1995 JEEP YJ check engine

VEHICLE SAFETY CERTIFICATION LABEL
A vehicle safety certification label (Fig. 1) is at-
tached to every Jeep vehicle. The label certifies that
the vehicle conforms to all applicable Federal Motor
Vehicle Safety Standards. The label also lists:
²Gross vehicle weight rating (GVWR) and the gross
front and rear axle weight ratings (GAWR's) based on
a minimum tire rim size and a maximum cold tire
inflation pressure.
²Month and year of vehicle manufacture.
²Vehicle identification number (VIN).
²Type of vehicle.
²Month, day and hour (MDH) of final assembly.
The label is located on the driver-side door shut-
face.
VEHICLE IDENTIFICATION NUMBER (VIN) PLATE
The Vehicle Identification Number (VIN) plate islocated on the lower windshield fence near the left
A-pillar. The VIN contains 17 characters that provide
data concerning the vehicle. Refer to the VIN decod-
ing chart to determine the identification of a vehicle.
The Vehicle Identification Number is also imprinted
on the:
²Body Code Plate.
²Vehicle Safety Certification Label.
²Frame rail.
To protect the consumer from theft and possible
fraud the manufacturer is required to include a
Check Digit at the ninth position of the Vehicle Iden-
tification Number. The check digit is used by the
manufacturer and government agencies to verify the
authenticity of the vehicle and official documentation.
The formula to use the check digit is not released to
the general public.
VEHICLE CODE PLATE
A metal vehicle code plate is attached to the left
(driver) side of the dash panel in the engine compart-
ment (Fig. 2). There can be a maximum of seven rows
of vehicle information imprinted on the plate. The
information should be read from left to right, starting
with line 1 at the bottom of the plate up through line
7 (as applicable) at the top of the code plate.
Refer to the decoding chart to decode lines 1 up
through 3.
Lines 4 through 7 (if used) on the vehicle code plate
are imprinted on the plate (in sequence) according to
the following:
VEHICLE IDENTIFICATION NUMBER (VIN) DECODING
Fig. 1 Vehicle Safety Certification LabelÐTypical
4 INTRODUCTIONJ

MAINTENANCE SCHEDULES
INTRODUCTION
There are two maintenance schedules that show
proper service intervals for Jeep Cherokee and Jeep
Wrangler vehicles. Use the schedule that best de-
scribes the conditions the vehicle is operated under.
When mileage and time is listed, follow the interval
that occurs first.
ScheduleÐAlists all the scheduled maintenance
to be performed under normal operating conditions.
ScheduleÐBis a schedule for vehicles that are
usually operated under one or more of the following
conditions.
²Frequent short trip driving less than 5 miles (8
km).
²Frequent driving in dusty conditions.
²Trailer towing or heavy load hauling.
²Frequent long periods of engine idling.
²Sustained high speed operation.
²Desert operation.
²Frequent starting and stopping.
²Cold climate operation.
²Off road driving.
²Commercial service.
²Snow plow operation.
²More than half of vehicle operation occurs in
heavy city traffic during hot weather (above 90É F).
AT EACH STOP FOR GASOLINE
²Check engine oil level and add as required.
²Check windshield washer solvent and add as re-
quired.
ONCE A MONTH
²Check tire pressure and look for unusual tire wear
or damage.
²Check fluid levels of coolant reservoir, brake mas-
ter cylinder, power steering and transmission. Add
fluid as required.
²Check all lights and other electrical items for cor-
rect operation.
²Inspect battery and clean and tighten terminals as
required.
²Check rubber seals on each side of the radiator for
proper fit.
AT EACH OIL CHANGE
²Inspect exhaust system.
²Inspect brake hoses.
²Rotate the tires at each oil change interval shown
on ScheduleÐA: (7,500 Miles) or every other interval
shown on ScheduleÐB: (6,000 Miles).
²Check engine coolant level, hoses, and clamps.
²Lubricate 4x4 steering linkage.
