Subaru Legacy (2005 year). Manual - part 473

EN(H6DO)(diag)-205

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

BO:DTC P0458 EVAPORATIVE EMISSION SYSTEM PURGE CONTROL VALVE 

CIRCUIT LOW

DTC DETECTING CONDITION:
Detects when malfunction occurs in 2 continuous driving cycles.
TROUBLE SYMPTOM:
Erroneous idling

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H6DO)(diag)-41, 
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H6DO)(diag)-34, PROCEDURE, 
Inspection Mode.>.
WIRING DIAGRAM:

EN-03503

PURGE CONTROL

SOLENOID VALVE

E4

B47

B47

3

4

1

2

5

6

SBF-7

BATTERY

MAIN RELAY

14

B21

E2

48

41

B134

ECM

2

1

E4

1 2

E

B21

1 2 3 4

12 13 14 15

5 6 7 8

16 17 18 19

9 10 11

20 21 22

23 24 25 26 27 28 29 30 31 32 33

35

34

37

36

39

38

41

40

43

42

44

45

47

46

49

48

51

50

53

52

54

B134

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

33 34

29

32

30 31

10

2

E76

E77

1 2

3 4

5

6

7

8

9

10

E77

6
4

EN(H6DO)(diag)-206

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B134) No. 14 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Even if the mal-

function indicator 
light illuminates, 
the circuit has 
returned to a nor-
mal condition at 
this time.

Go to step 2.

2

CHECK HARNESS BETWEEN PURGE CON-
TROL SOLENOID VALVE AND ECM CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from purge con-
trol solenoid valve and ECM.
3) Measure the resistance of harness 
between purge control solenoid valve connec-
tor and engine ground.

Connector & terminal

(E4) No. 2 — Engine ground:

Is the resistance more than 1 
M

Ω?

Go to step 3.

Repair the ground 
short circuit of har-
ness between 
ECM and purge 
control solenoid 
valve connector.

3

CHECK HARNESS BETWEEN PURGE CON-
TROL SOLENOID VALVE AND ECM CON-
NECTOR.
Measure the resistance of harness between 
ECM and purge control solenoid valve.

Connector & terminal

(B134) No. 14 — (E4) No. 2:

Is the resistance less than 1 
Ω?

Go to step 4.

Repair the open 
circuit of harness 
between ECM and 
purge control sole-
noid valve connec-
tor.

NOTE:
In this case, repair
the following:
• Open circuit of 
harness between 
ECM and purge 
control solenoid 
valve connector
• Poor contact in 
coupling connector

4

CHECK PURGE CONTROL SOLENOID 
VALVE.
1) Remove the purge control solenoid valve.
2) Measure the resistance between purge 
control solenoid valve terminals.

Terminal

No. 1 — No. 2:

Is the resistance 10 — 100 

Ω? Go to step 5.

Replace the purge 
control solenoid 
valve. <Ref. to 
EC(H6DO)-7, 
Purge Control 
Solenoid Valve.>

5

CHECK POWER SUPPLY TO PURGE CON-
TROL SOLENOID VALVE.
1) Turn the ignition switch to ON.
2) Measure the voltage between purge control 
solenoid valve and engine ground.

Connector & terminal

(E4) No. 1 (+) — Engine ground (

−

):

Is the voltage more than 10 V? Go to step 6.

Repair the open 
circuit of harness 
between main 
relay and purge 
control solenoid 
valve connector.

6

CHECK POOR CONTACT.
Check poor contact in purge control solenoid 
valve connector.

Is there poor contact in purge 
control solenoid valve connec-
tor?

Repair the poor 
contact in purge 
control solenoid 
valve connector.

Replace the ECM. 
<Ref. to 
FU(H6DO)-34, 
Engine Control 
Module (ECM).>

EN(H6DO)(diag)-207

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

BP:DTC P0459 EVAPORATIVE EMISSION SYSTEM PURGE CONTROL VALVE 

CIRCUIT HIGH

DTC DETECTING CONDITION:
Detects when malfunction occurs in 2 continuous driving cycles.
TROUBLE SYMPTOM:
Erroneous idling

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H6DO)(diag)-41, 
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H6DO)(diag)-34, PROCEDURE, 
Inspection Mode.>.
WIRING DIAGRAM:

EN-03503

PURGE CONTROL

SOLENOID VALVE

E4

B47

B47

3

4

1

2

5

6

SBF-7

BATTERY

MAIN RELAY

14

B21

E2

48

41

B134

ECM

2

1

E4

1 2

E

B21

1 2 3 4

12 13 14 15

5 6 7 8

16 17 18 19

9 10 11

20 21 22

23 24 25 26 27 28 29 30 31 32 33

35

34

37

36

39

38

41

40

43

42

44

45

47

46

49

48

51

50

53

52

54

B134

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

33 34

29

32

30 31

10

2

E76

E77

1 2

3 4

5

6

7

8

9

10

E77

6
4

EN(H6DO)(diag)-208

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to OFF.
2) Connect the test mode connector at the 
lower portion of instrument panel (on the 
driver’s side).
3) Turn the ignition switch to ON.
4) While operating the purge control solenoid 
valve, measure voltage between ECM and 
chassis ground.

NOTE:

Purge control solenoid valve operation can be
executed using Subaru Select Monitor. Refer to
“Compulsory Valve Operation Check Mode” for
procedures. <Ref. to EN(H6DO)(diag)-42,
Compulsory Valve Operation Check Mode.>

Connector & terminal

(B134) No. 14 (+) — Chassis ground (

−

):

Is the voltage 0 — 10 V?

Go to step 2.

Even if the mal-
function indicator 
light illuminates, 
the circuit has 
returned to a nor-
mal condition at 
this time. In this 
case, repair the 
poor contact in 
ECM connector.

2

CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B134) No. 14 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Go to step 4.

Go to step 3.

3

CHECK POOR CONTACT.
Check poor contact in ECM connector.

Is there poor contact in ECM 
connector?

Repair the poor 
contact in ECM 
connector.

Replace the ECM. 
<Ref. to 
FU(H6DO)-34, 
Engine Control 
Module (ECM).>

4

CHECK HARNESS BETWEEN PURGE CON-
TROL SOLENOID VALVE AND ECM CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from purge con-
trol solenoid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B134) No. 14 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Repair the battery 

short circuit of har-
ness between 
ECM and purge 
control solenoid 
valve connector. 
After repair, 
replace the ECM. 
<Ref. to 
FU(H6DO)-34, 
Engine Control 
Module (ECM).>

Go to step 5.

5

CHECK PURGE CONTROL SOLENOID 
VALVE.
1) Turn the ignition switch to OFF.
2) Measure the resistance between purge 
control solenoid valve terminals.

Terminal

No. 1 — No. 2:

Is the resistance less than 1 
Ω?

Replace the purge 
control solenoid 
valve <Ref. to 
EC(H6DO)-7, 
Purge Control 
Solenoid Valve.> 
and ECM. <Ref. to 
FU(H6DO)-34, 
Engine Control 
Module (ECM).>

Go to step 6.

6

CHECK POOR CONTACT.
Check poor contact in ECM connector.

Is there poor contact in ECM 
connector?

Repair the poor 
contact in ECM 
connector.

Replace the ECM. 
<Ref. to 
FU(H6DO)-34, 
Engine Control 
Module (ECM).>