Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 241

EN(H4DOTC)(diag)-188

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK OUTPUT SIGNAL OF ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM connec-
tor and chassis ground.

Connector & terminal

(B134) No. 33 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step

2.

Go to step

3.

2

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.

Even if DTC is
detected, the cir-
cuit has returned to
a normal condition
at this time. Repro-
duce the failure,
and then perform
the diagnosis
again.
NOTE:

In this case, tem-
porary open or
short circuit of har-
ness or temporary
poor contact of
connector may be
the cause.

3

CHECK POWER SUPPLY TO WASTEGATE
CONTROL SOLENOID VALVE.
Measure the voltage between wastegate con-
trol solenoid valve connector and engine
ground.

Connector & terminal

(E64) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more?

Go to step

4.

Repair the power
supply circuit.

4

CHECK HARNESS BETWEEN ECM AND
WASTEGATE CONTROL SOLENOID VALVE
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
wastegate control solenoid valve.
3) Measure the resistance between wastegate
control solenoid valve connector and engine
ground.

Connector & terminal

(E64) No. 2 — Engine ground:

Is the resistance 1 MΩ or
more?

Go to step

5.

Repair ground
short circuit of har-
ness between
ECM connector
and wastegate
control solenoid
valve connector.

5

CHECK HARNESS BETWEEN ECM AND
WASTEGATE CONTROL SOLENOID VALVE
CONNECTOR.
Measure the resistance of harness between
ECM connector and wastegate control solenoid
valve connector.

Connector & terminal

(B134) No. 33 — (E64) No. 2:

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

wastegate

control

solenoid

valve connector
• Poor contact of
coupling connector

EN(H4DOTC)(diag)-189

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

6

CHECK WASTEGATE CONTROL SOLE-
NOID VALVE.
1) Remove the wastegate control solenoid
valve.
2) Measure the resistance between wastegate
control solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance 10 — 100 Ω? Repair poor con-

tact of wastegate
control solenoid
valve connector.

Replace the
wastegate control
solenoid valve.
<Ref. to FU(STI)-
52, Wastegate
Control Solenoid
Valve.> <Ref. to
FU(w/o STI)-51,
Wastegate Control
Solenoid Valve.>

Step

Check

Yes

No

EN(H4DOTC)(diag)-190

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BD:DTC P0246 TURBO/SUPER CHARGER WASTEGATE SOLENOID “A” HIGH

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-112, DTC P0246 TURBO/SUPER CHARGER

WASTEGATE SOLENOID “A” HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Poor driving performance
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.>

ECM

EN-08729

B220

24

23

22

21

15A

B220

3

4

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

4

8

50

E2

B21

1 2

E64

B21

E64

33

B134

54

52 53

50 51

48 49

46 47

45

44

42 43

40 41

38 39

36 37

34 35

33

32

31

30

29

28

27

26

25

24

23

22

21

20

11

10

9

19

18

17

16

8

7

6

5

15

14

13

12

4

3

2

1

SBF-7

E

BATTERY

WASTEGATE CONTROL

SOLENOID VALVE

FUSE

(RELAY BLOCK)

MAIN RELAY

EN(H4DOTC)(diag)-191

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK HARNESS BETWEEN ECM AND
WASTEGATE CONTROL SOLENOID VALVE
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
wastegate control solenoid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM connec-
tor and chassis ground.

Connector & terminal

(B134) No. 33 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair short circuit
to power in har-
ness between
ECM connector
and wastegate
control solenoid
valve connector.

Go to step

2.

2

CHECK WASTEGATE CONTROL SOLE-
NOID VALVE.
1) Turn the ignition switch to OFF.
2) Measure the resistance between wastegate
control solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance less than 1 Ω? Replace the

wastegate control
solenoid valve.
<Ref. to FU(STI)-
52, Wastegate
Control Solenoid
Valve.> <Ref. to
FU(w/o STI)-51,
Wastegate Control
Solenoid Valve.>

Repair the poor
contact of ECM
connector.