²Lubricate propeller shaft universal joints and slip
spline, if equipped.After completion of off-road (4WD) operation, the
underside of the vehicle should be thoroughly in-
spected. Examine threaded fasteners for looseness.
HARSH SURFACE ENVIRONMENTS
After vehicle operation in a harsh surface environ-
ment, the following components should be inspected
and cleaned as soon as possible:
²Brake drums.
²Brake linings.
²Front wheel bearings (2WD vehicles only).
²Axle coupling joints.
This will prevent wear and/or unpredictable brake
action.
EMISSION CONTROL SYSTEM MAINTENANCE
The schedule emission maintenance listed inbold
typeon the following schedules, must be done at the
mileage specified to assure the continued proper
functioning of the emission control system. These,
and all other maintenance services included in this
manual, should be done to provide the best vehicle
performance and reliability. More frequent mainte-
nance may be needed for vehicles in severe operating
conditions such as dusty areas and very short trip
driving.
SCHEDULEÐA
7,500 MILES (12 000 KM) OR AT 6 MONTHS
²Change engine oil.
²Replace engine oil filter.
²Lubricate steering linkage (4x4).
15,000 MILES (24 000 KM) OR AT 12 MONTHS
²Change engine oil.
²Replace engine oil filter.
²Lubricate steering linkage.
22,500 MILES (36 000 KM) OR AT 18 MONTHS
²Change engine oil.
²Replace engine oil filter.
²Lubricate steering linkage (4x4).
²Inspect brake linings.
30,000 MILES (48 000 KM) OR AT 24 MONTHS
²Replace air cleaner element.
²Replace spark plugs.
²Adjust belt tension on non-automatic tensioning
drive belts.
²Change engine oil.
²Replace engine oil filter.
²Lubricate steering linkage.
²Drain and refill automatic transmission.
²Drain and refill transfer case.
0 - 4 LUBRICATION AND MAINTENANCEJ

(3) Cover the open end of the transmission exten-
sion housing.
4WD VEHICLESÐXJ
(1) Shift transfer case lever to NEUTRAL.
(2) Place ignition switch in the unlocked position.
4WD VEHICLESÐYJ
CAUTION: Follow these steps to be certain that the
transfer case is fully in N (NEUTRAL) and that the
axle is completely disengaged before flat towing to
prevent damage to internal parts.
(1) Shift transfer case into 2H and check that the
4WD light goes out.
(2) Start engine and drive the vehicle 3 mm (10 ft.)
rearward and then 3 mm (10 ft.) forward to make
sure the axle is disengaged.(3) Shift transmission to Neutral.
(4) Turn off engine with the ignition key in the un-
locked OFF position.
(5) Shift transfer case lever from 2H to N (NEU-
TRAL) position.
(6) Shift manual transmission into gear or auto-
matic transmission into P (PARK).
WARNING: WITH THE TRANSFER CASE IN NEU-
TRAL POSITION, THE VEHICLE COULD ROLL UN-
EXPECTEDLY. THE PARKING BRAKE SHOULD
ALWAYS BE APPLIED BEFORE THE TOW BAR IS
ATTACHED.
(7) Attach vehicle to the tow vehicle with tow bar.
CAUTION: Do not use a bumper mounted clamp-on
tow bar, damage to bumper face bar may occur.
0 - 14 LUBRICATION AND MAINTENANCEJ

CONTAINER IDENTIFICATION
Standard engine oil identification notations have
been adopted to aid in the proper selection of engine
oil. The identifying notations are located on the label
of engine oil plastic bottles and the top of engine oil
cans (Fig. 2).
ENGINE OIL ADDITIVES
In some instances, such as infrequent operation,
short trip driving, and during break-in after a major
overhaul, addition of special materials containing an-
ti-rust and anti-scuff additives are beneficial. A suit-
able product for this purpose is MOPAR Engine Oil
Supplement.
