1988 JEEP CHEROKEE engine
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has been incorporated which includes the "mystery shopping" of
outlets.
We welcome you to join us as we continue our outreach... with
your support, both the automotive repair industry and your customers
will reap the benefits. Please visit MAP at our Internet site www.
motorist.org or contact us at:
1444 I Street, NW Suite 700
Washington, DC 20005
Phone (202) 712-9042 Fax (202) 216-9646
January 1999
MAP UNIFORM INSPECTION GENERAL GUIDELINES
OVERVIEW OF SERVICE REQUIREMENTS & SUGGESTIONS
It is MAP policy that all exhaust, brake, steering,
suspension, wheel alignment, drive-line, engine performance and
maintenance, and heating, ventilation and air conditioning, and
electrical services be offered and performed under the standards and
procedures specified in these sections.
Before any service is performed on a vehicle, an inspection
of the appropriate system must be performed. The results of this
inspection must be explained to the customer and documented on an
inspection form. The condition of the vehicle and its components will
indicate what services/part replacements may be "Required" or
"Suggested". In addition, suggestions may be made to satisfy the
requests expressed by the customer.
When a component is suggested or required to be repaired or
replaced, the decision to repair or replace must be made in the
customer's best interest, and at his or her choice given the options
available.
This section lists the various parts and conditions that
indicate a required or suggested service or part replacement.
Although this list is extensive, it is not fully inclusive. In
addition to this list, a technician may make a suggestion. However,
any suggestions must be based on substantial and informed experience,
or the vehicle manufacturer's recommended service interval and must be
documented.
Some conditions indicate that service or part replacement is
required because the part in question is no longer providing the
function for which it is intended, does not meet a vehicle
manufacturer's design specification or is missing.
Example:
An exhaust pipe has corroded severely and has a hole
in it through which exhaust gases are leaking. Replacement
of the exhaust pipe in this case is required due to
functional failure.
Example:
A brake rotor has been worn to the point where it measures
less than the vehicle manufacturer's discard specifications.
Replacement of the rotor is required because it does not meet
design specifications.
Some conditions indicate that a service or part replacement
is suggested because the part is close to the end of its useful life
or addresses a customer's need, convenience or request. If a
customer's vehicle has one of these conditions, the procedure may be
only to suggest service.
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NOTE: Whenever transmission or drivetrain service is performed
that affects the suspension alignment, for example,
removing the engine cradle, it is required that the
alignment be checked and corrected if necessary.
AUTOMATIC TRANSMISSION/TRANSAXLE ASSEMBLIES
AUTOMATIC TRANSMISSION/TRANSAXLE ASSEMBLY INSPECTION \
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Condition Code Procedure
Any internal component
failure that requires
removal of the assembly
from the vehicle for
service. ( 1) ........... A ........... ( 2) Require repair or
replacement of the automatic
transmission/transaxle
assembly.
( 1) - It is Required that the torque converter and all other
failure related components be inspected for cause and
condition.
( 2) - For components not requiring removal of the assembly,
refer to the component listing in this document.
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DIFFERENTIAL AND FINAL DRIVE ASSEMBLIES
NOTE: Does not include half shafts.
DIFFERENTIAL AND FINAL DRIVE ASSEMBLY INSPECTION
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Condition Code Procedure
Any internal component
failure that requires
removal of the assembly
from the vehicle for
service. ( 1) ........... A ... Require repair or replacement
of the differential assembly.
( 1) - For components not requiring removal of the assembly,
refer to the component listing in this document.
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MANUAL TRANSMISSION/TRANSAXLE ASSEMBLIES
MANUAL TRANSMISSION/TRANSAXLE ASSEMBLY INSPECTION \
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Condition Code Procedure
Any internal component
failure that requires
removal of the assembly
from the vehicle for
service. ( 1) ........... A ... Require repair or replacement
of the manual
transmission/transaxle
assembly.
( 1) - For components not requiring removal of the assembly,
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![JEEP CHEROKEE 1988 Service Repair Manual Torn .................... A ............ Require replacement. \
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\](/manual-img/16/57037/w960_57037-454.png "JEEP CHEROKEE 1988 Service Repair Manual Torn .................... A ............ Require replacement. \
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Torn .................... A ............ Require replacement. \
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ENGINE MOUNTS
See MOUNTS (ENGINE, TRANSAXLE AND TRANSMISSION) .
