1998 MITSUBISHI MONTERO light

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

AUTO TRANS DIAGNOSIS - R4AW3 & V4AW3
1998 Mitsubishi Montero
1997-98 AUTOMATIC TRANSMISSIONS
Mitsubishi R4AW3 & V4AW3 Electronic Controls
Montero, Montero Sport
APPLICATION
TRANSMISSION APPLICATION








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Vehicle Transmission Model
Montero Sport 2WD ............................................ R4AW3
Montero & Montero Sport 4WD .................................. V4AW3









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CAUTION: Vehicle is equipped with Supplemental Restraint System (SRS).
When servicing vehicle, use care to avoid accidental air bag
deployment. SRS-related components are located in steering
column, center console, instrument panel and lower panel on
instrument panel. DO NOT use electrical test equipment on
these circuits. If necessary, deactivate SRS before servicing
components. See AIR BAG SERVICING article in APPLICATIONS &
IDENTIFICATION.
DESCRIPTION
Automatic transmission is a 4-speed electronically controlled
transmission. Solenoids that control shift changes are located in
valve body. Solenoids are controlled by a Transmission Control Module
(TCM). TCM receives information from various input devices and uses
this information to control shift solenoids for transmission shifting
and lock-up solenoid for torque converter lock-up.
An Overdrive (OD) switch is mounted on the shift lever. When
OD switch is depressed to ON position, transmission will shift into
4th gear when shift lever is in "D" position, and OD OFF light on
instrument panel will go off. When OD switch is released to OFF
position, transmission will shift into 3rd gear, and OD OFF light on
instrument panel will illuminate.
A pattern select switch is located near shift lever on center
console. Pattern select switch contains a NORMAL and a HOLD operating
position. When pattern select switch is depressed (HOLD position) with\
shift lever in Drive position, transmission starts in 2nd gear.
Upshifts and downshifts will occur at a higher vehicle speed than with
switch in NORMAL position. See MITSUBISHI R4AW3 & V4AW3 OVERHAUL
article. Indicator light on instrument panel indicates pattern select
switch is in HOLD position.
Transmission is equipped with a shift lock and key interlock
system. Shift lock system prevents shift lever from being moved from
Park unless brake pedal is depressed. Key interlock system prevents
ignition key from being moved from ACC to LOCK position on ignition
switch unless shift lever is in Park. See MITSUBISHI SHIFT LOCK
SYSTEMS article.
OPERATION
TCM
TCM receives information from various input devices and uses

this information to control solenoids on transmission valve body. TCM
controls transmission shifting and torque converter lock-up.
TCM contains a self-diagnostic system, which will store
Diagnostic Trouble Codes (DTC) if failure or problem exists in
electronic control system. DTC can be retrieved to determine problem
area. See SELF-DIAGNOSTIC SYSTEM. TCM is located under left side of
instrument panel, left of steering column. See Fig. 1.
TCM INPUT DEVICES
Brakelight Switch Signal
Brakelight switch delivers input signal to TCM, indicating
vehicle braking. Brakelight switch is located on brake pedal support.
Cruise Control Electronic Control Unit (ECU)
Cruise control ECU delivers an input signal to control
overdrive operation in accordance with vehicle speed when cruise
control is operating. When in overdrive with cruise control on, if
vehicle speed drops 2 MPH less than the set speed, overdrive is
released to prevent reduction in vehicle speed. Once vehicle speed is
more than the set speed, overdrive function is resumed. If coolant
temperature is low, transmission will not shift into overdrive. Cruise
control ECU is located below center A/C vent, behind temperature
control panel on Montero. On Montero Sport, cruise control ECU is
located behind driver's kick panel.
Engine Coolant Temperature Sensor (ECT) Signal
Engine coolant temperature sensor delivers input signal to
TCM, indicating engine coolant temperature. Coolant temperature sensor
is located on engine.
Input & Output Shaft Speed Sensors
Sensors are magnetic pick-ups that monitor input and output
shaft speeds. AC waveforms are input to TCM by sensors. Sensors are
located on front and rear side of transmission case.
OD Switch Signal
The OD switch provides an input signal to TCM to indicate
when overdrive is selected by operator. When OD switch is depressed to
ON position, transmission will shift into 4th gear when shift lever is
in "D" position, and OD OFF light on instrument panel will go off.
When OD switch is released to OFF position, transmission will shift
into 3rd gear, and OD OFF light on instrument panel will come on. The
OD switch is mounted on shift lever.
Oil Temperature Sensor Signal
Oil temperature sensor provides TCM with ATF temperature
values. TCM uses this information to control shift points for maximum
performance. If transmission oil temperature exceeds standard values,
instrument panel ATF - TEMP light will come on. Sensor is mounted to
cooler line at transmission.
Park/Neutral Position (PNP) Switch Signal
PNP switch delivers an input signal to TCM indicating shift
lever position. Switch is located on side of transmission.
Throttle Position (TP) Sensor Signal
TP sensor delivers closed throttle and variable throttle
position input signals to TCM. TP sensor is located on side of
throttle body.
4WD Low Range Detection Switch
4WD low range detection switch provides information to TCM

