Subaru 2009 IMPREZA Service Manual page 1192

COOLING
Step
18 CHECK HARNESS BETWEEN SUB FAN RE-
LAY AND ECM.
1) Disconnect the connectors from ECM.
2) Measure the resistance between the sub
fan relay terminal and ECM connector.
Connector & terminal
(B136) No. 18 — (F27) No. 12:
19 CHECK POOR CONTACT.
Check for poor contact of ECM connector.
20 CHECK MAIN FAN RELAY 1.
1) Turn the ignition switch to OFF.
2) Remove main fan relay 1 from the main fuse
box.
3) Measure the resistance of terminal in main
fan relay 1 switch.
21 CHECK MAIN FAN RELAY 1.
1) Connect the main fan relay 1 coil side termi-
nal to the battery.
2) Measure the resistance between terminals
of main fan relay 1 switch.
22 CHECK HARNESS BETWEEN MAIN FAN
RELAY 1 AND MAIN FAN MOTOR CONNEC-
TOR.
1) Disconnect the connector from the main fan
motor.
2) Measure the resistance of the harness
between main fan relay 1 terminal and main fan
motor connector.
Connector & terminal
(F17) No. 1 — (F36) No. 6:
23 CHECK HARNESS BETWEEN MAIN FAN
RELAY 1 AND ECM.
1) Disconnect the connectors from ECM.
2) Measure the resistance between main fan
relay 1 terminal and ECM connector.
Connector & terminal
(B136) No. 29 — (B143) No. 7:
24 CHECK HARNESS BETWEEN MAIN FAN
RELAY 2 AND ECM.
Measure the resistance between main fan relay
2 terminal and ECM connector.
Connector & terminal
(B136) No. 29 — (F27) No. 22:
25 CHECK FUSE.
1) Turn the ignition switch to OFF.
2) Remove the fuse No. 2 and 26.
3) Check the condition of fuse.
26 CHECK POOR CONTACT.
Check for poor contact of ECM connector.
27 CHECK OPERATION OF RADIATOR FAN.
If the both fans do not rotate at high speed in the
condition of step 2, check whether the radiator
sub fan is rotating.
Radiator Fan System
Check
Is the resistance less than 1 ? Go to step 19.
Is there poor contact of ECM
connector?
Is the resistance 1 M or
more?
Is the resistance less than 1 ? Go to step 22.
Is the resistance less than 1 ? Go to step 23.
Is the resistance less than 1 ? Go to step 24.
Is the resistance less than 1 ? Go to step 25.
Is the fuse blown out?
Is there poor contact of ECM
connector?
Does the radiator sub fan
rotate?
CO(H4DOTC)-12
Yes No
Repair the open
circuit of harness
between sub fan
relay terminal and
ECM.
Repair the poor Check the DTC.
contact of ECM Repair the trouble
connector. cause. <Ref. to
EN(H4DOTC)(diag
)-42, Read Diag-
nostic Trouble
Code (DTC).>
Go to step 21. Replace the main
fan relay 1.
Replace the main
fan relay 1.
Repair the open
circuit of the har-
ness between
main fan relay 1
terminal and main
fan motor connec-
tor.
Repair the open
circuit of the har-
ness between
main fan relay 1
terminal and ECM.
Repair the open
circuit of the har-
ness between
main fan relay 2
terminal and ECM.
Replace the fuse. Go to step 26.
Repair the poor Repair the power
contact of ECM supply circuit to the
connector. main fuse box.
Go to step 20. Go to step 28.