ECO mode MITSUBISHI MONTERO 1991 Owner's Manual

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* S YM PTO M C HEC K L IS T *
1 991 M it s u bis h i M onte ro
SYMPTOM CHECK LIST WORKSHEETS
* PLEASE READ THIS FIRST *
NOTE: This article is intended for general information purposes
only. It does not apply specifically to one make or model.
PURPOSE
Why Use the Symptom Check List Worksheets?
One of the most difficult and critical lines of communication
is between the service customer and the technician. The clearer the
technician understands the customer's concerns, the more likely the
problem will be "fixed right the first time".
The Symptom Check List Worksheets in this article are
designed to improve this communication. When used consistently, they
can be helpful in reducing shop comebacks, increasing technician
productivity, and producing satisfied customers. They also provide
other benefits:
* Reduce "No Trouble Found" problems
* Increase customer involvement
* Customer perceive that "they really care and listen"
* Save time during peak write-up periods
* Reduce recontacting customers for additional information
* Improve night drop information
* Insure all the right questions are asked at write-up
Making the Worksheets a Part of Your Normal Routine
The following information contains ideas that may be helpful
in forming habits that promote daily use of the Symptom Check Lists:
* HAVE THE SERVICE ADVISER FILL OUT THE FORM(S) WITH THE
CUSTOMER WHENEVER POSSIBLE.
* Place them in your night drop for the customer to fill out,
along with an instruction sheet to help them understand what
to do.
* Hand out the worksheets to customers while they wait in line
during the peak morning rush and ask them to fill it out. It
will save time for all concerned and improve the quality of
information received from the customer.
* Make sure it is attached to the hard copy when it goes to the
technician.
* Place a copy with the final repair papers and review it with
the customer at delivery.
* Put a new worksheet in the glovebox of all departing
customers.
* Require that you personally see a copy of all worksheets
filled out for shop comebacks.
* Hold a shop meeting to get employee buy-in and their ideas on
how to make it effective in your shop.
There are many other ways to utilize the concept, but as with
every other idea, successful implementation depends on employee
involvement and buy-in.
SYMPTOM CHECK LIST WORKSHEETS

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G - T E STS W /C O DES
1991 Mitsubishi Montero
1990-91 ENGINE PERFORMANCE
Chrysler Motors/Mitsubishi Self-Diagnostics
Dodge; Colt, Colt Vista, Colt Wagon
Eagle; Summit
Mitsubishi; Eclipse, Galant, Mirage, Montero, Precis (1990)
Plymouth; Colt, Colt Vista, Colt Wagon
INTRODUCTION
If no faults were found while performing F - BASIC TESTING,
proceed with self-diagnostics. If no fault codes or only pass codes
are present after entering self-diagnostics, proceed to H - TESTS W/O
CODES article for diagnosis by symptom (i.e. ROUGH IDLE, NO START,
etc.).
SELF-DIAGNOSTIC SYSTEM
Use Chrysler Motors code charts when using Chrysler's
Diagnostic Readout Box (DRB-II). If DRB-II is not available or if
working on a Mitsubishi Motors vehicle, system diagnosis can only be
accomplished using a voltmeter or appropriate scan tester. To diagnose
Chrysler Motors and Mitsubishi models using a voltmeter, see
ENTERING ON-BOARD DIAGNOSTICS (USING VOLTMETER) in this article.
SYSTEM DIAGNOSIS
SYSTEM DIAGNOSIS DESCRIPTION
NOTE: Chrysler Motors recommends using DRB-II to diagnose system.
Voltmeter usage has limited diagnostic capabilities but can
be used if DRB-II is not available or if working on a
Mitsubishi Motors vehicle.
The Engine Control Unit (ECU) monitors several different
engine control system circuits. If an abnormal input signal occurs, a
fault code is stored in ECU memory and given a fault code number. Each
circuit has its own fault number and message. A specific fault code
indicates a particular system failure, but it DOES NOT indicate that
cause of failure is necessarily within system. A fault code DOES NOT
condemn any specific component; it simply points out a probable
malfunctioning area. If a critical fault code is set, the ECU will
turn on CHECK ENGINE light. All fault codes except speed sensor are
considered critical.
Fault codes can be confirmed by using a voltmeter on Chrysler
Motors and Mitsubishi models or Chrysler's Diagnostic Readout Box
(DRB-II) on Chrysler Motors vehicles. See
ENTERING ON-BOARD DIAGNOSTICS (USING VOLTMETER) or ENTERING ON-BOARD
DIAGNOSTICS (USING DRB-II) in this article. By using the DRB-II, the
self-diagnostic capabilities of this system can simplify testing and
reduce diagnostic time.
System malfunctions encountered are identified as either hard
failures or intermittent failures as determined by the ECU.
HARD FAILURES
Hard failures cause CHECK ENGINE light to illuminate and
remain on until the malfunction is repaired. If light comes on and

