Subaru Legacy IV (2008 year). Service manual — part 312

EN(H4DOTC)(diag)-69

Diagnostics for Engine Starting Failure

ENGINE (DIAGNOSTICS)

8

CHECK INPUT VOLTAGE OF STARTER RE-
LAY.
1) Remove the starter relay.
2) Connect the connector to ignition switch.
3) Turn the ignition switch to START.
4) Measure the voltage between starter relay
connector and chassis ground.

Connector & terminal

(B225) No. 13 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step 9.

Repair the open
circuit of harness
between starter
relay connector
and ignition switch
connector.

9

CHECK STARTER RELAY.
1) Connect the battery to starter relay termi-
nals No. 15 and No. 16.
2) Measure the resistance between starter
relay terminals.

Terminals

No. 13 — No. 14:

Is the resistance less than 1

:? Go to step 10.

Replace the starter
relay.

10

CHECK HARNESS BETWEEN ECM AND
STARTER RELAY CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance of harness between
ECM and starter relay connector.

Connector & terminal

(B136) No. 20 — (B225) No. 16:

Is the resistance less than 1

:? Go to step 11.

Repair the open
circuit of harness
between ECM and
starter relay con-
nector.

11

CHECK TRANSMISSION TYPE.

Is the transmission type AT?

Go to step 16.

Go to step 12.

12

CHECK INPUT VOLTAGE OF STARTER RE-
LAY.
1) Depress the clutch pedal.
2) Turn the ignition switch to START.
3) Measure the voltage between starter relay
connector and chassis ground.

Connector & terminal

(B225) No. 15 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step 13.

Go to step 14.

13

CHECK HARNESS BETWEEN ECM AND
CLUTCH START SWITCH CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the clutch start switch connec-
tor.
3) Measure the resistance of harness between
ECM and clutch start switch connector.

Connector & terminal

(B136) No. 32 — (B106) No. 2:

Is the resistance less than 1

:? Check the ECM

power supply and
ground line. <Ref.
to
EN(H4DOTC)(diag)
-71, CHECK
POWER SUPPLY
AND GROUND
LINE OF ENGINE
CONTROL MOD-
ULE (ECM), Diag-
nostics for Engine
Starting Failure.>

Repair the open
circuit of harness
between ECM and
clutch start switch
connector.

14

CHECK INPUT VOLTAGE OF CLUTCH
START SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the clutch start switch connec-
tor.
3) Turn the ignition switch to START.
4) Measure the voltage between the clutch
start switch connector and chassis ground.

Connector & terminal

(B106) No. 1 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step 15.

Check the follow-
ing item and repair
if necessary.
• Blown out of fuse
• Open or ground
short circuit of har-
ness between igni-
tion switch
connector and
clutch start switch
connector

Step

Check

Yes

No

EN(H4DOTC)(diag)-70

Diagnostics for Engine Starting Failure

ENGINE (DIAGNOSTICS)

15

CHECK CLUTCH START SWITCH.
Measure the resistance between clutch start
switch terminals while depressing the clutch
pedal.

Terminals

No. 1 — No. 2:

Is the resistance less than 1

:? Repair the open

circuit of harness
between clutch
start switch con-
nector and starter
relay connector.

Replace the clutch
start switch. <Ref.
to CL-37, Clutch
Switch.>

16

CHECK INPUT VOLTAGE OF STARTER RE-
LAY.
1) Connect the connector to ECM.
2) Place the select lever in “P” range or “N”
range.
3) Turn the ignition switch to START.
4) Measure the voltage between starter relay
connector and chassis ground.

Connector & terminal

(B225) No. 15 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step 17.

Go to step 18.

17

CHECK HARNESS BETWEEN ECM AND IN-
HIBITOR RELAY CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the inhibitor relay connector.
3) Measure the resistance of harness between
ECM and inhibitor relay connector.

Connector & terminal

(B136) No. 31 — (B226) No. 7:
(B136) No. 32 — (B226) No. 10:

Is the resistance less than 1

:? Check the ECM

power supply and
ground line. <Ref.
to
EN(H4DOTC)(diag)
-71, CHECK
POWER SUPPLY
AND GROUND
LINE OF ENGINE
CONTROL MOD-
ULE (ECM), Diag-
nostics for Engine
Starting Failure.>

Repair the open
circuit of harness
between ECM and
inhibitor relay con-
nector.

