ECU JEEP CHEROKEE 1988 Service Owner's Guide
[x] Cancel search | Manufacturer: JEEP, Model Year: 1988, Model line: CHEROKEE, Model: JEEP CHEROKEE 1988Pages: 1378, PDF Size: 19.9 MB
Page 163 of 1378
CAN TAP INSTALLATION
FLAT TYPE SEAL CANS
On cam-lock or one-piece can taps, first turn the handle out
to the fully open position. Securely engage the locking lugs over the
flange of the can, and lock them in place by turning the cam lock or
locking nut. Screw the tap assembly into the adapter so the sealing
gasket is fully seated against the can top. Turn the tap inward to
pierce the can and close the tap. DO NOT open the tap until ready to
purge the service hose or dispense refrigerant into the system.
On 2-piece can taps, be certain the tap handle is turned
fully in, so it is closed. Check that the locking base is turned to
its outer limit. Securely engage the locking lugs over the can
flange. Turn the entire tap assembly (without disturbing the closed
setting) down into the locking base to pierce the can. Do not open
the tap until ready to dispense into system.
SCREW TYPE SEAL CANS
Ensure can tap is fully closed. Screw refrigerant can into
can tap fitting until tight. This will pierce the can. Connect tap to
center hose on manifold gauge set. DO NOT open tap until ready to
dispense R-12 into system.
WARNING: DO NOT open high side hand valve while air conditioning
system is in operation. This high pressure could rupture
can or possibly burst fitting at safety can valve,
resulting in damage and physical injury.
COMPRESSOR OIL CHECK
GENERAL PROCEDURES
Some models have compressor-mounted service valves that allow
oil checking by isolating the compressor. On all others, system must
be discharged, using approved refrigerant recovery/recycling
equipment, and compressor may need to be removed to check oil. After
oil level is checked and adjusted, A/C system must be evacuated and
recharged.
ISOLATING COMPRESSOR
1) Connect manifold gauge set to service valves on the
compressor. Close both gauge valves. Open both service valves to
themid-position.
2) Start engine and operate air conditioning. Turn suction
service valve slowly clockwise toward front-seated position. When
suction pressure is reduced to zero or less, stop engine and quickly
close suction service valve (front-seated).
3) Front-seat the discharge valve. Loosen oil check plug
slowly to release any internal pressure. Service valves can now be
removed from compressor and compressor removed from vehicle (if
necessary). Purge compressor after servicing.
PURGING COMPRESSOR
1) Remove gauge set and place caps on service valve ports.
Back-seat the suction service valve to allow refrigerant to enter
compressor.
Page 168 of 1378
BEFORE OPENING THE SYSTEM
Before disconnecting any lines or fittings, the system must
be completely discharged using approved refrigerant recovery/recycling
equipment.
DISCONNECTING LINES & FITTINGS
1) After system is discharged, carefully clean entire area
around coupling nut to prevent dirt entering system. Always use two
wrenches to avoid twisting or distorting lines and fittings (hold
fitting with one wrench while loosening coupling nut with second
wrench).
2) Ford spring-coupling fittings require a special coupling
tool (Motorcraft YT-1056) to open or close. See procedure under
CONNECTING LINES & FITTINGS.
3) Cap or plug all LINES and FITTINGS immediately to prevent
entry of air and moisture into the system. Do not remove these caps
until connections are being made.
COMPONENT REPLACEMENT
When components are replaced, system oil level must be
adjusted. Add refrigeration oil to replacement component. See
Compressor Oil Check article, as well as, Component Oil Replacement
Quantities" chart under A/C SYSTEM SERVICE SPECIFICATIONS in this
article.
CONNECTING LINES & FITTINGS
All Except Ford Spring-Coupling Fitting
1) A new "O" ring should be used in all instances when
connecting lines and fittings (dip "O" ring in clean refrigeration oil
and make certain it is not twisted during installation). Always use
two wrenches to avoid twisting or distorting lines and fittings.
Tighten coupling nuts securely.
2) Ford spring-coupling fittings require a special coupling
tool (Motorcraft YT-1056) to open or close. Use the following
procedure to connect or disconnect the spring-coupling fitting.
Ford Spring-Coupling Fitting
1) Discharge system using approved refrigerant
recovery/recycling equipment. Place proper end of tool over
refrigerant line. Tool fits both 3/8" and 1/2" fittings. Push tool
into fitting cage to release spring inside. Pull lines apart and
remove tool.
