Subaru Impreza 2003 Service Manual page 1119

Step
24 CHECK FUSE.
1)Turn the ignition switch to OFF.
2)Remove the fuse No. 18 from joint box.
3)Check the condition of fuse.
25 CHECK MAIN FAN RELAY.
1)Turn the ignition switch to OFF.
2)Remove the main fan relay2.
3)Measure the resistance of main fan relay2.
Terminals
No. 23 — No. 24:
26 CHECK MAIN FAN RELAY.
1)Connect the battery to terminals No. 21 and
No. 22 of main fan relay1.
2)Measure the resistance of main fan relay2.
Terminals
No. 23 — No. 24:
27 CHECK HARNESS BETWEEN MAIN FAN
RELAY TERMINAL AND MAIN FAN MOTOR
CONNECTOR.
Measure the resistance of harness between
main fan motor connector and main fan relay
terminal.
Connector & terminal
(F17) No. 2 — (F27) No. 24:
28 CHECK HARNESS BETWEEN MAIN FAN
RELAY AND ECM.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from ECM.
3)Measure the resistance of harness between
main fan relay connector and ECM connector.
Connector & terminal
(F27) No. 22 — (B84) No. 28:
29 CHECK POOR CONTACT.
Check poor contact in connector between main
fan and ECM.
RADIATOR MAIN FAN SYSTEM
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 main fan motor
and ECM?
CO(H4DOTC)-11
Check
Replace the fuse.
Go to step 26.
Go to step 27.
Go to step 28.
Go to step 29.
Repair the poor
contact connector.
COOLING
Yes No
Repair the open
circuit in harness
between main fan
relay and ignition
switch.
Replace the main
fan relay.
Replace the main
fan relay.
Repair the open
circuit in harness
between main fan
motor connector
and main fan relay
terminal.
Repair the open
circuit in harness
between main fan
relay and ECM.
Record the DTC.
Repair the trouble
cause. <Ref. to
EN(H4DOTC)-39,
Read Diagnostic
Trouble Code
(DTC).>