Subaru Legacy IV (2008 year). Service manual — part 81

CO(H4SO)-10

Radiator Fan System

COOLING

9

CHECK HARNESS BETWEEN SUB FAN RE-
LAY TERMINAL AND SUB FAN MOTOR
CONNECTOR.
1) Disconnect the connector from the sub fan
motor.
2) Measure the resistance of harness between
the sub fan relay terminal and sub fan motor
connector.

Connector & terminal

(F16) No. 2 — (F27) No. 11:

Is the resistance less than 1

:? Go to step 10.

Repair the open
circuit of harness
between sub fan
relay terminal and
sub fan motor con-
nector.

10

CHECK HARNESS BETWEEN SUB FAN MO-
TOR CONNECTOR AND MAIN FAN RELAY 2
CONNECTOR.
1) Remove the main fan relay 2 from the relay
holder.
2) Measure the resistance of harness between
sub fan motor connector and main fan relay 2
connector.

Connector & terminal

(F16) No. 1 — (F27) No. 18:

Is the resistance less than 1

:? Go to step 11.

Repair the open
circuit of the har-
ness between sub
fan motor connec-
tor and main fan
relay 2 connector.

11

CHECK POOR CONTACT.
Check poor contact of sub fan motor connector.

Is there poor contact in the sub
fan motor connector?

Repair the poor
contact of sub fan
motor connector.

Go to step 12.

12

CHECK SUB FAN MOTOR.
Connect the battery positive (+) terminal to ter-
minal No. 2 of the sub fan motor, and the ground
(–) terminal to terminal No. 1.

Does the radiator sub fan
rotate?

Go to step 13.

Replace the sub
fan motor. <Ref. to
CO(H4SO)-26,
Radiator Sub Fan
and Fan Motor.>

13

CHECK MAIN FAN RELAY 2.
Measure the resistance of main fan relay 2.

Terminals

No. 21 — No. 18:

Is the resistance less than 1

:? Go to step 14.

Replace the main
fan relay 2. <Ref. to
AC-41, Relay and
Fuse.>

14

CHECK HARNESS BETWEEN MAIN FAN
RELAY 2 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 2 terminal and main fan
motor connector.

Connector & terminal

(F17) No. 2 — (F27) No. 21:

Is the resistance less than 1

:? Go to step 15.

Repair the open
circuit of the har-
ness between
main fan relay 2
terminal and main
fan motor connec-
tor.

15

CHECK MAIN FAN MOTOR AND GROUND
CIRCUIT.
Measure the resistance between main fan
motor connector and chassis ground.

Connector & terminal

(F17) No. 1 — Chassis ground:

Is the resistance less than 5

:? Go to step 16.

Repair the open
circuit of the har-
ness between
main fan motor
connector and
chassis ground.

16

CHECK POOR CONTACT.
Check poor contact of main fan motor connec-
tor.

Is there poor contact in the
main fan motor connector?

Repair the poor
contact of main fan
motor connector.

Go to step 17.

17

CHECK MAIN FAN MOTOR.
Connect the battery positive (+) terminal to ter-
minal No. 2 of the main fan motor, and the
ground (–) terminal to terminal No. 1.

Does the radiator main fan
rotate?

Go to step 18.

Replace the main
fan motor. <Ref. to
CO(H4SO)-24,
Radiator Main Fan
and Fan Motor.>

Step

Check

Yes

No

CO(H4SO)-11

Radiator Fan System

COOLING

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:

Is the resistance less than 1

:? Go to step 19.

Repair the open
circuit of harness
between sub fan
relay terminal and
ECM.

19

CHECK POOR CONTACT.
Check for poor contact of the ECM connector.

Is there poor contact in ECM
connector?

Repair the poor
contact of ECM
connector.

Check the DTC.
Repair the trouble
cause. <Ref. to
EN(H4SO)(diag)-
40, Read Diagnos-
tic Trouble Code
(DTC).>

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.

Is the resistance 1 M

: or

more?

Go to step 21.

Replace the main
fan relay 1. <Ref. to
AC-41, Relay and
Fuse.>

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.

Is the resistance less than 1

:? Go to step 22.

Replace the main
fan relay 1. <Ref. to
AC-41, Relay and
Fuse.>

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. 2 — (F36) No. 6:

Is the resistance less than 1

:? Go to step 23.

Repair the open
circuit of the har-
ness between
main fan relay 1
terminal and main
fan motor connec-
tor.

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:

Is the resistance less than 1

:? Go to step 24.

Repair the open
circuit of the har-
ness between
main fan relay 1
terminal and ECM.

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:

Is the resistance less than 1

:? Go to step 25.

Repair the open
circuit of the har-
ness between
main fan relay 2
terminal and ECM.

25

CHECK FUSE.
1) Turn the ignition switch to OFF.
2) Remove the fuse No. 4 and 26.
3) Check the condition of fuse.

Is the fuse blown out?

