1998 MITSUBISHI MONTERO coolant temperature

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

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

Disconnect electrical connector from coolant temperature
sensor. Using ohmmeter, check resistance between terminals of coolant
temperature sensor. Resistance should be as specified in accordance
with the TEMPERATURE-TO-RESISTANCE VALUES table. Replace coolant
temperature if resistance is not within specification.
TEMPERATURE-TO-RESISTANCE VALUES









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Temperature F (C) Ohms
32 (0) ......................................................... 5.8\
68 (20) ........................................................ 2.4\
104 (40) ....................................................... 1.1\
176 (80) ....................................................... 0.3\









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INPUT SPEED SENSOR
Disconnect solenoid and sensor connector. Using ohmmeter,
measure resistance between terminals No. 9 and No. 10. See Fig. 9.
Resistance should be 560-680 ohms at 68
F (20C). If resistance is not
as specified, replace No. 2 speed sensor.
OIL TEMPERATURE SENSOR
Disconnect solenoid and sensor connector. Using ohmmeter,
check resistance between sensor connector terminals No. 1 and No. 2.
See Fig. 9 . Resistance should be 10 k/ohms when oil temperature is
77
F (25C). With oil temperature at 248F (120C), resistance should
be 615 ohms. If resistance is not as specified, replace oil
temperature sensor.
OUTPUT SPEED SENSOR
Disconnect solenoid and sensor connector. Using ohmmeter,
measure resistance between terminals No. 3 and No. 4. See Fig. 9.
Resistance should be 560-680 ohms at 68
F (20C). If resistance is not
as specified, replace output speed sensor.
OVERDRIVE SWITCH
Using a screwdriver, remove overdrive switch from selector
lever, located below selector lever button. Using a DVOM, check
continuity between overdrive switch terminals No. 3 and 5 with switch
in ON position. Continuity should exist. With switch in OFF position,
check continuity between terminals No. 3 and 4. Continuity should
exist. If continuity is not as specified, replace switch. See Fig. 10.
Fig. 10: Identifying Overdrive Switch Terminals
Courtesy of Mitsubishi Motor Sales of America.
PARK/NEUTRAL POSITION (PNP) SWITCH

Repair or replace components as necessary. If no problems exist, go to
next step.
2) Ground fan motor 3-pin connector terminal No. 3 (Black
wire). Using a fused jumper wire, connect battery voltage to 3-pin
connector terminal No. 2 (Blue wire). See WIRING DIAGRAMS. Fan motor
should operate with no abnormal noises or interferences. Repair or
replace components as necessary.
Engine Coolant Temperature (ECT) Sensor
Remove ECT sensor from vehicle. Suspend sensor in water so
that sensor does not touch container. Slowly heat water. Using an
ohmmeter, check sensor continuity as temperature increases. Replace
ECT sensor if resistance is not as specified. See
ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE table.
ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE









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Temperature F (C) Ohms
Diamante, Eclipse 2.0L Turbo & 2.4L
32 (0) ................................................. 5100-6500\
68 (20) ................................................ 2100-2700\
104 (40) ................................................ 900-1300\
176 (80) ................................................. 260-360\
Eclipse Non-Turbo
77 (25) ................................................. 900-1100\
212 (100) ................................................ 600-800\
Galant & Mirage
68 (20) ................................................ 2100-2700\
176 (80) ................................................. 260-360\
Montero
68 (20) ................................................ 2130-2610\
176 (80) ................................................. 258-322\
Montero Sport
68 (20) ................................................ 2100-2700\
176 (80) ................................................. 260-360\
3000GT
32 (0) ...................................................... 5800\
68 (20) ..................................................... 2400\
104 (40) .................................................... 1100\
176 (80) ..................................................... 300\









