Subaru Legacy IV (2008 year). Manual - part 149

EN(H4SO)(diag)-199

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK FUEL FILLER CAP.
1) Turn the ignition switch to OFF.
2) Check the fuel filler cap.

NOTE:
The DTC is stored in memory if fuel filler cap is
or was loose or if the cap chain has caught while
tightening.

Is the fuel filler cap tightened 
securely?

Go to step 2.

Tighten fuel filler 
cap securely.

2

CHECK FUEL FILLER CAP.

Is the fuel filler cap genuine?

Go to step 3.

Replace with a 
genuine fuel filler 
cap.

3

CHECK FUEL FILLER PIPE GASKET.

Is there any damage to the seal 
between fuel filler cap and fuel 
filler pipe?

Repair or replace 
the fuel filler cap 
and fuel filler pipe. 
<Ref. to 
FU(H4SO)-52, 
Fuel Filler Pipe.>

Go to step 4.

4

CHECK DRAIN VALVE.
1) Connect the delivery (test) mode connector.
2) Turn the ignition switch to ON.
3) Operate the drain valve using the Subaru 
Select Monitor.

NOTE:
The drain valve can be operated using Subaru
Select Monitor. For the procedures, refer to
“Compulsory Valve Operation Check Mode”.
<Ref. to EN(H4SO)(diag)-51, Compulsory
Valve Operation Check Mode.>

Does the drain valve operate?

Go to step 5.

Replace the drain 
valve. <Ref. to 
EC(H4SO)-16,
Drain Valve.>

5

CHECK PURGE CONTROL SOLENOID 
VALVE.
Operate the purge control solenoid valve using 
the Subaru Select Monitor.

NOTE:
Purge control solenoid valve operation can be
executed using Subaru Select Monitor. For the
procedures, refer to “Compulsory Valve Opera-
tion Check Mode”. <Ref. to EN(H4SO)(diag)-
51, Compulsory Valve Operation Check
Mode.>

Does the purge control sole-
noid valve operate?

Go to step 6.

Replace the purge 
control solenoid 
valve. <Ref. to 
EC(H4SO)-7,
Purge Control 
Solenoid Valve.>

6

CHECK PRESSURE CONTROL SOLENOID 
VALVE.
Operate the pressure control solenoid valve 
using the Subaru Select Monitor.

NOTE:
The pressure control solenoid valve operation
can be executed using the Subaru Select Mon-
itor. For the procedures, refer to “Compulsory
Valve Operation Check Mode”. <Ref. to
EN(H4SO)(diag)-51, Compulsory Valve Opera-
tion Check Mode.>

Does the pressure control sole-
noid valve operate?

Go to step 7.

Replace the pres-
sure control sole-
noid valve. <Ref. to 
EC(H4SO)-13,
Pressure Control 
Solenoid Valve.>

7

CHECK EVAPORATIVE EMISSION CON-
TROL SYSTEM LINE.
1) Turn the ignition switch to OFF.
2) Disconnect the delivery (test) mode connec-
tor.

Is there any hole of more than 
1.0 mm (0.04 in) dia. on evapo-
ration line?

Repair or replace 
the evaporation 
line. <Ref. to 
FU(H4SO)-65, 
Fuel Delivery and 
Evaporation 
Lines.>

Go to step 8.

EN(H4SO)(diag)-200

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

8

CHECK CANISTER.

Is the canister damaged or is 
there a hole of more than 
1.0 mm (0.04 in) dia. in it?

Repair or replace 
the canister. <Ref. 
to EC(H4SO)-5, 
Canister.>

Go to step 9.

9

CHECK FUEL TANK.
Remove the fuel tank. <Ref. to FU(H4SO)-45, 
Fuel Tank.>

Is the fuel tank damaged or is 
there any hole of more than 
1.0 mm (0.04 in) dia. in it?

Repair or replace 
the fuel tank. <Ref. 
to FU(H4SO)-45, 
Fuel Tank.>

Go to step 10.

10

CHECK ANY OTHER MECHANICAL TROU-
BLE IN EVAPORATIVE EMISSION CON-
TROL SYSTEM.

Is there any hole of more than 
1.0 mm (0.04 in) dia., crack, 
clogging, or disconnections, 
bend, misconnection of hoses 
or pipes in evaporative emis-
sion control system?

Repair or replace 
the hoses or pipes.

Repair the poor 
contact of ECM 
connector.

Step

Check

Yes

No

EN(H4SO)(diag)-201

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BG:DTC P0447 EVAPORATIVE EMISSION CONTROL SYSTEM VENT CONTROL 

CIRCUIT OPEN

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4SO)-117, DTC P0447 EVAPORATIVE EMISSION CONTROL
SYSTEM VENT CONTROL CIRCUIT OPEN, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4SO)(diag)-50,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4SO)(diag)-41, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

EN-06841

16

10 11 12 13 14 15

25

24

30

9

8

7

17 18 19 20
28

21 22 23

29

32

31

1

2

3

4

5

6

27

26

33 34 35

B136

17

B97

R1

1

2

7

R144

R15

R213

R46

R67

ECM

B136

SBF-7

5
3

6
4

2
1

B47

6

1

E

DRAIN
VALVE

MAIN RELAY

BATTERY

B47

3

4

1

2

5

6

1 2

3

4 5 6 7 8

1

2

3 4 5 6

R67

R213

B97

14

1 2 3 4

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20

1 2

R144

EN(H4SO)(diag)-202

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK OUTPUT SIGNAL OF ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B136) No. 17 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the poor 
contact of ECM 
connector.

Go to step 2.

2

CHECK HARNESS BETWEEN ECM AND 
DRAIN VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from the ECM 
and drain valve.
3) Measure the resistance between the drain 
valve connector and chassis ground.

Connector & terminal

(R144) No. 2 — Chassis ground:

Is the resistance 1 M

: or 

more?

Go to step 3.

Repair the ground 
short circuit of har-
ness between 
ECM and drain 
valve connector.

3

CHECK HARNESS BETWEEN ECM AND 
DRAIN VALVE.
Measure the resistance of harness between 
ECM and drain valve connector.

Connector & terminal

(B136) No. 17 — (R144) No. 2:

Is the resistance less than 1 

:? Go to step 4.

Repair the harness 
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and drain
valve connector
• Poor contact of
coupling connector

4

CHECK DRAIN VALVE.
Measure the resistance between drain valve 
terminals.

Terminals

No. 1 — No. 2:

Is the resistance between 10 — 
100 

:?

Go to step 5.

Replace the drain 
valve. <Ref. to 
EC(H4SO)-16,
Drain Valve.>

5

CHECK POWER SUPPLY TO DRAIN VALVE.
1) Turn the ignition switch to ON.
2) Measure the voltage between drain valve 
and chassis ground.

Connector & terminal

(R144) No. 1 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair poor con-
tact of the drain 
valve connector.

Repair the harness 
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
main relay connec-
tor and drain valve
connector
• Poor contact of
coupling connector
• Poor contact of
main relay connec-
tor