ECU MITSUBISHI MONTERO 1991 Workshop Manual
[x] Cancel search | Manufacturer: MITSUBISHI, Model Year: 1991, Model line: MONTERO, Model: MITSUBISHI MONTERO 1991Pages: 1333, PDF Size: 24.61 MB
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remains on (light may flash) during vehicle operation, cause of
malfunction must be determined by using DIAGNOSTIC FAULT CHARTS (if
testing with voltmeter) or diagnostic CODE CHARTS (if testing with
DRB-II). If a sensor fails, ECU will use a substitute value in its
calculations to continue engine operation. In this condition, vehicle
is functional, but loss of good driveability may result.
INTERMITTENT FAILURES
Intermittent failures may cause CHECK ENGINE light to flicker
or illuminate and go out after the intermittent fault goes away.
However, the corresponding trouble code will be retained in ECU
memory. If related fault does not reoccur within a certain time frame,
related trouble code will be erased from ECU memory. Intermittent
failures may be caused by a sensor, connector or wiring related
problems. See INTERMITTENTS in H - TESTS W/O CODES article.
PRETEST INSPECTION
Before proceeding with diagnosis, the following precautions
must be followed:
* Vehicle must have a fully charged battery and functional
charging system.
* Visually inspect connectors and circuit wiring being worked
on.
* DO NOT disconnect battery or ECU. This will erase any fault
codes stored in ECU.
* DO NOT cause short circuits when performing electrical tests.
This will set additional fault codes, making diagnosis of original
problem more difficult.
* DO NOT use a test light in place of a voltmeter.
* When checking for spark, ensure coil wire is NO more than
1/4" from ground. If coil wire is more than 1/4" from ground,
damage to vehicle electronics and/or ECU may result.
* DO NOT prolong testing of fuel injectors. Engine may
hydrostatically (liquid) lock.
* When a vehicle has multiple fault codes, always repair lowest
number fault code first.
* If DRB-II is being used to diagnose system, always perform
verification test after repairs are made.
ENTERING ON-BOARD DIAGNOSTICS (USING VOLTMETER)
1) Before entering on-board diagnostics, refer to PRETEST
INSPECTION in this article. Turn ignition switch to OFF position.
Locate self-diagnostic connector. See SELF-DIAGNOSTIC TEST CONNECTOR
LOCATION table. Using an analog voltmeter, connect voltmeter positive
lead to self-diagnostic connector terminal No. 1 and negative lead to
terminal No. 12 (ground). See Fig. 6.
2) Turn ignition switch to ON position and disclosure of ECU
memory will begin. If 2 or more systems are non-functional, they are
indicated by order of increasing code number. Indication is made by
12-volt pulses of voltmeter pointer. A constant repetition of short
12-volt pulses indicates system is normal. If system is abnormal,
voltmeter will pulse between zero and 12 volts.
3) Signals will appear on voltmeter as long and short 12-volt
pulses. Long pulses represent tens; short pulses represent ones. For
example 4 long pulses and 3 short pulses indicates Code 43. See
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Figs. 1 and 2. After recording abnormal code(s), perform necessary
repair.
4) After repair, turn ignition off and disconnect negative
battery cable for 10 seconds to erase ECU memory. Reconnect power
supply and repeat self-diagnostics to confirm repair.
SELF-DIAGNOSTIC TEST CONNECTOR LOCATION TABLE
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Application Location
Colt, Colt 200, Colt Wagon & Summit
1.5L ................................ Next to fuse block
1.6L .................................. Right kick panel
Colt Wagon & Colt Vista
1.8L & 2.0L SOHC .................... Next to fuse block
Eclipse ............................... Next to fuse block
Galant ................................... Left kick panel
Mirage ................................... Left kick panel
Montero .......................... Inside top of glove box
Precis ................................... Left kick panel
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Fig. 1: Diagnostic Fault Chart (1 of 2)
Courtesy of Mitsubishi Motor Sales of America.
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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
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sensor is shorted or disconnected. Watch minimum and maximum
values to help diagnose intermittent problems.
* Monitors - This screen shows technician sensors and system
controllers which affect fuel control, spark advance, RPM and
A/C relay. There are 4 different screens available. As an
example, screen No. 1 will show: airflow sensor, O2 sensor,
battery and fuel injector. All of these inputs affect fuel
control.