PROCEDURE chart after repairs. Ensure charts apply to engine
being tested.
DRB-II KEY FUNCTIONS
* YES or Down Arrow & NO or Up Arrow
Keys will move lines on screen up or down allowing you to
choose an item or scroll through all selections
available.
* F1 & F2 Keys
Keys are used to scroll through sensor displays.
* ATM Key
Key will return you to previous screen.
* ENTER Key
Allows you to select a test or display. The flashing
arrow must be on the display you wish to select. Pressing
ENTER in the sensor state will cause display to change
from a 3-line display to a 1-line display.
* F3 Key
Key is used to display a help screen. This key may be
used at any time.
* Number Keys
Keys are used for choosing a display or test by the
number for the test or display.
* READ/HOLD Key
Key is used to freeze any sensor display.
* MODE & ATM Key
Pressing MODE and ATM key at the same time will cause
DRB-II to reset to copyright screen.
ENTERING ON-BOARD DIAGNOSTICS (USING DRB-II)
* PLEASE READ THIS FIRST *
1) Before entering on-board diagnostics, refer to PRETEST
INSPECTION in this article. Turn ignition off. Locate self-diagnostic
connector. See SELF-DIAGNOSTIC TEST CONNECTOR LOCATION table in this
article. Using appropriate Mitsubishi cartridge and adapter, connect
DRB-II to diagnostic connector.
2) Ensure all accessories are off. Turn ignition on. All
character positions will illuminate and copyright information will
appear on screen for a few seconds.
3) If DRB-II screen displays an error message, refer to DRB-
II ERROR SCREENS in this article. The DRB-II will offer 4 menus:
VEHICLES TESTED, HOW TO USE, CONFIGURE and SELECT VEHICLE.
VEHICLES TESTED
Press "1" key or ENTER key when VEHICLES TESTED appears on
DRB-II. DRB-II shows models covered by cartridge. Screen will display
for 5 seconds and return to DRB-II menu. To return to DRB-II menu
sooner, press ATM key.
HOW TO USE
Press "2" key or press down arrow to display HOW TO USE
option and press ENTER. Press and hold F3 key. DRB-II displays
instructions for cartridge usage. To return to DRB-II menu, press ATM
key.
CONFIGURE

