Subaru Legacy (2005 year). Service manual — part 344

EN(H4DOTC)(diag)-145

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AM: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, 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-03527

B47

1

2

4

6

3

5

E

B21

E2

B47

B134

B134

E4

ECM

14

2

1

SBF-7

3

4

1

2

5

6

41

48

E4

B21

1 2

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

BATTERY

PURGE CONTROL
SOLENOID VALVE

MAIN RELAY

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

EN(H4DOTC)(diag)-146

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.

Terminals

No. 1 — No. 2:

Is the resistance 29 — 35

Ω?

Go to step 5.

Replace the purge
control solenoid
valve. <Ref. to
EC(H4DOTC)-6,
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(H4DOTC)-34,
Engine Control
Module (ECM).>

EN(H4DOTC)(diag)-147

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AN: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, 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-03527

B47

1

2

4

6

3

5

E

B21

E2

B47

B134

B134

E4

ECM

14

2

1

SBF-7

3

4

1

2

5

6

41

48

E4

B21

1 2

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

BATTERY

PURGE CONTROL
SOLENOID VALVE

MAIN RELAY

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

EN(H4DOTC)(diag)-148

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AO:DTC P0500 VEHICLE SPEED SENSOR “A”

DTC DETECTING CONDITION:
Immediately at fault recognition

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 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.

Does the purge control sole-
noid valve operate?

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 PURGE CONTROL SOLENOID
VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from purge con-
trol solenoid valve.
3) Measure the resistance between purge
control solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance less than 29
— 35

Ω?

Go to step 3.

Replace the purge
control solenoid
valve. <Ref. to
EC(H4DOTC)-6,
Purge Control
Solenoid Valve.>

3

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 less than 1 V?

Go to step 4.

Repair the battery
short circuit of har-
ness between
ECM and purge
control solenoid
valve connector.
After repair,
replace the ECM.
<Ref. to
FU(H4DOTC)-34,
Engine Control
Module (ECM).>

4

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(H4DOTC)-34,
Engine Control
Module (ECM).>

Step

Check

Yes

No

1

CHECK DTC OF ABS.
Check DTC of ABS.

Is DTC of ABS displayed?

Perform the diag-
nosis according to
DTC. <Ref. to
ABS(diag)-38, List
of Diagnostic Trou-
ble Code (DTC).>

Repair the poor
contact in ECM.