Subaru Legacy (2005 year). Manual — part 320

EN(H4DOTC)(diag)-49

ENGINE (DIAGNOSTICS)

Diagnostics for Engine Starting Failure

16.Diagnostics for Engine Starting Failure

A: PROCEDURE

1. Check for fuel amount.

↓

2. Inspection of starter motor circuit. <Ref. to EN(H4DOTC)(diag)-50, STARTER MOTOR CIRCUIT, Diagnostics for Engine Start-
ing Failure.>

↓

3. Inspection of ECM power supply and ground line. <Ref. to EN(H4DOTC)(diag)-53, CHECK POWER SUPPLY AND GROUND
LINE OF ENGINE CONTROL MODULE (ECM), Diagnostics for Engine Starting Failure.>

↓

4. Inspection of ignition control system. <Ref. to EN(H4DOTC)(diag)-55, IGNITION CONTROL SYSTEM, Diagnostics for Engine
Starting Failure.>

↓

5. Inspection of fuel pump circuit. <Ref. to EN(H4DOTC)(diag)-58, FUEL PUMP CIRCUIT, Diagnostics for Engine Starting Fail-
ure.>

↓

6. Inspection of fuel injector circuit. <Ref. to EN(H4DOTC)(diag)-60, FUEL INJECTOR CIRCUIT, Diagnostics for Engine Starting
Failure.>

EN(H4DOTC)(diag)-50

ENGINE (DIAGNOSTICS)

Diagnostics for Engine Starting Failure

B: STARTER MOTOR CIRCUIT

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
37, OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)(diag)-30, PROCE-
DURE, Inspection Mode.>.
WIRING DIAGRAM:

Step

Check

Yes

No

1

CHECK OPERATION OF STARTER MOTOR. Does the starter motor oper-

ate?

Go to step 2.

Go to step 3.

2

CHECK DTC.

Is DTC displayed? <Ref. to
EN(H4DOTC)(diag)-29,
OPERATION, Read Diagnos-
tic Trouble Code (DTC).>

Inspect the rele-
vant DTC using
List of Diagnostic
Trouble Code
(DTC). <Ref. to
EN(H4DOTC)(diag
)-62, List of Diag-
nostic Trouble
Code (DTC).>

Repair the poor
contact in ECM
connector.

EN-03518

No.21

B225

B225

MAIN SBF

SBF-6

E

16

14

15

13

ECM

B137

D:

B135

B:

B137

B72

D:

B135

B:

B32

D8

B72

B14

3

2

M

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

2

7

8 9

5

6

3

4

10 11 12

19 20 21

29

30 31

13 14 15 16 17

27

28

18

22 23

24 25

26

1

2

7

8 9

5

6

3

4

10 11 12

19

20 21

29 30 31

13 14 15 16 17

27

28

18

22 23

24 25

26

32 33

34 35

1

3

4 5 6

2

BATTERY

IGNITION
SWITCH

STARTER RELAY

STARTER MOTOR

EN(H4DOTC)(diag)-51

ENGINE (DIAGNOSTICS)

Diagnostics for Engine Starting Failure

3

CHECK INPUT SIGNAL OF STARTER MO-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from starter
motor.
3) Turn the ignition switch to START.
4) Measure the power supply voltage between
starter motor connector terminal and engine
ground.

Connector & terminal

(B14) No. 1 (+) — Engine ground (

−

):

NOTE:

• For AT model, place the select lever in “P” or
“N” range.
• For MT model, depress the clutch pedal.

Is the voltage more than 10 V? Go to step 4.

Go to step 5.

4

CHECK GROUND CIRCUIT OF STARTER
MOTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the ground cable terminal from
starter motor.
3) Measure the resistance of ground cable
between ground cable terminal and engine
ground.

Is the resistance less than 5
Ω?

Check the starter
motor. <Ref. to
SC(H4SO 2.0)-6,
Starter.>

Repair the open
circuit of ground
cable.

5

CHECK HARNESS BETWEEN BATTERY
AND IGNITION SWITCH CONNECTOR.
1) Disconnect the connector from ignition
switch.
2) Measure the power supply voltage between
ignition switch connector and chassis ground.

Connector & terminal

(B72) No. 3 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Go to step 6.

Check the follow-
ing and repair if
necessary.

• Blown out
fuse
• Open circuit
of harness
between igni-
tion switch and
battery

6

CHECK IGNITION SWITCH.
1) Disconnect the connector from ignition
switch.
2) Measure the resistance between ignition
switch terminals after turning the ignition
switch to START position.

Terminals

No. 2 — No. 3:

Is the resistance less than 5
Ω?

Go to step 7.

Replace the igni-
tion switch.

7

CHECK INPUT VOLTAGE OF STARTER RE-
LAY.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from starter relay.
3) Connect the connector to ignition switch.
4) Measure the input voltage between starter
relay connector and chassis ground after turn-
ing the ignition switch to START position.

Connector & terminal

(B225) No. 14 (+) — Chassis ground (

−

):

(B225) No. 16 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Go to step 8.

Repair the open or
ground short cir-
cuit of harness
between starter
relay and ignition
switch.

8

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
Ω?

Go to step 9.

Replace the
starter relay.

Step

Check

Yes

No

EN(H4DOTC)(diag)-52

ENGINE (DIAGNOSTICS)

Diagnostics for Engine Starting Failure

9

CHECK INPUT VOLTAGE OF ECM.
1) Turn the ignition switch to OFF.
2) Connect the starter relay connector.
3) Disconnect the connector from ECM.
4) Measure the resistance of harness
between ECM and starter relay connector.

Connector & terminal

(B135) No. 32 — (B225) No. 15:

Is the resistance less than 1
Ω?

Go to step 10.

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

10

CHECK INPUT VOLTAGE OF STARTER MO-
TOR.
1) Turn the ignition switch to OFF.
2) Connect the connector to ECM.
3) Turn the ignition switch to START.
4) Measure the voltage between starter motor
and engine ground.

Connector & terminal

(B14) No. 1 (+) — Engine ground (

−

):

Is the voltage more than 10 V? Go to step 11.

Repair the open or
ground short cir-
cuit of harness
between starter
relay and starter.

11

CHECK HARNESS BETWEEN IGNITION
SWITCH AND ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ignition
switch and ECM.
3) Measure the resistance of harness
between ignition switch and ECM connector.

Connector & terminal

(B137) No. 8 — (B72) No. 2:

Is the resistance less than 1
Ω?

Check the engine
control module
(ECM) power sup-
ply and ground
line. <Ref. to
EN(H4DOTC)(diag
)-53, CHECK
POWER SUPPLY
AND GROUND
LINE OF ENGINE
CONTROL MOD-
ULE (ECM), Diag-
nostics for Engine
Starting Failure.>

Repair the open
circuit between
ignition switch and
ECM.

Step

Check

Yes

No