Press "3" key or press down arrow to display CONFIGURE option
and press ENTER. Configure allows user to customize DRB-II display.
For example, If metric system is more useful, select METRIC from the
menu. All selections in CONFIGURE option remain active until user
changes selection.
SELECT VEHICLE
1) This allows the user to enter information about vehicle
being tested. Usually, this option has more than one display screen.
Use ENTER key to enter vehicle information.
2) When all information about vehicle is entered, DRB-II will
display an information summary the technician has entered. DRB-II will
show an additional option marked CONFIRM. If information is correct,
press CONFIRM. DRB-II will display MAIN MENU.
MAIN MENU
The MAIN MENU represents all diagnostic functions available.
Functions are SYSTEM TESTS, READ FAULTS, STATE DISPLAYS, ACTUATOR
TESTS and ADJUSTMENTS. SYSTEM TESTS is NOT available.
READ FAULTS
This allows technician to read fault codes stored in ECU
memory.
STATE DISPLAYS
1) This allows technician to view conditions at signal level.
The 2 types of signals are analog and digital. Analog signals are
monitored at pins corresponding to vehicle harness splices (e.g. fuel
pump relay).
2) Digital signals correspond to data transmitted by the
system controllers. Both signals are displayed in common units (e.g.
temperature). Use up and down arrow keys on DRB-II to scroll through
displays available.
3) The following ENGINE state displays are available on DRB-
II:
* Module Information - This mode allows technician to read ECU
part number and application.
* Engine Sensors - This mode allows technician to look at
various engine sensors during engine operation.
* Inputs/Outputs - This mode allows technician to read input
and output states of various switches and sensors.
* Custom Display - This screen allows technician to set up
his/her own custom display. Two custom display screens can be
programmed into DRB-II.
* Minimum/Current/Maximum - The MIN/CURRENT/MAX display shows a
history of conditions for a specific sensor. When this option
is selected, maximum, current (static) and minimum values can\
be displayed for a specific sensor. To reset sensors to a
zero value, simply press ENTER key. This display may be used
to isolate intermittent faults. The MIN/CURRENT/MAX display
allows technician to observe operation of 6 different sensor
values. Information is displayed as a 3-digit number. The
first value displayed is the minimum reading, the second
number is the current reading and third valve is the maximum
reading. Typically sensors range between 2-252. Values less
than 2 or greater than 252 will usually indicate that a

44 (5) ..... Open or short in either ignition coil circuit
( 1) - Except Montero & Sigma.
( 2) - Will not turn on CHECK ENGINE light.
( 3) - 2.0L turbo only.
( 4) - California only. Except Sigma.
( 5) - Chrysler Motors models only.









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CLEARING CODES
Using DRB-II, from main menu select ADJUSTMENTS. Enter ERASE
FAULTS. Follow DRB-II instructions to accomplish this task. If DRB-II
is not available, fault codes may be cleared by disconnecting negative
battery cable for at least 10 seconds, allowing ECU to clear fault
codes.
TEST CHARTS
* PLEASE READ THIS FIRST *
NOTE: The following charts are supplied for Chrysler Motors
vehicles.
NS-1: TESTING IGNITION CIRCUIT - 1.5L
Fig. 7: Circuit Diagram NS-1 (1.5L) (1 of 2)
Fig. 8: Circuit Diagram NS-1 (1.5L) (2 of 2)

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E - T H EO RY/O PER ATIO N - E FI

1 991 M it s u bis h i M onte ro
1990-91 ENGINE PERFORMANCE
Chrysler/Mitsubishi Theory & Operation - Fuel Injection
All Models
INTRODUCTION
This article covers basic description and operation of engine
performance-related systems and components. Read this article before
diagnosing vehicles or systems with which you are not completely
familiar.
AIR INDUCTION SYSTEM
NON-TURBOCHARGED ENGINES
All Chrysler/Mitsubishi engines with Port Fuel Injection
(PFI), called Multi-Point Injection (MPI) by the manufacturer, use t\
he
same basic air induction system. Remote air filter (with airflow
sensor) is ducted to a plenum-mounted throttle body.
TURBOCHARGED ENGINES
In addition to basic air induction system used on all other
models, turbocharging system components include turbocharger, air-to-
air intercooler, air by-pass valve, wastegate actuator, wastegate
control solenoid valve and intake ducting.
Wastegate Control Solenoid Valve
Engine Control Unit (ECU) energizes solenoid valve,
controlling leakage rate of turbocharger pressure to wastegate
actuator.
COMPUTERIZED ENGINE CONTROLS
Multi-Point Injection (MPI) is a computerized engine control
system which controls fuel injection, ignition timing, idle speed and
emission control systems.
ELECTRONIC CONTROL UNIT (ECU)
NOTE: Components are grouped into 2 categories. The first category
covers INPUT DEVICES, which control or produce voltage
signals monitored by the Engine Control Unit (ECU). The
second category covers OUTPUT SIGNALS, which are components
controlled by the ECU.
ECU receives and processes signals from input devices. Such
operating conditions as cold starting, altitude, acceleration and
deceleration affect input device signals. Based upon signals received,
ECU sends signals to various components which control fuel injection,
ignition timing, idle speed and emission control systems.
INPUT DEVICES
Vehicles are equipped with different combinations of input
devices. Not all input devices are used on all models. To determine

