Subaru Impreza 2002 Service Manual page 1006

Step
7 CHECK POWER SUPPLY TO MAIN FAN
RELAY1.
1)Turn the ignition switch to OFF.
2)Remove the main fan relay1 from A/C relay
holder.
3)Measure the voltage between main fan
relay1 terminal and chassis ground.
Connector & terminal
(F66) No. 26 (+) — Chassis ground ( − − − − ):
8 CHECK POWER SUPPLY TO MAIN FAN
RELAY1.
1)Turn the ignition switch to ON.
2)Measure the voltage between main fan
relay1 terminal and chassis ground.
Connector & terminal
(F66) No. 27 (+) — Chassis ground ( − − − − ):
9 CHECK 30 A FUSE.
1)Remove the 30 A fuse from A/C relay holder.
2)Check the condition of fuse.
10 CHECK POWER SUPPLY TO A/C RELAY
HOLDER 30 A FUSE TERMINAL.
Measure the voltage of harness between A/C
relay holder 30 A fuse terminal and chassis
ground.
Connector & terminal
(F27) No. 1 (+) — Chassis ground ( − − − − ):
11 CHECK FUSE.
1)Turn the ignition switch to OFF.
2)Remove the fuse No. 18 from joint box.
3)Check the condition of fuse.
12 CHECK MAIN FAN RELAY.
1)Turn the ignition switch to OFF.
2)Remove the main fan relay1.
3)Measure the resistance of main fan relay1.
Terminal
No. 26 — No. 25:
13 CHECK MAIN FAN RELAY.
1)Connect the battery to terminals No. 27 and
No. 28 of main fan relay1.
2)Measure the resistance of main fan relay1.
Terminal
No. 26 — No. 25:
14 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. 3 — (F66) No. 25:
15 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
(F66) No. 28 — (B137) No. 17:
RADIATOR MAIN FAN SYSTEM
Is the voltage more than 10 V? Go to step 8.
Is the voltage more than 10 V? Go to step 12.
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?
CO-15
Check
Replace the fuse.
circuit in harness
between 30 A fuse
and main fan relay
terminal.
Replace the fuse.
Go to step 13.
Go to step 14.
Go to step 15.
Go to step 16.
COOLING
Yes No
Go to step 9.
Go to step 11.
Go to step 10.
Repair the open
circuit in harness
between main fuse
box connector and
30 A fuse terminal.
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.