18

CHECK INPUT VOLTAGE OF INHIBITOR RE-
LAY.
1) Turn the ignition switch to OFF.
2) Disconnect the inhibitor relay connector.
3) Turn the ignition switch to START.
4) Measure the voltage between inhibitor relay
connector and chassis ground.

Connector & terminal

(B226) No. 9 (+) — Chassis ground (–):
(B226) No. 11 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step 19.

Check the follow-
ing item and repair
if necessary.
• Blown out of fuse
• Open or ground
short circuit of har-
ness between igni-
tion switch
connector and
inhibitor relay con-
nector

19

CHECK INHIBITOR RELAY.
1) Connect the battery to inhibitor relay termi-
nals No. 7 and No. 9.
2) Measure the resistance between inhibitor
relay terminals.

Terminals

No. 10 — No. 11:

Is the resistance less than 1

:? Go to step 20.

Replace the inhibi-
tor relay.

20

CHECK HARNESS BETWEEN INHIBITOR
RELAY CONNECTOR AND STARTER RE-
LAY CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness between
inhibitor relay connector and starter relay con-
nector.

Connector & terminal

(B226) No. 10 — (B225) No. 15:

Is the resistance less than 1

:? Repair the open

circuit of harness
between TCM and
inhibitor relay con-
nector.

Repair the open
circuit of harness
between inhibitor
relay connector
and starter relay
connector.

Step

Check

Yes

No

EN(H4DOTC)(diag)-71

Diagnostics for Engine Starting Failure

ENGINE (DIAGNOSTICS)

C: CHECK POWER SUPPLY AND GROUND LINE OF ENGINE CONTROL MODULE

(ECM)

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-05666

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:

SBF-6

MAIN SBF

SBF-7

B72

A7

B2

C23

D2

A5

D3

B5

B19

No.12

B47

E2

B21

1

2

4

6

5

3

E

E

B134

B135

A:

C: B136

D: B137

B:

35

34

40

3

4

1

2

5

6

B47

No.13

D7

36

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

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

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:

D:

SBF-5

D1

37

3

1

MAIN RELAY

TO OXYGEN SENSOR

IGNITION
SWITCH

BATTERY

ECM

EN(H4DOTC)(diag)-72

Diagnostics for Engine Starting Failure

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK MAIN RELAY.
1) Turn the ignition switch to OFF.
2) Remove the main relay.
3) Connect the battery to main relay terminals
No. 1 and No. 2.
4) Measure the resistance between main relay
terminals.

Terminals

No. 3 — No. 5:
No. 4 — No. 6:

Is the resistance less than 1

:? Go to step 2.

Replace the main
relay. <Ref. to
EN(H4DOTC)(diag)
-8, Electrical Com-
ponent Location.>

2

CHECK GROUND CIRCUIT FOR ECM.
1) Disconnect the connectors from ECM.
2) Measure the resistance of harness 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 resistance less than 5

:? Go to step 3.

Repair the harness
and connector.

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

3

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

Connector & terminal

(B135) No. 5 (+) — Chassis ground (–):
(B135) No. 19 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step 4.

Repair the open or
ground short circuit
of harness of
power supply cir-
cuit.

4

CHECK INPUT VOLTAGE OF MAIN RELAY.
Measure the voltage between main relay con-
nector and chassis ground.

Connector & terminal

(B47) No. 2 (+) — Chassis ground (–):
(B47) No. 5 (+) — Chassis ground (–):
(B47) No. 6 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step 5.

Repair the open or
ground short circuit
of harness of
power supply cir-
cuit.

5

CHECK INPUT VOLTAGE OF ECM.
1) Turn the ignition switch to OFF.
2) Install the main relay.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM and
chassis ground.

Connector & terminal

(B136) No. 23 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step 6.

Repair the open or
ground short circuit
of harness
between ECM and
main relay connec-
tor.

6

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

Connector & terminal

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

Is the voltage 10 V or more?

Check ignition con-
trol system. <Ref.
to
EN(H4DOTC)(diag)
-73, IGNITION
CONTROL SYS-
TEM, Diagnostics
for Engine Starting
Failure.>

Repair the harness
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and main re-
lay connector
• Poor contact of
main relay connec-
tor