motor to increase idle speed. To prevent A/C compressor from switching
on before idle speed has increased, ECU momentarily opens A/C relay
circuit.
Idle Speed Control (ISC) Motor
Controls pintle-type air valve (DOHC engines) or throttle
plate angle (SOHC engines) to regulate volume of intake air at idle.
During start mode, ECU controls idle intake air volume
according to coolant temperature input. After starting, with idle
position switch activated (throttle closed), fast idle speed is
controlled by ISC motor and fast idle air control valve (if equipped).\
When idle switch is deactivated (throttle open), ISC motor
moves to a preset position in accordance with coolant temperature
input.
When automatic transmission (if equipped) is shifted from
Neutral to Drive, A/C is turned on or power steering pressure reaches
a preset value, ECU signals ISC motor to increase engine RPM.
Fast Idle Air Control Valve
Some models use a coolant temperature-sensitive fast idle air
control valve, located on throttle body, to admit additional intake
air volume during engine warm-up. Control valve closes as temperature
increases, restricting by-pass airflow rate. At engine warm-up, valve
closes completely.
IGNITION SYSTEMS
DIRECT IGNITION SYSTEM (DIS) - DOHC ENGINES
Ignition system is a 2-coil, distributorless ignition system.
Crankshaft angle and TDC sensor assembly, mounted in place of
distributor, are optically controlled.
Power Transistors & Ignition Coils
Based on crankshaft angle and TDC sensor inputs, ECU controls
timing and directly activates each power transistor to fire coils.
Power transistor "A" controls primary current of ignition coil "A" to
fire spark plugs on cylinders No. 1 and 4 at the same time. Power
transistor "B" controls primary current of ignition coil "B" to fire
spark plugs on cylinders No. 2 and 3 at the same time.
Although each coil fires 2 plugs at the same time, ignition
takes place in only one cylinder since the other cylinder is on its
exhaust stroke when plug fires.
ELECTRONIC IGNITION SYSTEM - SOHC ENGINES
Mitsubishi breakerless electronic ignition system uses a disc
and optical sensing unit to trigger power transistor.
Power Transistor & Ignition Coil
Power transistor is mounted inside distributor with disc and
optical sensing unit. When ignition is on, ignition coil primary
circuit is energized. As distributor shaft rotates, disc rotates,
triggering optical sensing unit. ECU receives signals from optical
sensing unit. Signals are converted and sent to power transistor,
interrupting primary current flow and inducing secondary voltage.
IGNITION TIMING CONTROL SYSTEM
Ignition timing is controlled by ECU. ECU adjusts timing
based upon various conditions, such as engine temperature, altitude
and detonation (turbo vehicles only).

