Subaru Legacy (2005 year). Manual — part 140

EN(H4SO 2.0)(diag)-149

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

6

CHECK HARNESS BETWEEN EGR SOLE-
NOID VALVE AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from EGR sole-
noid valve and ECM.
3) Measure the resistance of harness
between EGR solenoid valve and ECM con-
nector.

Connector & terminal

(B134) No. 4 — (E18) No. 6:
(B134) No. 12 — (E18) No. 1:
(B134) No. 3 — (E18) No. 4:
(B134) No. 13 — (E18) No. 3:

Is the resistance less than 1
Ω?

Go to step 7.

Repair the open
circuit of harness
between ECM and
EGR solenoid
valve connector.

7

CHECK HARNESS BETWEEN EGR SOLE-
NOID VALVE AND ECM CONNECTOR.
Measure the resistance of harness between
EGR solenoid valve and chassis ground.

Connector & terminal

(B134) No. 4 — Chassis ground:
(B134) No. 3 — Chassis ground:
(B134) No. 12 — Chassis ground:
(B134) No. 13 — Chassis ground:

Is the resistance more than 1
M

Ω?

Go to step 8.

Repair the short
circuit of harness
between main
relay and EGR
solenoid valve
connector.

8

CHECK POOR CONTACT.
Check poor contact in ECM and EGR solenoid
valve connector.

Is there poor contact of ECM or
EGR solenoid valve connec-
tor?

Repair the poor
contact of ECM
and EGR solenoid
valve connector.

Even if the mal-
function indicator
light illuminates,
the circuit has
returned to the
specified condi-
tion at this time.

Step

Check

Yes

No

EN(H4SO 2.0)(diag)-150

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AJ:DTC P0420 CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD

(BANK1)

DTC DETECTING CONDITION:
Detects when malfunction occurs in 2 continuous driving cycles.
TROUBLE SYMPTOM:
• Engine stalls.
• Idle mixture is out of specifications.

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4SO 2.0)(diag)-
38, OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4SO 2.0)(diag)-32, PRO-
CEDURE, Inspection Mode.>.
WIRING DIAGRAM:

EN-03476

B47

T5

3

4

5

6

1

2

1 2
3 4

BATTERY

B47

MAIN RELAY

1

2

4

6

3

5

A1

C19

C18

C30

B5

B6

REAR
OXYGEN SENSOR

ECM

1

4

3

2

52

B21

T5

E2

1

B135

B:

SBF-5

C: B136

E

E

A: B134

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

B136

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

35

B135

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

A:

B:

C:

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

1 2 3 4
5 6 7 8

B138

B83

1

T5

B19

2

2

B19

B83

B138

:LHD

:RHD

*

*

*

*

1

*

: TERMINAL No. RANDOM
ARRANGEMENT AMONG
1,2,5, AND 6

2

*

: TERMINAL No. RANDOM
ARRANGEMENT AMONG
3,4,7, AND 8

EN(H4SO 2.0)(diag)-151

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK FOR ANY OTHER DTC ON DIS-
PLAY.

Is any other DTC displayed?

Inspect the rele-
vant DTC using
“List of Diagnostic
Trouble Code
(DTC)”. <Ref. to
EN(H4SO
2.0)(diag)-64, List
of Diagnostic Trou-
ble Code (DTC).>

NOTE:
In this case, it is
not necessary to
inspect DTC
P0420.

Go to step 2.

2

CHECK HARNESS BETWEEN ECM AND
REAR OXYGEN SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
rear oxygen sensor.
3) Measure the resistance of harness
between ECM and rear oxygen sensor con-
nector.

Connector & terminal

(B136) No. 19 — (B19) No. 4:
(B136) No. 18 — (B19) No. 3:

Is the resistance less than 1
Ω?

Go to step 3.

Repair open circuit
in harness
between ECM and
rear oxygen sen-
sor connector.

3

CHECK HARNESS BETWEEN REAR OXY-
GEN SENSOR AND ECM CONNECTOR.
Measure the resistance between rear oxygen
sensor harness connector and chassis ground.

Connector & terminal

(B136) No. 30 — Chassis ground:

Is the resistance less than 1
Ω?

Go to step 4.

Repair open circuit
in harness
between ECM and
rear oxygen sen-
sor connector.

4

CHECK EXHAUST SYSTEM.
Check for gas leaks or air suction caused by
loose or dislocated nuts and bolts, and open
hole at exhaust pipes.

NOTE:

Check the following positions.
• Between cylinder head and front exhaust
pipe
• Between front exhaust pipe and front cata-
lytic converter
• Between front catalytic converter and rear
catalytic converter

Is there a fault in exhaust sys-
tem?

Repair or replace
the exhaust sys-
tem. <Ref. to
EX(H4SO 2.0)-2,
General Descrip-
tion.>

Go to step 5.

5

CHECK CATALYTIC CONVERTER.

Is there damage at rear face or
front face of front catalyst?

Replace the cata-
lytic converter.
<Ref. to EC(H4SO
2.0)-3, Front Cata-
lytic Converter.>

Contact the SUB-
ARU Dealer.

EN(H4SO 2.0)(diag)-152

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AK: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(H4SO 2.0)(diag)-
38, OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4SO 2.0)(diag)-32, PRO-
CEDURE, Inspection Mode.>.
WIRING DIAGRAM:

EN-03484

PURGE CONTROL

SOLENOID VALVE

E4

B21

E2

B47

B47

3

4

1

2

5

6

SBF-7

BATTERY

MAIN RELAY

1

2

4

6

3

5

8

2

1

48

41

B134

ECM

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

E4

1 2