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Electric Cooling Fan Relay (Diamante, Eclipse, Galant &
Mirage)
1) Remove radiator fan motor relay from relay box located at
right side of engine compartment. Check for continuity between relay
terminals No. 1 and 3. If continuity exists, go to next step. If
continuity does not exist, replace cooling fan relay. See Fig. 8.
2) Using a fused jumper wire, connect battery voltage to
cooling fan relay terminal No. 1. Using another jumper wire, connect
cooling fan relay terminal No. 3 to battery ground. With cooling fan
relay energized, there should be continuity between cooling fan relay
terminals No. 4 and 5. With cooling fan relay not energized, there
should be no continuity between terminals No. 4 and 5. If continuity
does not exist as specified, replace cooling fan relay. See Fig. 8.
Electric Cooling Fan Relay (Montero, Montero Sport & 3000GT)
1)Remove relay from relay box in engine compartment relay
box. Check for continuity between relay terminals No. 2 and 4. If
continuity exists, go to next step. If continuity does not exist,
replace cooling fan relay. See Fig. 9.
2) Using a fused jumper wire, connect battery voltage to

speed, coolant temperature and A/C operation request, PCM
will command low, medium or high speed fan operation.
Diamante
1) If only the radiator fan does not operate, check fusible
link No. 6 located in engine compartment relay box. If only the
condenser fan does not operate, check dedicated fuse No. 16 (20-amp)
located in engine compartment relay box. See WIRING DIAGRAMS. Repair
as necessary.
2) If radiator fan and condenser fan operate in all speeds
except low, check appropriate low speed relay. See COMPONENT TESTS.
See WIRING DIAGRAMS . If low speed relay is okay, check PCM. See
appropriate G - TESTS W/CODES article in ENGINE PERFORMANCE.
* G - TESTS W/CODES - 1997
* G - TESTS W/CODES - 1998
3) If radiator fan and condenser fan operate in all speeds
except high, check appropriate high speed relay. See COMPONENT TESTS.
See WIRING DIAGRAMS . If high speed relay is okay, check PCM. See
appropriate G - TESTS W/CODES article in ENGINE PERFORMANCE.
* G - TESTS W/CODES - 1997
* G - TESTS W/CODES - 1998
4) To confirm radiator fan or condenser fan operation, see
FAN OPERATING MODE (DIAMANTE) table. If fan operation is not as
specified, check wiring harness for opens or shorts. Repair as
necessary.
FAN OPERATING MODE (DIAMANTE) ( 1)









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Power Circuit
Coolant Operating Radiator Condenser
Temp.
F (C) Low/High Fan Speed Fan Speed
13 MPH ( 2)
221 (105) ( 2) ........ On/Off ....... Low ................ Low
221 (105) ( 3) ........ Off/On ....... Mid ................ Mid
239 (115) ( 3) ........ On/On ........ High .............. High
13 MPH ( 3)
221 (105) ( 2) ........ On/Off ....... Low ................ Low
221 (105) ( 2) ........ On/On ........ High .............. High
30 MPH ( 2)
203 (95) ( 2) ........ Off/Off ....... Off ................ Off
203 (95) ( 3) ......... On/Off ....... Low ................ Off
221 (105) ( 3) ........ Off/On ....... Mid ................ Mid
30 MPH ( 3)
194 (90) ( 2) ........ Off/Off ....... Off ................ Off
194 (90) ( 3) ......... On/Off ....... Low ................ Off
221 (105) ( 3) ........ On/On ........ High ............... Mid
50 MPH ( 3)
221 (105) ( 2) ....... Off/Off ....... Off ................ Off
221 (105) ( 3) ........ On/On ........ High ............... Mid
( 1) - A/C request switch is turned off.
( 2) - Approximate vehicle speed/coolant temperature or less.
( 3) - Approximate vehicle speed/coolant temperature or more.









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NOTE: Operation of radiator and condenser fans is controlled by
vehicle Powertrain Control Module (PCM). Based on vehicle
speed, coolant temperature and A/C operation request, PCM

242 (117) (3) ......... High ........ High .............. High
( 1) - A/C request switch is turned off.
( 2) - Approximate vehicle speed/coolant temperature or less.
( 3) - Approximate vehicle speed/coolant temperature or more.
( 4) - A/C request switch is turned on.









