Subaru Impreza 2004 - Radiator Sub Fan System

CO(H4SO)-10
COOLING
Radiator Sub Fan System
B: INSPECTION
NOTE:
System for A/C equipped models only.
DETECTING CONDITION:
Condition (1):
• Engine coolant temperature is below 95°C (203°F).
• A/C switch is turned ON.
• Vehicle speed is below 19 km/h (12 MPH).
Condition (2):
• Engine coolant temperature is above 100°C (212°F).
• A/C switch is turned OFF.
• Vehicle speed is below 19 km/h (12 MPH).
TROUBLE SYMPTOM:
Radiator sub fan does not rotate under conditions (1) and (2) above.
Step Check Yes No
1 CHECK POWER SUPPLY TO SUB FAN MO-
TOR.
C
AUTI
O
N:
Be careful not to overheat the engine during
repair.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from sub fan motor
and main fan motor.
3)Start the engine, and warm it up until engine
coolant temperature increases over 100°C
(212°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. 2 (+) — Chassis ground (
−
−−
−
):
Is the voltage more than 10 V? Go to step 2. Go to step 5.
2 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. 1 — Chassis ground:
Is the resistance less than 5
Ω?
Go to step 3. Repair the open
circuit in harness
between sub fan
motor connector
and chassis
ground.
3 CHECK POOR CONTACT.
Check poor contact in sub fan motor connec-
tor.
Is there poor contact in sub fan
motor connector?
Repair the poor
contact in sub fan
motor connector.
Go to step 4.
4 CHECK SUB FAN MOTOR.
Connect the battery positive (+) terminal to ter-
minal No. 2, and ground (−) terminal to termi-
nal No. 1 of sub fan motor connector.
Does the sub fan rotate? Repair the poor
contact in sub fan
motor connector.
Replace the sub
fan motor with a
new one.
5 CHECK POWER SUPPLY TO SUB FAN RE-
LAY.
1)Turn the ignition switch to OFF.
2)Remove the sub fan relay from A/C relay
holder.
3)Measure the voltage between sub fan relay
terminal and chassis ground.
Connector & terminal
(F27) No. 18 (+) — Chassis ground (
−
−−
−
):
Is the voltage more than 10 V? Go to step 6. Go to step 7.