Subaru Legacy III (2000-2003 year). Service manual — part 515

EN(H4DOSTC)-230

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

BI: DTC P1250 — RELIEF VALVE CONTROL SOLENOID VALVE 2 CIRCUIT

HIGH —

• 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)-231

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. 11 (+) — 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 RELIEF
VALVE CONTROL SOLENOID VALVE 2 AND
ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from relief valve

control solenoid valve 2.

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

chassis ground.

Connector & terminal

(B136) No. 11 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Repair the battery
short circuit in har-
ness between
ECM and relief
valve control sole-
noid valve 2 con-
nector. After
repair, replace the
ECM. <Ref. to
FU(H4DOSTC)-
40, Engine Con-
trol Module.>

Go to step 4.

4

CHECK RELIEF VALVE CONTROL SOLE-
NOID VALVE 2.
1) Turn the ignition switch to OFF.
2) Measure the resistance between relief

valve control solenoid valve 2 terminals.

Terminals

No. 1 — No. 2:

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

1

Ω

Replace the relief
valve control sole-
noid valve 2.
<Ref. to
IN(H4DOSTC)-19,
Solenoid Box
Assembly.> and
replace ECM
<Ref. to
FU(H4DOSTC)-
40, Engine Con-
trol Module.>

Go to step 5.

5

CHECK POOR CONTACT.
Check poor contact in ECM and relief valve
control solenoid valve 2 connectors.
Are there poor contact in ECM and relief valve
control solenoid valve 2 connectors?

There are poor contacts.

Repair the poor
contact in ECM
and relief valve
control solenoid
valve 2 connec-
tors.

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

EN(H4DOSTC)-232

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

BJ:DTC P1507 — IDLE CONTROL SYSTEM MALFUNCTION (FAIL-SAFE) —

• TROUBLE SYMPTOM:

• Engine keeps running at higher revolution than specified idling revolution.
• Fuel is cut according to fail-safe function.

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-00947

BATTERY

MAIN RELAY

E

E

6
4

5
3

2
1

10

IDLE
AIR CONTROL
SOLENOID
VALVE

1

3

E7

B47

B47

3

4

1

2

5

6

1 2

7

8 9

5

6

3

4

10 11 12
19 20 21

13 14 15 16

17 18

22 23 24

B136

B136 ECM

2

1

B22

E3

SBF-5

B22

E7

1 2 3

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

13 14 15 16

B21

E2

B21

12

EN(H4DOSTC)-233

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

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).>

NOTE:
In this case, it is
not necessary to
inspect DTC
P0507.

Go to step 2.

2

CHECK AIR INTAKE SYSTEM.
1) Turn the ignition switch to ON.
2) Start the engine, and idle it.
3) Check the following items:
•Loose installation of intake manifold, idle air
control solenoid valve and throttle body
•Cracks of intake manifold gasket, idle air con-
trol solenoid valve gasket and throttle body
gasket
•Disconnections of vacuum hoses

Is there a fault in the air intake system?

There is no problem.

Go to step 3.

Repair the air suc-
tion and leaks.

3

CHECK THROTTLE CABLE.
Does the throttle cable have play for adjust-
ment?

Cable has play correctly.

Go to step 4.

Adjust the throttle
cable. <Ref. to
SP(H4SO)-10,
Accelerator Con-
trol Cable.>

4

CHECK AIR BY-PASS LINE.
1) Turn the ignition switch to OFF.
2) Remove the idle air control solenoid valve

from throttle body. <Ref. to
FU(H4DOSTC)-35, Idle Air Control Sole-
noid Valve.>

3) Confirm that there are no foreign particles

in the by-pass air line.
Are foreign particles in the by-pass air line?

Foreign particles are in the by-
pass air line.

Remove the for-
eign particles from
by-pass air line.

Replace the idle
air control solenoid
valve. <Ref. to
FU(H4DOSTC)-
35, Idle Air Con-
trol Solenoid
Valve.>