OIL LEVEL INDICATOR (DIPSTICK)
The engine oil level indicator (Dipstick) is located
at the right rear of both 2.5L engines and 4.0L en-
gines (Fig. 3).
CRANKCASE OIL LEVEL INSPECTION
CAUTION: Do not overfill crankcase with engine oil,
oil foaming and oil pressure loss can result.
Inspect engine oil level approximately every 800 ki-
lometers (500 miles). Unless the engine has exhibited
loss of oil pressure, run the engine for about five
minutes before checking oil level. Checking engine oil
level on a cold engine is not accurate.
To ensure proper lubrication of an engine, the en-
gine oil must be maintained at an acceptable level.
The acceptable levels are indicated between the ADD
and SAFE marks on the engine oil dipstick (Fig. 4
and 5).
(1) Position vehicle on level surface.
(2) With engine OFF, allow approximately ten min-
utes for oil to settle to bottom of crankcase, remove
engine oil dipstick.
(3) Wipe dipstick clean.
(4) Install dipstick and verify it is seated in the
tube.
(5) Remove dipstick, with handle held above the
tip, take oil level reading (Figs.4 and 5).
(6) Add oil only if level is below the ADD mark on
dipstick.
ENGINE OIL CHANGE AND FILTER REPLACEMENT
ENGINE OIL CHANGE
Change engine oil at mileage and time intervals
described in Maintenance Schedules.
TO CHANGE ENGINE OIL
Run engine until achieving normal operating tem-
perature.
(1) Position the vehicle on a level surface and turn
engine off.
(2) Hoist and support vehicle on safety stands. Re-
fer to Hoisting and Jacking Recommendations in this
group.
Fig. 2 API Certification Mark
Fig. 3 Engine Oil Dipstick LocationÐTypical
Fig. 4 Engine Oil DipstickÐ2.5L Engine
0 - 16 LUBRICATION AND MAINTENANCEJ

(2) Remove the air cleaner element from the body/
housing.
(3) Hold a shop light on throttle body side of ele-
ment. Inspect air intake side of element. If element
is saturated with oil or light is not visible, replace fil-
ter. If element is saturated with oil, perform crank-
case ventilation system tests.
(4) Wash the air cleaner cover and body/housing
(Fig. 10) with cleaning solvent and wipe dry.
(5) Install the air cleaner element and attach the
cover to the body/housing.
CRANKCASE VENTILATION SYSTEM
All Jeep 2.5L and 4.0L engines are equipped with a
crankcase ventilation (CCV) system. Refer to Group
25 Emissions, for additional information.
FUEL FILTER
The fuel filter requires service only when a fuel
contamination problem is suspected. For proper diag-
nostic and service procedures refer to Group 14, Fuel
System.
FUEL USAGE STATEMENTÐGAS ENGINES
Jeep vehicles are designed to meet all emission reg-
ulations and provide excellent fuel economy using
high quality unleaded gasoline. Only use unleaded
gasolines having a minimum posted octane of 87.
If a Jeep vehicle develops occasional light spark
knock (ping) at low engine speeds, this is not harm-
ful. However,continued heavy knock at high
speeds can cause damage and should be
checked immediately.
In addition to using unleaded gasoline with the
proper octane rating,those that contain deter-
gents, corrosion and stability additives are rec-
ommended.Using gasolines that have these
additives will help improve fuel economy, reduce
emissions and maintain vehicle performance.
Poor quality gasolinecan cause problems such
as hard starting, stalling and stumble. If these prob-
lems occur, use another brand of gasoline before con-
sidering servicing the vehicle.
GASOLINE/OXYGENATE BLENDS
Some fuel suppliers blend unleaded gasoline with
materials that contain oxygen such as alcohol, MTBE
and ETBE. The type and amount of oxygenate used
in the blend is important. The following are generally
used in gasoline blends:
ETHANOL
Ethanol (Ethyl or Grain Alcohol) properly blended,
is used as a mixture of 10 percent ethanol and 90
percent gasoline.Gasoline with ethanol may be
used in your vehicle.
