Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 305

EN(H4DOTC)(diag)-444

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

• Models with SI-DRIVE <Ref. to WI-48, WITH SI-DRIVE, WIRING DIAGRAM, Engine Electrical System.>

EN-08735

F9

13

12

11

14

1

2

2

1

3

4

16

15

5

6

B143

F37

B144

B21

E2

E40

E41

B134

A:

A:

B135

B:

B135

B:

B137

D:

F37

F11

F9

10A

60A

9

10

8

7

11

5

20

8

B8

B20
B27
A19

D9

A29

6

1

2

8

47

3

2

1

6

4

1

2

9
2

16
18

14
12
10

4

14

4

B134

46

B220

24

23

22

21

B137

D:

31

30

29

28

27

21

20

19

18

17

16

26

25

24

15

14

13

12

11

23

22

10

3

4

9

1

2

8

7

6

5

F11

1 2

29

4

3

1

2

7

6

5

10 11 12 13 14 15

25

24

16

30

9

8

17 18 19

20
28

21 22 23

32

31

26 27

33

34 35

B220

18

19

6

7

4

3
5

2

1

12

11

10

9

8

40

36 39

38

37

34

33

35

32

28 31

30

29

23

22

21

20

26

25

24

27

17

16

15

14

13

4

3

B220

15A

16

15

8

7

4

14

13

11

12

10

9

2

1

3

6

5

B143

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

F37

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

B144

3
8

2
6

7

1
5

4
9

31

30

32

29

34

33

21

20

19

18

17

16

28

27

26

15

14

13

12

11

25

23

22

24

10

3

4

9

1

2

8

7

6

5

E40

2

6

5

4

3

1

E41

2

1

54

52 53

50 51

48 49

46 47

45

44

42 43

40 41

38 39

36 37

34 35

33

32

31

30

29

28

27

26

25

24

23

22

21

20

11

10

9

19

18

17

16

8

7

6

5

15

14

13

12

4

3

2

1

B21

E

E

E

ECM

SBF-7

FUSE

(RELAY BLOCK)

MAIN SBF

MAIN RELAY

SECONDARY

AIR COMBINATION

VALVE RELAY 2

SECONDARY

AIR PUMP

RELAY

SECONDARY

AIR COMBINATION

VALVE RH

SECONDARY

AIR COMBINATION

VALVE LH

(WITH BUILT-IN

PRESSURE SENSOR)

SECONDARY

AIR COMBINATION

VALVE RELAY 1

SECONDARY

AIR PUMP

MAIN FUSE BOX

(M/B)

RELAY HOLDER

BATTERY

EN(H4DOTC)(diag)-445

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK CURRENT DATA.
1) Turn the ignition switch to ON.
2) Read the value of «Sec. Air Piping Pres-
sure» using Subaru Select Monitor.
NOTE:

For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOTC)(diag)-40, Subaru Select Moni-
tor.>

Is the value of «Sec. Air Piping
Pressure» 133.3 kPa (1,000
mmHg, 39.4 inHg) or more?

Go to step

2.

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,
temporary open or
short circuit of har-
ness may be the
cause.

2

CHECK HARNESS BETWEEN ECM AND
SECONDARY AIR COMBINATION VALVE
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from secondary
air combination valve RH (models without SI-
DRIVE) or LH (models with SI-DRIVE).
3) Turn the ignition switch to ON.
4) Read the value of «Sec. Air Piping Pres-
sure» using Subaru Select Monitor.
NOTE:

For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOTC)(diag)-40, Subaru Select Moni-
tor.>

Is the value of «Sec. Air Piping
Pressure» 133.3 kPa (1,000
mmHg, 39.4 inHg) or more?

Repair the short
circuit to power
supply in harness
between ECM con-
nector and sec-
ondary air
combination valve
RH or LH connec-
tor.

Go to step

3.

3

CHECK HARNESS BETWEEN ECM AND
SECONDARY AIR COMBINATION VALVE
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance of the harness
between secondary air combination valve RH
or LH connector and engine ground.

