ECU JEEP CHEROKEE 1994 Service Repair Manual

²if the vehicle is damaged, secure the loose and pro-
truding parts;
²always use a safety chain system that is indepen-
dent of the lifting and towing equipment;
²do not allow any of the towing equipment to con-
tact the disabled vehicle's fuel tank;
²do not allow anyone to be under the disabled vehi-
cle while it is lifted by the towing equipment;
²do not allow passengers to ride in a vehicle being
towed;
²always observe all state and local laws involving
warning signals, night illumination, speed, etc.
²do not attempt a towing operation that could jeop-
ardize the safety of the operator, bystanders or other
motorists;
²do not exceed a towing speed of 48 km/h (30 mph);
²avoid towing distances of more than 24 km (15
miles) whenever possible; and
²do not attach tow chains or a tow sling to a
bumper, the steering linkage, the universal joints,
the constant velocity (CV) joints, or a drive shaft.
CLEARANCES AND RAMP ANGLE
SURFACE CLEARANCE
The end of the disabled vehicle that is attached to
the tow vehicle should be lifted a minimum of 10 cm
or four inches off the surface. Inspect to ensure that
the opposite end of the disabled vehicle has clearance
from the surface.
RAMP ANGLEÐFLAT-BED TOWING
If a vehicle with flat-bed towing equipment is used,
the approach ramp angle should not exceed 15 de-
grees.
SLING-TYPE, FRONT-END TOWING
XJ VEHICLES
Use the following guidelines when the tow vehicle
is attached to the front end of a disabled vehicle.
(1) Always tow with the front wheels lifted off the
surface and turned all the way to the right.
(2) Attach a J-hook to the disabled vehicle at the
left side of the axle (Fig. 10).
(3) Position the sling crossbar close to the J-hook
and below the front bumper (Fig. 11).
(4) Secure a chain to the right side of vehicle by
placing it over the axle shaft tube and attaching it to
a structural member.
(5) Attach the safety chains to the vehicle.
2WD With Manual Or Automatic Transmission
(6) Turn the ignition switch to the OFF position to
unlock the steering wheel.
(7) Shift the transmission to NEUTRAL, mark the
drive shaft and axle drive pinion gear shaft yoke for
installation reference. Remove the drive shaft from
the vehicle.(8) Cover the exposed end of the transmission ex-
tension housing and the universal joints. Store the
drive shaft in a safe place.
4WD, Command-Trac (231 Part-Time 4WD
Transfer Case) And Manual Transmission
(6) Turn the ignition switch to the OFF position to
unlock the steering wheel.
When the transfer case is in the NEUTRAL po-
sition, both axles are disengaged from the pow-
ertrain. This allows the vehicle to be towed
without removing the drive shafts.
(7) Shift the manual transmission into a forward
gear and the transfer case to NEUTRAL.
4WD, Command-Trac (231 Part-Time 4WD
Transfer Case) And Automatic Transmission
(6) Turn the ignition switch to the OFF position to
unlock the steering wheel.
Fig. 10 Sling-Type, Front-End Towing (XJ Front
View)
Fig. 11 Sling-Type, Front-End Towing (XJ Rear
View)
JLUBRICATION AND MAINTENANCE 0 - 9

(7) Apply a small amount of chassis lubricant (or
an equivalent protective coating) to the cable termi-
nals to minimize corrosion.
RUBBER AND PLASTIC DUCTS/HOSES/TUBING
RECOMMENDED MAINTENANCE
Rubber and plastic ducts/hoses/tubing should be in-
spected at the same time the engine oil is changed
and the oil filter is replaced.
The conditions associated with vehicle operation
determines the usable life of the rubber and plastic
ducts/hoses/tubing. These conditions include:
²the extent and quality of vehicle maintenance,
²the geographic area of vehicle operation, and
²the length of exposure time to excess heat and
chemical contaminants.
DUCT/HOSE/TUBING INSPECTIONÐEXCEPT
EMISSION CONTROL HOSES/TUBING
Refer to Group 25ÐEmission Control Systems.