Actuator Tests
This mode allows technician to actuate injectors, fuel pump,
purge control, EGR solenoid, fuel pressure solenoid and wastegate.
Adjustments
This option provides a means for erasing fault code
information stored in ECU. Follow DRB-II instructions to accomplish
this task.
DRB-II ERROR SCREENS
ERROR SCREENS
SYSTEM FAULT ROM CHECK SUM XXXX Message
Cartridge or DRB-II failure.
SYSTEM FAULT KEYBOARD FAILURE Message
Restart DRB-II. Ensure DRB-II keys are not pressed during
power up. Another possibility is DRB-II failure.
SYSTEM FAULT ROM FAILURE XXXX
DRB-II failure.
SYSTEM FAULT EEPROM FAILURE
DRB-II failure.
SYSTEM FAILURE, COMMUNICATION FAILURE, REFER TO DIAGNOSTIC
PROCEDURES Message
Perform diagnostic connector test. See DRIVEABILITY TEST No.
8 (DR-8). Failure of Mitsubishi Motor Corporation (MMC) adapter is
another possibility.
SYSTEM FAILURE NO RESPONSE FROM ADAPTER or SYSTEM FAILURE
ADAPTER REQUIRED TO DIAGNOSE WITH THIS CARTRIDGE Message
Ensure you are using a correct Mitsubishi Motor Corporation
cartridge. Failure of MMC adapter is another possibility.
Fig. 3: 10-Way ECU Connector
Courtesy of Chrysler Motors.
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Fig. 4: 18-Way ECU Connector
Courtesy of Chrysler Motors.
Fig. 5: 24-Way ECU Connector
Courtesy of Chrysler Motors.
Fig. 6: Self-Diagnostic Connector Terminal Identification
Courtesy of Mitsubishi Motor Sales of America.
FAULT CODES
FAULT CODES TABLE \
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Fault Code System Fault Description
11 .................... Open or short in O2 sensor circuit
12 ............... Open or short in airflow sensor circuit
13 ...... Open or short in intake air temp. sensor circuit
14 .......................... Open or short in TPS circuit
15 (1) .... Open or short in motor position sensor circuit
21 ......... Open or short in coolant temp. sensor circuit
22 ........ No voltage change in crank angle sensor signal
23 ............... No voltage change in TDC sensor circuit
24 ( 2) .. No voltage change in vehicle speed sensor signal
25 ........... Open or short in barometric pressure sensor
31 ( 3) ........ Open or short in detonation sensor circuit
41 ..................... Open or short in injector circuit
42 .............. Open or short in fuel pump drive circuit
43 ( 4) ......... Open or short in EGR temp. sensor circuit
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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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that all of the engine control systems are operating as they were
designed to. Therefore, they are not the cause of the driveability
problem.
The following additional items can not be overlooked as possible
causes of a driveability problem.
1. THROTTLE VALVE AREA - Dirt or ice buildup causing rough idle and
stalling.
2. ENGINE IGNITION TIMING - Must be set with timing terminal
grounded.
3. ENGINE VACUUM - Must be normal for your altitude.
4. ENGINE VALVE TIMING - To specifications.
5. ENGINE COMPRESSION - To specifications.
6. ENGINE P.C.V. SYSTEM - Must flow freely.
7. ENGINE EXHAUST SYSTEM - Must be free of any restrictions.
8. POWER BRAKE BOOSTER - No internal vacuum leaks.
9. TORQUE CONVERTER CONDITION - May cause very low power at breakaway
or high speed (Only 1 condition at a time).
10. FUEL CONTAMINATION - High alcohol or water content.
11. FUEL INJECTORS - Rough idle may be caused by injector wiring not
connected to correct injector.
12. ENGINE SECONDARY IGNITION CHECK - Abnormal scope patterns.
13. TECHNICAL SERVICE BULLETINS - Any that apply to vehicle.
14. All air intake piping and vacuum hoses must be in place and
secure. The proper air filter element must be used.
15. FUEL PRESSURE - Must be correct.
Specification: With no vacuum at the regulator:
48 PSI on V6 & non-turbo 4 Cyl. engines
36 PSI on turbo engines
NS-1: TESTING IGNITION CIRCUIT - 1.6L
Fig. 75: Circuit Diagram NS-1 (1.6L)
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The following additional items can not be overlooked as
possible causes of a driveability problem.
