Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 304

EN(H4DOTC)(diag)-440

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» less than 53.3 kPa
(400 mmHg, 15.8 inHg)?

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 POWER SUPPLY OF SECONDARY
AIR COMBINATION VALVE.
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) Measure the voltage between the second-
ary air combination valve RH or LH connector
and chassis ground.

Connector & terminal

Models without SI-DRIVE

(E41) No. 1 (+) — Chassis ground (–):

Models with SI-DRIVE

(E40) No. 1 (+) — Chassis ground (–):

Is the voltage 4.5 V or more?

Go to step

3.

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

3

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

Connector & terminal

Models without SI-DRIVE

(B137) No. 9 — (E41) No. 2:

Models with SI-DRIVE

(B137) No. 9 — (E40) No. 2:

Is the resistance less than 1 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
coupling connector

4

CHECK HARNESS BETWEEN ECM AND
SECONDARY AIR COMBINATION VALVE
CONNECTOR.
Measure the resistance between ECM connec-
tor and chassis ground.

Connector & terminal

(B137) No. 9 — Chassis ground:

Is the resistance 1 MΩ or
more?

Go to step

5.

Repair the ground
short circuit in har-
ness between
ECM connector
and secondary air
combination valve
RH or LH connec-
tor.

EN(H4DOTC)(diag)-441

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

5

CHECK FOR POOR CONTACT.
Check for poor contact of the ECM and second-
ary air combination valve RH or LH connector.

Is there poor contact of ECM or
secondary air combination
valve RH or LH connector?

Repair the poor
contact of the ECM
or secondary air
combination valve
RH or LH connec-
tor.

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.>

Step

Check

Yes

No

EN(H4DOTC)(diag)-442

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

FJ: DTC P2433 SECONDARY AIR INJECTION SYSTEM AIR FLOW /PRESSURE

SENSOR CIRCUIT HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-286, DTC P2433 SECONDARY AIR INJECTION SYS-

TEM AIR FLOW /PRESSURE SENSOR CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Crite-

ria.>
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)-443

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