ABS MITSUBISHI MONTERO 1998 User Guide

ANTI-LOCK BRAKE SYSTEM
1998 Mitsubishi Montero
1997-98 BRAKES
Mitsubishi - Anti-Lock
Montero
DESCRIPTION
CAUTION: See ANTI-LOCK BRAKE SAFETY PRECAUTIONS article in GENERAL
INFORMATION.
NOTE: For more information on brake system, see BRAKE SYSTEM
article.
The Anti-Lock Brake System (ABS) is designed to prevent wheel\
lock-up during heavy braking. This allows operator to maintain
steering control while stopping vehicle in shortest distance possible.
Major components are a hydraulic unit, wheel speed sensors, "G"
sensor, ABS Electronic Control Unit (ECU) and ANTI-LOCK warning light.\
ABS has a self-diagnostic system to indicate a system malfunction and
for use in system trouble shooting.
OPERATION
Each wheel sensor sends an AC electrical signal to the ECU.
The ECU reads this information as wheel speed. When any decelerating
wheel speed rate is determined to be excessive in comparison to other
monitored wheels, the hydraulic unit cycles hydraulic brake pressure
to each wheel to equalize speed of all wheels. ABS turns itself off
when vehicle drops to 4 MPH. Minor lock-up may occur at this point.
With engine running and vehicle speed greater than 4 MPH,
pump motor will operate for a short period of time and may be heard
inside vehicle. During pump motor operation, ABS system is completing
a self-check. During ABS system operation, a pulsing brake pedal and
vibration in steering wheel and vehicle body may be experienced. These
conditions are normal.
BLEEDING BRAKE SYSTEM
BLEEDING PROCEDURES
CAUTION: When adding brake fluid, ensure filter is properly fitted on
reservoir tank.
ABS system is bled using conventional method. With engine
running, manually bleed system using an assistant. For bleeding order,
see BRAKE LINE BLEEDING SEQUENCE table. Ensure Load Sensing
Proportioning Valve (LSPV) is bled in sequence. Remove all air from
brake system. Refill brake fluid reservoir after bleeding procedure is
complete.
BRAKE LINE BLEEDING SEQUENCE









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Application Sequence
Montero ....................................... RR, LR, LSPV, RF, LF









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for one second, and then go out. Turn ignition switch to START
position. Warning light should come on and stay on.
2) When ignition switch is turned from START to ON position,
warning light should come on for one second, and then go out. If
warning light functions as specified, go to step 3). If warning light
does not function as specified, see appropriate trouble shooting test:
* IGNITION SWITCH IN ON POSITION (ENGINE NOT RUNNING),
ANTI-LOCK WARNING LIGHT INOPERATIVE
* AFTER ENGINE STARTS, ANTI-LOCK WARNING LIGHT REMAINS ON
* IGNITION SWITCH IN START POSITION, ANTI-LOCK WARNING LIGHT
INOPERATIVE
* 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, THEN TURNS OFF
3) Test drive vehicle. If ANTI-LOCK warning light does not
come on at low speed, go to next step. If light comes on at low speed,
motor relay, solenoid valve or Wheel Speed Sensor (WSS) malfunction is\
indicated. Go to step 6). If insufficient braking force or ABS
malfunction exists, go to next step. If none of listed symptoms exist,
go to step 6).
4) Check conventional brake system components for proper
operation. Check for mechanical lock of hydraulic unit solenoid valve.
Check for plugged hydraulic line in hydraulic unit. Repair or replace
as necessary. If hydraulic unit is okay, go to next step.
5) Ensure WSS rotor gap is correct. See WHEEL SPEED SENSOR
(WSS) under ADJUSTMENTS. Check for faulty wheel speed sensor. See
WHEEL SPEED SENSOR (WSS) under COMPONENT TESTS. Replace sensor as
necessary. See WHEEL SPEED SENSOR (WSS) under REMOVAL & INSTALLATION.
Inspect ECU connectors and related wiring harness. See WIRING DIAGRAMS
. If testing indicates no mechanical or electrical failures,
substitute ECU with known-good unit and retest.
6) Enter ABS self-diagnostics and retrieve Diagnostic Trouble
Codes (DTCs). See RETRIEVING DTCs under SELF-DIAGNOSTIC SYSTEM. If no
DTCs are displayed, fault may be intermittent. Attempt to make
malfunction reoccur. If no diagnostic output exists, check and repair
wiring harness between ECU and data link connector. See
WIRING DIAGRAMS .
NOTE: Trouble shoot ANTI-LOCK warning light in following sequence:
instrument cluster circuit, ECU and valve relay.
Ignition Switch In ON position (Engine Not Running),
ANTI-LOCK Warning Light Inoperative
1) If all other warning lights come on with ignition on, go
to step 3). If other warning lights do not come on, check fuse No. 11
in main fuse panel. If fuse is blown, correct cause of blown fuse, and
replace fuse. If fuse is okay, go to next step.
2) Remove instrument cluster. Turn ignition on. Using DVOM,
check voltage between vehicle ground and instrument cluster ANTI-LOCK
warning light terminal No. 28. See Fig. 2. If light does not come on,
go to next step. If light comes on, check and repair connectors and
related wiring harness between instrument cluster, ABS valve relay and
ECU. See WIRING DIAGRAMS .
3) Turn ignition off. Check for faulty warning light bulb.
Replace bulb as necessary. If bulb is okay, check and repair
connectors and related wiring harness between instrument cluster and
ECU. See WIRING DIAGRAMS . If connectors and wiring are okay, replace
instrument cluster.

