1998 MITSUBISHI MONTERO light

1) Inspect ABS relay box. See Fig. 3. Replace ABS relay box
if needed. If ABS relay box is okay, go to next step.
2) Disconnect ECU 22-pin connector and ABS relay box 8-pin
connector. Turn ignition on. Using a DVOM, check voltage between ABS
relay box 8-pin harness connector terminal No. 5 and ground. See
Fig. 4 . If battery voltage does not exist, go to next step. If battery
voltage exists, check and repair connectors and related wiring harness
between ABS valve relay and ground. See WIRING DIAGRAMS.
3) Check and repair connectors and related wiring harness
between instrument cluster and ABS valve relay. See WIRING DIAGRAMS.
Fig. 4: Identifying ABS Relay Box Connector Terminals
Courtesy of Mitsubishi Motor Sales of America.
Ignition Switch In ON Position, ANTI-LOCK Warning Light
Blinks Twice. In START Position, Light Stays On. When
Ignition Switch Is Cycled From START To ON Position, Light
Blinks Once
1) Disconnect ABS relay box connectors. See Fig. 3.
Disconnect ECU 22-pin connector. Turn ignition on. Check voltage
between ECU connector terminal No. 50 and ground. See Figs. 5-6. If
battery voltage is not present, check and repair connectors and
related wiring harness between instrument cluster and ECU. See
WIRING DIAGRAMS . If battery voltage is present, go to next step.
2) Check and repair ECU 22-pin connector. If connector is
okay, replace ECU.

Fig. 5: Identifying ECU Harness Connector Terminals 22-Pin Connector
Courtesy of Mitsubishi Motor Sales of America.
Fig. 6: Identifying ECU Harness Connector Terminals 26-Pin Connector
Courtesy of Mitsubishi Motor Sales of America.
SELF-DIAGNOSTIC SYSTEM
RETRIEVING DTCs
Using Scan Tool
1) With ignition off, connect scan tool and ROM Pack to Data
Link Connector (DLC) located under driver's side of dash, and to
cigarette lighter socket. See Fig. 7.
2) Turn ignition on. ANTI-LOCK warning light should come on
as ABS goes into self-diagnostic mode. Read and record all Diagnostic
Trouble Codes (DTCs) from ECU memory. Refer to scan tool
manufacturer's instructions for specific DTC retrieval procedure.
3) After all of the DTCs have been retrieved and recorded,
clear codes from ECU memory. Refer to scan tool manufacturer's
instructions for specific DTC clearing instructions. Refer to DTC
DEFINITION under SELF-DIAGNOSTIC SYSTEM . Refer to the appropriate DTC
under DIAGNOSTIC TESTS .
4) If DTCs cannot be cleared, ECU is currently detecting a
malfunction. If codes can be cleared, problem is either intermittent
or only appears while driving.

Fig. 7: Connecting Scan Tool
Courtesy of Mitsubishi Motor Sales of America.
Using ANTI-LOCK Warning Light
1) To retrieve stored DTCs, locate Data Link Connector (DLC)\
under left side of dash. Turn ignition off. Ground DLC terminal No. 1.
See Fig. 8 .
2) If DTCs are stored in ECU memory, ANTI-LOCK light will
begin to flash intermittently. Long flashes represent first digit of
DTC; short flashes represent second digit. For example, 4 long flashes
and 3 short flashes indicate DTC 43. If 2 or more DTCs are stored,
lowest number will be displayed first. DTC 51 will always be displayed
if valve relay is removed.
3) After recording DTC(s), see DTC DEFINITION table and
perform appropriate DTC test(s) under DIAGNOSTIC TESTS. If no DTCs are
stored, ANTI-LOCK warning light will flash constantly.

