1991 MITSUBISHI MONTERO relay

not present, check circuit between relay and battery, including
fusible link No. 1.
Fig. 10: MPI Control Relay Connector Term. ID (8 Pin)
Courtesy of Mitsubishi Motor Sales of America.
2) Disconnect wiring harness connector at relay. Remove
relay. Check continuity between terminals No. 1 and 4, terminals No. 2
and 4 and terminals No. 3 and 4. If there is no continuity, go to next

step. If there is continuity, replace relay.
3) Check diode operation between terminals No. 6 and 8. If
there is continuity in only one direction, go to next step. If there
is no continuity in either direction or if there is continuity in both
directions, replace relay.
4) Measure resistance between terminals No. 6 and 7. If
resistance is approximately 35 ohms, go to next step. If resistance is
not approximately 35 ohms, replace relay.
5) Measure resistance between terminals No. 2 and 5 and
between terminals No. 3 and 5. In both tests, if resistance is
approximately 95 ohms, go to next step. If resistance is not
approximately 95 ohms, replace relay.
6) Connect positive lead of 12-volt source to terminal No. 7
and negative lead to terminal No. 6. If there is continuity between
terminals No. 1 and 4, go to next step. If there is no continuity,
replace relay.
7) Connect positive lead of 12-volt source to terminal No. 5
and negative lead to terminal No. 2. If there is continuity between
terminals No. 1 and 4, go to next step. If there is no continuity,
replace relay.
8) Connect positive lead of 12-volt source to terminal No. 5
and negative lead to terminal No. 3. If there is continuity between
terminals No. 1 and 4, go to next step. If there is no continuity,
replace relay.
9) Connect positive lead of 12-volt source to terminal No. 8
and negative lead to terminal No. 6. If there is continuity between
terminals No. 3 and 4 and between terminals No. 2 and 4, relay is
okay. If there is no continuity, replace relay.
SOLENOIDS
Fuel Pressure Control Solenoid Valve
See FUEL DELIVERY under FUEL SYSTEM.
Fuel Injector Solenoids
See FUEL CONTROL under FUEL SYSTEM.
FUEL SYSTEM
FUEL DELIVERY
NOTE: For fuel system pressure testing, see F - BASIC TESTING
article in the ENGINE PERFORMANCE Section.
FUEL CONTROL
Fuel Injectors
1) Using a stethoscope, check operating sound of injector(s)\
during engine cranking or idling. If clicking sound is heard,
injectors are okay. If clicking sound is not heard at each injector,
go to step 2).
2) Disconnect injector electrical connector. Measure
resistance between injector connector terminals. At 68
F (20C), if
resistance is not 13-16 ohms, replace injector.
3) If resistance is within specification, check injector
wiring circuit for open or short to ground. If wiring circuit tests
okay, replace injector.
IDLE CONTROL SYSTEM
NOTE: ISC motor adjusts throttle plate angle to regulate idle air

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

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.

Fig. 20: Flow Chart NS-5 (1.5L) (2 of 2)
NS-6: TESTING CONTROL RELAY - 1.5L

NS-5: TESTING CONTROL RELAY CIRCUIT - 1.6L
Fig. 93: Circuit Diagram NS-5 (1.6L)

Fig. 182: Flow Chart NS-5 (1.8L) (2 of 2)
NS-6: TESTING CONTROL RELAY - 1.8L

Fig. 245: NS-4 Flow Chart & Circuit Diagram (2.0L) (2 of 2)
NS-5: CHECKING CONTROL RELAY CIRCUIT - 2.0L