Mitsubishi Engine cooling, Workshop Manual, Page: 6 / 26

ENGINE COOLING -
Troubleshooting
14-6
Inspection Procedure 2
Radiator fan and condenser fan do not change speed or
stop. <Vehicles with A/C>
Radiator fan does not change speed or stop.
<Vehicles without A/C>
Probable cause
The fan controller carries out step-free control of the radiator fan motor and the condenser
fan motor speeds using signals transmitted from the engine-ECU.
D Malfunction of fan control relay
D Malfunction of fan controller
D Malfunction of engine-ECU
D Malfunction of wiring harness or connector
<Vehicles with A/C>
OK
NG
Repair
OK
NG
Replace
Check the automatic compressor-ECU <manual air conditioner>
or A/C-ECU <automatic air conditioner>, and repair if necessary.
(Refer to GROUP 55 - Troubleshooting.)
YES NO
Engine-ECU terminal voltage check (Refer to GROUP 13A - Trou-
bleshooting.)
Replace the radiator fan motor and fan controller assembly.
NOTE
*1: 4G6
*2: 6A1
*3: 4D6
OK
Measure at the engine-ECU connectors C-34*1, C-33*2, C-53*3.
D Connect the connector.
<Except 4D6>
D Pull out the terminal No.21 to disconnect it (Ignition switch: ON)
OK:
The radiator fan motor and condenser fan motor operate.
D Connect the terminal No.21 to the body earth (Ignition switch: ON)
OK:
The radiator fan motor and condenser fan motor stop.
<4D6>
D Pull out the terminal No.18 to disconnect it (Ignition switch: ON)
OK:
The radiator fan motor and condenser fan motor operate.
D Connect the terminal No.18 to the body earth (Ignition switch: ON)
OK:
The radiator fan motor and condenser fan motor stop.
OK
Fan controller check (Refer to P.14-12.)
NG
Replace the radiator fan motor and fan controller assembly.
Engine-ECU terminal voltage check (Refer to GROUP 13A - Trou-
bleshooting.)
OK
Measure at the engine-ECU connectors C-34*1, C-33*2, C-53*3.
D Connect the connector.
<Except 4D6>
D Voltage between 21 and body earth
(Engine: idling, engine coolant temperature: 80 _ C or less)
OK:
0 - 0.3 V (Engine: idling, A/C switch: ON)
OK:
0.7 V or more (When A/C compressor is operating)
<4D6>
D Voltage between 18 and body earth
(Engine: idling, engine coolant temperature: 80 _ C or less)
OK:
0 - 0.3 V (Engine: idling, A/C switch: ON)
OK:
0.7 V or more (When A/C compressor is operating)
NG
Check the harness wire between fan controller and engine-ECU.
OK
D Check the harness wire between fan control relay and fusible
link (7).
D Check the harness wire between fan control relay and body
earth.
D Check the harness wire between fan control relay and fan
controller.
NG
Repair
Fan control relay check (Refer to P.14-12.)
NG
Replace