Subaru Legacy IV (2008 year). Manual — part 345

EN(H4DOTC)(diag)-201

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK HARNESS BETWEEN ECM AND
SECONDARY AIR COMBINATION VALVE
RELAY 1.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and
secondary air combination valve relay 1.
3) Measure the voltage between ECM and
chassis ground.

Connector & terminal

(B136) No. 30 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the short
circuit to power in
the harness
between ECM and
secondary air com-
bination valve relay
1.

Repair the poor
contact of ECM
connector.

EN(H4DOTC)(diag)-202

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BG:DTC P0416 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE “B“

CIRCUIT OPEN

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-103, DTC P0416 SECONDARY AIR INJECTION SYS-
TEM SWITCHING VALVE “B“ CIRCUIT OPEN, Diagnostic Trouble Code (DTC) Detecting Criteria.>

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.>.

EN(H4DOTC)(diag)-203

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

EN-05678

B47

1

2

4

6

3

5

SBF-7

E

F9

13

12

11

14

1

2

2

1

3

4

16

15

5

6

B143

F37

B144

B21

E2

E41

E40

B134

A:

B136

C:

F37

F11

B21

E40

B47

B144

F9

B143

F37

E41

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

MAIN
SBF

10A

60A

9

10

8

7

E

E

11

5

20

8

C30
C19

C8

A19
A27
A29

6

1

28

47

3

2

1

6

4

1

2

9
2

16
18

14
12
10

4

14

4

F11

1 2

3

4

1

2

5

6

1

3

4 5 6

2

B134

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

33 34

29

32

30 31

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

1
5

7

6

2

8

3

4
9

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 9

10 11 12 13 14 15 16 17 18 19 20

5

6

3

1
2

9

10

12

11

13

14

4

7 8

15

16

46

MAIN RELAY

BATTERY

RELAY HOLDER

SECONDARY
AIR
COMBINATION
VALVE RELAY1

SECONDARY
AIR
COMBINATION
VALVE RELAY2

SECONDARY
AIR PUMP
RELAY

SECONDARY
AIR PUMP

MAIN FUSE
BOX (M/B)

ECM

SECONDARY AIR

COMBINATION VALVE RH

(WITH BUILT-IN PRESSURE SENSOR)

SECONDARY AIR

COMBINATION

VALVE LH

EN(H4DOTC)(diag)-204

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK HARNESS BETWEEN ECM AND
SECONDARY AIR COMBINATION VALVE
RELAY 2.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and
secondary air combination valve relay 2.
3) Measure the resistance of harness between
ECM and secondary air combination valve relay
2.

Connector & terminal

(B136) No. 19 — (F9) No. 9:

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 in
harness between
ECM and second-
ary air combination
valve relay 2
• Poor contact of
coupling connector

2

CHECK HARNESS BETWEEN ECM AND
SECONDARY AIR COMBINATION VALVE
RELAY 2.
Measure the resistance between ECM and
chassis ground.

Connector & terminal

(B136) No. 19 — Chassis ground:

Is the resistance 1 M

: or

more?

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.

Repair the ground
short circuit of har-
ness between
ECM and second-
ary air combination
valve relay 2.