Fig. 4: Checking Operation Of Shift Solenoids No. 1 & No. 2
Courtesy of Mitsubishi Motor Sales of America.
SELF-DIAGNOSTIC SYSTEM
SYSTEM DIAGNOSIS
NOTE: Before testing transmission, ensure fluid level is correct
and throttle and shift cables are properly adjusted. Ensure
engine starts with shift lever in Park and Neutral to ensure
proper adjustment of park/neutral position switch.
Transmission must first be tested by checking for stored
codes. See RETRIEVING DIAGNOSTIC TROUBLE CODES (DTC).
TCM monitors transmission operation and contains a self-
diagnostic system which stores a DTC if an electronic control system
failure or problem exists. If a problem exists in any of the solenoids
or speed sensors and a DTC is set, TCM delivers a signal to blink the
ATF TEMP light on instrument panel to warn the driver. DTC may be set
if a failure exists and can be retrieved for transmission diagnosis.
RETRIEVING DIAGNOSTIC TROUBLE CODES (DTC)
NOTE: Before retrieving DTC, ensure proper battery voltage exists
for proper self-diagnosis system operation. DO NOT disconnect
battery or ECM connectors before retrieving DTC.
Retrieving Codes Using Scan Tool
Ensure ignition switch is in OFF position. Connect scan tool
to Data Link Connector (DLC). See Fig. 5. Turn ignition switch to ON
position. Check for stored DTC and record code(s). See DIAGNOSTIC
TROUBLE CODE IDENTIFICATION table.

Fig. 5: Retrieving Codes Using Scan Tool
Courtesy of Mitsubishi Motor Sales of America.
Retrieving Codes Using Oil Temperature Warning Light
1) Using jumper wire, ground DLC terminal No. 1. See Fig. 6.
Note number of flashes from oil temperature warning light on
instrument panel. See Fig. 7. If normal system operation exists, oil
temperature warning light will blink 2 times per second. See Fig. 8.
2) If system is operating correctly and no DTC exists, turn
ignition off and remove jumper wire. If DTC exists, oil temperature
warning light will flash once every 2 seconds. The number of flashes
will equal first digit of DTC. After a pause of 2 seconds, second
digit will be displayed. Oil temperature warning light will flash once
every half second for second digit. See Fig. 8.
3) If more than one DTC exists, next DTC will be displayed
after pause of 3 seconds. Smallest DTC number will be first. DTCs will
be repeated.
4) Once DTC is obtained, determine probable cause and
symptom. See DIAGNOSTIC TROUBLE CODE IDENTIFICATION table. To trouble
shoot DTC, see DIAGNOSTIC TESTS. Turn ignition off and remove jumper
wire.
NOTE: Once repairs have been performed, DTCs must be cleared from
TCM memory. See CLEARING DIAGNOSTIC TROUBLE CODES (DTC).

