Subaru Legacy IV (2008 year). Manual - part 339

EN(H4DOTC)(diag)-177

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AW:DTC P0327 KNOCK SENSOR 1 CIRCUIT LOW (BANK 1 OR SINGLE SENSOR)

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-86, 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 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-05675

15

25

29

1

2

4

6

B134

B21

E2

E14

E

E14

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

1 2 3 4 5 6 7 8 9 10 11

12 13 14 15 16 17 18 19 20 21 22
23 24 25

34 35

36 37 38 39 40 41

48 49

50 51 52 53 54

42 43

44 45

46 47

26 27 28 29 30 31 32 33

B21

1 2

KNOCK SENSOR

ECM

EN(H4DOTC)(diag)-178

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

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

Connector & terminal

(B134) No. 15 — (B134) No. 29:

Is the resistance 600 k

: or 

more?

Go to step 2.

Repair the poor 
contact of ECM 
connector.

2

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

Terminals

No. 1 — No. 2:

Is the resistance 600 k

: or 

more?

Replace the knock 
sensor. <Ref. to 
FU(H4DOTC)-34, 
Knock Sensor.>

Repair the harness 
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and knock
sensor
• Poor contact of
the knock sensor
connector
• Poor contact of
coupling connector

EN(H4DOTC)(diag)-179

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AX:DTC P0328 KNOCK SENSOR 1 CIRCUIT HIGH (BANK 1 OR SINGLE SENSOR)

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-87, 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 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-05675

15

25

29

1

2

4

6

B134

B21

E2

E14

E

E14

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

1 2 3 4 5 6 7 8 9 10 11

12 13 14 15 16 17 18 19 20 21 22
23 24 25

34 35

36 37 38 39 40 41

48 49

50 51 52 53 54

42 43

44 45

46 47

26 27 28 29 30 31 32 33

B21

1 2

KNOCK SENSOR

ECM

EN(H4DOTC)(diag)-180

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

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

Connector & terminal

(B134) No. 15 — (B134) No. 29:

Is the resistance less than 
500 k

:?

Go to step 2.

Go to step 3.

2

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

Terminals

No. 1 — No. 2:

Is the resistance less than 
500 k

:?

Replace the knock 
sensor. <Ref. to 
FU(H4DOTC)-34, 
Knock Sensor.>

Repair the short 
circuit to ground in 
harness between 
ECM 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 ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B134) No. 15 (+) — 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
may be the cause.

Repair the poor 
contact of ECM 
connector.