Subaru Legacy IV (2008 year). Manual — part 125

EN(H4SO)(diag)-103

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

I:

DTC P0076 INTAKE VALVE CONTROL SOLENOID CIRCUIT LOW (BANK 1)

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4SO)-23, DTC P0076 INTAKE VALVE CONTROL SOLENOID
CIRCUIT LOW (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
Improper idling

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-05704

B21

E2

B137

E67

24

2

1

24

23

E67

B21

1 2

25

B137

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

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

ECM

OIL SWITCHING SOLENOID VALVE RH

EN(H4SO)(diag)-104

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK HARNESS BETWEEN ECM AND OIL
SWITCHING SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from the ECM
and oil switching solenoid valve.
3) Measure the resistance of harness between
ECM and oil switching solenoid valve.

Connector & terminal

(B137) No. 25 — (E67) No. 1:
(B137) No. 24 — (E67) No. 2:

Is the resistance less than 1

:? Go to step 2.

Repair the harness
and connector.

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

2

CHECK HARNESS BETWEEN ECM AND OIL
SWITCHING SOLENOID VALVE.
Measure the resistance between ECM and
chassis ground.

Connector & terminal

(B137) No. 25 — Chassis ground:
(B137) No. 24 — Chassis ground:

Is the resistance 1 M

: or

more?

Go to step 3.

Repair the ground
short circuit of har-
ness between
ECM and oil
switching solenoid
valve connector.

3

CHECK OIL SWITCHING SOLENOID VALVE.
Measure the resistance between oil switching
solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance between 6 —
12

:?

Repair the poor
contact of ECM
and oil switching
solenoid valve con-
nector.

Replace the oil
switching solenoid
valve. <Ref. to
ME(H4SO)-89, Oil
Switching Solenoid
Valve.>

EN(H4SO)(diag)-105

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

J: DTC P0077 INTAKE VALVE CONTROL SOLENOID CIRCUIT HIGH (BANK 1)

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4SO)-24, DTC P0077 INTAKE VALVE CONTROL SOLENOID
CIRCUIT HIGH (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
Improper idling

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-05704

B21

E2

B137

E67

24

2

1

24

23

E67

B21

1 2

25

B137

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

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

ECM

OIL SWITCHING SOLENOID VALVE RH

EN(H4SO)(diag)-106

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK HARNESS BETWEEN ECM AND OIL
SWITCHING SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from the ECM
and oil switching solenoid valve.
3) Measure the voltage between ECM and
chassis ground.

Connector & terminal

(B137) No. 25 (+) — Chassis ground (–):
(B137) No. 24 (+) — Chassis ground (–):

Is the voltage less than 1 V?

Go to step 2.

Repair the short
circuit of harness
to power supply
between ECM and
oil switching sole-
noid valve connec-
tor.

2

CHECK HARNESS BETWEEN ECM AND OIL
SWITCHING SOLENOID VALVE.
Measure the resistance of harness between
ECM and oil switching solenoid valve connec-
tor.

Connector & terminal

(B137) No. 25 — (E67) No. 1:
(B137) No. 24 — (E67) No. 2:

Is the resistance less than 1

:? Go to step 3.

Repair the harness
and connector.

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

3

CHECK OIL SWITCHING SOLENOID VALVE.
Measure the resistance between oil switching
solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance between 6 —
12

:?

Repair the poor
contact of ECM
and oil switching
solenoid valve con-
nector.

Replace the oil
switching solenoid
valve. <Ref. to
ME(H4SO)-89, Oil
Switching Solenoid
Valve.>