Subaru Legacy IV (2008 year). Service manual — part 535

EN(H6DO)(diag)-113

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

O: DTC P0057 HO2S HEATER CONTROL CIRCUIT LOW (BANK 2 SENSOR 2)

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H6DO)-26, DTC P0057 HO2S HEATER CONTROL CIRCUIT
LOW (BANK 2 SENSOR 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H6DO)(diag)-52,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H6DO)(diag)-44, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

B47

3

4

5

6

1

2

B22

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

1 2 3 4
5 6 7 8

B83

B138

3 4

1 2

E25

E61

B47

1

2

3

5

4

6

E3

B22

14

MAIN RELAY

2

4

3

1

E25

13

15

16

E3

B22

10

11

12

9

SBF-5

BATTERY

2

E61

4

3

1

*

1

*

1

*

1

B83

B138

ECM

B134

A:

B135

B:

B136

C:

B137

D3

A3

D2

D1

D7

A5

D:

C5

*

*

2

2

C4

E

B1

B15

B4

B30

35

34

52

36

37

B21

E2

E

E

: TERMINAL No. OPTIONAL ARRANGEMENT

*

1

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

*

2

EN-06868

16

10 11 12 13 14 15

25

24

30

9

8

7

17 18 19 20
28

21 22 23

29

32

31

1

2

3

4

5

6

27

26

33 34 35

B136

C:

5

6

7

8

2

1

9

4

3

10

22 23

11 12 13 14 15

24 25

26

16 17

18 19 20 21

27

28 29

30 31

B137

D:

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

B135

B:

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

B134

A:

B21

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

42

43

36

37

38

39

48

49

50

51

52

53

54

40

41

44

45

46

47

REAR
OXYGEN
SENSOR LH

REAR
OXYGEN
SENSOR RH

EN(H6DO)(diag)-114

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK POWER SUPPLY TO REAR OXY-
GEN SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from rear oxygen
sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between rear oxygen
sensor connector and engine ground.

Connector & terminal

(E25) No. 2 (+) — Engine ground (–):

Is the voltage 10 V or more?

Go to step 2.

Repair the power
supply line.

NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
main relay and rear
oxygen sensor
• Poor contact of
main relay connec-
tor
• Poor contact of
coupling connector
• Malfunction of
main relay

2

CHECK HARNESS BETWEEN ECM AND
REAR OXYGEN SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance between the ECM
and oxygen sensor connector.

Connector & terminal

(B136) No. 5 — (E25) No. 1:

Is the resistance less than 1

:? Go to step 3.

Repair the harness
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and rear oxy-
gen sensor con-
nector
• Poor contact of
coupling connector

3

CHECK GROUND CIRCUIT FOR ECM.
Measure the resistance of harness between
ECM and chassis ground.

Connector & terminal

(B134) No. 3 — Chassis ground:
(B134) No. 5 — Chassis ground:
(B137) No. 1 — Chassis ground:
(B137) No. 2 — Chassis ground:
(B137) No. 3 — Chassis ground:
(B137) No. 7 — Chassis ground:

Is the resistance less than 5

:? Go to step 4.

Repair the harness
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and engine
ground
• Poor contact of
coupling connector

4

CHECK REAR OXYGEN SENSOR.
Measure the resistance between rear oxygen
sensor connector terminals.

Terminals

No. 2 — No. 1:

Is the resistance between 5 —
7

:?

Repair the poor
contact of ECM
connector.

Replace the rear
oxygen sensor.
<Ref. to
FU(H6DO)-34,
Rear Oxygen Sen-
sor.>

EN(H6DO)(diag)-115

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

P: DTC P0058 HO2S HEATER CONTROL CIRCUIT HIGH (BANK 2 SENSOR 2)

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H6DO)-26, DTC P0058 HO2S HEATER CONTROL CIRCUIT
HIGH (BANK 2 SENSOR 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H6DO)(diag)-52,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H6DO)(diag)-44, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

B47

3

4

5

6

1

2

B22

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

1 2 3 4
5 6 7 8

B83

B138

3 4

1 2

E25

E61

B47

1

2

3

5

4

6

E3

B22

14

MAIN RELAY

2

4

3

1

E25

13

15

16

E3

B22

10

11

12

9

SBF-5

BATTERY

2

E61

4

3

1

*

1

*

1

*

1

B83

B138

ECM

B134

A:

B135

B:

B136

C:

B137

D3

A3

D2

D1

D7

A5

D:

C5

*

*

2

2

C4

E

B1

B15

B4

B30

35

34

52

36

37

B21

E2

E

E

: TERMINAL No. OPTIONAL ARRANGEMENT

*

1

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

*

2

EN-06868

16

10 11 12 13 14 15

25

24

30

9

8

7

17 18 19 20
28

21 22 23

29

32

31

1

2

3

4

5

6

27

26

33 34 35

B136

C:

5

6

7

8

2

1

9

4

3

10

22 23

11 12 13 14 15

24 25

26

16 17

18 19 20 21

27

28 29

30 31

B137

D:

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

B135

B:

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

B134

A:

B21

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

42

43

36

37

38

39

48

49

50

51

52

53

54

40

41

44

45

46

47

REAR
OXYGEN
SENSOR LH

REAR
OXYGEN
SENSOR RH

EN(H6DO)(diag)-116

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK HARNESS BETWEEN ECM AND
REAR OXYGEN SENSOR.
1) Turn the ignition switch to OFF.
2) Measure the voltage between ECM and
chassis ground.

Connector & terminal

(B136) No. 5 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the short
circuit to power in
the harness
between ECM and
rear oxygen sensor
connector.

Go to step 2.

2

CHECK GROUND CIRCUIT FOR ECM.
1) Disconnect the connectors from ECM.
2) Measure the resistance between ECM and
chassis ground.

Connector & terminal

(B134) No. 3 — Chassis ground:
(B134) No. 5 — Chassis ground:
(B137) No. 1 — Chassis ground:
(B137) No. 2 — Chassis ground:
(B137) No. 3 — Chassis ground:
(B137) No. 7 — Chassis ground:

Is the resistance less than 5

:? Repair the poor

contact of ECM
connector.

Repair the harness
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and engine
ground
• Poor contact of
coupling connector