Subaru Legacy IV (2008 year). Manual - part 525

EN(H6DO)(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(H6DO)(diag)-52,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H6DO)(diag)-44, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

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

E34

E45

E31

E32

E46

E33

1
2
3

ECM

B137

23

19

18

21

22

20

SBF-7

4

6

B327

E46

E2

B21

E32

18

14

13

16

17

3

2

3

1

2

E34

3

2

E45

3

2

15

6

26

54

49

1

1

1

E31

3

1

2

E33

3

1

2

1

2

B225

9

10

1

2

3

4

5

6

7

8

11 12

14

15 16

13

18

19 20

17

22

23 24

21

38

39 40

37

34

35 36

33

30

31 32

29

26

27 28

25

B225

B327

3

4

1

2

5

6

E

MAIN RELAY 2

IGNITION COIL 

No. 1

RELAY BLOCK

IGNITION COIL 

No. 2

IGNITION COIL 

No. 3

IGNITION COIL 

No. 4

IGNITION COIL 

No. 5

IGNITION COIL 

No. 6

EN-06865

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

BATTERY

EN(H6DO)(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(H6DO)-
4, REMOVAL, Spark Plug.>
2) Check the spark plug condition. <Ref. to 
IG(H6DO)-5, INSPECTION, Spark Plug.>

Is the spark plug condition nor-
mal?

Go to step 2.

Replace the spark 
plug. <Ref. to 
IG(H6DO)-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(H6DO)-43, RELEASING OF FUEL PRES-
SURE, PROCEDURE, Fuel.>
3) Contact the spark plug’s thread portion to 
the engine.
4) While opening the throttle valve fully, start 
the engine to check if spark occurs at each cyl-
inder.

Does spark occur at each cylin-
der?

Check fuel pump 
system. <Ref. to 
EN(H6DO)(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 (–):
(E45) No. 3 (+) — Engine ground (–):
(E46) 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 circuit or
short circuit to
ground in power
supply circuit
• Blown out of fuse
• 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:
(E45) No. 2 — Engine ground:
(E46) 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 connector
and the 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:
(B137) No. 22 — (E45) No. 1:
(B137) No. 23 — (E46) 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(H6DO)(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 connector and chassis ground.

Connector & terminal:

(B137) No. 18 — Chassis ground:
(B137) No. 19 — Chassis ground:
(B137) No. 20 — Chassis ground:
(B137) No. 21 — Chassis ground:
(B137) No. 22 — Chassis ground:
(B137) No. 23 — Chassis 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(H6DO)-7, Igni-
tion Coil.>

Step

Check

Yes

No

EN(H6DO)(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(H6DO)(diag)-52,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H6DO)(diag)-44, PROCEDURE,
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(H6DO)(diag)-53, Compulsory Valve Opera-
tion Check Mode.>

Does the fuel pump emit oper-
ating sound?

Check the fuel 
injector circuit. 
<Ref. to 
EN(H6DO)(diag)-
77, FUEL INJEC-
TOR CIRCUIT, 
Diagnostics for 
Engine Starting 
Failure.>

Display the DTC. 
<Ref. to 
EN(H6DO)(diag)-
43, OPERATION, 
Read Diagnostic 
Trouble Code 
(DTC).>

E

E

M

10

7

6

5

6

No.11

B362

R122

B135

B:

B136

C:

R58

7

B33

C12

1

2

9

8

5

FUEL PUMP CONTROL UNIT

FUEL PUMP

ECM

BATTERY

FUEL PUMP

RELAY

B362

5
6

7 8

3
4

1 2

R1

B97

19

8

20

B97

R1

R46

R67

3

5

R58

2

5

4
6

1
3

B135

B:

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

B97

1 2 3 4

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20

R67

1

2

3 4 5 6

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:

EN-05654