2) Before connecting, check internal spring for damage. If
Necessary, pry spring out and replace it. Clean fittings and install
new "O" rings.
CAUTION: Use ONLY "O" rings designed for these Ford fittings
(Motorcraft YF-982). Normal refrigerant "O" rings will NOT
seal.
Page 278 of 1378
in the brake fluid.
4) Using proper sized rod, apply and release master cylinder
until no air bubbles exist in brake fluid flow. Once all air bubbles
are gone from master cylinder secure cap and install.
5) Bleeder tubes should be left installed on master cylinder
until master cylinder in installed. Master cylinder must be bled at
brake lines and wheels after installation.
Bleeding On Vehicle
1) Install master cylinder on vehicle after bench bleeding.
Remove bleeder lines and install brake lines. DO NOT fully tighten
brake lines at this time.
2) Slowly force brake pedal to the floor and hold in this
position. Tighten brake lines and release brake pedal. Repeat
procedure until no air bubbles exist at brake lines. Remaining wheel
cylinder or calipers may be require bleeding.
HYDRAULIC CONTROL VALVES
Hold Off Valve
1) Prior to the pressure tank bleeding procedure, the hold
off valve incorporated in the combination valve must be correctly
positioned. This allows brake fluid to flow through the combination
valve to the entire brake system.
2) The valve stem of the hold off valve may be retained using
tools available from Chrysler Motors (C-4121) or General Motors
(J-23709) during bleeding procedure. See Figs. 2 and 3. Remove valve
retainer once brake bleeding procedure is complete.
CAUTION: DO NOT use rigid clamp to position valve stem. Damage to
the valve assembly may result causing brake failure.
Fig. 2: Positioning Hold Off Valve
Courtesy of American Motors/Jeep Corp.
Page 298 of 1378
Wear indicator device
(mechanical) contacts
rotor .................. .. ......... (6) Further inspection
required.
Worn close to minimum
specifications ......... 1 ........ ( 7) Suggest replacement.
Worn to, or below minimum
specifications ......... B ............ Require replacement.
( 1) - Identify and repair cause of contamination prior to
replacing friction material.
( 2) - When reconditioning or replacing drums or rotors,
replacement of friction material may be suggested
depending on the severity of the grooves or ridges.
( 3) - Some vehicles use pads that are tapered by design. Refer
to specific vehicle application. If not normal, require
replacement of pads and correction of cause.
( 4) - Uneven pad thickness is normal on some vehicles. Refer to
specific vehicle applications.
( 5) - The pad wear indicator light may come on due to other
electrical problems.
( 6) - Explain to the customer that the purpose of the wear
indicator is to alert him or her to check for friction
wear. Wear indicators may be bent or broken. Therefore,
the friction material must be measured. The need for
friction material replacement is determined based upon
the conditions stated in this section. Periodic inspection
is suggested.
( 7) - When the part appears to be close to the end of its useful
life, replacement may be suggested.
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G SENSORS
See ACCELEROMETERS .
HOSES
HOSE INSPECTION \
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Condition Code Procedure
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............. A ... Require repair or replacement
of hardware.
Blistered ............... B ............ Require replacement.
Fitting threads damaged . A .. Require repair or replacement.
Fitting threads stripped
(threads missing) ...... A ............ Require replacement.
Incorrectly secured ..... B ................. Require repair.
Inner fabric
(webbing) cut .......... B ............ Require replacement.
Leaking ................. A ............ Require replacement.
Missing ................. C ............ Require replacement.
Outer covering is cracked
to the extent that
inner fabric of hose
Page 314 of 1378
![JEEP CHEROKEE 1988 Service Owners Guide (3) - Inspect for conditions related to wheel cylinder.
( 4) - Leaking is defined as a drop or more. Dampness is normal.
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\](/img/16/57037/w960_57037-313.png "JEEP CHEROKEE 1988 Service Owners Guide (3) - Inspect for conditions related to wheel cylinder.
( 4) - Leaking is defined as a drop or more. Dampness is normal.
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(3) - Inspect for conditions related to wheel cylinder.
( 4) - Leaking is defined as a drop or more. Dampness is normal.
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WIRING HARNESSES
NOTE: Copied from Electrical UIGs.
WIRING HARNESS INSPECTION
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Condition Code Procedure
Application incorrect ... B .. Require repair or replacement.
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted ........ A ........... ( 1) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Insulation damaged,
conductors exposed ..... A .. Require repair or replacement.
