Subaru 2002 IMPREZA Service Manual page 331

Step
6 CHECK POWER SUPPLY TO SUB FAN RE-
LAY.
1)Turn the ignition switch to ON.
2)Measure the voltage between sub fan relay
terminal and chassis ground.
Connector & terminal
(F29) No. 20 (+) — Chassis ground ( − − − − ):
7 CHECK 20 A FUSE.
1)Remove the 20 A fuse from A/C relay holder.
2)Check the condition of fuse.
8 CHECK POWER SUPPLY TO A/C RELAY
HOLDER 20 A FUSE TERMINAL.
Measure the voltage of harness between A/C
relay holder 20 A fuse terminal and chassis
ground.
Connector & terminal
(F27) No. 3 (+) — Chassis ground ( − − − − ):
9 CHECK FUSE.
1)Turn the ignition switch to OFF.
2)Remove the fuse No. 17 from joint box.
3)Check the condition of fuse.
10 CHECK SUB FAN RELAY.
1)Turn the ignition switch to OFF.
2)Measure the resistance of sub fan relay.
Terminal
No. 17 — No. 18:
11 CHECK SUB FAN RELAY.
1)Connect the battery to terminals No. 20 and
No. 19 of sub fan relay.
2)Measure the resistance of sub fan relay.
Terminal
No. 17 — No. 18:
12 CHECK HARNESS BETWEEN SUB FAN RE-
LAY TERMINAL AND SUB FAN MOTOR
CONNECTOR.
Measure the resistance of harness between
sub fan motor connector and sub fan relay ter-
minal.
Connector & terminal
(F16) No. 2 — (F29) No. 17:
13 CHECK HARNESS BETWEEN SUB FAN RE-
LAY AND ECM.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from ECM.
3)Measure the resistance of harness between
sub fan relay connector and ECM connector.
Connector & terminal
(F29) No. 19 — (B134) No. 12:
14 CHECK POOR CONTACT.
Check poor contact in connector between sub
fan and ECM.
NOTE:
Inspection by your Subaru distributor is required,
because probable cause is deterioration of multiple
parts.
RADIATOR SUB FAN SYSTEM
Is the voltage more than 10 V? Go to step 10.
Is the fuse blown-out?
Is the voltage more than 10 V? Repair the open
Is the fuse blown-out?
Is the resistance more than 1
MΩ?
Is the resistance less than 1
Ω?
Is the resistance less than 1
Ω?
Is the resistance less than 1
Ω?
Is there poor contact in con-
nector between sub fan motor
and ECM?
CO-21
Check
Replace the fuse.
circuit in harness
between 20 A fuse
and sub fan relay
terminal.
Replace the fuse.
Go to step 11.
Go to step 12.
Go to step 13.
Go to step 14.
Repair the poor
contact connector.
COOLING
Yes No
Go to step 9.
Go to step 8.
Repair the open
circuit in harness
between main fuse
box connector and
20 A fuse terminal.
Repair the open
circuit in harness
between sub fan
relay and ignition
switch.
Replace the sub
fan relay.
Replace the sub
fan relay.
Repair the open
circuit in harness
between sub fan
motor and sub fan
relay connector.
Repair the open
circuit in harness
between sub fan
relay and ECM.
Contact with your
Subaru distributor
service.