27 ..................... (3) Rear Differential Lock Detection Switch
32 ............................................... "G" Sensor System
33 ......................................... Stoplight Switch System
41 ....................................... RF Solenoid Valve Circuit
42 ....................................... LF Solenoid Valve Circuit
43 ..................................... Rear Solenoid Valve Circuit
51 ..................................................... Valve Relay
53 ..................................................... Motor Relay
63 Or 64 ............................................ ( 4) Faulty ECU
( 1) - See appropriate DTC under DIAGNOSTIC TESTS.
( 2) - Vehicles with differential lock.
( 3) - Vehicles without differential lock.
( 4) - Replace ECU.









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DIAGNOSTIC TESTS
DTC 11, 12, 13 OR 14: WHEEL SPEED SENSOR (OPEN/SHORT
CIRCUIT)
NOTE: DTC will set if ECU detects a wheel speed sensor open or
short circuit.
1) Ensure sensor is properly installed. See WHEEL SPEED
SENSOR (WSS) under REMOVAL & INSTALLATION . Correct installation if
needed. If installation is okay, go to next step.
2) Disconnect ECU 26-pin connector. Check resistance between
specified ECU connector terminals. See
WHEEL SPEED SENSOR OUTPUT CIRCUIT IDENTIFICATION table. See Figs. 5-6.
Resistance for front sensors should be 1170-1350 ohms. Resistance for
rear sensors should be 1300-1500 ohms. If resistance is as specified,
go to next step. If resistance is not as specified, check and repair
connectors and related wiring between ECU and suspect sensor. See
WIRING DIAGRAMS .
WHEEL SPEED SENSOR OUTPUT CIRCUIT IDENTIFICATION









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Application Terminals No.
Left Front .................................................. 7 & 20
Left Rear ................................................... 9 & 22
Right Front ................................................ 10 & 23
Right Rear .................................................. 8 & 21









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3) Raise and support vehicle. Disconnect ECU connectors.
Using DVOM, backprobe specified ECU connector terminals. See
WHEEL SPEED SENSOR OUTPUT CIRCUIT IDENTIFICATION table. See Figs. 5-6.
Check voltage between each harness connector terminal while rotating
wheel at 1/2 to one rotation per second. If pulse voltage is 70 mV or
more, go to step 8). If voltage is not as specified, go to next step.
4) Inspect condition of suspect speed sensor. Ensure tip of
speed sensor is clean. If speed sensor is okay, go to next step.
5) Disconnect sensor connector. Using DVOM, check resistance
across sensor terminals. Resistance for front sensors should be 1170-
1350 ohms. Resistance for rear sensors should be 1300-1500 ohms. If
resistance is as specified, go to next step. If resistance is not as
specified, replace sensor.
6) Remove sensor. Check resistance between each sensor
terminal and sensor body. If resistance is 100,000 ohms or more, go to
next step. If resistance is not as specified, replace sensor.

