Subaru Legacy IV (2008 year). Service manual — part 337

EN(H4DOTC)(diag)-169

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AR:DTC P0246 TURBO/SUPER CHARGER WASTEGATE SOLENOID “A” HIGH

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-79, DTC P0246 TURBO/SUPER CHARGER WASTE-
GATE SOLENOID “A” HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
Poor driving performance

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
52, OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-43, PRO-
CEDURE, Inspection Mode.>.
WIRING DIAGRAM:

EN-05674

1

2

7

8 9

5

6

3

4

10 11 12

19 20 21

29

30 31

13 14 15 16 17

27

28

18

22 23

24 25

26

3

4

1

2

5

6

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

B47

1

2

4

6

3

5

B137

E

27

SBF-7

B47

B137

E64

B21

E64

2

1

B21

E2

50

48

MAIN RELAY

BATTERY

ECM

WASTEGATE CONTROL
SOLENOID VALVE

EN(H4DOTC)(diag)-170

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AS:DTC P0301 CYLINDER 1 MISFIRE DETECTED

NOTE:
For the diagnostic procedure, refer to DTC P0304. <Ref. to EN(H4DOTC)(diag)-171, DTC P0304 CYLIN-
DER 4 MISFIRE DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

AT:DTC P0302 CYLINDER 2 MISFIRE DETECTED

NOTE:
For the diagnostic procedure, refer to DTC P0304. <Ref. to EN(H4DOTC)(diag)-171, DTC P0304 CYLIN-
DER 4 MISFIRE DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

AU:DTC P0303 CYLINDER 3 MISFIRE DETECTED

NOTE:
For the diagnostic procedure, refer to DTC P0304. <Ref. to EN(H4DOTC)(diag)-171, DTC P0304 CYLIN-
DER 4 MISFIRE DETECTED, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

Step

Check

Yes

No

1

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

Connector & terminal

(B137) No. 27 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair short cir-
cuit of the harness
to power supply
between ECM and
wastegate control
solenoid valve con-
nector.

Go to step 2.

2

CHECK WASTEGATE CONTROL SOLE-
NOID VALVE.
1) Turn the ignition switch to OFF.
2) Measure the resistance between wastegate
control solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance less than 1

:? Replace the waste-

gate control sole-
noid valve. <Ref. to
FU(H4DOTC)-45,
Wastegate Control
Solenoid Valve.>

Repair the poor
contact of ECM
connector.

EN(H4DOTC)(diag)-171

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AV:DTC P0304 CYLINDER 4 MISFIRE DETECTED

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• Immediately at fault recognition (A misfire which could damage catalyst occurs.)
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-85, DTC P0304 CYLINDER 4 MISFIRE DETECTED,
Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
• Engine stalls.
• Improper idling
• Rough driving

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
52, OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-43, PRO-
CEDURE, Inspection Mode.>.
WIRING DIAGRAM:

EN-05668

E

#4

1

2

SBF-7

#3

1

2

#2

1

2

B21

#1

1

2

48

54

53

52

51

8

9

10

11

1 2

5
3

6
4

2
1

B21

B137

E5

E5

E2

E6

E6

E16

E16

E17

B47

E17

B47

3

4

1

2

5

6

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

MAIN RELAY

ECM

BATTERY

FUEL INJECTOR

EN(H4DOTC)(diag)-172

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 on faulty cylinders.

Connector & terminal

#1 (B137) No. 8 (+) — Chassis ground (–):
#2 (B137) No. 9 (+) — Chassis ground (–):
#3 (B137) No. 10 (+) — Chassis ground (–):
#4 (B137) No. 11 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step 6.

Go to step 2.

2

CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel injector
on faulty cylinders.
3) Measure the resistance between fuel injec-
tor connector and engine ground on faulty cylin-
ders.

Connector & terminal

#1 (E5) No. 1 — Engine ground:
#2 (E16) No. 1 — Engine ground:
#3 (E6) No. 1 — Engine ground:
#4 (E17) No. 1 — Engine ground:

Is the resistance 1 M

: or

more?

Go to step 3.

Repair the ground
short circuit of har-
ness between
ECM and fuel
injector.

3

CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR.
Measure the resistance of harness between
ECM and fuel injector on faulty cylinders.

Connector & terminal

#1 (B137) No. 8 — (E5) No. 1:
#2 (B137) No. 9 — (E16) No. 1:
#3 (B137) No. 10 — (E6) No. 1:
#4 (B137) No. 11 — (E17) No. 1:

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 of
harness between
ECM and fuel in-
jector connector
• Poor contact of
coupling connector

4

CHECK FUEL INJECTOR.
Measure the resistance between fuel injector
terminals on faulty cylinder.

Terminals

No. 1 — No. 2:

Is the resistance between 5 —
20

:?

Go to step 5.

Replace the faulty
fuel injector. <Ref.
to FU(H4DOTC)-
38, Fuel Injector.>

5

CHECK POWER SUPPLY LINE.
1) Turn the ignition switch to ON.
2) Measure the voltage between fuel injector
and engine ground on faulty cylinders.

Connector & terminal

#1 (E5) No. 2 (+) — Engine ground (–):
#2 (E16) No. 2 (+) — Engine ground (–):
#3 (E6) No. 2 (+) — Engine ground (–):
#4 (E17) No. 2 (+) — Engine ground (–):

Is the voltage 10 V or more?

Repair the poor
contact of all con-
nectors in fuel
injector circuit.

Repair the harness
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
the main relay and
fuel injector con-
nector on faulty
cylinders
• Poor contact of
coupling connector
• Poor contact of
main relay connec-
tor