Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 245

EN(H4DOTC)(diag)-204

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BJ:DTC P0327 KNOCK SENSOR 1 CIRCUIT LOW (BANK 1 OR SINGLE SEN-

SOR)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-124, DTC P0327 KNOCK SENSOR 1 CIRCUIT LOW

(BANK 1 OR SINGLE SENSOR), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Poor driving performance

• Knocking occurs
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-08730

D2

D

8

A29

B21

B137

D:

A:

31

30

29

28

27

21

20

19

18

17

16

26

25

24

15

14

13

12

11

23

22

10

3

4

9

1

2

8

7

6

5

2

1

E14

33

32

31

30

29

28

27

26

47

46

45

44

43

42

54

53

52

51

50

49

48

41

40

39

38

37

36

35

34

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

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

B134

E14

E2

B21

B137

B134

D:

A:

6

4

2

1

E

KNOCK SENSOR

EN(H4DOTC)(diag)-205

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK HARNESS BETWEEN ECM AND
KNOCK SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance between ECM con-
nectors.

Connector & terminal

(B137) No. 2 — (B134) No. 29:

Is the resistance less than 500
kΩ?

Go to step

2.

Go to step

3.

2

CHECK KNOCK SENSOR.
1) Disconnect the connector from the knock
sensor.
2) Measure the resistance between knock
sensor connectors.

Terminals

No. 1 — No. 2:

Is the resistance less than 500
kΩ?

Replace the knock
sensor. <Ref. to
FU(STI)-40, Knock
Sensor.> <Ref. to
FU(w/o STI)-39,
Knock Sensor.>

Repair the short
circuit to ground in
harness between
ECM connector
and knock sensor
connector.
NOTE:

The harness be-
tween both con-
nectors

are

shielded. Remove
the shield and re-
pair the short cir-
cuit of harness.

3

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

Connector & terminal

(B137) No. 2 (+) — Chassis ground (–):

Is the voltage 2 V or more?

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 poor con-
tact of connector,
temporary open or
short circuit of har-
ness may be the
cause.

Repair the short
circuit to ground in
harness between
ECM connector
and knock sensor
connector.
NOTE:

The harness be-
tween both con-
nectors

are

shielded. Remove
the shield and re-
pair the short cir-
cuit of harness.

EN(H4DOTC)(diag)-206

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

BK:DTC P0328 KNOCK SENSOR 1 CIRCUIT HIGH (BANK 1 OR SINGLE SEN-

SOR)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-126, DTC P0328 KNOCK SENSOR 1 CIRCUIT HIGH

(BANK 1 OR SINGLE SENSOR), Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Poor driving performance

• Knocking occurs
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-08730

D2

D

8

A29

B21

B137

D:

A:

31

30

29

28

27

21

20

19

18

17

16

26

25

24

15

14

13

12

11

23

22

10

3

4

9

1

2

8

7

6

5

2

1

E14

33

32

31

30

29

28

27

26

47

46

45

44

43

42

54

53

52

51

50

49

48

41

40

39

38

37

36

35

34

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

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

B134

E14

E2

B21

B137

B134

D:

A:

6

4

2

1

E

KNOCK SENSOR

EN(H4DOTC)(diag)-207

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK HARNESS BETWEEN ECM AND
KNOCK SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance between ECM con-
nectors.

Connector & terminal

(B137) No. 2 — (B134) No. 29:

Is the resistance 600 kΩ or
more?

Go to step

2.

Repair the poor
contact of ECM
connector.

2

CHECK KNOCK SENSOR.
1) Disconnect the connector from the knock
sensor.
2) Measure the resistance between knock
sensor terminals.

Terminals

No. 1 — No. 2:

Is the resistance 600 kΩ or
more?

Replace the knock
sensor. <Ref. to
FU(STI)-40, Knock
Sensor.> <Ref. to
FU(w/o STI)-39,
Knock Sensor.>

Repair the harness
and connector.
NOTE:

In this case, repair
the following item:
• Open circuit in
harness between
ECM

connector

and knock sensor
connector
• Poor contact of
knock sensor con-
nector
• Poor contact of
coupling connector