2) Disconnect ECU 26-pin connector. Check resistance between
specified ECU connector terminals. See
WHEEL SPEED SENSOR OUTPUT CIRCUIT IDENTIFICATION table. See Figs. 5-6.
Resistance for front sensors should be 1170-1350 ohms. Resistance for
rear sensors should be 1300-1500 ohms. If resistance is as specified,
go to next step. If resistance is not as specified, check and repair
connectors and related wiring between ECU and suspect sensor. See
WIRING DIAGRAMS .
3) Raise and support vehicle. Disconnect ECU connectors.
Using DVOM, backprobe specified ECU connector terminals. See
WHEEL SPEED SENSOR OUTPUT CIRCUIT IDENTIFICATION table. See Figs. 5-6.
Check voltage between each harness connector terminal while rotating
wheel at 1/2 to one rotation per second. If pulse voltage is 70 mV or
more, go to step 8). If voltage is not as specified, go to next step.
4) Inspect condition of suspect speed sensor. Ensure tip of
speed sensor is clean. If speed sensor is okay, go to next step.
5) Disconnect sensor connector. Using DVOM, check resistance
across sensor terminals. Resistance for front sensors should be 1170-
1350 ohms. Resistance for rear sensors should be 1300-1500 ohms. If
resistance is as specified, go to next step. If resistance is not as
specified, replace sensor.
6) Remove sensor. Check resistance between each sensor
terminal and sensor body. If resistance is 100,000 ohms or more, go to
next step. If resistance is not as specified, replace sensor.
7) Inspect condition of toothed rotor. Check for broken or
deformed teeth. If toothed rotor is okay, go to next step.
8) Check ECU connectors. Repair connectors as needed. If
connectors are okay, replace ECU.
DTC 25: FREE WHEEL ENGAGE SWITCH
NOTE: DTC sets if ECU detects an open circuit in free wheel engage
switch.
1) Start engine. Ensure 4WD indicator light operates
correctly when transfer shift lever is moved to desired 4WD positions.
If indicator light operates correctly, go to step 3). If indicator
light does not operate correctly, go to next step.
2) Turn engine off. Check wiring harness between 4WD
indicator control unit (located behind radio) and free wheel engage
switch (located on right side of front differential housing, near
carrier assembly). If circuit is okay, replace 4WD indicator control
unit.
3) Disconnect ECU 22-pin connector. Turn ignition on. Using
DVOM, check voltage between ECU 22-pin connector terminal No. 45 and
ground. See Figs. 5-6. In 2WD, battery voltage should exist. Battery
voltage should not exist in 4WD. If voltage is as specified, go to
next step. If voltage is not as specified, check and repair connectors
and wiring harness between free wheel engage switch and ECU. See
WIRING DIAGRAMS .
4) Check and repair ECU 22-pin connector. If connector is
okay, replace ECU.
DTC 26: CENTER DIFFERENTIAL LOCK DETECTION SWITCH
NOTE: DTC sets if ECU detects an open circuit in center
differential lock detection switch system.
1) Start engine. Ensure 4WD indicator light operates
correctly when transfer shift lever is moved to desired 4WD positions.
If indicator light does not operate correctly, go to step 4). If
indicator light operates correctly, go to next step.
2) Disconnect ECU 22-pin connector. Turn ignition on. Using

DVOM, check voltage between ECU 22-pin connector terminal No. 35 and
ground. See Figs. 5-6. Battery voltage should exist in 4WD. Go to next
step.
3) If voltage is not as specified, check and repair
connectors and wiring harness between center differential lock
detection switch and ECU. See WIRING DIAGRAMS. Center differential
lock detection switch is located on side of transfer case. See Fig. 9.
If voltage is as specified, check and repair ECU 22-pin connector. If
connector is okay, replace ECU.
Fig. 9: Identifying 4WD Indicator Switch Location
Courtesy of Mitsubishi Motor Sales of America.
NOTE: When checking for short in ECU circuit, remove ECU connector
and ensure 4WD indicator light operates correctly. If 4WD
indicator light operates correctly, replace faulty ECU. If
4WD indicator light does not operate correctly, replace
faulty 4WD indicator control unit.
4) If no indicator lights come on, repair 4WD indicator power
circuit, or check for faulty 4WD indicator control unit. See 4WD
CONTROL UNIT under COMPONENT TESTS. If center differential light comes
on, regardless of position of transfer shift lever, check the
following:

