Subaru Legacy IV (2008 year). Manual — part 577

EN(H6DO)(diag)-281

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DG:DTC P1400 FUEL TANK PRESSURE CONTROL SOLENOID VALVE CIRCUIT

LOW

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H6DO)-169, DTC P1400 FUEL TANK PRESSURE CONTROL
SOLENOID VALVE CIRCUIT LOW, 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:

SBF-7

R68

B47

R67

B97

R213

1 2

3

4

1

2

5

6

R68

R213

R15

R67

R46

R1

B97

B47

E

28

5
3

6
4

2
1

1

2

7

15

6

5

B136

B136

ECM

MAIN RELAY

PRESSURE
CONTROL
SOLENOID
VALVE

BATTERY

1

2

3 4 5 6

1 2 3 4

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20

1 2

3

4 5 6 7 8

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

EN-05238

EN(H6DO)(diag)-282

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. 28 (+) — 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
PRESSURE CONTROL SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the ECM
and pressure control solenoid valve.
3) Measure the resistance between pressure
control solenoid valve and chassis ground.

Connector & terminal

(R68) 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 pressure
control solenoid
valve connector.

3

CHECK HARNESS BETWEEN ECM AND
PRESSURE CONTROL SOLENOID VALVE.
Measure the resistance of harness between
ECM and pressure control solenoid valve con-
nector.

Connector & terminal

(B136) No. 28 — (R68) 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 pressure
control solenoid
valve connector
• Poor contact of
coupling connector

4

CHECK PRESSURE CONTROL SOLENOID
VALVE.
Measure the resistance between pressure con-
trol solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance between 10 —
100

:?

Go to step 5.

Replace the pres-
sure control sole-
noid valve. <Ref. to
EC(H6DO)-13,
Pressure Control
Solenoid Valve.>

5

CHECK POWER SUPPLY TO THE PRES-
SURE CONTROL SOLENOID VALVE.
1) Turn the ignition switch to ON.
2) Measure the voltage between pressure con-
trol solenoid valve and chassis ground.

Connector & terminal

(R68) No. 1 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the poor
contact of pressure
control solenoid
valve connector.

Repair the harness
and connector.

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

EN(H6DO)(diag)-283

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

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

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H6DO)-171, 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(H6DO)(diag)-52,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H6DO)(diag)-44, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

SBF-7

R68

B47

R67

B97

R213

1 2

3

4

1

2

5

6

R68

R213

R15

R67

R46

R1

B97

B47

E

28

5
3

6
4

2
1

1

2

7

15

6

5

B136

B136

ECM

MAIN RELAY

PRESSURE
CONTROL
SOLENOID
VALVE

BATTERY

1

2

3 4 5 6

1 2 3 4

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20

1 2

3

4 5 6 7 8

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

EN-05238

EN(H6DO)(diag)-284

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(H6DO)-13,
Pressure Control
Solenoid Valve.>

Repair the poor
contact of ECM
connector.