Engine performance could be affected by air leaks
into various hoses.
Rubber/plastic ducts, hoses and tubing should
be replaced immediately if there is any evidence
of deterioration.
(1) Inspect all hose fittings for looseness and corro-
sion. Inspect rubber ducts (Fig. 12) and hoses for
brittleness and cracks. Examine the hose ends (those
that are slipped over nipple connectors) for splits.
(2) Inspect surface of hoses and tubing (Fig. 13) for
heat and mechanical damage.The hose and tubing
that is located near an exhaust manifold should
be given special attention.
(3) Inspect the rubber hose routing to ensure that
the hoses do not contact any heat source, moving
component, etc., that could potentially cause heat or
mechanical damage (Figs. 14, 15, and 16).
(4) Inspect all the hose connections to ensure that
they are secure and that there is no fluid leakage. Inmany instances, liquid lubricants are used to aid in
the connection of hoses to couplings.
Fig. 12 Intake Air Duct (XJ)ÐTypical
Fig. 13 Washer Fluid TubingÐTypical
Fig. 14 ATF Cooler Hoses ÐXJ Vehicles
Fig. 11 Brake Booster Vacuum Hose (XJ)ÐTypical
JLUBRICATION AND MAINTENANCE 0 - 19

(2) Inspect the surface of hoses and tubing for heat
and mechanical damage. Hose and tubing located
close to an exhaust pipe should be given special at-
tention.
(3) Inspect the rubber hose routing to ensure that
the hoses do not contact any heat source, moving
component, etc., that would potentially cause heat or
mechanical damage.
(4) Inspect all the hose connections to ensure that
they are secure and there is no fluid leakage. Actual
dripping of hot fluid should be noted and the clamps
tightened in an attempt to stop the leakage before
replacing the hose.
Fig. 18 Front Axle Vacuum Shift Tubing
Fig. 19 Transfer Case Vent Hose (4WD)ÐTypical
Fig. 20 Rear Axle Vent HoseÐXJ Vehicles
Fig. 21 Rear Axle Vent HoseÐYJ Vehicles
Fig. 22 Rear Axle Vent Hose At WheelhouseÐYJ
Vehicles
JLUBRICATION AND MAINTENANCE 0 - 29

FRONT WHEEL BEARINGS
Only 2WD XJ vehicles are equipped with front
wheel bearings. XJ vehicles have semi-floating axle
shafts and axle shaft bearings that are lubricated via
differential lube oil.
RECOMMENDED MAINTENANCEÐ2WD XJ
VEHICLES
The front wheel bearings should be lubricated (re-
packed) at the same time as front brake pad/caliper
service is conducted.
LUBRICANT SPECIFICATION
Wheel bearings should be lubricated with a lubri-
cant that is identified as NLGI GC-LB lubricant.
INSPECTION/LUBRICATION
(1) Remove the wheel/tire and the disc brake cali-
per.Do not disconnect the caliper brake fluid
hose unless the caliper must also be removed for
maintenance. Support the caliper with a hanger
to prevent brake fluid hose damage.
(2) Remove the dust cap, the cotter pin, the nut re-
tainer, the adjustment nut, and the thrust washer
from the spindle (Fig. 3). Discard the cotter pin.
(3) Remove the wheel outer bearing from the hub.
(4) Remove the wheel hub/disc brake rotor from
the spindle.
(5) Remove the seal and the inner wheel bearing
from the hub cavity.
(6) After removal, inspect both front wheel bearing
races for indications of pitting, brinelling and exces-
sive heat.
(7) Wipe the spindle clean and apply a small
amount of chassis/wheel bearing lubricant (NLGI
GC-LB lubricant) to prevent rust. Wipe the wheel
hub cavity clean.
CAUTION: Do not over-fill the wheel hub cavity with
lubricant. Excessive lubricant can cause overheat-ing and bearing damage. Also, excessive lubricant
can be forced out of the wheel hub cavity and con-
taminate the brake rotor/pads.
