1988 JEEP CHEROKEE engine

used with 2.5.L
The DRB-II has determined that the wrong Transmission Control
Unit (TCU) has been installed in the vehicle. There are two
transmission control units available for the Jeep AW4 transmission.
One is for the 4-cylinder 2.5L engine and the other is for the 6-
cylinder 4.0L engine.
1) using the DRB-II, read MODULE INFO. See HELP 1 for
assistance.
2) Determine what vehicle should be in the vehicle.
* 2.5L Engine: TCU 02 (Used in earlier years only)
* 4.0L Engine: TCU 01 (1993-94)
3) If the wrong transmission control unit is installed, the
vehicle shift points will be slightly different (the 2.5L engine TCU
has higher shift points).
TEST 10A - TESTING FOR INTERMITTENT SPEED SENSOR
NOTE: Perform TEST 1A - VERIFICATION OF THE COMPLAINT
before proceeding.
Fig. 115: Test 10A - Flow Chart (1 of 2)
Fig. 116: Test 10A - Schematic (Cherokee)

SHOE HARDWARE
SHOES
SOCKETS
SPEED SENSORS (ELECTRONIC WHEEL AND VEHICLE)
STEEL BRAKE LINES
STOPLIGHT SWITCHES
SWITCHES
TIRES
TOOTHED RINGS (TONE WHEEL)
VACUUM BOOSTERS
VACUUM HOSES
VALVES
WHEEL ATTACHING HARDWARE
WHEEL BEARINGS, RACES AND SEALS
WHEEL CYLINDERS
WIRING HARNESSES
INTRODUCTION TO MOTORIST ASSURANCE PROGRAM (MAP)
OVERVIEW OF MOTORIST ASSURANCE PROGRAM
The Motorist Assurance Program is the consumer outreach
effort of the Automotive Maintenance and Repair Association, Inc.
(AMRA). Participation in the Motorist Assurance Program is drawn from
retailers, suppliers, independent repair facilities, vehicle
manufacturers and industry associations.
Our organization's mission is to strengthen the relationship
between the consumer and the auto repair industry. We produce
materials that give motorists the information and encouragement to
take greater responsibility for their vehicles-through proper,
manufacturer-recommended, maintenance. We encourage participating
service and repair shops (including franchisees and dealers) to adopt:\
1) a Pledge of Assurance to their Customers and
2) the Motorist Assurance Program Standards of Service.
All participating service providers have agreed to subscribe
to this Pledge and to adhere to the promulgated Standards of Service
demonstrating to their customers that they are serious about customer
satisfaction.
These Standards of Service require that an inspection of the
vehicle's (problem) system be made and the results communicated to the\
customer according to industry standards. Given that the industry did
not have such standards, the Motorist Assurance Program successfully
promulgated industry inspection communication standards in 1994-95 for
the following systems: Exhaust, Brakes, ABS, Steering and Suspension,
Engine Maintenance and Performance, HVAC, and Electrical Systems.
Further, revisions to all of these inspection communication standards
are continually re-published. In addition to these, standards for
Drive Train and Transmissions have recently been promulgated.
Participating shops utilize these Uniform Inspection & Communication
Standards as part of the inspection process and for communicating
their findings to their customers.
The Motorist Assurance Program continues to work
cooperatively and proactively with government agencies and consumer
groups toward solutions that both benefit the customer and are
mutually acceptable to both regulators and industry. We maintain the
belief that industry must retain control over how we conduct our
business, and we must be viewed as part of the solution and not part
of the problem. Meetings with state and other government officials
(and their representatives), concerned with auto repair and/or
consumer protection, are conducted. Feedback from these sessions is
brought back to the association, and the program adjusted as needed.
To assure auto repair customers recourse if they were not

satisfied with a repair transaction, the Motorist Assurance Program
offers mediation and arbitration through MAP/BBB-CARE and other non-
profit organizations. MAP conducted pilot programs in twelve states
before announcing the program nationally in October, 1998. During the
pilots, participating repair shops demonstrated their adherence to the
Pledge and Standards and agreed to follow the UICS in communicating
the results of their inspection to their customers. To put some
"teeth" in the program, an accreditation requirement for shops was
initiated. The requirements are stringent, and a self-policing method
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 AND 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.

same axle to eliminate uneven braking behavior. Always wash drums
after servicing or before installing.
DRUM INSPECTION









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Condition Code Procedure
Balance weight missing .. .. ........ No service suggested or
required.
Bell-mouthed, affecting
performance ............ A ....... Require reconditioning or
replacement.
Cooling fin broken ...... .. ........ No service suggested or
required.
Cracked ................. B ............ Require replacement.
Drum diameter is greater
than OEM "machine to"
specifications but less
than "discard at"
specifications, and the
drum does not require
reconditioning ......... 1 ........ (1) Suggest replacement.
Drum diameter will exceed
OEM "machine to"
specifications after
required
reconditioning ......... B ........ ( 2) Require replacement.
Hard-spotted ............ 2 ....... Suggest reconditioning or
replacement.
Measured diameter is
greater than OEM discard
specifications ......... B ............ Require replacement.
Out-of-round (runout),
affecting performance .. A ....... Require reconditioning or
replacement.
Out-of-round (runout),
exceeding manufacturer's
specifications ......... B ....... Require reconditioning or
replacement.
Scored .................. B ....... Require reconditioning or
replacement.
Surface threaded due to
improper machining ..... B ....... Require reconditioning or
replacement.
Tapered, affecting
performance ............ A ....... Require reconditioning or
replacement.
( 1) - Only applies to vehicles for which OEM "machine to"
specifications exist. If OEM does not supply "machine to"
specifications, the drum may be worn to discard
specifications.
( 2) - If OEM does not supply "machine to" specifications, you
may machine to discard specifications.