Insulation damaged,
conductors not exposed . 1 ............ Suggest replacement.
Open .................... A .. Require repair or replacement.
Protective shield
(conduit) melted ....... 2 ........... ( 1) Suggest repair or
replacement.
Protective shield
(conduit) missing ...... 2 .. Suggest repair or replacement.
Resistance (voltage drop)
out of specification ... A .. Require repair or replacement.
Routed incorrectly ...... B ................. Require repair.
Secured incorrectly ..... B ................. Require repair.
Shorted ................. A .. Require repair or replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned, affecting
performance ............ A ........... ( 1) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Voltage drop out of
specification .......... A .. Require repair or replacement.
( 1) - Determine cause and correct prior to repair or
replacement of part.
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Page 322 of 1378
Fig. 5: Bleeding Master Cylinder
Courtesy of American Motors/Jeep Corp.
3) Fill master cylinder with clean brake fluid that meets DOT
3 specifications. Ensure that the end of bleeder tubes are submerged
in the brake fluid.
4) Using proper sized rod, apply and release master cylinder
until no air bubbles exist in brake fluid flow. Once all air bubbles
are gone from master cylinder secure cap and install.
5) Bleeder tubes should be left installed on master cylinder
until master cylinder in installed. Master cylinder must be bled at
brake lines and wheels after installation.
Bleeding On Vehicle
1) Install master cylinder on vehicle after bench bleeding.
Remove bleeder lines and install brake lines. DO NOT fully tighten
brake lines at this time.
2) Slowly force brake pedal to the floor and hold in this
position. Tighten brake lines and release brake pedal. Repeat
procedure until no air bubbles exist at brake lines. Remaining wheel
cylinder or calipers may be require bleeding.
HYDRAULIC CONTROL VALVES
Hold Off Valve
1) Prior to the pressure tank bleeding procedure, the hold
off valve incorporated in the combination valve must be correctly
positioned. This allows brake fluid to flow through the combination
valve to the entire brake system.
2) The valve stem of the hold off valve may be retained using
Page 329 of 1378
guide, adjuster screw assembly, parking brake lever and lever pivot
pin with molybdenum disulphide grease.
2) Connect parking brake lever to secondary brake shoe with
washer and "U" clip. Crimp ends of clip to secure clip on pivot.
Remove wheel cylinder clamp. Position brake shoes on brake support
plate and install hold-down springs.
3) Install parking brake lever strut and spring. Install
adjuster cable guide plate and adjuster cable on anchor pin. Install
primary return spring. Install guide to secondary brake shoe. Install
secondary return spring.
4) Install adjuster screw, spring and lever. Connect lever to
cable. Using Brake Gauge (J-21177-01), preset brake shoe adjustment.
Install brake drums. Adjust brake shoes with drum in place.
5) Install wheels and lower vehicle. To adjust and balance
brake system, apply and release brakes 10-15 times while driving
forward and backward. Road test vehicle.
DRUM BRAKE SHOES - GRAND WAGONEER
Removal
1) Raise vehicle and support with safety stands. Remove
wheels. On models with full-floating rear axle, remove 2 screws that
retain drum on hub.
2) On all models, remove primary shoe return spring,
automatic adjuster actuator spring and secondary shoe return spring.
Remove hold-down springs. Remove brake shoe assemblies. See Fig. 10.
3) Disengage parking brake cable from parking brake lever.
Remove parking brake strut and brake shoe assembly as a unit. Place
wheel cylinder clamps over cylinders in order to retain pistons.
4) Inspect automatic adjuster lever and pivot, actuating
lever, parking brake lever, automatic adjuster and springs. Replace
weak springs, bent levers and parts that are worn or broken.
Fig. 10: Exploded View of Drum Brake Assembly (Grand Wagoneer)
Courtesy of American Motors/Jeep Corp.
Installation
1) Clean support plate. Apply a thin film of molybdenum
Page 340 of 1378
CLU TC H
1988 J e ep C hero ke e
1988 Clutch
Hydraulic
Cherokee, Comanche, Wagoneer, Wrangler
DESCRIPTION
The clutch assembly consists of a single dry-disc driven
plate and a one-piece diaphragm spring-type clutch cover. On Wrangler
4-cylinder models, the clutch cover and driven plate diameter is 9.28"
(232 mm). On Wrangler 6-cylinder models, the clutch cover and driven
plate diameter is 10.5" (266 mm). On all other 4 and 6-cylinder
models, the clutch cover and driven plate diameter is 9.7"
(246 mm). The clutch is actuated through a hydraulic master cylinder
and slave cylinder.