(8) Partially fill the wheel hub cavity with chassis/
wheel bearing lubricant (NLGI GC-LB lubricant).
(9) Pack the wheel bearings with chassis/wheel
bearing lubricant (NLGI GC-LB lubricant). Ensure
that sufficient lubricant is forced between the bear-
ing rollers.
(10) Install the wheel inner bearing in the wheel
hub and install a replacement seal.
(11) Clean the disc brake rotor contact surfaces, if
necessary.
(12) Install the wheel hub/disc brake rotor on the
spindle.
(13) Install the wheel outer bearing, the thrust
washer, and the spindle nut.
(14) Tighten the spindle nut with 28 NIm (21 ft.
lbs.) torque while rotating the disc brake rotor to
seat the bearings.
(15) Loosen the spindle nut 1/2 turn. While rotat-
ing the disc brake rotor, tighten the spindle nut with
2NIm (19 in. lbs.) torque.
(16) Install the nut retainer and a replacement cot-
ter pin.
(17) Clean the dust cap and apply wheel bearing
lubricant to the inside surface.Do not fill the dust
cap with lubricant.
(18) Install the dust cap.
(19) Install the disc brake caliper.
POWER STEERING SYSTEM
RECOMMENDED MAINTENANCE
The condition of power steering system should be
inspected and the fluid level checked. Add fluid as
necessary.
FLUID SPECIFICATION
Jeeptpower steering systems require MOPAR
Power Steering Fluid, or an equivalent product.
The original power steering fluid installed in
Jeeptvehicles includes black-light leak detec-
tion dye.
INSPECTION
Inspect the power steering system (Figs. 4 and 5)
for the sources of fluid leaks, steering gear housing
cracks and ensure that the steering gear is securely
attached to the vehicle frame rail. Inspect the steer-
ing damper for leaks and loose connections.
FLUID LEVEL
The fluid level dipstick is attached to the reservoir
cap (Fig. 6). The fluid level in the reservoir can be
determined with the fluid either hot or cold.
(1) Remove the cap from the reservoir.
Fig. 3 2WD Front Wheel BearingsÐXJ Vehicles
JLUBRICATION AND MAINTENANCE 0 - 31

TOE POSITIONÐXJ VEHICLES
The wheel toe position adjustment should be the fi-
nal adjustment.
(1) Start the engine and turn wheels both ways be-
fore straightening the wheels. Secure the steering
wheel with the front wheels in the straight-ahead po-
sition.
(2) Loosen the adjustment sleeve clamp bolts (Fig.
4).
(3) Adjust the right wheel toe position with the
drag link. Turn the sleeve until the right wheel is at
specifications. Position the clamp bolts as shown
(Fig. 5) and tighten to 49 Nzm (36 ft. lbs.) torque.
Make sure the toe setting does not change dur-
ing clamp tightening.
(4) Adjust the left wheel toe position with the tie
rod. Turn the sleeve until the left wheel is at speci-
fications. Position the clamp bolts as shown (Fig. 5)
and tighten to 27 Nzm (20 ft. lbs.) torque.Make sure
the toe setting does not change during clamp
tightening.
(5) Verify the right toe setting.
Fig. 4 Steering LinkageÐXJ Vehicles
Fig. 5 Drag Link and Tie Rod Clamp Location
2 - 8 FRONT SUSPENSION AND AXLEJ

TOE POSITIONÐYJ VEHICLES
The wheel toe position should be the final front
wheel alignment adjustment. In all instances follow
the equipment manufacturer's recommended proce-
dure.
(1) Secure the steering wheel with the front wheels
in the straight-ahead position. For vehicles equipped
with power steering, start the engine before straight-
ening the wheels.(2) Loosen the adjustment sleeve clamp bolts on
the tie rod (Fig. 6).
YJ Vehicles
The tie rod and adjustment sleeve have both
right and left hand threads to provide equal ad-
justment for each wheel.
