Subaru Legacy III (2000-2003 year). Manual - part 509

EN(H4DOSTC)-206

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

6

CHECK POOR CONTACT.
Check poor contact in exhaust valve control 
solenoid valve (positive pressure) and ECM 
connectors.
Is there poor contact in exhaust valve control 
solenoid valve (positive pressure) and ECM 
connectors?

There is poor contact.

Repair the poor 
contact in exhaust 
valve control sole-
noid valve (posi-
tive pressure) and 
ECM connectors.

Contact SUBARU 
distributor service.

NOTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.

Step

Value

Yes

No

EN(H4DOSTC)-207

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

MEMO:

EN(H4DOSTC)-208

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

BA:DTC P1238 — EXHAUST CONTROL VALVE SOLENOID CIRCUIT HIGH 

(POSITIVE PRESSURE) —

• TROUBLE SYMPTOM:

• Poor driving performance

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:

EN-00939

B220

B47

E

BATTERY

MAIN RELAY

3

B136

ECM

SBF-5

5

2
1

4

6

B47

3

4

1

2

5

6

B220

SOLENOID 
BOX ASSY

1

2

3

4

5

6

7

8

9

10

11

12

(A)

(B)

(C)

(D)

(E)

(F)

(A): RELIEF VALVE SOLENOID 2
(B): RELIEF VALVE SOLENOID 1
(C): EXHAUST VALVE CONTROL SOLENOID VALVE
       (NEGATIVE PRESSURE)
(D): EXHAUST VALVE CONTROL SOLENOID VALVE
       (POSITIVE PRESSURE)
(E): INTAKE AIR CONTROL SOLENOID VALVE
(F): EXHAUST VALVE CONTROL DUTY SOLENOID VALVE

C:

B137

D:

C11

C12

C3

C1

D22

D11

1 2 3 4
5 6 7 8
9 10 11 12

B136

1 2

7

8 9

5

6

3

4

10 11 12
19 20 21

13 14 15 16

17 18

22 23 24

B137

1

2

7

8

9

5

6

3

4

10 11 12

19 20 21
29 30 31

13 14 15 16 17

27 28

18

22 23 24 25 26

EN(H4DOSTC)-209

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK INPUT SIGNAL TO ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and 

chassis ground.

Connector & terminal

(B136) No. 1 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 3.

Go to step 2.

2

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

There is poor contact.

Repair the poor 
contact in ECM 
connector.

Replace the ECM.  
<Ref. to 
FU(H4DOSTC)-
40, Engine Con-
trol Module.>

3

CHECK HARNESS BETWEEN EXHAUST 
VALVE CONTROL SOLENOID VALVE (POS-
ITIVE PRESSURE) AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from exhaust 

valve control solenoid valve (positive pres-
sure).

3) Turn the ignition switch to ON.
4) Measure the voltage between ECM and 

chassis ground.

Connector & terminal

(B136) No. 1 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Repair the battery 
short circuit in har-
ness between 
ECM and exhaust 
valve control sole-
noid valve (posi-
tive pressure)  
connector. After 
repair, replace the 
ECM.  <Ref. to 
FU(H4DOSTC)-
40, Engine Con-
trol Module.>

Go to step 4.

4

CHECK EXHAUST VALVE CONTROL SOLE-
NOID VALVE (POSITIVE PRESSURE).
1) Turn the ignition switch to OFF.
2) Measure the resistance between exhaust 

valve control solenoid valve (positive pres-
sure) terminals.

Terminals

No. 7 — No. 8:

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

1 

Ω

Replace the 
exhaust valve con-
trol solenoid valve 
(positive pres-
sure). <Ref. to 
IN(H4DOSTC)-19, 
Solenoid Box 
Assembly.> and 
ECM  <Ref. to 
FU(H4DOSTC)-
40, Engine Con-
trol Module.>

Go to step 5.

5

CHECK POOR CONTACT.
Check poor contact in ECM and exhaust valve 
control solenoid valve (positive pressure).
Is there poor contact in ECM and exhaust 
valve control solenoid valve (positive pres-
sure)?

There is poor contact.

Repair the poor 
contact in ECM 
and exhaust valve 
control solenoid 
valve (positive 
pressure).

Replace the ECM.  
<Ref. to 
FU(H4DOSTC)-
40, Engine Con-
trol Module.>