Subaru Legacy IV (2008 year). Manual - part 313

EN(H4DOTC)(diag)-73

Diagnostics for Engine Starting Failure

ENGINE (DIAGNOSTICS)

D: IGNITION CONTROL SYSTEM

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.>.
WIRING DIAGRAM:

EN-06952

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

SBF-6

MAIN SBF

B72

B137

18

19

20

21

ECM

No. 12

E

1

3

26

E2

B21

E31

E31

E32

E33

E34

E32

E33

E34

6

1
2
3

B21

3

1

2

3

1

2

9

49

20

31

10

41

3

1

2

3

1

2

B137

B72

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

1

3

4 5 6

2

IGNITION

SWITCH

IGNITION COIL 

No. 1

IGNITION COIL 

No. 3

IGNITION COIL 

No. 4

IGNITION COIL 

No. 2

BATTERY

EN(H4DOTC)(diag)-74

Diagnostics for Engine Starting Failure

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK SPARK PLUG CONDITION.
1) Remove the spark plug. <Ref. to 
IG(H4DOTC)-4, REMOVAL, Spark Plug.>
2) Check the spark plug condition. <Ref. to 
IG(H4DOTC)-5, INSPECTION, Spark Plug.>

Is the spark plug condition nor-
mal?

Go to step 2.

Replace the spark 
plug. <Ref. to 
IG(H4DOTC)-4, 
Spark Plug.>

2

CHECK IGNITION SYSTEM FOR SPARKS.
1) Connect the spark plug to ignition coil.
2) Release the fuel pressure. <Ref. to 
FU(H4DOTC)-57, RELEASING OF FUEL 
PRESSURE, PROCEDURE, Fuel.>
3) Contact the spark plug’s thread portion to 
the engine.
4) While opening the throttle valve fully, crank 
the engine to check that spark occurs at each 
cylinder.

Does spark occur at each cylin-
der?

Check fuel pump 
system. <Ref. to 
EN(H4DOTC)(diag)
-76, FUEL PUMP 
CIRCUIT, Diag-
nostics for Engine 
Starting Failure.>

Go to step 3.

3

CHECK POWER SUPPLY CIRCUIT OF IGNI-
TION COIL.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ignition coil.
3) Turn the ignition switch to ON.
4) Measure the voltage between ignition coil 
connector and engine ground.

Connector & terminal

(E31) No. 3 (+) — Engine ground (–):
(E32) No. 3 (+) — Engine ground (–):
(E33) No. 3 (+) — Engine ground (–):
(E34) No. 3 (+) — Engine ground (–):

Is the voltage 10 V or more?

Go to step 4.

Repair the harness 
and connector.

NOTE:
In this case, repair
the following item:
• Open harness
between ignition
coil and ignition
switch connector
• Poor contact of
coupling connector

4

CHECK HARNESS OF IGNITION COIL 
GROUND CIRCUIT.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness between 
ignition coil connector and engine ground.

Connector & terminal

(E31) No. 2 — Engine ground:
(E32) No. 2 — Engine ground:
(E33) No. 2 — Engine ground:
(E34) No. 2 — Engine ground:

Is the resistance less than 5 

:? Go to step 5.

Repair the harness 
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and ignition
coil connector
• Open circuit in
harness between
ECM and engine
ground terminal
• Poor contact of
coupling connector

5

CHECK HARNESS BETWEEN ECM AND IG-
NITION COIL CONNECTOR.
1) Disconnect the connectors from ECM.
2) Measure the resistance of harness between 
ECM and ignition coil connector.

Connector & terminal

(B137) No. 18 — (E31) No. 1:
(B137) No. 19 — (E32) No. 1:
(B137) No. 20 — (E33) No. 1:
(B137) No. 21 — (E34) No. 1:

Is the resistance less than 1 

:? Go to step 6.

Repair the harness 
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and ignition
coil connector
• Poor contact of
coupling connector

EN(H4DOTC)(diag)-75

Diagnostics for Engine Starting Failure

ENGINE (DIAGNOSTICS)

6

CHECK HARNESS BETWEEN ECM AND IG-
NITION COIL CONNECTOR.
Measure the resistance of harness between 
ECM and engine ground.

Connector & terminal

(B137) No. 18 — Engine ground:
(B137) No. 19 — Engine ground:
(B137) No. 20 — Engine ground:
(B137) No. 21 — Engine ground:

Is the resistance 1 M

: or 

more?

Go to step 7.

Repair the ground 
short circuit of har-
ness between 
ECM and ignition 
coil connector.

7

CHECK POOR CONTACT.
Check for poor contact of the ECM connector.

Is there poor contact in ECM 
connector?

Repair the poor 
contact of ECM 
connector.

Replace the igni-
tion coil. <Ref. to 
IG(H4DOTC)-7, 
Ignition Coil.>

Step

Check

Yes

No

EN(H4DOTC)(diag)-76

Diagnostics for Engine Starting Failure

ENGINE (DIAGNOSTICS)

E: FUEL PUMP CIRCUIT

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.>.
WIRING DIAGRAM:

Step

Check

Yes

No

1

CHECK OPERATING SOUND OF FUEL 
PUMP.
Make sure that the fuel pump operates for two 
seconds when turning the ignition switch to ON.

NOTE:
Fuel pump operation can be executed using the
Subaru Select Monitor.
For the procedures, refer to “Compulsory Valve
Operation Check Mode”. <Ref. to
EN(H4DOTC)(diag)-53, Compulsory Valve Op-
eration Check Mode.>

Does the fuel pump emit oper-
ating sound?

Check the fuel 
injector circuit. 
<Ref. to 
EN(H4DOTC)(diag)
-77, FUEL INJEC-
TOR CIRCUIT, 
Diagnostics for 
Engine Starting 
Failure.>

Display the DTC. 
<Ref. to 
EN(H4DOTC)(diag)
-42, OPERATION, 
Read Diagnostic 
Trouble Code 
(DTC).>

EN-05083

E

E

M

10

7

6

5

6

3

5

No.11

B362

R122

B135

B:

B136

C:

R58

B97

7

B33

C12

1

2

9

8

5

19

8

R1

20

R1

B97

R46

R67

FUEL PUMP
CONTROL UNIT

FUEL
PUMP

ECM

BATTERY

FUEL PUMP
RELAY

B135

B136

B362

R58

2

5

4
6

1
3

B:

C:

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

R122

3 4

1 2
5

8 9 10

6 7

5
6

7 8

3
4

1 2

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

B97

R67

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