Subaru Legacy III (2000-2003 year). Service manual — part 512

EN(H4DOSTC)-218

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

BE:DTC P1242 — 2STAGE TWIN TURBO SYSTEM (TWIN) —

• 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).

Operate 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).

Operate correctly.

Go to step 5.

Check the intake
valve control sole-
noid 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)-219

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

EN(H4DOSTC)-220

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

BF:DTC P1247 — RELIEF VALVE CONTROL SOLENOID VALVE 1 CIRCUIT LOW

—

• 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)-221

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. 12 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Even if MI lights
up, the circuit has
returned to a nor-
mal condition at
this time. Contact
with your Subaru
distributor.

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

Go to step 2.

2

CHECK HARNESS BETWEEN RELIEF
VALVE CONTROL SOLENOID VALVE 1 AND
ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from relief valve

control solenoid valve 1 and ECM.

3) Measure the resistance of harness

between relief valve control solenoid valve
1 connector and engine ground.

Connector & terminal

(B220) No. 4 — Engine ground:

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 3.

Repair the ground
short circuit in har-
ness between
ECM and relief
valve control sole-
noid valve 1 con-
nector.

3

CHECK HARNESS BETWEEN RELIEF
VALVE CONTROL SOLENOID VALVE 1 AND
ECM CONNECTOR.
Measure the resistance of harness between
ECM and relief valve control solenoid valve 1
of harness connector.

Connector & terminal

(B136) No. 12 — (B220) No. 4:

Is the measured value less than the specified
value?

1

Ω

Go to step 4.

Repair the open
circuit in harness
between ECM and
relief valve control
solenoid valve 1
connector.

4

CHECK RELIEF VALVE CONTROL SOLE-
NOID VALVE 1.
Measure the resistance between relief valve
control solenoid valve 1 terminals.

Terminals

No. 3 — No. 4:

Is the measured value within the specified
value?

37 — 44

Ω

Go to step 5.

Replace the relief
valve control sole-
noid valve 1.
<Ref. to
IN(H4DOSTC)-19,
Solenoid Box
Assembly.>

5

CHECK POWER SUPPLY TO RELIEF VALVE
CONTROL SOLENOID VALVE 1.
1) Turn the ignition switch to ON.
2) Measure the voltage between relief valve

control solenoid valve 1 and engine ground.

Connector & terminal

(B220) No. 3 (+) — Engine ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 6.

Repair the open
circuit in harness
between main
relay and relief
valve control sole-
noid valve 1 con-
nector.