Mitsubishi 380. Manual - part 234

ENGINE COOLING DIAGNOSIS

ENGINE COOLING

14-20

STEP 23. MUT-III self-diag code
Check if an MPI system self-diag code is set. (Refer to GROUP 
13A - Trouble shooting 

13A-5

).

Q: Diagnosis code set?

YES : Inspection chart for diagnosis code (Refer to GROUP 

13A - Trouble shooting 

13A-17

)

NO :  Replace the engine-ECU (Refer to GROUP 13A, 

Engine-ECU 

13A-675

 ). Then go to Step 24.

STEP 24. Check the symptoms.

Q: Does the radiator fan motor and the condenser fan 

motor operate correctly?
YES : This symptom is complete.
NO :  Return to Step 1.

INSPECTION PROCEDURE 4: Radiator Fan and Condenser Fan do not Change Speed or Stop

.

Radiator Fan and Condenser Fan Drive 
Circuit

Refer to 5.

.

TECHNICAL DESCRIPTION

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

troller power supply or earth circuit.

• If the communication line wiring harness between 

the fan controller and the engine-ECU is 
short-circuited to earth, the radiator fan motor 
and the condenser fan motor will not rotate.

• The cause could also be a malfunction of input 

signal from the A/C switch, the water temperature 
sensor unit and the vehicle speed sensor <M/T> 
or the output shaft speed sensor <A/T> to the 
engine-ECU.

• The cause could also be a malfunction of the fan 

controller or the engine-ECU.

.

TROUBLESHOOTING HINTS

• Malfunction of fusible link No.2

• 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 fan control relay.
Refer to 

14-31

.

Q: Is the fan control relay in good condition?

YES : Go to Step 2.
NO :  Replace the fan control relay. Then go to Step 8.

ENGINE COOLING DIAGNOSIS

ENGINE COOLING

14-21

STEP 2. Check the fan control relay connector A-10X.

Q: Is the connector in good condition?

YES : Go to Step 3.
NO :  Repair the connector or replace the relay box. Then 

go to Step 8.

STEP 3. Check the harness wire between fan control relay 
connector A-10X terminal 2 and fan controller connector 
A-24 terminal 3.

Q: Is the harness wire in good condition?

YES : Go to Step 4.
NO :  Repair the damaged harness wire. Then go to Step 8.

04DB012A

Fusible link

No.2

Relay box

Fan control

relay

A-10X

4

04DB012A

Fusible link

No.2

Relay box

Fan control

relay

A-10X

4

04DB008A

1

2

3

A-24

Connector: A-24

ENGINE COOLING DIAGNOSIS

ENGINE COOLING

14-22

STEP 4. Check the fan controller connector A-24, 
intermediate connector A-13 and engine-ECU connector  
B-21.

Q: Are these connectors in good condition?

YES : Go to Step 5.
NO :  Repair or replace the connector. Then go to Step 8.

04DB008A

1

2

3

A-24

Connector: A-24

AK303148

CONNECTOR: A-13

AB

A-13(GR)

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

ENGINE COOLING DIAGNOSIS

ENGINE COOLING

14-23

STEP 5. Check the harness wire between fan controller 
connector A-24 terminal 2 and engine-ECU connector  
B-21 terminal 71.

  

Q: Are these harness wires in good condition?

YES : Go to Step 6.
NO :  Repair the damaged harness wire. Then go to Step 8.

04DB008A

1

2

3

A-24

Connector: A-24

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER