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Mitsubishi Evolution X. Manual - part 230

ENGINE COOLING DIAGNOSIS

TSB Revision

ENGINE COOLING

14-7

AC708952

FUSIBLE
LINK

RADIATOR
FAN RELAY

FAN
CONTROL
RELAY

CONDENSER
FAN RELAY

RADIATOR
FAN
MOTOR

CONDENSER
FAN MOTOR

INPUT SIGNAL

ENGINE
COOLANT
TEMPERATURE
SENSOR

CAN DRIVE
CIRCUIT

INTERFACE
CIRCUIT

ENGINE
CONTROL
MODULE

JOINT
CONNECTOR
(CAN3)

JOINT
CONNECTOR
(CAN2)

INPUT SIGNAL

·FRONT WHEEL
SPEED SENSOR
·REAR WHEEL
SPEED SENSOR

ASC-ECU

INPUT SIGNAL

A/C SWITCH

A/C-ECU

JOINT
CONNECTOR
(CAN1)

CAN DRIVE
CIRCUIT

INTERFACE
CIRCUIT

ETACS-ECU

JOINT
CONNECTOR
(CAN2)

Radiator Fan and Condenser Fan Drive Circuit <TC-SST>

ENGINE COOLING DIAGNOSIS

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ENGINE COOLING

14-8

CIRCUIT OPERATION

• The ECM transmits the rotation signals of radiator

fan and condenser fan, based on the engine cool-
ant temperature signal from the engine coolant
temperature sensor, the vehicle speed signal
from the wheel speed sensor via the ASC-ECU,
and the A/C switch signal from the A/C-ECU
using the CAN bus line.

• The rotation signals of radiator fan and con-

denser fan, using the CAN bus line from ECM,
turn ON/OFF of the radiator fan relay, condenser
fan relay, and fan control relay via ETACS-ECU,
to control the radiator fan and condenser fan rota-
tion.

TECHNICAL DESCRIPTION

• When the radiator fan and condenser fan do not

operate, the wiring harness/connector, fan motor,
relay, and ETACS-ECU may have a failure.

• The radiator fan and condenser fan do not oper-

ate also when the CAN bus line, MFI system, or
ETACS system have a failure.

TROUBLESHOOTING HINTS

• Malfunction of CAN bus line

• Malfunction of MFI system

• Malfunction of ETACS system

• Damaged wiring harness or connector

• Malfunction of fusible link number 28

• Malfunction of fusible link number 29

• Malfunction of radiator fan relay

• Malfunction of condenser fan relay

• Malfunction of fan control relay

• Malfunction of radiator fan motor

• Malfunction of condenser fan motor

• Malfunction of ECM

• Malfunction of ETACS-ECU

DIAGNOSTIC PROCEDURE

Required Special Tools:

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: M.U.T.-III USB Cable

• MB991910: M.U.T.-III Main Harness A

• MB991223: Harness Set

• MB992006: Extra Fine Probe

AC708833AB

Connectors: A-35X, A-36X, A-37X

A-37X

A-35X

A-36X

Air cleaner

Engine
compartment
relay box

AC708834AB

A-45 (B)

Connectors: A-45, A-47

A-47 (B)

Radiator
assembly

AC708835AB

ETACS-ECU

Connector: C-312

ENGINE COOLING DIAGNOSIS

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ENGINE COOLING

14-9

CAUTION

If there is any problem in the CAN bus lines, an incorrect
diagnostic trouble code may be set. Prior to this diagno-
sis, diagnose the CAN bus lines (Refer to GROUP 54C,
Trouble code diagnosis

P.54C-9

STEP 1. Using scan tool MB991958, check the CAN bus
line diagnostics.
Use scan tool to diagnose the CAN bus line (Refer to GROUP
54C, Explanation About The Scan Tool Can Bus Diagnostics

P.54C-9

Q: Is the diagnostic trouble code set?

YES : Go to Step 2.
NO : Repair the CAN bus line (Refer to GROUP 54C,

Diagnosis

− Can Bus Diagnostic Table

P.54C-14

Then go to Step 22.

STEP 2. Using scan tool MB991958, check the MFI system
actuator test.
Using scan tool to check the MFI system actuator test (Refer to
GROUP 13A, MFI Diagnosis

− Diagnostic Function

P.13A-9

• Item 14: Cooling fan

(Refer to GROUP 13A, MFI Diagnosis

− Actuator Test Refer-

ence Table

P.13A-871

)

Q: Is the check result normal?

YES : Go to Step 21.
NO : Go to Step 3.

STEP 3. Using scan tool MB991958, read the MFI system
diagnostic trouble code (DTC).
Using scan tool to read the MFI system DTC (Refer to GROUP
13A, MFI Diagnosis

− Diagnostic Function

P.13A-9

Q: Is any DTC set?

YES : Repair the MFI system (Refer to GROUP 13A, MFI

Diagnosis

− Diagnostic Trouble Code Chart

P.13A-44

). Then go to Step 22.

NO : Go to Step 4.

STEP 4. Using scan tool MB991958, read the ETACS
system diagnostic trouble code (DTC).
Using scan tool to read the ETACS system DTC (Refer to
GROUP 54A, ETACS, Troubleshooting

− Diagnostic Function

P.54A-579

Q: Is any DTC set?

YES : Repair the ETACS system (Refer to GROUP 54A,

ETACS, Troubleshooting

− Diagnostic Trouble Code

Chart

P.54A-582

). Then go to Step 22.

NO : Go to Step 5.

ENGINE COOLING DIAGNOSIS

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ENGINE COOLING

14-10

STEP 5. Measure the voltage at ETACS-ECU connector
C-312.
(1) Disconnect the ETACS-ECU connector C-312, and

measure at front wiring harness connector side.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 2 and ground,

between terminal 8 and body ground, and between terminal
9 and body ground.

OK: System voltage

(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Connect the ETACS-ECU connector C-312.
Q: Is the check result normal?

YES : Go to Step 11.
NO : Go to Step 6.

STEP 6. Check the radiator fan relay connector A-35X,
condenser fan relay connector A-36X, fan control relay
connector A-37X, and ETACS-ECU connector C-312, for
loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Refer to GROUP 00E, Harness Connector Inspection

P.00E-2

Q: Is the connectors and terminals in good condition?

YES : Go to Step 7.
NO : Repair or replace damaged connectors. Then go to

Step 22.

STEP 7. Check the harness wire between fusible link
number 28 and condenser fan relay connector A-36X
terminal number 3, between fusible link number 28 and
condenser fan relay connector A-36X terminal number 4,
between condenser fan relay connector A-36X terminal
number 4 and fan control relay connector A-37X terminal
number 1, between fusible link number 29 and radiator fan
relay connector A-35X terminal number 3, for damage.
Q: Is the harness wires in good condition?

YES : Go to Step 8.
NO : Repair the damaged harness wire. Then go to Step

22.

AC708966AB

C-312 Harness connector:
Component side

AC708976

Fusible link
number 28

Fusible link number 29

Engine compartment
relay box

Air cleaner assembly

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