1991 MITSUBISHI MONTERO engine

TIE ROD ENDS (INNER AND OUTER)
TRACK BARS
TRAILING ARMS
WHEEL BEARINGS, RACES AND SEALS
Wheel Alignment
WHEEL ALIGNMENT
Wheels and Tires
TIRES
VALVE STEMS
WHEEL ATTACHMENT HARDWARE
WHEELS (RIMS)
MOTORIST ASSURANCE PROGRAM (MAP)
OVERVIEW
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 & 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.

Fig. 6: Engine Driveability & Automatic Transmission

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I - S YSTE M /C O M PO NEN T T E STS

1991 M it s u bis h i M onte ro
1991 ENGINE PERFORMANCE
System & Component Testing
Chrysler Motors: Ram-50
Mitsubishi: Montero, Pickup
INTRODUCTION
Before testing separate components or systems, perform
procedures in F - BASIC TESTING article in the ENGINE PERFORMANCE
Section. Since many computer controlled and monitored components set a
trouble code if they malfunction, also perform procedures in G - TESTS
W/CODES article in the ENGINE PERFORMANCE Section.
NOTE: Testing individual components does not isolate shorts or
opens. Perform all voltage tests with a Digital
Volt-Ohmmeter (DVOM) with a minimum 10-megohm input
impedance, unless stated otherwise in test procedure. Use
ohmmeter to isolate wiring harness shorts or opens.
COMPUTERIZED ENGINE CONTROLS
CONTROL UNIT
NOTE: To identify ECU power and ground circuits, see appropriate
L - WIRING DIAGRAMS article in the ENGINE PERFORMANCE
Section.
Ground Circuits
1) ECU is located near right kick panel. Turn ignition off.
Using an ohmmeter, check for continuity between ground and ECU
terminals No. 101 and 106. Resistance should be zero ohms. If
resistance is not zero ohms, repair open circuit between ECU connector
and ground.
2) Connect voltmeter negative lead to ground. Connect
positive lead to ECU ground terminals as in step 1). With vehicle
running, voltmeter should indicate less than one volt. If voltmeter
reading is greater than one volt, check for open, corrosion or loose
connection in ground circuit.
Power Circuits
ECU is located near right kick panel. Turn ignition on. Check
for battery voltage on ECU terminals No. 102 and 107. If battery
voltage is not present, check operation of MPI control relay. See
RELAYS under MOTORS, RELAYS & SOLENOIDS.
ENGINE SENSORS & SWITCHES
BAROMETRIC PRESSURE SENSOR
Sensor is a component part of airflow sensor assembly. See G
- TESTS W/CODES article in the ENGINE PERFORMANCE Section.
COOLANT TEMPERATURE SENSOR
1) Remove coolant temperature sensor located near thermostat
housing (2-wire connector). Place end of sensor in water with terminal\

mechanism. Testing information is not available from manufacturer. See
appropriate wiring diagram in L - WIRING DIAGRAMS article in the
ENGINE PERFORMANCE Section.
INTAKE AIR TEMPERATURE SENSOR
1) Sensor is incorporated in airflow sensor assembly inside
air filter housing. Disconnect airflow sensor connector. See Fig. 1.
Fig. 1: Airflow Sensor Connector Terminal ID
Courtesy of Mitsubishi Motor Sales of America.
2) Measure resistance between terminals No. 4 and 6 of
airflow sensor connector (sensor side of connector). For
specifications, see INTAKE AIR TEMPERATURE SENSOR RESISTANCE table.
Replace airflow sensor assembly if air temperature sensor resistance
is not within specification.

INTAKE AIR TEMP SENSOR RESISTANCE TABLE








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TemperatureF (C) Ohms
All Models
32 (0) ........................ 6000
68 (20) ....................... 2700
176 (80) ....................... 400









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MOTOR POSITION SENSOR
NOTE: Some engines are not equipped with Motor Position Sensor
(MPS). MPS may be a separate unit mounted to throttle body
or it may be incorporated in ISC motor assembly, depending
upon vehicle application.
Pickup 2.4L & Ram-50 2.4L
1) Disconnect MPS connector. See Fig. 2. Connect ohmmeter
lead to ground. Connect other ohmmeter lead to terminal No. 3 of
sensor connector. If continuity is not present, repair wiring harness
as necessary. If continuity is present, go to next step.
Fig. 2: Motor Pos. Sensor Connector Term. ID
Courtesy of Mitsubishi Motor Sales of America.
2) Connect ohmmeter leads to terminals No. 2 and 3.
Resistance should be 4000-6000 ohms. If resistance is not within

specified range, replace MPS.
CAUTION: DO NOT apply more than 6 volts to ISC motor.
3) Operate ISC motor by connecting a 6-volt source directly
to appropriate terminals of ISC motor connector. For ISC motor
operation test procedures, see IDLE SPEED CONTROL (ISC) MOTOR
OPERATION TEST under IDLE CONTROL SYSTEM.
4) While operating ISC motor, measure resistance between MPS
connector terminals No. 3 and 5. Observe ohmmeter during ISC motor
operation. If MPS resistance does not vary within a 4000-6000 ohm
range or if resistance does not change smoothly, replace MPS (vehicles
equipped with separate MPS) or ISC motor assembly (vehicles equipped
with MPS incorporated in ISC).
OXYGEN SENSOR
1-Wire Or 2-Wire
1) On all models, warm engine until coolant temperature is
185-205
F (85-96C). Disconnect oxygen sensor connector. See Fig. 3 or
4.
2) Connect digital voltmeter between terminal No. 1 and
ground. Repeatedly race engine and observe oxygen sensor output
voltage. If output is not 0.6-1.0 volt, replace oxygen sensor.
Fig. 3: O2 Sensor Connector Terminal ID (1 Wire)
Courtesy of Mitsubishi Motor Sales of America.

Fig. 4: O2 Sensor Connector Terminal ID (2 Wire)
Courtesy of Mitsubishi Motor Sales of America.
4-Wire Heated
1) Warm engine until coolant temperature is 185-205
F (85-