Subaru Legacy III (2000-2003 year). Manual - part 511

EN(H4DOSTC)-214

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

BC:DTC P1240 — EXHAUST CONTROL VALVE SOLENOID CIRCUIT HIGH 

(NEGATIVE 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)-215

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. 3 (+) — 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 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 (NEG-
ATIVE PRESSURE) AND ECM CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from exhaust 

valve control solenoid valve (negative pres-
sure).

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

chassis ground.

Connector & terminal

(B136) No. 3 (+) — 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 (nega-
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 (NEGATIVE PRESSURE).
1) Turn the ignition switch to OFF.
2) Measure the resistance between exhaust 

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

Terminals

No. 5 — No. 6:

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

1 

Ω

Replace the 
exhaust valve con-
trol solenoid valve 
(negative 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 (negative pressure) con-
nectors.
Are there poor contact in ECM and exhaust 
valve control solenoid valve (negative pres-
sure) connectors?

There are poor contacts.

Repair the poor 
contact in ECM 
connector.

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

EN(H4DOSTC)-216

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

BD:DTC P1241 — 2STAGE TWIN TURBO SYSTEM (SINGLE) —

• 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:

Step

Value

Yes

No

1

CHECK ANY OTHER DTC ON DISPLAY.
Is any other DTC displayed?

DTC indicated.

Inspect the rele-
vant DTC using 
“List of Diagnostic 
Trouble Code 
(DTC)”. <Ref. to 
EN(H4DOSTC)-
62, List of Diag-
nostic Trouble 
Code (DTC).>

Go to step 2.

2

CHECK OPERATION OF RELIEF VALVE 
CONTROL SOLENOID VALVE 2.
Operate the relief valve control solenoid valve 
2. <Ref. to EN(H4DOSTC)-36, Compulsory 
Valve Operation Check Mode.>
Does the relief valve control solenoid valve 2 
produce operating sound?

Operating sound produced.

Go to step 3.

Replace the relief 
valve control sole-
noid valve 2. <Ref. 
to IN(H4DOSTC)-
19, Solenoid Box 
Assembly.>

3

CHECK OPERATION OF EXHAUST CON-
TROL VALVE.
1) Operate the exhaust valve control solenoid 

valve. <Ref. to EN(H4DOSTC)-36, Compul-
sory Valve Operation Check Mode.>

2) Check the operation of exhaust control 

valve actuator.
Does the actuator rod operate correctly?.

NOTE:

Actuator rod operates in approx. 7 second cy-
cle, and stroke is approx. 30 mm (1.18 in).

Operates correctly.

Go to step 4.

Check the exhaust 
valve control sole-
noid valve and 
vacuum hose. 
<Ref. to 
IN(H4DOSTC)-19, 
Solenoid Box 
Assembly.>

4

CHECK OPERATION OF INTAKE AIR CON-
TROL VALVE.
1) Operate the intake air valve control sole-

noid valve. <Ref. to EN(H4DOSTC)-36, 
Compulsory Valve Operation Check 
Mode.>

2) Check the operation of intake air control 

valve actuator.
Does the actuator rod operate correctly?

NOTE:

Actuator rod operates in approx. 2 second cy-
cle, and stroke is approx. 12 mm (0.47 in).

Operates correctly.

Go to step 5.

Check the intake 
air control solenoid 
valve and vacuum 
hose. <Ref. to 
IN(H4DOSTC)-19, 
Solenoid Box 
Assembly.>

5

CHECK RELIEF VALVE.
1) Remove the relief valve.
2) Check the relief valve.

Is there a fault in the relief valve and hose 
routing?

There is no problem.

Go to step 6.

Replace or repair 
the relief valve and 
vacuum hose.

6

CHECK VACUUM HOSES OF EXHAUST 
VALVE CONTROL SOLENOID VALVE (POS-
ITIVE PRESSURE).
Are there cracks, stuck or improper routing on 
vacuum hose?

There is no problem.

Go to step 7.

Repair or replace 
the vacuum hoses.

EN(H4DOSTC)-217

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

7

CHECK VACUUM HOSES OF DIFFEREN-
TIAL PRESSURE SENSOR.
Are there cracks, stuck or improper routing on 
vacuum hose?

There is no problem.

Go to step 8.

Repair or replace 
the vacuum hoses.

8

CHECK VACUUM HOSES OF PRIMARY 
TURBOCHARGER WASTEGATE CONTROL 
VALVE.
Are there cracks, stuck or improper routing on 
vacuum hose?

There is no problem.

Go to step 9.

Repair or replace 
the vacuum hoses.

9

CHECK VACUUM HOSES BETWEEN SOLE-
NOID BOX AND SURGE TANK.
Are there cracks, stuck or improper routing on 
vacuum hose?

There is no problem.

Go to step 10.

Repair or replace 
the vacuum hoses.

10

CHECK PRIMARY TURBOCHARGER 
WASTEGATE VALVE.
Is there a fault on the primary turbocharger 
wastegate valve?

There is no problem.

Go to step 11.

Replace the pri-
mary turbo-
charger. <Ref. to 
IN(H4DOSTC)-15, 
Turbocharger.>

11

CHECK LH AND RH INTAKE DUCT.
Are there cracks or stuck on the LH and RH 
intake duct?

There is no problem.

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

Replace the air 
intake duct. <Ref. 
to IN(H4DOSTC)-
12, Intake Duct.>

Step

Value

Yes

No