Subaru Legacy III (2000-2003 year). Manual - part 220

EN(H4SOw/oOBD)-70

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

7

CHECK ENGINE COOLANT TEMPERATURE 
SENSOR.
1) Raise temperature up to approx. 90

°

C 

(194

°

F).

CAUTION:

Be careful not to burn yourself.

2) Measure resistance between engine cool-

ant temperature sensor terminals.

Terminals

No. 1 — No. 2:

Is the measured value within the specified 
value?

0.2 — 0.3 k

Ω

Replace ECM.

Replace engine 
coolant tempera-
ture sensor.

Step

Value

Yes

No

EN(H4SOw/oOBD)-71

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

E: DTC 22 KNOCK SENSOR

• DIAGNOSIS:

• The knock sensor signal is abnormal.
• The harness connector between ECM and knock sensor is in short or open.

• TROUBLE SYMPTOM:

• Poor driving performance

CAUTION:
After repair or replacement of faulty parts, conduct CLEAR MEMORY and INSPECTION MODES. <Ref. 
to EN(H4SOw/oOBD)-28, OPERATION, Clear Memory Mode.>  and <Ref. to EN(H4SOw/oOBD)-26, OP-
ERATION, Inspection Mode.>
• WIRING DIAGRAM:

EN-01053

4

25

KNOCK

SENSOR

16

2

2

3

5

4

6 7

8

2

1

9

3

10

22

23

11 12 13 14 15

24 25

26 27

16 17 18

28 29

19 20

21

30

B136

ECM

B136

B83

B21

E2

E14

B83

B21

E14

1 2

1 2

5

6 7

8

13

14 15

16

9 10

11 12

3 4

17 18

19 20

1 2 3 4 5 6 7 8 9 10 11 12

EN(H4SOw/oOBD)-72

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK INPUT SIGNAL FOR ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM connector 

and chassis ground.

Connector & terminal

(B136) No. 4 (+) — Chassis ground (–):

Does the measured value exceed the spec-
ified value?

3 V

Go to step 2.

Go to step 3.

2

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

There is poor contact.

Repair poor con-
tact in ECM con-
nector.

Replace ECM.  
<Ref. to 
FU(H4SOw/
oOBD)-42, Engine 
Control Module.>

3

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

connector terminal and engine ground.

Terminal

No. 2 — Engine ground:

Is the measured value within the specified 
value?

530 k

Ω

 — 590 k

Ω

Go to step 4.

Replace knock 
sensor.  <Ref. to 
FU(w/oOBD)-, 
Knock Sensor.>

4

CHECK HARNESS CONNECTOR BETWEEN 
ECM AND KNOCK SENSOR.
1) Remove ECM connector.
2) Measure resistance of harness connector 

between ECM and knock sensor.

Connector & terminal

(E14) No. 2 — (B136) No. 4:

Is the measured value less than the speci-
fied value?

1 

Ω

Go to step 5.

Repair harness 
and connector.

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 
(B21)

5

CHECK HARNESS CONNECTOR BETWEEN 
ECM AND KNOCK SENSOR.
Measure resistance of harness of harness con-
nector between ECM connector and knock 
sensor.

Connector & terminal

(B136) No. 4 — Chassis ground:

Does the measured value exceed the specified 
value?

1 M

Ω

Go to step 6.

Repair ground 
short circuit 
between ECM and 
knock sensor.

6

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

There is poor contact.

Repair poor con-
tact in ECM con-
nector.

Replace ECM.  
<Ref. to 
FU(H4SOw/
oOBD)-42, Engine 
Control Module.>

EN(H4SOw/oOBD)-73

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

F: DTC 24 IDLE AIR CONTROL SOLENOID VALVE

• DIAGNOSIS:

• The idle air control solenoid valve is not in function.
• The harness connector between ECM and idle air control solenoid valve is in short or open.

• TROUBLE SYMPTOM:

• Erroneous idling
• Hard to start
• Poor driving performance

CAUTION:
After repair or replacement of faulty parts, conduct CLEAR MEMORY and INSPECTION MODES. <Ref. 
to EN(H4SOw/oOBD)-28, OPERATION, Clear Memory Mode.>  and <Ref. to EN(H4SOw/oOBD)-26, OP-
ERATION, Inspection Mode.>
• WIRING DIAGRAM:

EN-01054

5

6

19

20

B21

E2

F44

B61

ECM

2

5

6

3

4

1

3

4

1

2

IDLE 

AIR CONTROL

SOLENOID 

VALVE

E7

B22

E3

B47

B134

B47

3

4

1

2

5

6

B134

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

26 27 28 29

30 31 32 33

34 35

B22

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

E7

1

3

4 5 6

2

B21

1 2

3 4

5

6 7

8

9 10

11 12

13

14 15

16

17 18

19 20

SBF-5

BATTERY

MAIN RELAY

1

2

3

5

4

6

1

6

LHD

LHD

RHD

RHD

1 2 3 4
5 6 7 8

F44