system consists of PCV valve, oil separator, breather and ventilation
hoses.
PCV valve is a one-way check valve, located in valve cover.
When engine is running, manifold vacuum pulls PCV valve open, allowing
crankcase fumes to enter intake manifold. If engine backfires through
intake manifold, PCV valve closes to prevent crankcase combustion.
SELF-DIAGNOSTIC SYSTEM
Self-diagnostic system monitors input and output signals. On
all models, codes can be read using analog voltmeter. On some models,
scan tool can be used to read codes. For additional information, see G
- TESTS W/ CODES article.
CHECK ENGINE Light
Also called Malfunction Indicator Light by manufacturer,
comes on when ignition is turned on. Light remains on for several
seconds after engine has started. If an abnormal input signal occurs,
light comes on and code is stored in memory. If an abnormal input
signal returns to normal, ECU turns light off but code remains stored
in memory until cleared. If ignition is turned on again, light will
not come on until ECU detects malfunction during system operation.
NOTE: ECU diagnostic memory is retained by direct power supply
from the battery. Memory is not erased by turning off
ignition but is erased if battery or ECU is disconnected.

Check transaxle/transmission and transfer case fluid level
every 30,000 miles. Change fluid at 30,000 miles if operated under
severe service conditions.
CHECKING FLUID LEVEL
TRANSAXLE/TRANSMISSION
Lubricant level is checked at fill hole on side of transaxle
or transmission. Lubricant must be at bottom of fill hole.
TRANSFER CASE
Transfer case contains separate drain and fill plugs.
Lubricant must reach to bottom of fill hole.
On 3000GT models, transfer case contains separate drain and
fill plugs. Lubricant should be .5" (13 mm) from bottom of fill hole.
RECOMMENDED FLUID
Use API GL-4 or GL-5 SAE 75W-85 gear oil.
FLUID CAPACITY SPECS TABLE
TRANSMISSION REFILL CAPACITIES TABLE








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Application Pts. (L)
Eclipse
F5M22 .............................. 3.8 (1.8)
F5M33 .............................. 4.7 (2.2)
Galant ............................... 3.8 (1.8)
Mirage
KM201 .............................. 3.8 (1.8)
KM210 .............................. 4.4 (2.0)
Montero
2.6L ............................... 4.7 (2.2)
3.0L ............................... 5.3 (2.6)
Pickup
2WD ................................ 4.9 (2.4)
4WD ................................ 4.7 (2.2)
Precis ............................... 4.4 (2.0)
Sigma ................................ 5.2 (2.5)









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1991 TRANSMISSION REFILL CAPACITIES








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Application Pts. (L)
Mirage (1.5L)
F4M21 ................................... 3.6 (1.7)
F5M21 ................................... 3.8 (1.8)
Eclipse, Galant (2WD) & Mirage (1.6L) ..... 3.8 (1.8)
Eclipse (Turbo) & 3000GT (2WD) ............ 4.9 (2.3)
Galant (AWD) .............................. 4.9 (2.3)
Montero & Pickup .......................... 5.2 (2.5)
Pickup .................................... 4.9 (2.3)
Pickup .................................... 4.6 (2.2)
Precis

Defective diodes or stator See Bench Test in
ALTERNATOR article









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Battery Does Loose or worn drive belt Check alternator drive
Stay Charged belt tension and
condition. See
Belt Adjustment in
appropriate TUNE-UP
article in the
TUNE-UP section
Loose or corroded battery Check all charging
connections system connections
Loose alternator connections Check all charging
system connections
Defective alternator or See On-Vehicle Tests
battery and Bench Tests in
ALTERNATOR article
Add-on electrical accessories Install larger
exceeding alternator capacity alternator









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Battery Defective battery Check alternator
Overcharged- output and repair as
Uses Too Much necessary
Water
Defective alternator See On-Vehicle Test and
Bench Tests in
ALTERNATOR article
Excessive alternator voltage Check alternator output
and repair as necessary









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IGNITION SYSTEM TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
Ignition Secondary Trouble Shooting Chart








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START: Visually inspect Spark Plug Wires, Coil Wires, 

Plug Wire Boots, Rotor, and Distributor Cap for 

signs of damage. 










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OK   NOT OK 




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* To test secondary ignition   * Repair or replace 

system, modify a Spark Plug   damaged components 

by attaching a ground wire   as necessary 

to the body of the plug and  









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