Subaru Legacy IV (2008 year). Manual - part 157

EN(H4SO)(diag)-231

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CA:DTC P0607 THROTTLE CONTROL SYSTEM CIRCUIT RANGE/PERFORMANCE

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4SO)-147, DTC P0607 THROTTLE CONTROL SYSTEM CIR-
CUIT RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
• Improper idling
• Poor driving performance

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4SO)(diag)-50,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4SO)(diag)-41, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

EN-06842

SBF-6

MAIN SBF

SBF-7

B72

B2

A7

C24

A5

D2

D1

D3

D7

B5

B27

No. 12

B47

E2

B21

2

1

4

6

5

3

E

3

4

B134

B135

A:

D: B137

B:

36

35

52

37

34

3

4

1

2

5

6

B47

No. 13

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

B135

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

29 30 31

32 33

34 35

B21

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

B72

1

3

4 5 6

2

A:

B:

MAIN RELAY

ECM

TO IGNITION COIL & IGNITOR ASSY

BATTERY

IGNITION
SWITCH

E

E

*

*

E

C: B136

B122

E57

: TERMINAL No. OPTIONAL ARRANGEMENT

A19

D4

D5

A29

A28

A18

C6

20

39

38

19

5

1

2

3

18

17

4

6

ELECTRONIC 
THROTTLE CONTROL

B122

3 4

5 6

1 2

7 8

B136

C:

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

*

B137

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

D:

E57

1 2 3 4 5 6

EN(H4SO)(diag)-232

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CB:DTC P0638 THROTTLE ACTUATOR CONTROL RANGE/PERFORMANCE 

(BANK 1)

NOTE:
For the diagnostic procedure, refer to DTC P2101. <Ref. to EN(H4SO)(diag)-276, DTC P2101 THROTTLE
ACTUATOR CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Procedure with Diagnos-
tic Trouble Code (DTC).>

CC:DTC P0700 TRANSMISSION CONTROL SYSTEM (MIL REQUEST)

NOTE:
For the diagnostic procedure, refer to AT section. <Ref. to 4AT(diag)-2, Basic Diagnostic Procedure.>

Step

Check

Yes

No

1

CHECK INPUT VOLTAGE OF ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B134) No. 7 (+) — Chassis ground (–):
(B135) No. 2 (+) — Chassis ground (–):

Is the voltage 10 — 13 V?

Go to step 2.

Repair the open or 
ground short circuit 
of power supply 
circuit.

2

CHECK INPUT VOLTAGE OF ECM.
1) Start the engine.
2) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B134) No. 7 (+) — Chassis ground (–):
(B135) No. 2 (+) — Chassis ground (–):

Is the voltage 13 — 15 V?

Go to step 3.

Repair the open or 
ground short circuit 
of power supply 
circuit.

3

CHECK HARNESS BETWEEN ECM AND 
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and 
electronic throttle control.
3) Measure the resistance of harness between 
ECM and electronic throttle control connector.

Connector & terminal

(B134) No. 19 — (E57) No. 5:
(B134) No. 29 — (E57) No. 3:

Is the resistance less than 1 

:? Go to step 4.

Repair the harness 
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and electron-
ic throttle control
connector
• Poor contact of
coupling connector

4

CHECK ECM GROUND HARNESS.
Measure the voltage between ECM and chassis 
ground.

Connector & terminal

(B134) No. 5 (+) — Chassis ground (–):
(B137) No. 1 (+) — Chassis ground (–):
(B137) No. 2 (+) — Chassis ground (–):
(B137) No. 3 (+) — Chassis ground (–):
(B137) No. 7 (+) — Chassis ground (–):

Is the voltage less than 1 V?

Repair the poor 
contact of ECM 
connector.

Repair the follow-
ing item.
• Open circuit of 
ground circuit
• Retightening of 
engine ground ter-
minals
• Poor contact of 
coupling connector

EN(H4SO)(diag)-233

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CD:DTC P0851 PARK/NEUTRAL SWITCH INPUT CIRCUIT LOW (AT MODEL)

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H4SO)-152, DTC P0851 PARK/NEUTRAL SWITCH INPUT CIR-
CUIT LOW (AT MODEL), Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
Improper idling

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4SO)(diag)-50,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4SO)(diag)-41, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

EN-06642

B12

T3

B14

T7

INHIBITOR

SWITCH

NEUTRAL
POSITION

SWITCH

STARTER MOTOR

(MAGNET)

P

R

N

D

6

9

12

11

B136

ECM

31

6

B12

B25

T7

1 2 3 4
5 6 7 8
9 10 11 12

B136

1

B25

T2

T2

B25

2

MT

AT

AT

AT

MT

MT

M

2

1

C:

C:

B122

*

*

: TERMINAL No. OPTIONAL ARRANGEMENT

*

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

B122

3 4

5 6

1 2

7 8

TO STARTER RELAY

1 2 3 4 5

7

6

9

8

EN(H4SO)(diag)-234

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK SELECT CABLE.

Are there any faults in the select 
cable?

Repair or adjust 
the select cable. 
<Ref. to CS-28, 
Select Cable.>

Go to step 2.

2

CHECK INPUT SIGNAL OF ECM.
1) Turn the ignition switch to ON.
2) Place the select lever in other than “P” range 
and “N” range.
3) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B136) No. 31 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the poor 
contact of ECM 
connector.

Go to step 3.

3

CHECK HARNESS BETWEEN ECM AND 
TRANSMISSION HARNESS CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and 
transmission harness connector (T3).
3) Measure the resistance between ECM and 
chassis ground.

Connector & terminal

(B136) No. 31 — Chassis ground:

Is the resistance 1 M

: or 

more?

Go to step 4.

Repair the ground 
short circuit of har-
ness between 
ECM and transmis-
sion harness con-
nector.

4

CHECK TRANSMISSION HARNESS CON-
NECTOR.
1) Disconnect the connector from inhibitor 
switch.
2) Measure the resistance between the trans-
mission harness connector and engine ground.

Connector & terminal

(T3) No. 11 — Engine ground:

Is the resistance 1 M

: or 

more?

Replace the inhibi-
tor switch. <Ref. to 
4AT-46, Inhibitor 
Switch.>

Repair the ground 
short circuit of har-
ness between 
transmission har-
ness connector 
and inhibitor switch 
connector.