Subaru Legacy (2005 year). Manual - part 345

EN(H4DOTC)(diag)-149

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AP:DTC P0512 STARTER REQUEST CIRCUIT

DTC DETECTING CONDITION:
Detects when malfunction occurs in 2 continuous driving cycles.
TROUBLE SYMPTOM:
Failure of engine to start

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
37, OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)(diag)-30, PROCE-
DURE, Inspection Mode.>.
WIRING DIAGRAM:

EN-03518

No.21

B225

B225

MAIN SBF

SBF-6

E

16

14

15

13

ECM

B137

D:

B135

B:

B137

B72

D:

B135

B:

B32

D8

B72

B14

3

2

M

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 36

39 40

37
38

1

2

9

3

4

5

6

7

8

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

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

32 33

34 35

1

3

4 5 6

2

BATTERY

IGNITION
SWITCH

STARTER RELAY

STARTER MOTOR

EN(H4DOTC)(diag)-150

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AQ:DTC P0519 IDLE AIR CONTROL SYSTEM PERFORMANCE

DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
• Engine keeps running at higher speed than specified idle speed.
• Fuel is cut according to fail-safe function.

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
37, OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)(diag)-30, PROCE-
DURE, Inspection Mode.>.

Step

Check

Yes

No

1

CHECK HARNESS BETWEEN IGNITION 
SWITCH AND ECM.
1) Disconnect the connector from ECM.
2) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B137) No. 32 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Repair the battery 

short circuit of har-
ness between igni-
tion switch and 
ECM.

Repair the poor 
contact in ECM.

Step

Check

Yes

No

1

CHECK ANY OTHER DTC ON DISPLAY.

Is any other DTC displayed?

Inspect the rele-
vant DTC using 
“List of Diagnostic 
Trouble Code 
(DTC)”. <Ref. to 
EN(H4DOTC)(diag
)-62, List of Diag-
nostic Trouble 
Code (DTC).>

NOTE:
In this case, it is
not necessary to
inspect DTC
P0519.

Go to step 2.

2

CHECK AIR INTAKE SYSTEM.
1) Turn the ignition switch to ON.
2) Start and idle the engine.
3) Check the following items.
• Loose installation of intake manifold and 
throttle body
• Cracks of intake manifold gasket and throttle 
body gasket
• Disconnections of vacuum hoses

Is there any fault in air intake 
system?

Repair air suction 
and leaks.

Go to step 3.

3

CHECK ELECTRONIC THROTTLE CON-
TROL.
1) Turn the ignition switch to OFF.
2) Remove the electronic throttle control.
3) Check the electronic throttle control.

Are foreign matters found 
inside the electronic throttle 
control?

Remove foreign 
matters from the 
electronic throttle 
control.

Perform the diag-
nosis of DTC 
P2101.

EN(H4DOTC)(diag)-151

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AR:DTC P0562 SYSTEM VOLTAGE LOW

DTC DETECTING CONDITION:
Detects when the power supply voltage of ECM is low.
TROUBLE SYMPTOM:
Charge indicator light illuminates.

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
37, OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)(diag)-30, PROCE-
DURE, Inspection Mode.>.
WIRING DIAGRAM:

EN-03528

B47

E

SBF-7

MAIN SBF

B47

B135

ECM

5

6

5
4

6
3

2
1

3

4

1

2

5

6

B135

GENERATOR

MAIN RELAY

BATTERY

5

6

7

8

2

1

9

4

3

10

24

22 23

25

11 12 13 14 15

26 27

28

16 17 18 19

20 21

29 30 31

32 33

34 35

EN(H4DOTC)(diag)-152

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK BATTERY.
1) Turn the ignition switch to OFF.
2) Measure the battery voltage and specific 
gravity of electrolyte.

Is the voltage more than 12 V 
and the specific gravity more 
than 1.26?

Go to step 2.

Charge or replace 
the battery. 

2

CHECK GENERATOR.
1) Start the engine.
2) Run the engine at idle after warming up.
3) Measure the voltage between generator B 
terminal and chassis ground.

Terminals

Generator B terminal (+) — Chassis 
ground (

−

):

Is the voltage more than 10.8 
V?

Go to step 3.

Repair the genera-
tor. <Ref. to 
SC(H4SO 2.0)-14, 
Generator.>

3

CHECK GENERATOR.
1) Run the engine at 5,000 rpm.
2) Measure the voltage between generator B 
terminal and chassis ground.

Terminals

Generator B terminal (+) — Chassis 
ground (

−

):

Is the voltage more than 10.8 
V?

Go to step 4.

Repair the genera-
tor. <Ref. to 
SC(H4SO 2.0)-14, 
Generator.>

4

CHECK BATTERY TERMINAL.
1) Turn the ignition switch to OFF.
2) Check the installation of positive and nega-
tive terminals of battery.

Are the positive and negative 
battery terminals clamped 
tightly?

Go to step 5.

Tighten the clamp 
of terminal.

5

CHECK INPUT VOLTAGE OF ECM.
1) Run the engine at idle.
2) Measure the voltage between ECM con-
nector and chassis ground.

Connector & terminal

(B135) No. 5 (+) — Chassis ground (

−

):

(B135) No. 6 (+) — Chassis ground (

−

):

Is the voltage more than 10.8 
V?

Go to step 6.

Repair the har-
ness connectors 
between battery, 
main relay and 
ECM.

6

CHECK POOR CONTACT IN CONNECTORS.
Check the poor contact in connectors between 
generator, battery and ECM.

Is there poor contact in con-
nectors between generator, 
battery and ECM?

Repair the poor 
contact.

Go to step 7.

7

CHECK ECM.
1) Connect all the connectors.
2) Perform the clear memory mode. <Ref. to 
EN(H4DOTC)(diag)-37, Clear Memory Mode.>
3) Perform the inspection mode. <Ref. to 
EN(H4DOTC)(diag)-30, Inspection Mode.>
4) Read the DTC. <Ref. to 
EN(H4DOTC)(diag)-29, Read Diagnostic Trou-
ble Code (DTC).>
Check if the same DTC is displayed.

Is the same DTC displayed?

Replace the gen-
erator.

Go to step 8.

8

CHECK OTHER DTC DETECTION.
Check if any other DTC is displayed.

Is any other DTC displayed?

Perform the diag-
nosis of DTC dis-
played.

Temporary poor 
contact occurs.