Connector & terminal

Models without SI-DRIVE

(E41) No. 3 — Engine ground:

Models with SI-DRIVE

(E40) No. 3 — Engine ground:

Is the resistance less than 5 Ω? Go to step

4.

Repair the harness
and connector.
NOTE:

In this case, repair
the following item:
• Open circuit in
harness between
ECM

connector

and secondary air
combination valve
RH or LH connec-
tor
• Poor contact of
ECM connector
• Poor contact of
coupling connector

4

CHECK FOR POOR CONTACT.
Check for poor contact of the secondary air
combination valve RH or LH connector.

Is there poor contact of the sec-
ondary air combination valve
RH or LH connector?

Repair the poor
contact of second-
ary air combination
valve RH or LH
connector.

Replace the sec-
ondary air combi-
nation valve RH or
LH. <Ref. to
EC(STI)-29, Sec-
ondary Air Combi-
nation Valve.>
<Ref. to EC(w/o
STI)-30, Second-
ary Air Combina-
tion Valve.>

EN(H4DOTC)(diag)-446

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FK:DTC P2440 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE

STUCK OPEN (BANK1)

DTC DETECTING CONDITION:

• Detected when 2 consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-287, DTC P2440 SECONDARY AIR INJECTION SYS-

TEM SWITCHING VALVE STUCK OPEN (BANK1), Diagnostic Trouble Code (DTC) Detecting Criteria.>
CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-63,

OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-49, PROCE-

DURE, Inspection Mode.>.

EN(H4DOTC)(diag)-447

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

WIRING DIAGRAM:

• Models without SI-DRIVE <Ref. to WI-32, WITHOUT SI-DRIVE, WIRING DIAGRAM, Engine Electrical

System.>

EN-08734

F9

13

12

11

14

1

2

2

1

3

4

16

15

5

6

B143

F37

B144

B21

E2

E41

E40

B134

A:

A:

B135

B:

B135

B:

B137

D:

F37

F11

B144

F9

B143

F37

E41

10A

60A

9

10

8

7

11

5

20

8

B8

B20
B27
A19

D9

A29

6

1

2

8

47

3

2

1

6

4

1

2

9
2

16
18

14
12
10

4

14

4

E40

B134

46

B220

24

23

22

21

B137

D:

31

30

29

28

27

21

20

19

18

17

16

26

25

24

15

14

13

12

11

23

22

10

3

4

9

1

2

8

7

6

5

1 2

F11

29

4

3

1

2

7

6

5

10 11 12 13 14 15

25

24

16

30

9

8

17 18 19

20
28

21 22 23

32

31

26 27

33

34 35

B220

18

19

6

7

4

3
5

2

1

12

11

10

9

8

40

36 39

38

37

34

33

35

32

28 31

30

29

23

22

21

20

26

25

24

27

17

16

15

14

13

4

3

B220

15A

16

15

8

7

4

14

13

11

12

10

9

2

1

3

6

5

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

3
8

2
6

7

1
5

4
9

31

30

32

29

34

33

21

20

19

18

17

16

28

27

26

15

14

13

12

11

25

23

22

24

10

3

4

9

1

2

8

7

6

5

2

6

5

4

3

1

2

1

54

52 53

50 51

48 49

46 47

45

44

42 43

40 41

38 39

36 37

34 35

33

32

31

30

29

28

27

26

25

24

23

22

21

20

11

10

9

19

18

17

16

8

7

6

5

15

14

13

12

4

3

2

1

B21

E

E

E

ECM

SBF-7

FUSE

(RELAY BLOCK)

MAIN RELAY

SECONDARY

AIR COMBINATION

VALVE RELAY 2

MAIN SBF

SECONDARY

AIR PUMP

RELAY

SECONDARY

AIR COMBINATION

VALVE LH

SECONDARY

AIR COMBINATION

VALVE RH

(WITH BUILT-IN

PRESSURE SENSOR)

SECONDARY

AIR COMBINATION

VALVE RELAY 1

SECONDARY

AIR PUMP

MAIN FUSE BOX

(M/B)

RELAY HOLDER

BATTERY