Replace the fuse.

Go to step 26.

26

CHECK POOR CONTACT.
Check for poor contact of the ECM connector.

Is there poor contact in ECM
connector?

Repair the poor
contact of ECM
connector.

Repair the power
supply circuit to the
main fuse box.

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.

Does the radiator sub fan
rotate?

Go to step 20.

Go to step 28.

Step

Check

Yes

No

CO(H4SO)-12

Radiator Fan System

COOLING

28

CHECK GROUND CIRCUIT OF MAIN FAN
RELAY 2.
1) Remove the main fan relay 2 from A/C relay
holder.
2) Measure the resistance between main fan
relay 2 terminal and chassis ground.

Connector & terminal

(F27) No. 19 — Chassis ground:

Is the resistance less than 1

:? Go to step 29.

Repair the open
circuit of harness
between main fan
relay 2 and chassis
ground.

29

CHECK POWER SUPPLY TO MAIN FAN RE-
LAY 2.
1) Turn the ignition switch to ON.
2) Measure the voltage between main fan relay
2 terminal and chassis ground.

Connector & terminal

(F27) No. 20 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step 30.

Repair the power
supply line.

30

CHECK MAIN FAN RELAY 2.
1) Turn the ignition switch to OFF.
2) Remove the main fan relay 2.
3) Measure the resistance of main fan relay 2.

Terminals

(F27) No. 18 — (F27) No. 19:

Is the resistance 1 M

: or

more?

Go to step 31.

Replace the main
fan relay 2. <Ref. to
AC-41, Relay and
Fuse.>

31

CHECK MAIN FAN RELAY 2.
1) Connect the battery to terminals No. 20 and
No. 22 of the main fan relay 2.
2) Measure the resistance of main fan relay 2.

Terminals

(F27) No. 18 — (F27) No. 19:

Is the resistance less than 1

:? Go to step 23.

Replace the main
fan relay 2. <Ref. to
AC-41, Relay and
Fuse.>

Step

Check

Yes

No

CO(H4SO)-13

Engine Coolant

COOLING

3. Engine Coolant

A: REPLACEMENT

1. DRAINING OF ENGINE COOLANT

1) Set the vehicle on a lift.
2) Lift up the vehicle.
3) Remove the under cover.
4) Remove the drain plug (A) to drain engine cool-
ant into container.

NOTE:
Remove the radiator cap so that engine coolant will
drain faster.

5) Install the drain plug.
6) Install the under cover.

2. FILLING OF ENGINE COOLANT

1) Pour cooling system conditioner through the fill-
er neck.

Cooling system protective agent:

Refer to “SPECIFICATION” for the cooling
system protective agent. <Ref. to CO(H4SO)-
2, SPECIFICATION, General Description.>

2) Pour engine coolant into the radiator up to the
filler neck position.

Recommended engine coolant:

Refer to “SPECIFICATION” for the recom-
mended engine coolant. <Ref. to CO(H4SO)-
2, SPECIFICATION, General Description.>

Amount of engine coolant:

Refer to “SPECIFICATION” for the amount of
engine coolant. <Ref. to CO(H4SO)-2, SPECI-
FICATION, General Description.>

Engine coolant concentration:

Refer to “ADJUSTMENT” for the engine cool-
ant concentration. <Ref. to CO(H4SO)-14,
ADJUSTMENT, Engine Coolant.>

NOTE:
The SUBARU Super Coolant containing anti-
freeze and anti-rust agents is especially made for
SUBARU engine, which has an aluminum cylinder
block. Always use SUBARU Super Coolant since
other coolants may cause corrosion.

3) Fill engine coolant into the reservoir tank up to
“FULL” level.

4) Close the radiator cap and start the engine.
Race 5 to 6 times at 3,000 rpm or less, then stop
the engine. (Complete this operation within 40 sec-
onds.)
5) Wait for one minute after the engine stops, open
the radiator cap. If the engine coolant level drops,
add engine coolant into radiator up to the filler neck
position.
6) Perform the procedures 4) and 5) again.
7) Attach the radiator cap and reservoir tank cap
properly.
8) Start the engine and operate the heater at max-
imum hot position and the blower speed setting to
“LO”
9) Run the engine at 2,000 rpm or less until radiator
fan starts and stops.

NOTE:
Be careful with the engine coolant temperature
gauge to prevent overheating.
10) Stop the engine and wait until the engine cool-
ant temperature drops to 30°C (86°F) or less.
11) Open the radiator cap. If the engine coolant lev-
el drops, add engine coolant into radiator up to the
filler neck position.
12) Attach the radiator cap correctly.
13) Set the heater setting to maximum hot position
and the blower speed setting to “LO” and start the
engine. Perform racing at 3,000 rpm or less. If the
flowing sound is heard at this time, perform the pro-
cedures from 9) again.

CO-02096

(A)

CO-00269

FULL

FULL

LOW

LOW