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.