Fig. 7: Locating A/T Temperature Warning Light
Courtesy of Mitsubishi Motor Sales of America.
Fig. 8: Identifying DTC Displays
Courtesy of Mitsubishi Motor Sales of America.
CLEARING DIAGNOSTIC TROUBLE CODES (DTC)

If DTC 51 is set also, go to DTC 51: 1ST GEAR RATIO SIGNAL
INCORRECT test. If DTC 51 is not set, check overdrive brake for a
mechanical failure. See OVERDRIVE BRAKE in MITSUBISHI R4AW3 & V4AW3
OVERHAUL article.
SYMPTOM TROUBLE SHOOTING
NOTE: Check system using appropriate scan tool. See WIRING DIAGRAMS
for electrical schematics and COMPONENT TESTING.
COMMUNICATION WITH SCAN TOOL NOT POSSIBLE
If scan tool cannot communicate with TCM, check proper
connection with DLC. Check TCM power circuits, TCM ground circuits and
malfunctioning TCM.
SHIFT POINTS INCORRECT
If shift points are incorrect, check for DTCs. If no DTC is
present, check oil temperature sensor, pattern select switch, 4WD low
range detection switch and TCM for proper operation.
UPSHIFTS OCCUR SPONTANEOUSLY
If upshifting occurs spontaneously, check park/neutral
position switch, overdrive switch and TCM for proper operation.
TCC LOCK-UP MALFUNCTIONING
If TCC lock-up system is not operating properly, check torque
converter, valve body, lock-up switch and oil temperature switch.
COMPONENT TESTING
A/T FLUID TEMPERATURE SWITCH
1) Remove fluid temperature switch, located to rear of
neutral safety switch. Immerse switch in container of ATF up to top
threaded portion of switch. Using a DVOM, check continuity between
switch terminals. Continuity should not exist when fluid temperature
is 257
F (125C) or less.
2) When fluid is heated to 289-304F (143-151C), continuity
should exist. Replace switch if necessary. Apply thread sealant to
fluid temperature switch threads and install in transmission.
BRAKELIGHT SWITCH
1) Disconnect electrical connector from brakelight switch,
located near brake pedal. Using ohmmeter, ensure continuity exists
between terminal No. 2 (White/Red wire) and terminal No. 3 (Green
wire) with brake pedal released. Replace brakelight switch if
continuity does not exist. Continuity should not exist between
terminals No. 2 and No. 3 with brake pedal depressed.
2) If continuity does not exist, ensure brake pedal is
properly adjusted so brakelight switch has proper travel for switch
operation. If proper brakelight switch travel exists, replace
brakelight switch.
ENGINE COOLANT TEMPERATURE (ECT) SENSOR

backprobe TCM connector. See Fig. 13. Check voltage between designated
terminals on TCM connector and ground. See TCM TERMINAL VOLTAGE
SPECIFICATIONS table. Voltage should be as specified.
Fig. 13: Identifying TCM Terminals
Courtesy of Mitsubishi Motor Sales of America.
TCM TERMINAL VOLTAGE SPECIFICATIONS








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Terminal Circuit  Condition  Voltage 


No.    
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1  Lock-Up Solenoid Lock-Up Clutch Engaged Battery 
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1  Lock-Up Solenoid  Lock-Up Clutch  0 Volts 

  Disengaged  
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2  Back-Up Power Supply  At All Times  Battery 
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5  Brakelight Switch  Brake Pedal Depressed 0 Volts 
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5  Brakelight Switch  Brake Pedal Released  Battery 
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8  TP Sensor Throttle Closed (Idle) .3-1.0 
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8  TP Sensor  Throttle Wide Open  4.4-5.0 
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11  Neutral Safety Switch In "P" Position  Battery 
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11  Neutral Safety Switch Except In "P"  0 Volts 
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12  Ground  Engine Idling  0 Volts