JEEP CHEROKEE 1988 Service Repair Manual
Page 921 of 1378
MAIN TE N AN CE R EM IN DER L IG HT R ESET P R O CED URES
1988 J e ep C hero ke e
1988-92 MAINTENANCE
Chrysler Motors Maintenance Reminder Lights
Jeep; Cherokee, Comanche, Wagoneer (1988-90), Wrangler
EMISSION MAINTENANCE INDICATOR LIGHT (1988-90)
Vehicles are equipped with an emission maintenance indicator
light on instrument cluster. This light will come on one time at 82,
500 miles to alert driver that emission service is required. At this
time, oxygen sensor and PCV valve must be replaced and all other
emission components should be inspected and serviced or replaced as
necessary.
Indicator timer is located under dash, near accelerator pedal
or to right of steering column. Timer cannot be reset. To turn off
light, timer must be replaced or disconnected. Since timer and sensor
are interdependent, if timer should fail prematurely, oxygen sensor
should be replaced at same time to preserve correct replacement
interval.
To replace timer on Cherokee, Comanche and Wagoneer models,
remove cruise control module (if equipped). Remove timer mounting
screws. Disconnect electrical connector. On Wrangler models, remove
timer mounting screws. Disconnect electrical connector. On all models,
install remaining components.
EMISSION MAINTENANCE INDICATOR LIGHT (1991-92)
Vehicles are equipped with an emission maintenance indicator
light on instrument cluster. This light will come on one time at 82,
500 miles to alert driver that emission service is required. At this
time, oxygen sensor must be replaced and all other emission components
should be inspected and serviced or replaced as necessary. Chrysler's
Diagnostic Readout Box (DRB-II) tester is required to reset the
emission maintenance indicator light.
Reset Procedure
Using DRB-II tester, access SELECT SYSTEMS. Select
appropriate engine. Select with or without A/C. Select FUEL &
IGNITION. Select ADJUSTMENTS. Select RESET EMR LIGHT. Reset EMR light.
When DRB-II is finished resetting light, DRB-II display will read EMR
LIGHT IS RESET.
Page 922 of 1378
METR IC C O NVER SIO NS
1988 J e ep C hero ke e
GENERAL INFORMATION
METRIC CONVERSIONS
METRIC CONVERSIONS
Metric conversions are making life more difficult for the
mechanic. In addition to doubling the number of tools required,
metric-dimensioned nuts and bolts are used alongside English
components in many new vehicles. The mechanic has to decide which tool
to use, slowing down the job. The tool problem can be solved by trial
and error, but some metric conversions aren't so simple. Converting
temperature, lengths or volumes requires a calculator and conversion
charts, or else a very nimble mind. Conversion charts are only part of
the answer though, because they don't help you "think" metric, or
"visualize" what you are converting. The following examples are
intended to help you "see" metric sizes:
LENGTH
Meters are the standard unit of length in the metric system.
The smaller units are 10ths (decimeter), 100ths (centimeter), and
1000ths (millimeter) of a meter. These common examples might help you
to visualize the metric units:
* A meter is slightly longer than a yard (about 40 inches).
* An aspirin tablet is about one centimeter across (.4 inches).
* A millimeter is about the thickness of a dime.
VOLUME
Cubic meters and centimeters are used to measure volume, just
as we normally think of cubic feet and inches. Liquid volume
measurements include the liter and milliliter, like the English quarts
or ounces.
* One teaspoon is about 4 cubic centimeters.
* A liter is about one quart.
* A liter is about 61 cubic inches.
WEIGHT
The metric weight system is based on the gram, with the most
common unit being the kilogram (1000 grams). Our comparable units are
ounces and pounds:
* A kilogram is about 2.2 pounds.
* An ounce is about 28 grams.
TORQUE
Torque is somewhat complicated. The term describes the amount
of effort exerted to turn something. A chosen unit of weight or force
is applied to a lever of standard length. The resulting leverage is
called torque. In our standard system, we use the weight of one pound
applied to a lever a foot long, resulting in the unit called a foot-
pound. A smaller unit is the inch-pound (the lever is one inch long).
Metric units include the meter kilogram (lever one meter long
with a kilogram of weight applied) and the Newton-meter (lever one
Page 923 of 1378
meter long with force of one Newton applied). Some conversions are:
* A meter kilogram is about 7.2 foot pounds.
* A foot pound is about 1.4 Newton-meters.
