Subaru Legacy III (2000-2003 year). Service manual - part 491

EN(H4DOSTC)-134

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

6

CHECK POOR CONTACT.
Check poor contact in ECM connector. 
Is there poor contact in ECM connector?

There is poor contact.

Repair the poor 
contact in ECM 
connector.

Inspection using 
“General Diagnos-
tic Table”. <Ref. to 
EN(H4DOSTC)-
246, INSPEC-
TION, General 
Diagnostic Table.>

Step

Value

Yes

No

EN(H4DOSTC)-135

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

MEMO:

EN(H4DOSTC)-136

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Z: DTC P0327 — KNOCK SENSOR 1 CIRCUIT LOW INPUT (BANK 1 OR SINGLE 

SENSOR) —

• TROUBLE SYMPTOM:

• Poor driving performance
• Knocking occurs.

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOSTC)-35, 
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOSTC)-33, Inspection 
Mode.> .
• WIRING DIAGRAM:

E1

E14

B20

 KNOCK
SENSOR

2

6

B135 ECM

22

4

E

E14

1 2

1 2

3 4

5

6

7

8

9

10

B20

B135

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

EN-00941

EN(H4DOSTC)-137

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

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

ness connector and chassis ground.

Connector & terminal

(B135) No. 4 — Chassis ground:

Does the measured value exceed the spec-
ified value?

700 k

Ω

Go to step 2.

Repair the har-
ness and connec-
tor.

NOTE:
In this case, repair
the following:
• Open circuit in 
harness between 
knock sensor and 
ECM connector
• Poor contact in 
knock sensor con-
nector
• Poor contact in 
coupling connector

2

CHECK KNOCK SENSOR.
1) Disconnect the connector from knock sen-

sor.

2) Measure the resistance between knock 

sensor connector terminal and engine 
ground.

Terminal

No. 2 — Engine ground:

Does the measured value exceed the spec-
ified value?

700 k

Ω

Go to step 3.

Repair the har-
ness and connec-
tor.

NOTE:
In this case, repair
the following:
• Open circuit in 
harness between 
knock sensor and 
ECM connector
• Poor contact in 
knock sensor con-
nector
• Poor contact in 
coupling connector

3

CHECK CONDITION OF KNOCK SENSOR 
INSTALLATION.
Is the knock sensor installation bolt tightened 
securely?

Tightened securely.

Replace the knock 
sensor.  <Ref. to 
FU(H4DOSTC)-
31, Knock Sen-
sor.>

Tighten the knock 
sensor installation 
bolt securely.