Subaru 2002 IMPREZA Service Manual page 330

COOLING
B: INSPECTION
1. NON-TURBO MODEL
NOTE:
System for A/C equipped vehicles 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
1 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
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 ( − − − − ):
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:
3 CHECK POOR CONTACT.
Check poor contact in sub fan motor connec-
tor.
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.
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
(F29) No. 18 (+) — Chassis ground ( − − − − ):
RADIATOR SUB FAN SYSTEM
Is the voltage more than 10 V? Go to step 2.
Is the resistance less than 5
Ω?
Is there poor contact in sub fan
motor connector?
Does the sub fan rotate?
Is the voltage more than 10 V? Go to step 6.
CO-20
Check
Go to step 3.
Repair the poor
contact in sub fan
motor connector.
Repair the poor
contact in sub fan
motor connector.
Yes No
Go to step 5.
Repair the open
circuit in harness
between sub fan
motor connector
and chassis
ground.
Go to step 4.
Replace the sub
fan motor with a
new one.
Go to step 7.