Subaru Legacy III (2000-2003 year). Manual - part 154

EN(H4SO)-228

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

AY:DTC P0507 — IDLE CONTROL SYSTEM RPM HIGHER THAN EXPECTED —

• DTC DETECTING CONDITION:

• Two consecutive driving cycles with fault

• TROUBLE SYMPTOM:

• Engine keeps running at higher revolution than specified idling revolution.

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode<Ref. to EN(H4SO)-47, OPER-
ATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4SO)-40, OPERATION, Inspection 
Mode.> .
• WIRING DIAGRAM:

EN-01134

F44

B61

6

RHD

RHD

20

6

5

19

B21

E2

ECM

2

5

6

3

4

1

3

4

1

2

IDLE 

AIR CONTROL

SOLENOID 

VALVE

E7

B22

E3

B47

B134

B47

3

4

1

2

5

6

B134

1 2

3 4

5 6

7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

24 25

26 27 28 29

30 31 32 33

34 35

B22

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

E7

1

3

4 5 6

2

B21

1 2

3 4

5

6 7

8

9 10

11 12

13

14 15

16

17 18

19 20

SBF-5

BATTERY

MAIN RELAY

1

2

3

5

4

6

1

1 2 3 4
5 6 7 8

F44

LHD

LHD

EN(H4SO)-229

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(H4SO)-83, List 
of Diagnostic 
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 ignition switch to ON.
2) Start 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 any fault in air intake system?

There is a fault.

Repair air suction 
and leaks.

Go to step 3.

3

CHECK THROTTLE CABLE.
Does throttle cable have play for adjustment?

Cable has play.

Go to step 4.

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

4

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

throttle body. <Ref. to FU(H4SO)-34, 
REMOVAL, Idle Air Control Solenoid 
Valve.>

3) Confirm that there are no foreign particles 

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

There are foreign particles.

Remove foreign 
particles from by-
pass air line.

Replace idle air 
control solenoid 
valve. <Ref. to 
FU(H4SO)-34, Idle 
Air Control Sole-
noid Valve.>

EN(H4SO)-230

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

AZ:DTC P0512 — STARTER REQUEST CIRCUIT —

• DTC DETECTING CONDITION:

• Two consecutive driving cycles with fault

• TROUBLE SYMPTOM:

• Failure of engine to start

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode<Ref. to EN(H4SO)-47, OPER-
ATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4SO)-40, OPERATION, Inspection 
Mode.> .

EN(H4SO)-231

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

• WIRING DIAGRAM:

Step

Value

Yes

No

1

CHECK OPERATION OF STARTER MOTOR.

NOTE:

Place the inhibitor switch in each position.

Does starter motor operate when ignition 
switch to “ON”?

Operates.

Repair battery 
short circuit in 
starter motor cir-
cuit.

Check starter 
motor circuit. <Ref. 
to EN(H4SO)-62, 
Diagnostics for 
Engine Starting 
Failure.>

EN-01118

12

INHIBITOR SWITCH

STARTER
MOTOR

7

P

R

N

D

3

2

1

SBF-4

SBF-1

B14

B72

12

11

T7

T3

B12

1
3

IGNITION
SWITCH

AT

MT

AT

MT

T7

1 2 3 4 5 6
7 8 9 10 11 12

B72

3 4

1 2

20

B136

ECM

BATTERY

B12

1 2 3 4
5 6 7 8
9 10 11 12

B136

5 6

7

2

1

9

8

4

3

23

21 22

24

10 11 12 13 14

25 26

15 16 17

18 19 20