(3) After the adjustment is completed, position the
tie rod adjustment sleeve clamp bolts as shown.
(4) Tighten the adjustment sleeve clamp bolts to
27 Nzm (20 ft. lbs.) torque.
(5) The steering wheel can be centered by the drag
link. Complete the adjustment. Position the drag link
clamp bolts as shown. Tighten the bolts to 49 Nzm
(36 ft. lbs.) torque.
Fig. 6 Steering Linkage
ALIGNMENT SPECIFICATIONSÐXJ VEHICLES
ALIGNMENT SPECIFICATIONSÐYJ VEHICLES
JFRONT SUSPENSION AND AXLE 2 - 9

WARNING: WRAP SHOP TOWELS AROUND FUEL
HOSES TO ABSORB ANY FUEL SPILLAGE DURING
FUEL TANK REMOVAL.
(5) Disconnect fuel vent supply and return tubes
from fittings on fuel pump module.
(6) Disconnect fuel pump module electrical harness
connector from main harness.
(7) Using a brass punch and hammer, remove fuel
pump module lock ring by carefully tapping it coun-
terclockwise (Fig. 1).
(8) Remove fuel pump module and O-ring seal.
Discard old O-ring and fuel pump module inlet filter.
DISASSEMBLYÐXJ MODELS
(1) Remove and discard fuel pump inlet filter.
The wire terminals to the fuel pump motor are dif-
ferent in size and cannot be connected to the wrong
terminal.
(2) Disconnect fuel pump terminal wires.
(3) Remove fuel pump outlet hose and clamp. Re-
place the hose if it shows any signs of fatigue or fail-
ure.
(4) Remove fuel pump top mounting bracket nut.
Remove fuel pump (Fig. 2).
ASSEMBLYÐXJ MODELS
Whenever the fuel pump is replaced, the fuel pump
inlet filter (sock) must also be replaced.
(1) Place fuel pump top mounting bracket over top
of pump.
(2) Position fuel pump into lower bracket. Slide
stud of top bracket through hole in fuel pump side
bracket. Tighten fuel pump top mounting nut.
(3) Install new fuel pump outlet hose. Secure with
new clamps.
(4) Connect wire terminals to motor.
(5) Install new fuel pump inlet filter.
INSTALLATIONÐXJ MODELS
Whenever the fuel pump is replaced, the fuel
pump inlet filter must also be replaced.
(1) Install new fuel pump inlet filter onto fuel
pump.
(2) Install fuel pump module assembly and new O-
ring seal. The rubber stopper on the end of the fuel
return tube of the assembly must be inserted into the
cup in the fuel tank reservoir (Fig. 3).
Fig. 1 Removing Lock RingÐXJ ModelsÐTypical
Fig. 2 Fuel Pump ModuleÐXJ
ModelsÐDisassemble/Assemble
Fig. 3 Fuel Pump ModuleÐXJ ModelsÐInstallation
JFUEL SYSTEM 14 - 3

(3) Install new fuel pump outlet hose. Secure with
new clamps.
(4) Connect wire terminals to motor.
(5) Install new fuel pump inlet filter.
INSTALLATIONÐYJ MODELS
(1) Install a new fuel pump inlet filter.
(2) Install fuel pump module assembly with a new
gasket between the assembly and tank. Tighten
mounting screws to 2 Nzm (18 in. lbs.) torque.
(3) Install fuel tank. Refer to Fuel Tank Installa-
tionÐYJ Models.
(4) Fill fuel tank. Install fuel tank cap.
(5) Install negative battery cable.
(6) Start vehicle and check for leaks.
FUEL PUMP ELECTRICAL CONTROL
For an electrical operational description of the fuel
pump, refer to the MFI SystemÐComponent Descrip-
tion/System Operation section of this group. See Au-
tomatic Shut Down (ASD) RelayÐPCM Output.
For the 1994 model year, the ballast resistor and
ballast resistor bypass relay are no longer used to
control the fuel pump circuit.