* A centimeter kilogram (cmkg) is equal to .9 inch pounds.
PRESSURE
Pressure is another complicated measurement. Pressure is
described as a force or weight applied to a given area. Our common
unit is pounds per square inch. Metric units can be expressed in
several ways. One is the kilogram per square centimeter (kg/cm
).
Another unit of pressure is the Pascal (force of one Newton on an area
of one square meter), which equals about 4 ounces on a square yard.
Since this is a very small amount of pressure, we usually see the
kiloPascal, or kPa (1000 Pascals). Another common automotive term for
pressure is the bar (used by German manufacturers), which equals 10
Pascals. Thoroughly confused? Try the examples below:
* Atmospheric pressure at sea level is about 14.7 psi.
* Atmospheric pressure at sea level is about 1 bar.
* Atmospheric pressure at sea level is about 1 kg/cm
.
* One pound per square inch is about 7 kPa.
CONVERSION FACTORS
CONVERSION FACTORS\
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TO CONVERT TO MULTIPLY BY
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LENGTH
Millimeters (mm) Inches .03937
Inches Millimeters 25.4
Meters (M) Feet 3.28084
Feet Meters .3048
Kilometers(Km) Miles .62137
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AREA
Square Centimeters (cm ) Square Inches .155
Square Inches Square Centimeters 6.45159
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VOLUME
Cubic Centimeters Cubic Inches .06103
Cubic Inches Cubic Centimeters 16.38703
Liters Cubic Inches 61.025
Cubic Inches Liters .01639
Liters Quarts 1.05672
Quarts Liters .94633
Liters Pints 2.11344
Pints Liters .47317
Liters Ounces 33.81497
Ounces Liters .02957
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WEIGHT
Grams Ounces .03527
Ounces Grams 28.34953
Kilograms Pounds 2.20462
Pounds Kilograms .45359
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WORK
Centimeter Kilograms Inch Pounds .8676
Pounds/Sq. Inch Kilograms/Sq.Centimeter .07031
Bar Pounds/Sq. Inch 14.504
Page 924 of 1378
Pounds/Sq. Inch Bar .06895
Atmosphere Pounds/Sq. Inch 14.696
Pounds/Sq. Inch Atmosphere .06805
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TEMPERATURE
Centigrade Degrees Fahrenheit Degrees ( Cx(9)/5)+32
Fahrenheit Degrees Centigrade Degrees ( F-32)x(5)/9
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CONVERSION FACTORS (Cont.)\
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INCHES DECIMALS mm
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1/64 ...................... .016 ........................ .397
1/32 ...................... .031 ........................ .794
3/64 ...................... .047 ....................... 1.191
1/16 ...................... .063 ....................... 1.588
5/64 ...................... .078 ....................... 1.984
3/32 ...................... .094 ....................... 2.381
7/64 ...................... .109 ....................... 2.778
1/8 ....................... .125 ....................... 3.175
9/64 ...................... .141 ....................... 3.572
5/32 ...................... .156 ....................... 3.969
11/64 ..................... .172 ....................... 4.366
3/16 ...................... .188 ....................... 4.763
13/64 ..................... .203 ....................... 5.159
7/32 ...................... .219 ....................... 5.556
15/64 ..................... .234 ....................... 5.953
1/4 ....................... .250 ....................... 6.350
17/64 ..................... .266 ....................... 6.747
9/32 ...................... .281 ....................... 7.144
19/64 ..................... .297 ....................... 7.541
5/16 ...................... .313 ....................... 7.938
21/64 ..................... .328 ....................... 8.334
11/32 ..................... .344 ....................... 8.731
23/64 ..................... .359 ....................... 9.128
3/8 ....................... .375 ....................... 9.525
25/64 ..................... .391 ....................... 9.992
13/32 ..................... .406 ...................... 10.319
27/64 ..................... .422 ...................... 10.716
7/16 ...................... .438 ...................... 11.113
29/64 ..................... .453 ...................... 11.509
15/32 ..................... .469 ...................... 11.906
31/64 ..................... .484 ...................... 12.303
1/2 ....................... .500 ...................... 12.700
33/64 ..................... .516 ...................... 13.097
17/32 ..................... .531 ...................... 13.494
35/64 ..................... .547 ...................... 13.891
9/16 ...................... .563 ...................... 14.288