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FAN OPERATING MODE (ECLIPSE 2.0L TURBO & 2.4L)








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With A/T With M/T
Coolant Radiator Radiator Condenser
Temp.
F (C) Fan Speed Fan Speed Fan Speed
28 MPH ( 1) ( 2)
203 (95) ( 2) .......... Off ......... Off ................ Off
203-210 (95-99) ....... Low ......... Mid ................ Off\
210 (99) ( 3) .......... High ........ High ............... Mid
28-50 MPH ( 1)
194 (90) ( 2) .......... Off ......... Off ................ Off
194-210 (90-99) ....... Low ......... Mid ................ Off\
210 (99) ( 3) .......... High ........ High ............... Mid
50 MPH ( 1) ( 3)
210 (99) ( 2) .......... Off ......... Off ................ Off
210 (99) ( 3) .......... High ........ High ............... Mid
12 MPH ( 2) ( 4)
210 (99) ( 2) .......... Low ......... Mid ................ Mid
210-242 (99-117) ...... High ........ High .............. High\
242 (117) ( 3) ......... High ........ High .............. High
12-50 MPH ( 4)
210 (99) ( 2) .......... Low ......... Mid ................ Mid
210-242 (99-117) ...... High ........ High .............. High\
242 (117) ( 3) ......... High ........ High .............. High
50 MPH ( 3) ( 4)
210 (99) ( 2) .......... Low ......... Mid ................ Mid
210-242 (99-117) ( 3) .. High ........ High .............. High
242 (117) ( 3) ......... High ........ High .............. High
( 1) - A/C request switch is turned off.
( 2) - Approximate vehicle speed/coolant temperature or less.
( 3) - Approximate vehicle speed/coolant temperature or more.
( 4) - A/C request switch is turned on.









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NOTE: Operation of radiator and condenser fans is controlled by
vehicle Powertrain Control Module (PCM). Based on vehicle
speed, coolant temperature and A/C operation request, PCM
will command low, medium or high speed fan operation.
Galant
1) If only the radiator fan does not operate, check fusible
link No. 5 (30-amp) located in engine compartment relay box. If only
the condenser fan does not operate, check dedicated fuse No. 3 (30-
amp) located in engine compartment relay box. See WIRING DIAGRAMS.
Repair as necessary.
2) If radiator fan and condenser fan operate in all speeds
except low, check appropriate low speed relay. See COMPONENT TESTS.
See WIRING DIAGRAMS . If low speed relay is okay, check PCM. See
appropriate G - TESTS W/CODES article in ENGINE PERFORMANCE.
* G - TESTS W/CODES - 1997
* G - TESTS W/CODES - 1998

3) If radiator fan and condenser fan operate in all speeds
except high, check appropriate high speed relay. See COMPONENT TESTS.
See WIRING DIAGRAMS . If high speed relay is okay, check PCM. See
appropriate G - TESTS W/CODES article in ENGINE PERFORMANCE.
* G - TESTS W/CODES - 1997
* G - TESTS W/CODES - 1998
4) To confirm radiator fan or condenser fan operation, see
appropriate FAN OPERATING MODE (GALANT) table. If fan operation is not\
as specified, check wiring harness for opens or shorts. Repair as
necessary.
FAN OPERATING MODE (GALANT) ( 1)









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Coolant Radiator Condenser
Temp. F (C) Fan Speed Fan Speed
28 MPH ( 2)
203 (95) ( 2) ................ Off .......................... Off
203-221 (95-105) ............ Low .......................... Low\
221 (105) ( 3) .............. High ......................... High
28-50 MPH
194 (90) ( 2) ................ Off .......................... Off
194-221 (90-105) ............ Low .......................... Low\
221 (105) ( 3) .............. High ......................... High
50 MPH ( 3)
221 (105) ( 2) ............... Off .......................... Off
221 (105) ( 3) .............. High ......................... High
Any Speed ( 4)
221 (105) ( 2) ............... Low .......................... Low
221 (105) ( 3) .............. High ......................... High
( 1) - A/C request switch is turned off.
( 2) - Approximate vehicle speed/coolant temperature or less.
( 3) - Approximate vehicle speed/coolant temperature or more.
( 4) - A/C request switch is turned on.