FUEL PRESSURE RELEASE PROCEDURE
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE (EVEN WITH THE ENGINE
OFF) OF APPROXIMATELY 131-269 KPA (19-39
PSI). THIS PRESSURE MUST BE RELEASED BE-
FORE SERVICING ANY FUEL SUPPLY OR FUEL RE-
TURN SYSTEM COMPONENT.
(1) Disconnect negative battery cable.
(2) Remove fuel tank filler neck cap to release fuel
tank pressure.
WARNING: DO NOT ALLOW FUEL TO SPILL ONTO
THE ENGINE INTAKE OR EXHAUST MANIFOLDS.
PLACE SHOP TOWELS UNDER AND AROUND THE
PRESSURE PORT TO ABSORB FUEL WHEN THE
PRESSURE IS RELEASED FROM THE FUEL RAIL.
WARNING: WEAR PROPER EYE PROTECTION
WHEN RELEASING FUEL SYSTEM PRESSURE.
(3) Remove protective cap from pressure test port
on the fuel rail (Fig. 7).
(4) Obtain the fuel pressure gauge/hose assembly
from fuel pressure gauge tool set 5069. Remove the
gauge from the hose.
(5) Place one end of hose (gauge end) into an ap-
proved gasoline container.
(6) Place a shop towel under the test port.
(7) To release fuel pressure, screw the other end of
hose onto the fuel pressure test port.(8) After fuel pressure has been released, remove
the hose from the test port.
(9) Install protective cap to fuel test port.
FUEL SYSTEM PRESSURE TEST
The fuel system is equipped with a vacuum as-
sisted fuel pressure regulator (Fig. 8). With engine at
idle speed, system fuel pressure should be approxi-
mately 214 kPa (31 psi) with the vacuum line con-
nected to the regulator. With the vacuum line
disconnected from the regulator, fuel pressure should
be approximately 269 kPa (39 psi). This is 55-69 kPa
(8-10 psi) higher.
(1) Remove the protective cap at the fuel rail (Fig.
7). Connect the 0-414 kPa (0-60 psi) fuel pressure
gauge (from Gauge Set 5069) to test port pressure fit-
ting on fuel rail (Fig. 9).
(2) Note pressure gauge reading. Fuel pressure
should be approximately 214 kPa (31 psi) at idle.
Fig. 7 Pressure Test PortÐTypical
Fig. 8 Fuel Pressure RegulatorÐTypical
JFUEL SYSTEM 14 - 5

(1) Place fuel filter in retaining strap with the
marked ends in the correct position.
(2) Install retaining strap bolt and tighten to 12
Nzm (106 in. lbs.) torque.
(3) Install inlet and outlet hoses and hose clamps.
For procedures, refer to Fuel Tubes/Lines/Hoses and
Clamps. Also refer to Quick-Connect Fittings. These
can be found in the Fuel Delivery System section of
this group.
(4) On YJ models, install fuel filter shield (Fig. 13).
(5) Lower vehicle.
(6) Connect negative battery cable.
(7) Start engine and check for leaks.
FUEL TUBES/LINES/HOSES AND CLAMPS
Also refer to the proceeding section on Quick-Con-
nect Fittings.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES-
SURE MUST BE RELEASED. REFER TO THE FUEL
PRESSURE RELEASE PROCEDURE IN THIS
GROUP.
Inspect all hose connections such as clamps, cou-
plings and fittings to make sure they are secure and
leaks are not present. The component should be re-
placed immediately if there is any evidence of degra-
dation that could result in failure.
Never attempt to repair a plastic fuel line/tube. Re-
place as necessary.
Avoid contact of any fuel tubes/hoses with other ve-
hicle components that could cause abrasions or scuff-
ing. Be sure that the plastic fuel lines/tubes are
properly routed to prevent pinching and to avoid heat
sources.
The lines/tubes/hoses used on fuel injected vehicles
are of a special construction. This is due to the
higher fuel pressures and the possibility of contami-
nated fuel in this system. If it is necessary to replace
these lines/tubes/hoses, only those marked EFM/EFI
may be used.
