Subaru Impreza 2003 Service Manual page 1123

Step
16 CHECK POOR CONTACT.
Check poor contact in connector between sub
fan and ECM.
17 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.
3)Start the engine, and warm it up until engine
coolant temperature increases over 96°C
(205°F).
4)Turn the A/C switch ON.
5)Measure the voltage while A/C compressor
is rotating.
6)Measure the voltage between sub fan motor
connector and chassis ground.
Connector & terminal
(F16) No. 2 (+) — Chassis ground ( − − − − ):
18 CHECK POOR CONTACT.
Check poor contact in sub fan motor connec-
tor.
19 CHECK SUB FAN MOTOR.
Connect the battery positive (+) terminal to ter-
minal No. 2, and ground (−) terminal to termi-
nal No. 3 or No. 4 of sub fan motor connector.
20 CHECK POWER SUPPLY TO SUB FAN
RELAY2.
1)Turn the ignition switch to OFF.
2)Remove the sub fan relay2 from A/C relay
holder.
3)Measure the voltage between sub fan relay2
terminal and chassis ground.
Connector & terminal
(F27) No. 18 (+) — Chassis ground ( − − − − ):
21 CHECK POWER SUPPLY TO SUB FAN
RELAY2.
1)Turn the ignition switch to ON.
2)Measure the voltage between sub fan relay2
terminal and chassis ground.
Connector & terminal
(F27) No. 20 (+) — Chassis ground ( − − − − ):
22 CHECK 30 A FUSE.
1)Remove the 30 A fuse from A/C relay holder.
2)Check the condition of fuse.
23 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. 3 (+) — Chassis ground ( − − − − ):
RADIATOR SUB FAN SYSTEM
Is there poor contact in con-
nector between sub fan motor
and ECM?
Is the voltage more than 10 V? Go to step 18.
Is there poor contact in sub fan
motor connector?
Does the main fan rotate?
Is the voltage more than 10 V? Go to step 21.
Is the voltage more than 10 V? Go to step 23.
Is the fuse blown out?
Is the voltage more than 10 V? Repair the open
CO(H4DOTC)-15
Check
Repair the poor
contact connector.
Repair the poor
contact in sub fan
motor connector.
Repair the poor
contact in sub fan
motor connector.
Replace the fuse.
circuit in harness
between 30 A fuse
and sub fan relay
terminal.
COOLING
Yes No
Record the DTC.
Repair the trouble
cause. <Ref. to
EN(H4DOTC)-39,
Read Diagnostic
Trouble Code
(DTC).>
Go to step 20.
Go to step 19.
Replace the sub
fan motor with a
new one.
Go to step 22.
Go to step 24.
Go to step 23.
Repair the open
circuit in harness
between sub fuse
box connector and
30 A fuse terminal.