wire harness protectors if
equipped, over the harnesses and snap in place on
steering column.
(44) Install the lockplate cover.
(45) Install the gear selector lever and the retain-
ing pin.
(46) Install the steering wheel. Refer to the instal-
lation procedure.
(47) Insert the ignition key in the key/lock cylin-
der; turn the cylinder to the OFF-UNLOCK position ;
move the ignition switch downward to eliminate any
switch-to-remote rod lash; and tighten the ignition
switch attaching screws to 4 Nzm (35 in. lbs.) torque.(48) Depress the dimmer switch slightly and insert
a 3/32-inch drill bit into the adjustment hole.
(49) Loosen the retaining screws and move the
dimmer switch toward the steering wheel. Tighten
the dimmer switch retaining screws to 4 Nzm (35 in.
lbs.) torque.
(50) Remove the drill bit and test operation by
moving the dimmer switch stalk. Test the dimmer
switch operation in the full-up, down and center
steering wheel positions.
(51) Install the steering column, if applicable. Re-
fer to the installation procedure.
Fig. 24 Lockplate Retaining Ring Installation
JSTEERING 19 - 73

(4) Tighten fittings at pump and gear to 28 Nzm
(21 ft. lbs.) torque.
(5) After installation, add power steering fluid, in-
spect and test for fluid leaks.
PUMP REPLACEMENT
REMOVAL
(1) Remove and cap pressure and return lines from
pump. Refer to Pressure and Return Line Replace-
ment in this section.(2) Remove belt tension, turn tensioner clock-wise
and slip belt off pulley (Fig. 6).
(3) Remove the screws retaining front bracket and
pump to the rear bracket (Fig. 7, 8).
(4) Remove screws that attach the front bracket to
the rear bracket (Fig. 9).
(5) Remove pump from bracket.
To remove the rear bracket from engine, the air
conditioning compressor and bracket must be re-
moved first. Refer to Group 24, Heating and Air Con-
ditioning for removal procedures.
(6) Remove fan from pulley and hub on rear
bracket.
(7) Remove 4 screws attaching the rear bracket to
block (Fig. 10, 11).
(8) Remove bracket from engine.
Fig. 6 Belt Tensioner
Fig. 7 Pump Mounting Screw Removal/Installation
Fig. 8 Power Steering Pump Mounting
Fig. 9 Front Bracket
19 - 76 STEERINGJ

INSTALLATION
(1) Install the rear bracket to engine. Install
screws finger tight.
(2) Tighten front screws to 48 Nzm (35 ft. lbs.)
torque. Tighten side screw to 48 Nzm (35 ft. lbs.)
torque. It is important to torque the front screws
FIRST and the side screw LAST. This will prevent
the bracket from twisting or distorting.
(3) Install fan to pulley and hub. Tighten the nuts
to 27 Nzm (20 ft. lbs.) torque.
(4) Install air conditioning bracket and compressor
to engine. Refer to Group 24, Heating and Air Condi-
tioning for installation procedures.(5) Loose assemble screws through front bracket,
pump and into rear bracket.
(6) Install screws that attach the front bracket to
the rear bracket (Fig. 8). Tighten the screws to 27
Nzm (20 ft. lbs.) torque (Fig. 7).
(7) Install belt, turn tensioner clockwise and slip
belt onto pulley (Fig. 6).
(8) Install pressure and return lines to pump. Re-
fer to Pressure and Return Line Replacement in this
section.
(9) After installation, add power steering fluid, in-
spect and test for fluid leaks. Refer to Power Steering
PumpÐInitial Operation.
Fig. 11 Rear Bracket (Side View)Fig. 10 Rear Bracket (Front View)
JSTEERING 19 - 77