The hose clamps used to secure rubber hoses on
fuel injected vehicles are of a special rolled edge con-
struction. This construction is used to prevent the
edge of the clamp from cutting into the hose. Only
these rolled edge type clamps may be used in this
system. All other types of clamps may cut into the
hoses and cause high pressure fuel leaks.
Use new original equipment type hose clamps.
Tighten hose clamps to 1 Nzm (15 in. lbs.) torque.
QUICK-CONNECT FITTINGS
Also refer to the previous Fuel Tubes/Lines/Hoses
and Clamps section.Different types of quick-connect fittings are used to
attach various fuel system components. These are: a
single-tab type, a two-tab type or a plastic retainer
ring type.
SINGLE-TAB TYPE
This type of fitting is equipped with a single pull
tab (Fig. 15). The tab is removable. After the tab is
removed, the quick-connect fitting can be separated
from the fuel system component.
CAUTION: The interior components (O-rings, spac-
ers) of this type of quick-connect fitting are not ser-
viced separately, but new pull tabs are available. Do
not attempt to repair damaged fittings or fuel lines/
tubes. If repair is necessary, replace the complete
fuel tube/quick-connect fitting assembly.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES-
SURE MUST BE RELEASED. REFER TO THE FUEL
PRESSURE RELEASE PROCEDURE IN THIS
GROUP.
DISCONNECTION/CONNECTION
(1) Disconnect negative battery cable from battery.
(2) Perform the fuel pressure release procedure.
Refer to the Fuel Pressure Release Procedure in this
section.
(3) Clean the fitting of any foreign material before
disassembly.
(4) Press the release tab on the side of fitting to re-
lease pull tab (Fig. 15).
Fig. 15 Single-Tab Type Fitting
JFUEL SYSTEM 14 - 9

REMOVALÐXJ MODELS
Perform the preceding Fuel System Pressure Re-
lease Procedure.
(1) Disconnect negative battery cable.
(2) Remove the fuel filler cap. Using an approved
portable gasoline siphon/storage tank, drain fuel
tank.
(3) Raise and support vehicle.
(4) Disconnect fuel fill hose and fill vent hose from
filler neck (Fig. 1).
(5) Disconnect fuel pump module wire connector.
Remove tie straps securing connector harness to fuel
supply and return tubes.
WARNING: WRAP SHOP TOWELS AROUND FUEL
HOSES TO ABSORB ANY FUEL SPILLAGE DURING
FUEL TANK REMOVAL.
(6) Disconnect fuel tank vent hose from vent tube.
(7) Disconnect fuel supply and return hoses from
tubes.
(8) If equipped, remove skid plate (Fig. 2).
(9) Remove fuel tank shield (Fig. 3).
(10) Center a transmission jack under the fuel tank.
(11) Remove support strap nuts. Move straps away
from tank (Fig. 3).
(12) Lower fuel tank on transmission jack.
INSTALLATIONÐXJ MODELS
(1) Raise fuel tank into position. Connect fuel fill
hose and vent hose to filler neck and tighten clamps.
(2) Wrap support straps around tank and over studs.
Tighten strap nuts to 11.3 Nzm (100 in. lbs.) torque.
(3) Remove transmission jack.(4) Install tank shield.
(5) If equipped, install tank skid plate.
(6) Connect vent hose to vent tube.
(7) Connect fuel supply hose to supply tube and
fuel return hose to return tube. Tighten hose clamps.
(8) Connect fuel pump module wire connector to
harness connector. Secure fuel pump module wire
harness to fuel tubes with tie straps.
(9) Lower vehicle.
(10) Fill fuel tank. Install filler cap.
(11) Connect negative battery cable to battery.
(12) Start vehicle and inspect for leaks.
Fig. 1 Filler Neck HosesÐXJ Models
Fig. 2 Skid PlateÐXJ Models
Fig. 3 Fuel Tank Remove/InstallÐXJ Models
JFUEL SYSTEM 14 - 13