Fig. 2: Identifying Instrument Cluster Connector Terminals
Courtesy of Mitsubishi Motor Sales of America.
After Engine Starts, ANTI-LOCK Warning Light Remains On
1) With ignition on, disconnect instrument cluster
connectors. If warning light remains on, replace instrument cluster.
If warning light goes off, go to next step.
2) Disconnect ECU 22-pin connector and ABS relay box 8-pin
connector. See Fig. 3. If warning light goes off, replace ECU. If
warning light stays on, check and repair connectors and related wiring
harness between ECU, instrument cluster, and ABS valve relay. See
WIRING DIAGRAMS .
Fig. 3: Exploded View Of Hydraulic Unit & Components
Courtesy of Mitsubishi Motor Sales of America.
Ignition Switch In START Position, ANTI-LOCK Warning Light
Inoperative

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.

NOTE: DTC is set if ECU detects stoplight switch stays on for 15
minutes or more, or an open circuit in stoplight switch
system.
1) Check if stoplights are functioning correctly. If
stoplights function correctly, go to next step. If stoplights do not
function correctly, check and repair stoplight circuit. See
WIRING DIAGRAMS.
2) Turn ignition off. Disconnect ECU 22-pin connector. Using
DVOM, measure voltage between ECU 22-pin connector terminal No. 34 and
ground while depressing brake pedal. 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 stoplight
switch and ECU. See WIRING DIAGRAMS.
3) Check and repair ECU 22-pin connector. If connector is
okay, replace ECU.
DTC 41, 42 OR 43: SOLENOID VALVE CIRCUIT
NOTE: DTC sets if ECU senses that solenoid is on with no power
supplied, or off with power supplied.
1) Disconnect hydraulic unit connectors. Using ohmmeter,
check resistance between hydraulic unit connectors terminals No. 4 and
12, 5 and 12, and 6 and 12. See Fig. 11. Resistance should be 4.04-4.
54 ohms. If resistance is as specified, go to next step. If resistance
is not as specified, replace faulty hydraulic unit. See HYDRAULIC UNIT
under REMOVAL & INSTALLATION .
2) Check resistance between hydraulic unit connectors
terminals No. 1 and 12, 2 and 12, and 3 and 12. Resistance should be
8.04-8.59 ohms. If resistance is as specified, go to next step. If
resistance is not as specified, replace faulty hydraulic unit. See
HYDRAULIC UNIT under REMOVAL & INSTALLATION .
3) Turn ignition off. Disconnect ECU connectors. Check
continuity of each circuit between ECU connectors and hydraulic unit
connectors. See WIRING DIAGRAMS. If continuity exists, go to next
step. If continuity does not exist, check and repair connectors and
related wiring harness between ECU and hydraulic unit. See
WIRING DIAGRAMS .
4) Check continuity between hydraulic unit connector terminal
No. 12 and ABS relay box terminal No. 1. See Figs. 4 and 11. If
continuity exists, go to next step. If continuity does not exist,
check and repair connectors and related wiring harness between
hydraulic unit and ABS relay box. See WIRING DIAGRAMS.
5) Check and repair ECU connectors. If connectors are okay,
replace ECU.
Fig. 11: Identifying Hydraulic Unit Connector Terminals
Courtesy of Mitsubishi Motor Sales of America.
DTC 51: VALVE RELAY

