Subaru Impreza 2003 Service Manual page 1121

B: INSPECTION
DETECTING CONDITION:
• Engine coolant temperature is above 96°C (205°F).
• A/C compressor is rotated.
• Vehicle speed is below 19 km/h (12 MPH).
TROUBLE SYMPTOM:
• Radiator sub fan does not rotate under the above conditions.
• Radiator sub fan does not rotate at high speed when the following conditions are both met:
(1) Engine coolant temperature is above 90°C (194°F).
(2) A/C is ON.
Step
1 CHECK OPERATION OF RADIATOR.
1)Run the engine at idle. (Vehicle stationary)
2)Turn the A/C switch to OFF.
3)Warm the engine coolant temperature over
96°C (205°F).
2 CHECK OPERATION OF RADIATOR.
Turn the A/C switch to ON at condition of step
1.
3 CHECK POWER SUPPLY TO SUB FAN MO-
TOR.
CAUTION:
Be careful not to overheat the engine during
repair.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from sub fan
motor.
3)Start the engine, and warm it up until engine
coolant temperature increases over 96°C
(205°F).
4)Stop the engine and turn ignition switch to
ON.
5)Measure the voltage between sub fan motor
connector and chassis ground.
Connector & terminal
(F16) No. 1 (+) — Chassis ground ( − − − − ):
4 CHECK GROUND CIRCUIT OF SUB FAN
MOTOR.
1)Turn the ignition switch to OFF.
2)Measure the resistance between sub fan
motor connector and chassis ground.
Connector & terminal
(F16) No. 3 — Chassis ground:
(F16) No. 4 — Chassis ground:
5 CHECK POOR CONTACT.
Check poor contact in sub fan motor connec-
tor.
6 CHECK MAIN FAN MOTOR.
Connect the battery positive (+) terminal to ter-
minal No. 1, and ground (−) terminal to termi-
nal No. 3 or No. 4 of sub fan motor connector.
RADIATOR SUB FAN SYSTEM
Does the radiator sub fan
rotate?
Does the radiator sub fan
rotate faster when A/C com-
pressor is operated?
Is the voltage more than 10 V? Go to step 4.
Is the resistance less than 5
Ω?
Is there poor contact in sub fan
motor connector?
Does the main fan rotate?
CO(H4DOTC)-13
Check
Go to step 2.
Radiator main fan
system is okay.
Go to step 5.
Repair the poor
contact in sub fan
motor connector.
Repair the poor
contact in sub fan
motor connector.
COOLING
Yes No
Go to step 3.
Go to step 17.
Go to step 7.
Repair the open
circuit in harness
between sub fan
motor connector
and chassis
ground.
Go to step 6.
Replace the sub
fan motor with a
new one.