EXCITER RINGS
See TOOTHED RINGS (TONE WHEELS) .
FILLER TUBES
See DIP STICK TUBES .
FILTERS AND SCREENS
FILTER AND SCREEN INSPECTION \
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Condition Code Procedure
At service interval ..... 3 ............ Suggest replacement.
Bent .................... A .. Require repair or replacement.
Exceeding service
interval ............... 3 ............ Suggest replacement.
Missing ................. C ............ Require replacement.
Near service interval ... 3 ............ Suggest replacement.
Restricted .............. A ........... ( 1) Require repair or
replacement.
Torn .................... A ............ Require replacement.
Worn, affecting
performance (metal or
nylon screen type) ..... A .. Require repair or replacement.
( 1) - Further inspection may be required to determine the
source of restriction or contamination.
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FLANGES
See COMPANION FLANGES .
FLEX PLATES
FLEX PLATE INSPECTION \
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Condition Code Procedure
Bent, affecting
performance ............ A ............ Require replacement.
Bent, not affecting
performance ............ .. ........ No service suggested or
required.
Bolt or stud holes
elongated .............. B ............ Require replacement.
Broken .................. A ............ Require replacement.
Cracked ................. A ............ Require replacement.
Ring gear worn close
to the end of its
useful life ............ 1 ............ Suggest replacement.
Ring gear worn to the
extent that it no longer
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Damaged, affecting
performance ............ A ............ Require replacement.
Missing ................. C ............ Require replacement.
Worn, affecting
performance ............ A ............ Require replacement.
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LUBRICANTS
See FLUIDS AND LUBRICANTS .
METAL-CLAD SEALS
See SEALS.
METALASTIC JOINTS
See RUBBER JOINTS (METALASTIC) .
MODULATOR PINS
MODULATOR PIN INSPECTION \
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Condition Code Procedure
Application incorrect ... B ............ Require replacement.
Missing ................. C ............ Require replacement.
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MODULATORS
MODULATOR INSPECTION \
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Condition Code Procedure
Bent, affecting
performance ............ A ............ Require replacement.
Contaminated (water, fuel,
etc.) .................. A ........ ( 1) Require replacement.
Housing cracked ......... A ............ Require replacement.
Inoperative ............. A ........ ( 2) Require replacement.
Leaking fluid
externally ............. A .. Require repair or replacement.
Leaking fluid
internally ............. A ............ Require replacement.
Leaking vacuum .......... A ............ Require replacement.
Nipple broken ........... A ............ Require replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
( 1) - Further inspection is required to determine the cause
of the contamination.
( 2) - Inoperative includes intermittent operation or out of OEM
specification.
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MOUNTS (ENGINE, TRANSAXLE AND TRANSMISSION)
MOUNT (ENGINE, TRANSAXLE AND TRANSMISSION) INSPECTION \
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incorrect .............. B ............ Require replacement.
Teeth broken ............ A ............ Require replacement.
Teeth damaged, affecting
performance ............ A ............ Require replacement.
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TORQUE CONVERTERS
TORQUE CONVERTER INSPECTION \
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Condition Code Procedure
Converter clutch lock-up
operation is faulty .... A ............ Require replacement.
Cover shell damaged,
affecting performance .. A ............ Require replacement.
Does not meet stall speed
specification .......... B ............ Require replacement.
End play exceeds
specifications ......... B ............ Require replacement.
Hub broken .............. A ............ Require replacement.
Hub cracked ............. A ............ Require replacement.
Internal component
failure ................ A ............ Require replacement.
Leaking ................. A .. Require repair or replacement.
Pilot broken ............ A ............ Require replacement.
Pilot worn, affecting
performance ............ A ............ Require replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
Weights missing ......... C ............ Require replacement.
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TRANSAXLE MOUNTS
See MOUNTS (ENGINE, TRANSAXLE AND TRANSMISSION) .
TRANSDUCERS (TRANSMISSION)
See SENSORS.
TRANSMISSION COOLERS
TRANSMISSION COOLER INSPECTION \
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Condition Code Procedure
Air flow obstruction .... A ................. Require repair.
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.
Connection leaking ...... A .. Require repair or replacement.
Contaminated ............ A .. Require repair or replacement.
Corroded ................ 1 .. Suggest repair or replacement.
Fins damaged, affecting
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performance ............ A .. Require repair or replacement.
