Mitsubishi Lancer Evolution IX. Manual - part 655

Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Grey R : Red P : Pink V : Violet PU : Purple

INPUT SIGNAL

· A/C SWITCH
· ENGINE
COOLANT
TEMPERATURE
SENSOR

· VEHICLE SPEED
SENSOR

ENGINE-
ECU

ENGINE
CONTROL
RELAY

SMOOTHING
CIRCUIT

FIELD EFFECT
TRANSISTOR
CIRCUIT

INPUT SIGNAL
PROCESSING

DRIVE
CIRCUIT

TEMPERATURE
DETECTION

CURRENT
DETECTION

RADIATOR
FAN
MOTOR

FAN CONTROLLER

ENGINE
CONTROL
SYSTEM

FUSIBLE
LINK

FAN
CONTROL
RELAY

AC505139

Cooling fan drive circuit <R.H. drive vehicles>

TROUBLESHOOTING

ENGINE COOLING

14-5

CIRCUIT OPERATION

• The fan controller is powered from fusible link

No.2.

• The engine-ECU judges the required revolution

speed of cooling fan motor using the input signals
transmitted from A/C switch, vehicle speed sen-
sor and engine coolant temperature sensor. The
engine-ECU activates the fan controller to drive
the cooling fan motor.

TROUBLESHOOTING

ENGINE COOLING

14-6

TECHNICAL DESCRIPTION

• The cause could be a malfunction of the fan con-

troller power supply or earth circuit.

• The cause could also be a malfunction of the fan

controller or the engine-ECU.

TROUBLESHOOTING HINTS

• Malfunction of fusible link

• Malfunction of fan control relay

• Malfunction of cooling fan motor

• Malfunction of fan controller

• Malfunction of engine-ECU

• Damaged wiring harness or connector

DIAGNOSIS

STEP 1. Check the circuit at fan controller
connector A-17 terminal 3.

AC210859

Connector: A-17

A-17 (GR)

Fan controller

Component side

(1) Disconnect fan controller connector A-17, and

measure at the harness side connector.

(2) Measure the voltage between terminal No.3 and

earth.

• When the ignition switch is turned to the "ON"

position, voltage should measure battery pos-
itive voltage.

Q: Is the voltage battery positive voltage when the

ignition switch is turned to the "ON" position?
YES :

Go to Step 7.

NO :

Go to Step 2.

STEP 2. Check the fan control relay.
Refer to

P.14-17

Q: Is the fan control relay in good condition?

YES :

Go to Step 3.

NO :

Replace it, then go to Step 1.

STEP 3. Check for harness damage between
fusible link No.2 and fan control relay connector
A-09X terminal 4.

AC310900AC

Fusible link (2)

Fusible link (2) And
Connector: A-09X

A-09X

Relay box
side

Q: Are the harness wires between fusible link No.2

and fan control relay connector A-09X damaged?
YES :

Repair or replace them, then go to Step 13.

NO :

Go to Step 4.

STEP 4. Check for harness damage between fan
control relay connector A-09X terminal 2 and fan
controller connector A-17 terminal 3.

AC310900AB

Connector: A-09X

A-09X

Relay box
side

AC210859

Connector: A-17

A-17 (GR)

Fan controller

Component side

Q: Are the harness wires between fan control relay

connector A-09X terminal 2 and fan controller
connector A-17 terminal 3 damaged?
YES :

Repair or replace them, then go to Step 13.

NO :

Go to Step 5.

TROUBLESHOOTING

ENGINE COOLING

14-7

STEP 5. Check for harness damage between J/C
(6) C-105 and fan control relay connector A-09X.
NOTE:

AC210877AC

Connector: A-13 <LHD>

A-13 (B)

AC310903AB

Connector: C-31 <RHD>

C-31

AC310901AB

Connector: C-105 <LHD>

C-105

AC310902AB

Connector: C-105 <RHD>

C-105

After inspecting intermediate connector A-13 <LHD>
terminal 3, intermediate connector C-31 <RHD> ter-
minal 12 and J/C (6) C-105 terminal 28, 33 inspect
the wires. If intermediate connector A-13 <LHD>,
C-31<RHD> and J/C (6) C-105 are damaged, repair
or replace them. Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

P.00-5

AC310900AB

Connector: A-09X

A-09X

Relay box
side

AC310901AB

Connector: C-105 <LHD>

C-105

AC310902AB

Connector: C-105 <RHD>

C-105

Q: Are the harness wires between J/C (6) C-105

terminal 28 and fan control relay connector A-09X
terminal 1 damaged?
YES :

Repair or replace them, then go to Step 13.

NO :

Go to Step 6.

STEP 6. Check for harness damage between fan
control relay connector A-09X terminal 3 and
earth.

AC310900AB

Connector: A-09X

A-09X

Relay box
side

TROUBLESHOOTING

ENGINE COOLING

14-8

Q: Are the harness wires between fan control relay

connector A-09X terminal 3 and earth damaged?
YES :

Repair or replace them, then go to Step 13.

NO :

Go to Step 7.

STEP 7. Check the cooling fan motor.
Refer to

P.14-17

Q: Is the cooling fan motor in good condition?

YES :

Go to Step 8.

NO :

Replace it, then go to Step 13.

STEP 8. Check the circuit at fan controller
connector A-17 terminal 1.

AC210859

Connector: A-17

A-17 (GR)

Fan controller

Component side

(1) Disconnect fan controller connector A-17, and

measure at the harness side connector.

(2) Measure the resistance between terminal No.1

and earth.

• The resistance should measure less than 2

ohms.

Q: Is the resistance less than 2 ohms?

YES :

Go to Step 10.

NO :

Go to Step 9.

STEP 9. Check the harness wire between fan
controller connector A-17 and earth.

AC210859

Connector: A-17

A-17 (GR)

Fan controller

Component side

Q: Are the harness wires between fan controller

connector A-17 and earth damaged?
YES :

Repair or replace them, then go to Step 13.

NO :

Go to Step 10.

STEP 10. Measure the output circuit voltage at
engine-ECU connector C-121 terminal 18 by
backprobing.

AC505254

1
9

2829

1415

3031

1718

JAE

Connector: C-121 <LHD>

Harness side

C-121 (GR)

Engine-ECU

AC505255

1
9

2829

1415

3031

1718

JAE

Connector: C-121 <RHD>

Harness side

C-121 (GR)

Engine-ECU

(1) Do not disconnect engine-ECU connector C-121.
(2) Start the engine and allow it to idle.
(3) Turn the A/C switch to the "ON" position.
(4) Measure the voltage between terminal No.18 and

earth by backprobing.

• The voltage should measure 0.7 volt or more

when the cooling fan is operating.

Q: Is the voltage 0.7 volt or more when the cooling fan

is operating?
YES :

Go to Step 12.

NO :

Go to Step 11.

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