37/64 ..................... .578 ...................... 14.684
19/32 ..................... .594 ...................... 15.081
39/64 ..................... .609 ...................... 15.478
5/8 ....................... .625 ...................... 15.875
41/64 ..................... .641 ...................... 16.272
21/32 ..................... .656 ...................... 16.669
43/64 ..................... .672 ...................... 17.066
11/16 ..................... .687 ...................... 17.463
45/64 ..................... .703 ...................... 17.859
23/32 ..................... .719 ...................... 18.256
47/64 ..................... .734 ...................... 18.653
3/4 ....................... .750 ...................... 19.050
49/64 ..................... .766 ...................... 19.447
Page 925 of 1378
25/32 ..................... .781 ...................... 19.844
51/64 ..................... .797 ...................... 20.241
13/16 ..................... .813 ...................... 20.638
53/64 ..................... .828 ...................... 21.034
27/32 ..................... .844 ...................... 21.431
55/64 ..................... .859 ...................... 21.828
7/8 ....................... .875 ...................... 22.225
57/64 ..................... .891 ...................... 22.622
29/32 ..................... .906 ...................... 23.019
59/64 ..................... .922 ...................... 23.416
15/16 ..................... .938 ...................... 23.813
61/64 ..................... .953 ...................... 24.209
31/32 ..................... .969 ...................... 24.606
63/64 ..................... .984 ...................... 25.003
1 ......................... 1.000 ..................... 25.400
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Page 926 of 1378
\003
MIR RO RS - P O W ER
1988 J e ep C hero ke e
1988 Power Mirrors
JEEP
DESCRIPTION
Outside power rear view mirrors consist of door-mounted
mirrors with internal motor drive and backing plate. The Ford
electronic day/night mirror will change from normal to non-glare
position when glare reaches mirror. The non-glare functions only at
night.
TESTING
Mirror Motors & Switches
1) Ensure fuse is okay by operating interior lights. If
neither mirror operates, check for battery voltage at power mirror
switch assembly. Connect a voltmeter between terminal "G" (Red with
White stripe) and ground. If battery voltage is present, connect
voltmeter between terminals "G" and "F" (Black). If battery voltage is\
not present, check circuit at Red with White stripe wire and Black
wire.
2) If one mirror does not operate, connect a voltmeter across
power mirror switch assembly terminals. See Fig. 1. Voltage will be
present when control switch and mirror select switch are operated for
that motor.
Fig. 1: Jeep Switch Assembly Check Chart
Courtesy of American Motors/Jeep Corp.
3) If voltage is present but mirror does not operate, check
motor and wiring. If voltage is not present when 2 switches are on,
Page 927 of 1378
replace switch assembly.
Page 928 of 1378
PO W ER S TE ER IN G G EN ER AL S ER VIC IN G
1988 J e ep C hero ke e
1988 STEERING
Jeep Power Steering General Servicing
Cherokee, Comanche, Grand Wagoneer, Pickup, Wagoneer,
Wrangler
LUBRICATION
SERVICE INTERVALS
Check fluid at every oil change.
CHECKING FLUID LEVEL
Check fluid level with engine stopped and fluid hot or cold.
Fluid level must be at "FULL-HOT" or "FULL-COLD" mark on dipstick. On
models with remote reservoir, keep fluid level 0.5-1.0" from top of
reservoir with wheels turned fully to left.
RECOMMENDED FLUID TABLE
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Application Part Number
Jeep ............................................. 8993342
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REFILLING & BLEEDING SYSTEM
1) Fill reservoir to correct level. Operate engine until
fluid reaches normal operating temperature. Stop engine. Add fluid (if
necessary). Turn wheels to full left position. Add fluid to reservoir
to fill to "FULL-COLD" mark on dipstick.
2) Start and operate engine at fast idle. Recheck reservoir
level. Add to "FULL-COLD" mark on dipstick. Turn wheels from side to
side without contacting stops. Maintain fluid level just above pump
body.
3) When air is removed, return wheels to straight-ahead
position. Operate engine 2-3 minutes. Stop engine. Road test vehicle.
Recheck fluid level. Level should be at "FULL-HOT" position after
system has stabilized. Add fluid (if necessary). DO NOT overfill.
BELT TENSION (Tension in Lbs. Using Boroughs Tension Gauge)
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Application New Belt Used Belt
Jeep ................ ( 1) 125-155 ............... 90-115
( 1) - Cherokee, Comanche and Wagoneer is 120-140 lbs.