METHANOL
CAUTION: Do not use gasolines containing metha-
nol. Use of methanol/gasoline blends may result in
starting and driveability problems. In addition, dam-
age may be done to critical fuel system compo-
nents.
Methanol (Methyl or Wood Alcohol) is used in a va-
riety of concentrations blended with unleaded gaso-
Fig. 9 Air Cleaner & Filter ElementÐ2.5L and 4.0L
Engines
Fig. 10 Air Cleaner Body/Housing & Cover
JLUBRICATION AND MAINTENANCE 0 - 19

ENGINE SUPPORTS
The general condition of the engine supports
should be inspected when engine compartment or un-
der vehicle service is performed.
INSPECTION
(1) Test the hardware that attaches the engine cyl-
inder block to the engine support brackets (Figs. 11
and 12) for the specified tightening torque.(2) Inspect the rubber in the engine support cush-
ions for softening and swelling. Slight surface deteri-
oration and wear at the ends will not affect the
functioning of an engine support.
ACCESSORY DRIVE BELT
Inspect and adjust drive belts at the interval de-
scribed in the Lubrication and Maintenance Sched-
ules. Refer to General Information section of this
group. For proper inspection and adjustment proce-
dures, see Group 7, Cooling System.
EXHAUST SYSTEM
The exhaust system should be inspected when un-
der vehicle service is performed or as specified in the
Lubrication and Maintenance Schedules.
INSPECTION
When inspecting an exhaust system, inspect for
cracked or loose joints, stripped screw/bolt threads,
corrosion damage, and worn or broken hangers
(Slight cracking in rubber isolator or hanger is ac-
ceptable). Replace all components that are corroded
or damaged. Do not attempt repair. Also, inspect for
the following obvious conditions and correct as neces-
sary:
²Exhaust system leaks, damage, misalignment.
²Contact with body panels metal or the frame.
²Catalytic converter bulging or excessive heat dam-
age.
CAUTION: A catalytic converter will become con-
taminated if leaded gasoline is burned in the en-
gine. If this occurs, the complete converter must be
replaced.
For proper service procedures see Group 11, Ex-
haust System and Intake Manifold.
AIR-CONDITIONER COMPRESSOR
LUBRICANT AND REFRIGERANT
The lubricant level in the air-conditioner compres-
sor should be checked if there are indications that oil
was lost. Loss of lubricating oil usually accompanies
a loss of refrigerant.
For additional information involving the A/C sys-
tem, refer to Group 24, Heater And Air Conditioning.
Fig. 11 Front Engine SupportÐTypical
Fig. 12 Rear Engine SupportÐTypical
JLUBRICATION AND MAINTENANCE 0 - 21

If the transmission is warm, lube oil could
drip out of the fill hole. This is acceptable but
the lube oil should not gush out of the fill hole.
(2) If not acceptable, raise the lube oil level to the
bottom edge of the transmission fill hole.
Add lube oil in small amounts to raise the
level.
(3) Install the fill-hole plug in the transmission.
Tighten the plug with 37 Nzm (27 ft. lbs.) torque.
LUBE OIL CHANGE
When it becomes necessary to change manual
transmission lube oil, use the following procedure.
(1) Raise and support the vehicle.
(2) Remove the fill-hole plug from the transmis-
sion.
(3) Place a container to collect the lube oil under
the transmission drain-hole plug.
(4) Remove the drain-hole plug and drain the lube
oil from the transmission into the container.
Care should be exercised when disposing
used lube oil after it has been drained from a
transmission.
(5) Install the drain-hole plug in the transmission.
Tighten the plug with 37 Nzm (27 ft. lbs.) torque.
(6) Fill the transmission until the lube oil begins to
drip out of the fill hole.
(7) Install the fill-hole plug in the transmission.
Tighten the plug with 37 Nzm (27 ft. lbs.) torque.