NOTE: DTC is set if valve relay is removed or if no power is
supplied to relay.
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 ABS relay box 8-pin connector. Turn ignition
on. Using a DVOM, check voltage between ABS relay box 8-pin harness
connector terminal No. 6 and ground. See Fig. 4. If battery voltage
exists, go to next step. If battery voltage does not exist, check and
repair wiring harness between ABS valve relay and fusible link No. 1.
See WIRING DIAGRAMS .
3) Disconnect ECU connectors. Check resistance between ECU
22-pin connector terminal No. 37 and ECU 26-pin connector terminal No.
26. Resistance should be 60-120 ohms. If resistance is as specified,
go to next step. If resistance is not as specified, check and repair
connectors and related wiring harness between ABS valve relay and ECU.
See WIRING DIAGRAMS .
4) Check continuity between ECU 22-pin connector terminal No.
48 and ground. If continuity exists, go to next step. If continuity
does not exist, check and repair wiring harness between ABS valve
relay and ECU. See WIRING DIAGRAMS.
5) Check and repair ECU 22-pin connector. If connector is
okay, replace ECU.
DTC 53: MOTOR RELAY
NOTE: DTC is set when ECU detects motor relay on but motor does
not run, motor relay off but motor does not stop, or when
motor relay is faulty.
1) Using scan tool, perform hydraulic unit actuator test. If
motor is not operating, go to next step. If motor is still operating,
repair wiring harness between hydraulic unit and ECU. See
WIRING DIAGRAMS .
2) Inspect ABS relay box. See Fig. 3. Replace ABS relay box
if needed. If ABS relay box is okay, go to next step.
3) Disconnect ABS relay box 2-pin connector. Using DVOM,
check voltage between 2-pin connector terminal No. 11 and ground. See
Fig. 4 . If battery voltage is present, go to next step. If battery
volt age is not present, check and repair wiring harness between ABS
motor relay and fusible link No. 1. See WIRING DIAGRAMS.
4) Turn ignition off. Disconnect ECU connectors. Check
resistance between ECU 22-pin connector terminal No. 38 and 26-pin
connector terminal No. 26. Resistance should be 26-38 ohms. If
resistance is as specified, go to next step. If resistance is not as
specified, check and repair connectors and related wiring harness
between ABS motor and ECU. See WIRING DIAGRAMS.
5) Check resistance between ECU 22-pin connector terminal No.
49 and ground. Resistance should be 0.1-0.3 ohm. If resistance is as
specified, go to next step. If resistance is not as specified, check
and repair hydraulic unit motor ground connection or wiring harness
between ECU and hydraulic unit. See WIRING DIAGRAMS.
6) Check motor operation. Momentarily apply battery voltage
to hydraulic unit connector terminal No. 11. See Fig. 11. If motor
operates, go to next step. If motor does not operate, replace
hydraulic unit.
7) Check and repair ECU 22-pin connector. If connector is
okay, replace ECU.
COMPONENT TESTS
4WD CONTROL UNIT

Fig. 16: Locating Electronic Control Unit (ECU)
Courtesy of Mitsubishi Motor Sales of America.
"G" SENSOR
CAUTION: DO NOT turn "G" sensor upside-down or lay unit on its side.
DO NOT drop "G" sensor. DO NOT disassemble unit. Replace "G"
sensor as an assembly.
Removal & Installation
Sensor is located under center console, near shifter. See
Fig. 10 . Remove center console assembly. Disconnect sensor wiring
harnes s connector. Remove sensor. To install, reverse removal
procedure. Tighten bolts to specification. See TORQUE SPECIFICATIONS.
HYDRAULIC UNIT
Removal
Remove brakelines from hydraulic unit. Remove ABS relay box
cover. See Fig. 3. Disconnect ground wire and wiring harness
connectors from hydraulic unit. Remove hydraulic unit retaining nuts.
Carefully remove hydraulic unit.
Installation
To install, reverse removal procedure. Install hydraulic unit
brakelines. Ensure brakelines are installed in correct location. See
Fig. 17. Bleed brake system. See BLEEDING BRAKE SYSTEM.

Fig. 18: Anti-Lock Brake System (ABS) Wiring Diagram (1997 Montero)\

Fig. 19: Anti-Lock Brake System (ABS) Wiring Diagram (1998 Montero)\