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TROUBLE SHOOTING
Refer to TROUBLE SHOOTING - BASIC PROCEDURES article in the
GENERAL TROUBLE SHOOTING section.
TESTING
Page 929 of 1378
PREPARATION
1) With belt tension correct, disconnect power steering pump
pressure hose. Keep hose end raised to prevent fluid loss. Connect
pressure hose of gauge to power steering pump fitting. Connect other
hose from valve side of tester to steering gear inlet.
2) Open valve. Run engine until fluid reaches normal
operating temperature of 170
F (77C). Check fluid level. Add fluid
(if necessary).
PRESSURE TEST
1) Note pressure reading with valve open and engine idling.
Pressure should be 80-125 psi (5.6-8.8 kg/cm).
2) If pressure is above 200 psi (14.1 kg/cm), check hoses
for restrictions and poppet valve (Saginaw gears) for proper assembly.\
3) Close gate valve completely and reopen 3 times. Record
highest reading each time. DO NOT close valve for more than 5 seconds.
If pressure is less than specification, clean or replace flow control
valve in pump. If pressures are still low, replace pump.
4) If readings are within specifications and within 50 psi
(3.5 kg/cm
) of each other, pump is operating properly. Refer to the
PRESSURE TEST SPECIFICATIONS table. If pressures are high, but do not
repeat within 50 psi (3.5 kg/cm
), flow control valve in pump is
sticking. Remove flow control valve. Clean or replace flow control
valve.
5) If pump is within specifications, open valve and turn
steering wheel from right to left stops. Record pressure. DO NOT hold
wheel against stops more than 5 seconds.
6) Pressure should measure the same as specified. See the
PRESSURE TEST SPECIFICATIONS table. If pressure is low, steering gear
is leaking internally and must be overhauled.
7) Turn steering wheel from left to right with engine idling
at 600-800 RPM. See PRESSURE TEST SPECIFICATIONS table.
8) If pressure is low, momentarily close valve. If pressure
is less than specified, pump is faulty. If pressure is within
specification but was low at previous reading, steering gear is
faulty.
PRESSURE TEST SPECIFICATIONS TABLE
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Application Idle: psi (kg/cm) Relief: psi (kg/cm)
Jeep ............... 80-125 (6-9) ............. 1400-1500 (98-105\
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Page 930 of 1378
PO W ER S TE ER IN G P U M P
1988 J e ep C hero ke e
1988 STEERING
Jeep Power Steering Pumps - Saginaw Vane-Type
Cherokee, Comanche, Grand Wagoneer, Pickup, Wagoneer,
Wrangler
DESCRIPTION
Saginaw vane-type power steering pump can be identified by
"ham-shaped" fluid reservoir can. Rectangular pumping vanes carried by
a shaft driven rotor move fluid from intake to pressure cavities of
cam ring.
Centrifugal force throws vanes against inside surface of cam
ring to pick up residual oil. As more oil is picked up, it is forced
into cavities of thrust plate, into 2 cross-over holes in cam ring and
pressure plate and into a high pressure area between pressure plate
and housing end plate.
Filling the high pressure area causes oil to flow under vanes
in slots of rotor. This forces vanes to follow inside oval surface of
cam ring. As vanes rotate to small area of cam ring, oil is forced out
from between vanes.
TROUBLE SHOOTING
Refer to TROUBLE SHOOTING - BASIC PROCEDURES article in the
GENERAL TROUBLE SHOOTING section.
LUBRICATION & TESTING
See POWER STEERING GENERAL SERVICING article in the STEERING
section.
REMOVAL & INSTALLATION
POWER STEERING PUMP
Removal & Installation
1) Loosen pump adjusting bolt (or nut) and pump mounting
bolts. Remove pump drive belt. Disconnect pressure and return hoses
from pump. Cap ends to prevent loss of fluid or contamination.
2) Remove pump bracket-to-engine bolts. Remove pump, pulley
and mounting bracket as an assembly. To install, reverse removal
procedure. Bleed system.
OVERHAUL
CAUTION: When clamping pump in vise, be careful not to exert
excessive force on front hub or pump. DO NOT use hammer to
remove pulley.
DISASSEMBLY
1) Drain pump reservoir. Clean exterior of unit. Remove
mounting bracket(s). Using a puller, withdraw pulley from shaft. See
Fig. 1 .