(8) Remove the support and lower the vehicle.
AUTOMATIC TRANSMISSION
The automatic transmission fluid should be
changed and bands adjusted at the intervals de-
scribed in the Maintenance Schedules section of this
Group. The automatic transmission should be in-
spected for fluid leaks and proper fluid level whenother under hood service is performed. Refer to
Group 21, Transmission for proper service proce-
dures.
CAUTION: To minimize fluid contamination, verify
that dipstick is seated in the fill tube after fluid level
reading is taken.
TO INSPECT THE TRANSMISSION FLUID
LEVEL
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT PUT YOUR
HANDS NEAR THE DRIVE BELT, PULLEYS OR FAN
BLADE. DO NOT STAND IN A DIRECT LINE WITH
THE FAN BLADE.
(1) Be sure transmission fluid is at normal operat-
ing temperature. Normal operating temperature is
reached after approximately 15 miles (25km) of oper-
ation.
(2) Position the vehicle on a level surface. This is
important for an accurate fluid level check.
(3) While sitting in driver seat, apply brakes and
place gear selector in each position, then move the
selector to:
²XJ vehicles-P (Park).
²YJ vehicles-N (Neutral).
(4) Apply parking brake.
(5) Raise hood and wipe off dipstick handle to pre-
vent dirt from entering fill tube. Then remove trans-
mission fluid level indicator (dipstick) and wipe clean
with a wiping cloth.
(6) Install dipstick and verify it is seated in fill
hole or tube.
(7) Remove dipstick, with handle above tip, take
fluid level reading. If the vehicle has been driven for
at least 15 minutes before inspecting fluid level,
transmission can be considered hot and reading
should be in the OK area. If vehicle has run for less
than 15 minutes and more than 60 seconds transmis-
sion can be considered warm and reading should be
above MIN mark. Add fluid only if level is below
MIN mark on dipstick when transmission is warm
(Fig. 4).
CAUTION: Do not overfill automatic transmission,
leakage or damage can result.
AUTOMATIC TRANSMISSION FLUID
SPECIFICATION
When it becomes necessary to add fluid or when
the ATF is replaced, use:
²MOPAR Dexron IIE/Mercon ATFonlyfor AW-4
automatic transmissions (XJ vehicles).
²MOPAR ATF PLUS type 7176 (YJ vehicles).
Fig. 3 Manual Transmission Fill- & Drain-Hole
PlugsÐTypical
JLUBRICATION AND MAINTENANCE 0 - 23

ALIGNMENT MEASUREMENTS AND ADJUSTMENTS
Before each alignment reading, the vehicle should
be jounced (rear first, then front). Grasp each
bumper at the center and jounce the vehicle up and
down several times. Always release the bumper in
the down position.Set the front end alignment to
specifications with the vehicle at its NOR-
MALLY RIDE HEIGHT.
CAMBER
The wheel camber angle is preset. This angle is not
adjustable and cannot be altered.
CASTER
Before checking the caster of the front axle for cor-
rect angle, be sure the axle is not bent or twisted.
Road test the vehicle, make left and right turns. If
the steering wheel returns to the center position un-
assisted, the caster angle is correct. If steering wheeldoes not return toward the center position unas-
sisted, an incorrect caster angle is probable.
Caster can be adjusted by installing the appropri-
ate size shims (Fig. 2, 3).Changing caster angle
will also change the front propeller shaft angle.
The propeller shaft angle has priority over
caster. Refer to Group 16, Propeller Shafts for
additional information.
TOE POSITIONÐXJ VEHICLES
The wheel toe position adjustment should be the fi-
nal adjustment.
(1) Start the engine if equipped with power steer-
ing. Turn wheels both ways before straightening the
Fig. 2 AdjustmentÐYJ Vehicles
Fig. 3 AdjustmentÐXJ Vehicles
Fig. 4 Steering LinkageÐXJ (LHD)
2 - 8 FRONT SUSPENSION AND AXLEJ