Subaru Legacy IV (2008 year). Manual - part 573

EN(H6DO)(diag)-265

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CT:DTC P0507 IDLE AIR CONTROL SYSTEM RPM HIGHER THAN EXPECTED

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H6DO)-149, DTC P0507 IDLE AIR CONTROL SYSTEM RPM
HIGHER THAN EXPECTED, Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
Engine keeps running at higher speed than specified idle speed.

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H6DO)(diag)-52,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H6DO)(diag)-44, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

B20

1 2 3 4 5 6

E57

1 2 3 4
5 6 7 8

B122

1 2

7 8

3
4

5
6

B362

36

52

34

35

37

E

E2

B21

E

A5

C21

C1

A29

19

E1

B20

A18

C6

A28

6

4

15

*

*

B122

16

E

38

39

20

D5

D4

A19

D7

D1

A3

D2

D3

3

E57

ELECTRONIC THROTTLE 

CONTROL

2

1

5

B134

B362

5

7

6

A:

B137

B136

D:

C:

ECM

*

: TERMINAL No. OPTIONAL ARRANGEMENT

E

SBF-7

BATTERY

ELECTRONIC 
THROTTLE
CONTROL RELAY

MAIN RELAY

8

6

4

B47

B47

3

4

1

2

5

6

EN-06873

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

C:

5

6

7

8

2

1

9

4

3

10

22 23

11 12 13 14 15

24 25

26

16 17

18 19 20 21

27

28 29

30 31

B137

D:

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

B134

A:

B21

1 2 3 4 5 6 7 8 9 10 11

12 13 14 15 16 17 18 19 20 21 22
23 24 25 26 27 28 29 30 31 32 33

34

35

42

43

36

37

38

39

48

49

50

51

52

53

54

40

41

44

45

46

47

EN(H6DO)(diag)-266

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed?

Check the appro-
priate DTC using 
the “List of Diag-
nostic Trouble 
Code (DTC)”. 
<Ref. to 
EN(H6DO)(diag)-
81, List of Diagnos-
tic Trouble Code 
(DTC).>

Go to step 2.

2

CHECK AIR INTAKE SYSTEM.
1) Start and idle the engine.
2) Check the following items.
• Loose installation of intake manifold and 
throttle body
• Cracks of intake manifold gasket and throttle 
body gasket
• Disconnection of vacuum hoses

Is there any fault in air intake 
system?

Repair air suction 
and leaks.

Go to step 3.

3

CHECK ELECTRONIC THROTTLE CON-
TROL.
1) Turn the ignition switch to OFF.
2) Remove the electronic throttle control.
3) Check the electronic throttle control.

Are foreign matter found inside 
electronic throttle control?

Remove foreign 
matter from elec-
tronic throttle con-
trol.

Perform the diag-
nosis of DTC 
P2101. <Ref. to 
EN(H6DO)(diag)-
324, DTC P2101 
THROTTLE 
ACTUATOR CON-
TROL MOTOR 
CIRCUIT RANGE/
PERFORMANCE, 
Diagnostic Proce-
dure with Diagnos-
tic Trouble Code 
(DTC).>

EN(H6DO)(diag)-267

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CU:DTC P0512 STARTER REQUEST CIRCUIT

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H6DO)-150, DTC P0512 STARTER REQUEST CIRCUIT, Diag-
nostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
Failure of engine to start

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H6DO)(diag)-52,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H6DO)(diag)-44, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

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

32

31

20

No.21

B225

MAIN SBF

SBF-6

E

15

13

16

14

ECM

B136

TCM

B55

B72

B14

M

2

3

B225

B72

B136

10

11 12

13
14

15 16

17
18

19 20

21
22

23 24

25
26

27 28

29

30

31 32

33
34

35 36

39 40

37
38

1

2

9

3

4

5

6

7

8

1

3

4 5 6

2

B226

9

11

7

10

11

EN-05651

B226

B55

5

6

7

2

1

3

4

29

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

2

3 4

8

10
11

7

5
6

1

9

IGNITION

SWITCH

INHIBITOR 

RELAY

STARTER 

RELAY

STARTER MOTOR

BATTERY

EN(H6DO)(diag)-268

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CV:DTC P0600 SERIAL COMMUNICATION LINK

NOTE:
For the diagnostic procedure, refer to LAN section. <Ref. to LAN(diag)-2, Basic Diagnostic Procedure.>

Step

Check

Yes

No

1

CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed?

Check the appro-
priate DTC using 
the “List of Diag-
nostic Trouble 
Code (DTC)”. 
<Ref. to 
EN(H6DO)(diag)-
81, List of Diagnos-
tic Trouble Code 
(DTC).>

Go to step 2.

2

CHECK HARNESS BETWEEN ECM AND IG-
NITION SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B136) No. 32 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the short 
circuit to power in 
the harness 
between the ECM 
and ignition switch.

Repair the poor 
contact of ECM 
connector.