* Check for short in center differential lock switch circuit.
* Check for faulty center differential lock switch.
* Check for short in ECU circuit or faulty ECU.
* Check for short in indicator control unit circuit or faulty
4WD indicator control unit.
Repair wiring harness or replace component as necessary. See
WIRING DIAGRAMS .
5) If 4WD indicator light does not come on with transfer
shift lever in "4H" position, repair wiring harness between 4WD
indicator control unit and center differential lock switch. Check for
faulty 4WD indicator control unit.
6) If 4WD indicator light does not come on with transfer
shift lever in "4H" position, repair wiring harness between 4WD
indicator control unit and free wheel engage switch. See
WIRING DIAGRAMS . Check ground wire at engage switch. Check for faulty
free wheel engage switch.
DTC 27: REAR DIFFERENTIAL LOCK DETECTION SWITCH (WITH
DIFFERENTIAL LOCK)
NOTE: DTC is set if ECU detects an open circuit in rear
differential lock detection switch system.
1) Start engine. Ensure rear differential indicator light
comes on when top of rear differential lock switch (located below
radio) is pushed. If indicator light comes on, go to step 3). If
indicator light does not come on, go to next step.
2) Turn engine off. Check wiring harness between rear
differential lock control unit and rear differential lock switch. See
WIRING DIAGRAMS . Check rear differential lock control unit power
circuit. See REAR DIFFERENTIAL CONTROL UNIT under COMPONENT TESTS. If
circuit is okay, replace rear differential lock control unit.
3) Disconnect ECU 22-pin connector. Turn ignition on. Using
DVOM, check voltage between terminal No. 46 and ground. See Figs. 5-6.
When rear differential is locked, battery voltage should not be
present. When rear differential is unlocked, battery voltage should be
present. If voltage is as specified, go to next step. If voltage is
not as specified, repair connectors and related wiring harness between
ECU and rear differential lock switch. See WIRING DIAGRAMS.
4) Check and repair ECU 22-pin connector. If connector is
okay, replace ECU.
DTC 27: REAR DIFFERENTIAL LOCK DETECTION SWITCH (WITHOUT
DIFFERENTIAL LOCK)
NOTE: DTC is set if ECU detects an interruption of battery voltage
at ECU terminal No. 46.
1) Check fuse No. 18 in main fuse block. If fuse is blown,
correct cause of blown fuse, and replace fuse. If fuse is okay, go to
next step.
2) Disconnect ECU 22-pin connector. Turn ignition on. Using
DVOM, check voltage between terminal No. 46 and ground. See Figs. 5-6.
If battery voltage is present, go to next step. If battery voltage is
not present, check and repair connectors and related wiring harness
between ECU and fuse No. 18. See WIRING DIAGRAMS.
3) Check and repair ECU 22-pin connector. If connector is
okay, replace ECU.
DTC 32: "G" SENSOR SYSTEM
NOTE: DTC is set if ECU detects "G" sensor output voltage less

than 0.5 volt or more than 4.5 volts, or an open or short
circuit in "G" sensor system.
1) Disconnect "G" sensor connector. Sensor is located on
bracket under center console, next to shifter. See Fig. 10. Connect
Special Tool (MB991348) between sensor and connector. Using a DVOM,
check voltage between sensor connector terminals No. 2 (Blue/White
wire) and No. 3 (Black/Red wire). Voltage should be 2.38-2.62 volts.
If voltage is as specified, reconnect sensor connector and go to step
3). If voltage is not as specified, leave special tool and DVOM
connected and go to next step.
2) Note top center position of sensor, and remove sensor. See
"G" SENSOR under REMOVAL & INSTALLATION . Secure sensor so that arrow
on sensor is facing straight down. Voltage should be 3.4-3.6 volts. If
voltage is specified, reinstall sensor and go to next step. If voltage
is not as specified, replace sensor.
3) Turn ignition off. Disconnect ECU 26-pin connector. Turn
ignition on. Check voltage between ECU 26-pin connector terminals No.
4 and 17. See Figs. 5-6. Voltage should be 2.4-2.6 volts. If voltage
is as specified, go to next step. If voltage is not as specified,
check and repair connectors and related wiring harness between ECU and
sensor. See WIRING DIAGRAMS .
4) Check and repair ECU 26-pin connector. If connector is
okay, replace ECU.
Fig. 10: Locating "G" Sensor
Courtesy of Mitsubishi Motor Sales of America.
DTC 33: STOPLIGHT SWITCH SYSTEM