1. ENGINE IGNITION TIMING - Must be set with timing terminal
grounded.
2. ENGINE VACUUM - Must be normal for your altitude.
3. ENGINE VALVE TIMING - To specifications.
4. ENGINE COMPRESSION - To specifications.
5. ENGINE P.C.V. SYSTEM - Must flow freely.
6. ENGINE EXHAUST SYSTEM - Must be free of any restrictions.
7. POWER BRAKE BOOSTER - No internal vacuum leaks.
8. TORQUE CONVERTER CONDITION - May cause very low power at breakaway
or high speed (Only 1 condition at a time).
9. FUEL CONTAMINATION - High alcohol or water content.
10. FUEL INJECTORS - Rough idle may be caused by injector wiring not
connected to correct injector.
11. ENGINE SECONDARY IGNITION CHECK - Abnormal scope patterns.
12. TECHNICAL SERVICE BULLETINS - Any that apply to vehicle.
13. All air intake piping and vacuum hoses must be in place and
secure. The proper air filter element must be used.
14. FUEL PRESSURE - Must be correct.
Specification: With no vacuum at the regulator:
48 PSI on V6 & non-turbo 4 Cyl. engines
36 PSI on turbo engines
NS-VER: NO START VERIFICATION PROCEDURE - 1.6L
Fig. 168: Flow Chart NS-VER (1.6L)
DR-VER: DRIVEABILITY VERIFICATION PROCEDURE - 1.6L
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2. ENGINE IGNITION TIMING - Must be set with timing terminal
grounded.
3. ENGINE VACUUM - Must be normal for your altitude.
4. ENGINE VALVE TIMING - To specifications.
5. ENGINE COMPRESSION - To specifications.
6. ENGINE P.C.V. SYSTEM - Must flow freely.
7. ENGINE EXHAUST SYSTEM - Must be free of any restrictions.
8. POWER BRAKE BOOSTER - No internal vacuum leaks.
9. TORQUE CONVERTER CONDITION - May cause very low power at breakaway
or high speed (Only 1 condition at a time).
10. FUEL CONTAMINATION - High alcohol or water content.
11. FUEL INJECTORS - Rough idle may be caused by injector wiring not
connected to correct injector.
12. ENGINE SECONDARY IGNITION CHECK - Abnormal scope patterns.
13. TECHNICAL SERVICE BULLETINS - Any that apply to vehicle.
14. All air intake piping and vacuum hoses must be in place and
secure. The proper air filter element must be used.
15. FUEL PRESSURE - Must be correct.
Specification: With no vacuum at the regulator:
48 PSI on V6 & non-turbo 4 Cyl. engines
36 PSI on turbo engines
NS-1: IGNITION CHECK FLOW CHARTS - 2.0L
Fig. 235: NS-1 Flow Chart & Circuit Diagram (2.0L) (1 of 5)
Page 1136 of 1333
determined that all of the engine controls systems are operating as
they were designed to. Therefore, they are not the cause of the
driveability problem. The following additional items should be checked
as possible causes:
1) ENGINE VACUUM - Must be at least 13 inches in neutral.
2) ENGINE VALVE TIMING - Set to specifications.
3) ENGINE COMPRESSION - To specifications.
4) EXHAUST SYSTEM - Free from any restrictions.
5) PCV SYSTEM - Must flow freely.
6) DRIVE SPROCKETS - Camshaft and crank shaft.
7) TORQUE CONVERTER STALL SPEED - To specifications.
8) POWER BRAKE BOOSTER - No internal vacuum leak.
9) FUEL CONTAMINATION - High alcohol and water content.
10) FUEL INJECTORS - Rough idle may be caused by injector
control wire not connected to correct injector.
11) TECHNICAL SERVICE BULLETINS - Any that may apply to
vehicle.
12) ENGINE SECONDARY IGNITION CHECK - Any abnormal scope
pattern.
13) TECHNICAL SERVICE BULLETINS - Any that apply to vehicle.
14) All air intake piping and vacuum hoses must be in place
and secure. The proper air filter element must be used.
15) FUEL PRESSURE - Must be correct.
Specification: With no vacuum at the regulator:
48 PSI on V6 & non-turbo 4 Cyl. engines
36 PSI on turbo engines
DR-VER: DRIVEABILITY VERIFICATION TEST - 2.0L
Fig. 300: DR-VER Flow Chart (2.0L)
SUMMARY