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NOTE: Operation of radiator and condenser fans is controlled by
vehicle Powertrain Control Module (PCM). Based on vehicle
speed, coolant temperature and A/C operation request, PCM
will command low, medium or high speed fan operation.
Mirage
1) If only the radiator fan does not operate, check fusible
link No. 5 (30-amp) located in engine compartment relay box. If only
the condenser fan does not operate, check fusible link No. 2 (100-amp)\
and dedicated fuse No. 1 (25-amp) located in engine compartment relay
box. See WIRING DIAGRAMS . Repair as necessary.
2) If fusible links and dedicated fuse are okay, check
appropriate fan relay and/or fan motor for proper operation. See
COMPONENT TESTS. See WIRING DIAGRAMS. If fan relay and motor are okay,
check PCM. See appropriate G - TESTS W/CODES article in ENGINE
PERFORMANCE.
* G - TESTS W/CODES - 1.5L - 1997
* G - TESTS W/CODES - 1.8L - 1997
* G - TESTS W/CODES - 1998
3) To confirm radiator fan or condenser fan operation, see
appropriate FAN OPERATING MODE (MIRAGE) table. If fan operation is not\
as specified, check wiring harness for opens or shorts. Repair as

necessary.
FAN OPERATING MODE (MIRAGE)









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Power Circuit
Coolant Operating Radiator Condenser
Temp.
F (C) RAD/COND Fan Speed Fan Speed
203 (95) ( 1) ( 2) ...... Off/Off ....... Off ................ Off
203-221 (95-105) ( 1) ... On/Off ........ On ................ Off
221 (105) ( 1) ( 3) ...... On/On ......... On ................. On
All Temp. ( 4) .......... On/On ......... On ................. On
( 1) - A/C request switch is turned off.
( 2) - Approximate coolant temperature or less.
( 3) - Approximate coolant temperature or more.
( 4) - A/C request switch is turned on.









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NOTE: Operation of radiator and condenser fans is controlled by
vehicle Powertrain Control Module (PCM). Based on vehicle
speed, coolant temperature and A/C operation request, PCM
will command low, medium or high speed fan operation.
3000GT
1) If neither the radiator fan nor the condenser fan operate,
check fusible link No. 5 (40-amp). See WIRING DIAGRAMS. If only the
condenser fan does not operate, check dedicated fuse No. 8 (20-amp).
2) If the condenser fan operates in all speeds except low and
A/C compressor clutch does not enter the ON state, check for A/C
compressor lock controller unit output signal. If the A/C compressor
clutch does enter the ON state, check condenser fan low speed relay
operation.
3) If the radiator fan and the condenser fan operate in all
speeds except high, check PCM. See appropriate G - TESTS W/CODES
article in ENGINE PERFORMANCE. If fan operation is not as specified,
check wiring harness for opens or shorts. Repair as necessary.
* G - TESTS W/CODES - NON-TURBO - 1997
* G - TESTS W/CODES - TURBO - 1997
* G - TESTS W/CODES - 1998
4) To confirm radiator fan or condenser fan operation, see
appropriate FAN OPERATING MODE (3000GT) table. If fan operation is not\
as specified, check wiring harness for opens or shorts. Repair as
necessary.
FAN OPERATING MODE (3000GT)









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Power Circuit
Coolant Operating Radiator Condenser
Temp.
F (C) Low/High Fan Speed Fan Speed
50 MPH ( 1) ( 2)
203 (95) ( 2) ........ Off/Off ....... Off ................ Off
203-221 (95-105) ..... On/Off ....... Low ................ Off\
221 (105) ( 3) ........ On/On ........ High .............. High
50 MPH ( 1) ( 3)
221 (105) ( 2) ....... Off/Off ....... Off ................ Off
221 (105) ( 3) ........ On/On ........ High .............. High
All Speeds
221 (105) ( 2) ........ On/Off ....... Low ................ Low
221 (105) ( 3) ........ On/On ........ High .............. High