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.>