On Wrangler models, the slave cylinder is mounted inside the
clutch housing. The bearing is permanently attached to the cylinder
piston.
TRANSMISSION APPLICATION
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Vehicle Model Transmission Model
Cherokee, Comanche, Wagoneer ........... Aisin AX4 4-Speed
Aisin AX5 5-Speed O/D
Wrangler ........................... Aisin AX5 5-Speed O/D
Peugeot BA 10/5 5-Speed O/D
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REMOVAL & INSTALLATION
TRANSMISSION
Removal
1) Remove the shift knob and lock nut from transmission and
transfer case shift levers (if equipped). On Wrangler models, remove
screws attaching transmission and transfer case shift lever boots and
remove both boots.
2) On all other models, raise outer gearshift lever boot and
remove upper part on center console. Remove lower part of console,
remove inner boot and gearshift lever.
3) On Wrangler models, remove transmission shift tower dust
cover. Remove transmission shift lever and stub shaft. DO NOT remove
shift lever from stub shaft.
4) On all models, raise and support vehicle. Drain
transmission lubricant. Mark rear drive shaft for reassembly and
remove rear drive shaft. Support transmission assembly and remove
crossmember. Disconnect speedometer cable and wiring from back-up
light switch.
5) On 4WD models, drain transfer case lubricant. Disconnect
transfer case vacuum hoses and linkage. Tag vacuum hoses for
reassembly. Disconnect front drive shaft and secure out of way.
6) On all models, remove clutch slave cylinder. Position
transmission jack under transmission assembly. Remove bolts securing
clutch housing to engine and remove transmission assembly. Remove
throw-out lever, bearing, and pivot ball from clutch housing.
Installation
To install, reverse removal procedure.
Page 474 of 1378
![JEEP CHEROKEE 1988 Service Owners Guide WHEEL SPEED SENSORS
See SPEED SENSORS (ELECTRONIC WHEEL AND VEHICLE) .
WIRING HARNESSES AND CONNECTORS
WIRING HARNESS AND CONNECTOR INSPECTION \](/img/16/57037/w960_57037-473.png "JEEP CHEROKEE 1988 Service Owners Guide WHEEL SPEED SENSORS
See SPEED SENSORS (ELECTRONIC WHEEL AND VEHICLE) .
WIRING HARNESSES AND CONNECTORS
WIRING HARNESS AND CONNECTOR INSPECTION \")
WHEEL SPEED SENSORS
See SPEED SENSORS (ELECTRONIC WHEEL AND VEHICLE) .
WIRING HARNESSES AND CONNECTORS
WIRING HARNESS AND CONNECTOR INSPECTION \
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Condition Code Procedure
Application incorrect ... B .. Require repair or replacement.
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A .. Require repair or replacement
of hardware.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted ........ A ........... ( 1) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Insulation damaged,
conductors exposed ..... A .. Require repair or replacement.
Insulation damaged,
conductors not exposed . 1 ............ Suggest replacement.
Open .................... A .. Require repair or replacement.
Protective shield
(conduit) melted ....... 2 ........... ( 1) Suggest repair or
replacement.
Protective shield
(conduit) missing ...... 2 .. Suggest repair or replacement.
Resistance (voltage drop)
out of specification ... A .. Require repair or replacement.
Routed incorrectly ...... B ................. Require repair.
Secured incorrectly ..... B ................. Require repair.
Shorted ................. A .. Require repair or replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned, affecting
performance ............ A ........... ( 1) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Transmission connector
leaking ................ .. ..... See TRANSMISSION ASSEMBLY.
Voltage drop out of
specification .......... A .. Require repair or replacement.
( 1) - Determine cause and correct prior to repair or
replacement of part.
Page 492 of 1378
switch.
Fuse C Taped to engine wiring
harness, by alternator.
Fuse D Taped to engine wiring
harness, near power steering
switch.
Cruise Control Under left side of dash, near
brake pedal.
Radio Under center of dash, behind
radio.
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CONTROL UNITS
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Component Component Location
Audio Alarm Module On side of fuse block.
Cruise Control Regulator Module Under dash, above brake pedal.
Elect. Control Unit (ECU) Under dash, above accelerator
pedal.