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ELECTRICAL PUMPS AND MOTORS
Copied fuel pump conditions from engine UIGs & deleted
pulsator from leaking conditions.
ELECTRICAL PUMP AND MOTOR INSPECTION









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NOTE: Copied Vehicle Speed Sensors from Engine UIGs & added
Air Gap incorrect, loose, and wire lead misrouted. For
"contaminated" removed coolant & fuel examples from note.
SPEED SENSOR INSPECTION









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Condition Code Procedure
Air gap incorrect ....... B ....... (1) Require adjustment or
replacement.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware
threads damaged ........ A ... Require repair or replacement
of hardware.
Attaching hardware
threads stripped
(threads missing) ...... 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 ........... ( 2) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Contaminated ............ A ........... ( 3) Require repair or
replacement.
Inoperative ............. B ........... ( 4) Require repair or
replacement. Further
inspection required.
Lead routing incorrect .. B ..... Require rerouting according
to vehicle manufacturer's
specifications.
Leaking ................. A .. Require repair or replacement.
Loose ................... A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Resistance out of
specification .......... B .. Require repair or replacement.
Sensor housing cracked .. 2 ............ Suggest replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned,
affecting performance .. A ........... ( 2) 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.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped
(threads missing) ...... A ............ Require replacement.
Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead corroded ...... A .. Require repair or replacement.
Wire lead misrouted ..... B . Require re-routing according to
vehicle manufacturer's

disulphide grease or chassis lubricant on support plate ledges, anchor
pin, adjuster screw threads and pivot.
2) Apply grease to adjuster lever-to-secondary brake shoe
contact surface, parking brake lever pivot and portion of lever that
contacts secondary brake shoe.
3) Attach parking brake cable to parking brake lever on
secondary shoe. Pinch "U" clip to retain lever on shoe. Install
secondary brake shoe, automatic adjuster lever and lever pivot as an
assembly.
4) Install brake shoe hold-down spring. Install return spring
on actuating lever tang. Large end of tapered spring should rest on
brake shoe.
5) Install primary shoe and hold-down spring. Install guide
plate on anchor pin. Install parking brake strut and spring on brake
shoes.
6) Install adjusting screw and spring. Short end of hooked
spring attaches to primary brake shoe. Long hooked end attaches to
secondary brake shoe.
7) Install secondary shoe return spring, adjuster spring and
primary return spring. Install brake drums. Adjust brakes. Bleed brake
system.
8) Install wheels and lower vehicle. Apply and release brakes
10-15 times while driving forward and backward to adjust and balance
brake system. Road test vehicle.
MASTER CYLINDER - EXCEPT GRAND WAGONEER
Removal
1) With engine off, depress brake pedal several times to
release vacuum in power unit. Clean dirt and grease from brake line
connections.
2) Disconnect and plug brake lines at master cylinder. Remove
retaining nuts and master cylinder.
Installation
To install, reverse removal procedure. Bleed brake system.
See BRAKE SYSTEM BLEEDING in this article.
MASTER CYLINDER - GRAND WAGONEER
Removal
Disconnect brake lines at master cylinder and plug. On
vehicles without power assist units, disconnect brake pedal push rod
at brake pedal. Remove master cylinder retaining nuts at firewall.
Remove master cylinder.
Installation
1) Master cylinder should be bench bled before installation.
See BRAKE SYSTEM BLEEDING in this article. Position master cylinder on
vehicle. Loosely install retaining nuts. Loosely install brake lines
to cylinder. Tighten retaining nuts. Tighten brake lines.
2) Connect brake pedal push rod (if removed). Fill reservoir\
with brake fluid and bleed brake system. See BRAKE SYSTEM BLEEDING in
this article.
REAR AXLE BEARING & SEAL
Removal
1) Raise vehicle and support with safety stands. Remove wheel
assembly and brake drum. Remove support plate retaining nuts through
hole provided in axle flange. Use a slide hammer to remove axle shaft.
2) If wheel bearing cup remains in housing, use Slide Hammer
(J-2619-01) and Bearing Remover (J-26941) to remove bearing cups.

CEC C O M PO NEN T R EM OVA L & IN STA LLA TIO N

1988 J e ep C hero ke e
1984-86 Computerized Engine Controls
JEEP 4-CYLINDER COMPUTERIZED ENGINE CONTROL
COMPONENT REMOVAL & INSTALLATION
Cherokee, CJ/Scrambler, Comanche, Wagoneer, Wrangler
MICROCOMPUTER CONTROL UNIT (MCU) R & I
The MCU is located behind the right front kick panel. Remove
MCU mounting bolts and disconnect wiring harness connector. Do not
bend connector pins when removing. Reconnect harness to MCU and
replace mounting bolts.
MIXTURE CONTROL (M/C) SOLENOID R & I
Remove air cleaner and disconnect solenoid harness connector.
Remove retaining screws and remove solenoid from carburetor. Coat
rubber seal, on end of solenoid stem, with silicone grease or light
engine oil prior to reinsertion. Using a new gasket, replace solenoid.
Reconnect wiring harness and replace air cleaner.
Fig. 1: M/C Solenoid Location on Carburetor
OXYGEN (O2) SENSOR R & I

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.