Subaru Legacy IV (2008 year). Manual - part 161

EN(H4SO)(diag)-247

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CL:DTC P1420 FUEL TANK PRESSURE CONTROL SOL. VALVE CIRCUIT HIGH

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H4SO)-163, DTC P1420 FUEL TANK PRESSURE CONTROL
SOL. VALVE CIRCUIT HIGH, 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-06840

5
3

6
4

2
1

B47

SBF-7

E4

1

2

E2

B21

41

48

D29

R68

1

2

R213

R15

1

5

R1

B97

14

15

R67

R46

7

6

C17

C28

R144

1

2

B136

C:

B137

D:

3

1

2

4

5

6

B47

R213

E

PURGE CONTROL 

SOLENOID VALVE

ECM

DRAIN VALVE

PRESSURE CONTROL

SOLENOID VALVE

MAIN RELAY

BATTERY

B21

E4

1 2

1 2 3 4

12 13 14 15

5 6 7 8

16 17 18 19

9 10 11

20 21 22

23 24 25 26 27 28 29 30 31 32 33

35

34

37

36

39

38

41

40

43

42

44

45

47

46

49

48

51

50

53

52

54

1 2

3

4 5 6 7 8

1 2

R68

1 2

B97

R144

R67

1

2

3 4 5 6

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:

1 2 3 4

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20

EN(H4SO)(diag)-248

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK HARNESS BETWEEN ECM AND 
PRESSURE CONTROL SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the ECM 
and pressure control solenoid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B136) No. 28 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the short 
circuit to power 
supply in the har-
ness between the 
ECM and pressure 
control solenoid 
valve connector.

Go to step 2.

2

CHECK PRESSURE CONTROL SOLENOID 
VALVE.
1) Turn the ignition switch to OFF.
2) Measure the resistance between pressure 
control solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance less than 1 

:? Replace the pres-

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

Repair the poor 
contact of ECM 
connector.

EN(H4SO)(diag)-249

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CM:DTC P1443 VENT CONTROL SOLENOID VALVE FUNCTION PROBLEM

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4SO)-165, DTC P1443 VENT CONTROL SOLENOID VALVE
FUNCTION PROBLEM, Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
Improper fuel supply

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)-250

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed?

Check the appro-
priate DTC using 
the “List of Diag-
nostic Trouble 
Code (DTC)”. 
<Ref. to 
EN(H4SO)(diag)-
80, List of Diagnos-
tic Trouble Code 
(DTC).>

Go to step 2.

2

CHECK DRAIN HOSE.
Check the drain hose for clogging.

Is there clogging in the drain 
hose?

Replace the drain 
hose.

Go to step 3.

3

CHECK DRAIN VALVE OPERATION.
1) Turn the ignition switch to OFF.
2) Connect the delivery (test) mode connector 
at the lower portion of instrument panel (on the 
driver’s side).
3) Turn the ignition switch to ON.
4) Operate the drain valve.

NOTE:
Drain valve can be operated using the 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?

Repair the poor 
contact of ECM 
connector.

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