Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 214

EN(H4DOTC)(diag)-80

Diagnostics for Engine Starting Failure

ENGINE (DIAGNOSTICS)

D: IGNITION CONTROL SYSTEM

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-63,

OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-49, PROCE-

DURE, Inspection Mode.>.

WIRING DIAGRAM:

• Engine electrical system, without SI-DRIVE <Ref. to WI-32, WITHOUT SI-DRIVE, WIRING DIAGRAM,

Engine Electrical System.>

• Engine electrical system, with SI-DRIVE <Ref. to WI-48, WITH SI-DRIVE, WIRING DIAGRAM, Engine

Electrical System.>

Step

Check

Yes

No

1

CHECK SPARK PLUG CONDITION.
1) Remove the spark plug. <Ref. to IG(STI)-4,
REMOVAL, Spark Plug.> <Ref. to IG(w/o STI)-
5, REMOVAL, Spark Plug.>
2) Check the spark plug condition. <Ref. to
IG(STI)-5, INSPECTION, Spark Plug.> <Ref. to
IG(w/o STI)-6, INSPECTION, Spark Plug.>

Is the spark plug condition nor-
mal?

Go to step

2.

Replace the spark
plug. <Ref. to
IG(STI)-4, Spark
Plug.> <Ref. to
IG(w/o STI)-5,
Spark Plug.>

ECM

EN-08716

B72

B134

21

22

31

32

1

3

E2

B21

E31

E32

E33

E34

E34

E33

E32

E31

1
2
3

B21

3

1

2

3

1

2

9

49

20

31

10

3

1

2

3

1

2

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

B134

31

30

32

29

34

33

21

20

19

18

17

16

28

27

26

15

14

13

12

11

25

23

22

24

10

3

4

9

1

2

8

7

6

5

2

6

5

4

3

1

SBF-6

E

E

IGNITION COIL

No. 2

IGNITION COIL

No. 4

IGNITION COIL

No. 3

IGNITION COIL

No. 1

IGNITION

SWITCH

No. 12

MAIN

SBF

BATTERY

EN(H4DOTC)(diag)-81

Diagnostics for Engine Starting Failure

ENGINE (DIAGNOSTICS)

2

CHECK IGNITION SYSTEM FOR SPARKS.
1) Connect the spark plug to ignition coil.
2) Release the fuel pressure. <Ref. to FU(STI)-
67, RELEASING OF FUEL PRESSURE, PRO-
CEDURE, Fuel.> <Ref. to FU(w/o STI)-65,
RELEASING OF FUEL PRESSURE, PROCE-
DURE, Fuel.>
3) Contact the spark plug thread portion to
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)
-82, FUEL PUMP
CIRCUIT, Diagnos-
tics for Engine
Starting Failure.>

Go to step

3.

3

CHECK IGNITION COIL POWER SUPPLY
CIRCUIT.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ignition coil.
3) Turn the ignition switch to ON.
4) Measure the power supply 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 circuit or
short circuit to
ground in power
supply circuit
• Poor contact of
coupling connector
• Blown out of fuse

4

CHECK HARNESS OF IGNITION COIL
GROUND CIRCUIT.
1) Turn the ignition switch to OFF.
2) Measure the resistance 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 1 Ω? Go to step

5.

Repair the open
circuit in harness
between ignition
coil connector and
engine ground.

5

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

Connector & terminal

(B134) No. 21 — (E31) No. 1:
(B134) No. 22 — (E32) No. 1:
(B134) No. 31 — (E33) No. 1:
(B134) No. 32 — (E34) No. 1:

Is the resistance less than 1 Ω? Go to step

6.

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
• Poor contact of
coupling connector

6

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

Connector & terminal

(B134) No. 21 — Engine ground:
(B134) No. 22 — Engine ground:
(B134) No. 31 — Engine ground:
(B134) No. 32 — Engine ground:

Is the resistance 1 MΩ or
more?

Go to step

7.

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

Step

Check

Yes

No

EN(H4DOTC)(diag)-82

Diagnostics for Engine Starting Failure

ENGINE (DIAGNOSTICS)

E: FUEL PUMP CIRCUIT

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-63,

OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-49, PROCE-

DURE, Inspection Mode.>.

7

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

Is there poor contact of ECM
connector?

Repair the poor
contact of ECM
connector.

Replace the igni-
tion coil. <Ref. to
IG(STI)-7, Ignition
Coil.> <Ref. to
IG(w/o STI)-8, Igni-
tion Coil.>

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)-64, Compulsory Valve Op-
eration Check Mode.>

Does the fuel pump emit oper-
ating sound?

Check the fuel
injector circuit.
<Ref. to
EN(H4DOTC)(diag)
-83, FUEL INJEC-
TOR CIRCUIT,
Diagnostics for
Engine Starting
Failure.>

Display the DTC.
<Ref. to
EN(H4DOTC)(diag)
-48, OPERATION,
Read Diagnostic
Trouble Code
(DTC).>

Step

Check

Yes

No

EN(H4DOTC)(diag)-83

Diagnostics for Engine Starting Failure

ENGINE (DIAGNOSTICS)

F: FUEL INJECTOR CIRCUIT

CAUTION:

• Check or repair only faulty parts.

• After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-

63, OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-49, PRO-

CEDURE, Inspection Mode.>.

WIRING DIAGRAM:

• Engine electrical system, without SI-DRIVE <Ref. to WI-32, WITHOUT SI-DRIVE, WIRING DIAGRAM,

Engine Electrical System.>

• Engine electrical system, with SI-DRIVE <Ref. to WI-48, WITH SI-DRIVE, WIRING DIAGRAM, Engine

Electrical System.>

ECM

EN-08718

#4

2

1

#3

2

1

#2

2

1

B21

#1

2

1

4

8

54

53

52

51

10

11

12

13

1 2

B21

E5

E5

E2

E6

E6

E16

E16

E17

E17

B134

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

B220

24

23

22

15A

B220

3

4

21

B134

31

30

32

29

34

33

21

20

19

18

17

16

28

27

26

15

14

13

12

11

25

23

22

24

10

3

4

9

1

2

8

7

6

5

B220

18

19

6

7

4

3
5

2

1

12

11

10

9

8

40

36 39

38

37

34

33

35

32

28 31

30

29

23

22

21

20

26

25

24

27

17

16

15

14

13

E

SBF-7

MAIN RELAY

FUSE

(RELAY BLOCK)

FUEL INJECTOR

BATTERY