Subaru Legacy IV (2008 year). Service manual — part 384

EN(H4DOTC)(diag)-357

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EG:DTC P2441 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE

STUCK CLOSED (BANK1)

NOTE:
For the diagnostic procedure, refer to DTC P2440. <Ref. to EN(H4DOTC)(diag)-353, DTC P2440 SECOND-
ARY AIR INJECTION SYSTEM SWITCHING VALVE STUCK OPEN (BANK1), Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>

13

CHECK HARNESS BETWEEN ECM AND
SECONDARY AIR COMBINATION VALVE
RELAY 1 CONNECTOR.
Measure the resistance between the secondary
air combination valve relay 1 connector and
chassis ground.

Connector & terminal

(F9) No. 2 — Chassis ground:

Is the resistance 1 M

: or

more?

Repair the poor
contact of ECM
connector.

Repair the ground
short circuit of har-
ness between
ECM and second-
ary air combination
valve relay 1 con-
nector.

Step

Check

Yes

No

EN(H4DOTC)(diag)-358

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EH:DTC P2442 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE

STUCK OPEN (BANK2)

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-231, DTC P2442 SECONDARY AIR INJECTION SYS-
TEM SWITCHING VALVE STUCK OPEN (BANK2), 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)-359

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)-360

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK SECONDARY AIR COMBINATION
VALVE FUSE.
Check if the secondary air combination valve
fuse (10 A) is blown out.

Is the fuse blown out?

Go to step 2.

Go to step 3.

2

CHECK HARNESS BETWEEN FUSE BOX
AND SECONDARY AIR COMBINATION
VALVE LH.
1) Remove the secondary air combination
valve fuse (10 A) from the fuse box.
2) Disconnect the connector from the second-
ary air combination valve LH.
3) Measure the resistance between the sec-
ondary air combination valve fuse and second-
ary air combination valve LH connector, and
chassis ground.

Connector & terminal

(F9) No. 5 — Chassis ground:
(E40) No. 2 — Chassis ground:

Is the resistance 1 M

: or

more?

Replace the fuse
with a new part,
and connect the
secondary air com-
bination valve LH
connector.
Go to step 3.

Repair the ground
short circuit of har-
ness between the
fuse box and the
secondary air com-
bination valve LH.

3

CHECK SECONDARY AIR COMBINATION
VALVE LH OPERATION.
1) Connect the delivery (test) mode connector.
2) Turn the ignition switch to ON.
3) Perform operation check for the secondary
air combination valve LH using the Subaru
Select Monitor.

NOTE:
Refer to “Compulsory Valve Operation Check
Mode” for more operation procedures. <Ref. to
EN(H4DOTC)(diag)-53, Compulsory Valve Op-
eration Check Mode.>

Does the secondary air combi-
nation valve LH repeatedly
switch to ON and OFF?

Go to step 4.

Go to step 6.

4

CHECK DUCT BETWEEN SECONDARY AIR
PUMP AND SECONDARY AIR COMBINA-
TION VALVE LH.
Check the duct between the secondary air
pump and secondary air combination valve LH.

Is there damage, clog or dis-
connection of the duct?

Replace, clean or
connect the duct.

Go to step 5.

5

CHECK PIPE BETWEEN SECONDARY AIR
COMBINATION VALVE LH AND CYLINDER
HEAD.
Check the pipe between the secondary air com-
bination valve LH and cylinder head.

Is there damage, clog or dis-
connection of the pipe?

Replace, clean or
connect the pipe.

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.

6

CHECK POWER SUPPLY TO SECONDARY
AIR COMBINATION VALVE LH.
1) Disconnect the connector from the second-
ary air combination valve LH.
2) In the condition of step 3, measure the volt-
age between the secondary air combination
valve LH and the chassis ground.

Connector & terminal

(E40) No. 2 (+) — Chassis ground (–):

Does the voltage repeatedly
change between 10 V and 0 V?

Replace the sec-
ondary air combi-
nation valve LH.
<Ref. to
EC(H4DOTC)-22,
Secondary Air
Combination
Valve.>

Go to step 7.