Subaru Legacy IV (2008 year). Manual - part 569

EN(H6DO)(diag)-249

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CI: DTC P0453 EVAPORATIVE EMISSION CONTROL SYSTEM PRESSURE 

SENSOR HIGH INPUT

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H6DO)-132, DTC P0453 EVAPORATIVE EMISSION CONTROL
SYSTEM PRESSURE SENSOR HIGH INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H6DO)(diag)-52,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H6DO)(diag)-44, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

B83

3

1

2

22

32

30

ECM

B135

R47

R213

R15

R1

B97

B97

1 2 3

R47

B135

7

4

6

6

13

17

B83

R213

FUEL
TANK
PRESSURE
SENSOR

1 2 3 4

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20

3 4

5 6

1 2

7 8

1 2

3

4 5 6 7 8

:TERMINAL No. OPTIONAL 
 ARRANGEMENT

*

*

*

5

6

7

8

2

1

9

4

3

10

24

22 23

25

11 12 13 14 15

26 27

28

16 17 18 19

20 21

29 30 31

32 33

34 35

EN-05233

EN(H6DO)(diag)-250

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK CURRENT DATA.
1) Turn the ignition switch to ON.
2) Read the data of fuel tank pressure sensor 
signal using the Subaru Select Monitor or gen-
eral scan tool.

NOTE:
• SUBARU SELECT MONITOR
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H6DO)(diag)-34, Subaru Select Moni-
tor.>
• General Scan Tool
For detailed operation procedures, refer to the
general scan tool operation manual.

Is the measured value 7.98 kPa 
(59.85 mmHg, 2.357 inHg) or 
more?

Go to step 2.

Even if DTC is 
detected, the cir-
cuit has returned to 
a normal condition 
at this time. Repro-
duce the failure, 
and then perform 
the diagnosis 
again.

NOTE:
In this case, tem-
porary poor con-
tact of connector
may be the cause.

2

CHECK HARNESS BETWEEN ECM AND 
FUEL TANK PRESSURE SENSOR CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the fuel tank 
pressure sensor.
3) Turn the ignition switch to ON.
4) Read the data of fuel tank pressure sensor 
signal using the Subaru Select Monitor or gen-
eral scan tool.

NOTE:
• SUBARU SELECT MONITOR
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H6DO)(diag)-34, Subaru Select Moni-
tor.>
• General Scan Tool
For detailed operation procedures, refer to the
general scan tool operation manual.

Is the measured value 7.98 kPa 
(59.85 mmHg, 2.357 inHg) or 
more?

Repair the short 
circuit to power 
supply in the har-
ness between the 
ECM and fuel tank 
pressure sensor 
connector.

Go to step 3.

3

CHECK HARNESS BETWEEN ECM AND 
FUEL TANK PRESSURE SENSOR CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness between 
fuel tank pressure sensor connector and engine 
ground.

Connector & terminal

(R47) No. 1 — Engine ground:

Is the resistance less than 5 

:? Go to step 4.

Repair the harness 
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and fuel tank
pressure sensor
connector
• Poor contact in
ECM connector
• Poor contact of
coupling connector

4

CHECK POOR CONTACT.
Check for poor contact of the fuel tank pressure 
sensor connector.

Is there poor contact in fuel tank 
pressure sensor connector?

Repair the poor 
contact in the fuel 
tank pressure sen-
sor connector.

Replace the fuel 
tank pressure sen-
sor. <Ref. to 
EC(H6DO)-12,
Fuel Tank Pres-
sure Sensor.>

EN(H6DO)(diag)-251

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CJ:DTC P0456 EVAPORATIVE EMISSION CONTROL SYSTEM LEAK DETECTED 

(VERY SMALL LEAK)

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H6DO)-133, DTC P0456 EVAPORATIVE EMISSION CONTROL
SYSTEM LEAK DETECTED (VERY SMALL LEAK), Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
• Fuel odor
• There is a hole of more than 0.5 mm (0.020 in) dia. in evaporation system or fuel tank.

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H6DO)(diag)-52,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H6DO)(diag)-44, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

SBF-7

E4

B47

E

5
3

6
4

2
1

ECM

2

1

C17

C28

D29

R15

R213

R68

R144

R1

B97

14

7

2

2

1

1

15

1

5

PURGE CONTROL

SOLENOID VALVE

DRAIN VALVE

PRESSURE CONTROL 

SOLENOID VALVE

MAIN RELAY

R68

E4

1 2

B47

3

4

1

2

5

6

R144

1 2

R213

1 2

3

4 5 6 7 8

R67

1

2

3 4 5 6

B97

1 2 3 4

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20

R46

R67

6

BATTERY

B21

E2

E76

E77

41

48

2

10

E77

1

3

4 5 6

2

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

C:

B137

5

6

7

8

2

1

9

4

3

10

22 23

11 12 13 14 15

24 25

26

16 17

18 19 20 21

27

28 29

30 31

D:

B136

C:

B137

D:

EN-06878

B21

1 2 3 4 5 6 7 8 9 10 11

12 13 14 15 16 17 18 19 20 21 22
23 24 25 26 27 28 29 30 31 32 33

34

35

42

43

36

37

38

39

48

49

50

51

52

53

54

40

41

44

45

46

47

EN(H6DO)(diag)-252

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(H6DO)-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:
Drain valve can be operated using the Subaru
Select Monitor. For the procedures, refer to
“Compulsory Valve Operation Check Mode”.
<Ref. to EN(H6DO)(diag)-53, Compulsory
Valve Operation Check Mode.>

Does the drain valve operate?

Go to step 5.

Replace the drain 
valve. <Ref. to 
EC(H6DO)-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(H6DO)(diag)-
53, 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(H6DO)-8,
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(H6DO)(diag)-53, 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(H6DO)-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 
0.5 mm (0.020 in) dia. on evap-
oration line?

Repair or replace 
the evaporation 
line. <Ref. to 
FU(H6DO)-65,
Fuel Delivery and 
Evaporation 
Lines.>

Go to step 8.