Fins damaged, not
affecting performance .. .. ........ No service suggested or
required.
Internal restrictions ... B .. Require repair or replacement.
Leaking ................. A .. Require repair or replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A .. Require repair or replacement.
Tubes damaged, affecting
performance ............ A .. Require repair or replacement.
Tubes damaged, not
affecting performance .. .. ........ No service suggested or
required.
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TRANSMISSION MOUNTS
See MOUNTS (ENGINE, TRANSAXLE AND TRANSMISSION) .
TRANSMISSION PANS
TRANSMISSION PAN INSPECTION \
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Condition Code Procedure
Bent, interfering with
filter or other internal
components ............. A .. Require repair or replacement.
Leaking ................. A .. Require repair or replacement.
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TRANSMISSION RANGE INDICATORS (PRNDL)
TRANSMISSION RANGE INDICATOR (PRNDL) INSPECTION \
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Condition Code Procedure
Binding ................. A .. Require repair or replacement.
Broken .................. A .. Require repair or replacement.
Components missing ...... C .. Require replacement of missing
components.
Loose, affecting
performance ............ A .. Require repair or replacement.
Out of adjustment ....... A ................. Require repair.
Worn, affecting
performance ............ A .. Require repair or replacement.
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TUBES
See HOSES, LINES AND TUBES .
UNIVERSAL JOINTS (CARDON OR CROSS TYPE)
UNIVERSAL JOINT (CARDON OR CROSS TYPE) INSPECTION \
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Condition Code Procedure
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
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EG R F U NCTIO N T E STIN G
1988 J e ep C hero ke e
1983-88 Exhaust Emission Systems
JEEP EXHAUST GAS RECIRCULATION
TESTING
EGR VALVE
Valve Opening Test
1) With engine at normal operating temperature and at idle,
rapidly open and close throttle. Open throttle sufficiently to obtain
at least 1500 RPM. Movement should be noticed in EGR diaphragm.
2) If diaphragm does not move, probable causes are: faulty
vacuum signal to EGR, defective EGR diaphragm or defective
backpressure sensor diaphragm (if equipped), or leaks in vacuum lines
or connections.
Valve Closing Test
1) With engine at normal operating temperature and at idle,
manually depress EGR valve diaphragm. RPM should immediately drop,
indicating that EGR valve is not leaking and had been properly
cutting off exhaust gas flow at idle.
2) If there is no change in RPM and engine is idling
properly, exhaust gases are not reaching combustion chamber. Check
for plugged passage between EGR valve and intake manifold.
3) If engine idles poorly and RPM is not greatly affected by
manually moving diaphragm up, EGR valve is not closing off exhaust
gas flow. Check for carbon between pintle, leaking EGR valve gasket
or bad EGR valve.
COOLANT TEMPERATURE OVERRIDE (CTO) SWITCH
NOTE: Engine coolant temperature must be below 100 F (38 C) to
perform this test.
1) Check vacuum lines for leaks and correct routing.
Disconnect vacuum line at backpressure sensor (if equipped) or at EGR
valve, and attach this line to vacuum gauge.
2) Operate engine at 1500 RPM. No vacuum should be indicated
on gauge. If vacuum is shown, replace CTO switch.
3) Idle engine until coolant temperature exceeds 100
F
(38 C) on 4-cylinder engines, or 115 F (46 C) on 6-cylinder and V8
engines.
4) Raise engine speed to 1500 RPM. Ported vacuum should be
shown on gauge. If not, replace CTO switch.
DUMP VALVE
1) With engine at normal operating temperature, remove dump
valve vacuum hose from manifold and plug manifold connection.
2) Raise engine speed to 2000 RPM. Vacuum should be present
at exhaust ports on bottom of valve. If not, replace valve.
3) Reconnect vacuum hose to manifold and raise engine speed
to 2000 RPM. No vacuum should be felt at exhaust ports on bottom of
valve. If vacuum is present, replace valve.
THERMAL VACUUM SWITCH (TVS)
1) With the air cleaner temperature below 40 F (-4 C),
disconnect vacuum hoses from TVS and connect vacuum source to large
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outlet.
2) Apply vacuum to TVS. TVS should hold vacuum. If not,
replace TVS.
3) Start engine and warm air cleaner to 55
F (13 C), or
greater. TVS should not hold vacuum. If it does, replace TVS.