Subaru Legacy (2005 year). Manual - part 121

 

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Subaru Legacy (2005 year). Manual - part 121

 

 

EN(H4SO 2.0)(diag)-73

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

7

CHECK FRONT OXYGEN (A/F) SENSOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between front oxy-
gen (A/F) sensor connector terminals.

Terminals

LHD model

No. 3 — No. 4:

RHD model

No. 1 — No. 3:

Is the resistance less than 10 
Ω?

Repair the har-
ness and connec-
tor.

NOTE:
In this case, repair
the following item:
• Open or ground 
short circuit of har-
ness between front 
oxygen (A/F) sen-
sor and ECM con-
nector
• Poor contact in 
front oxygen (A/F) 
sensor connector
• Poor contact in 
ECM connector

Replace the front 
oxygen (A/F) sen-
sor. <Ref. to 
FU(H4SO 2.0)-32, 
Front Oxygen (A/
F) Sensor.>

Step

Check

Yes

No

EN(H4SO 2.0)(diag)-74

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

C: DTC P0032 HO2S HEATER CONTROL CIRCUIT HIGH (BANK 1 SENSOR 1)

DTC DETECTING CONDITION:
Immediately at fault recognition

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:

Step

Check

Yes

No

1

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

Connector & terminal

(B135) No. 2 (+) — Chassis ground (

−

):

(B135) No. 3 (+) — Chassis ground (

−

):

Is the voltage more than 8 V?

Go to step 2.

Go to step 3.

EN-03475

3

4

1

2

5

6

B47

SBF-5

E

B47

E24

5
3

4
6

2
1

C34

C35

C33

B3

B2

B1

B135

E

B5

B6

52

B21

E2

B21

E2

50

51

3

4

E2

B21

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

E24

ECM

BATTERY

FRONT OXYGEN

(A/F) SENSOR

MAIN RELAY

B136

B:

C:

1

2

3

4

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

B:

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

C:

E24

3

2

*

1

*

*

3

  LHD : 4

RHD : 1

*

1

*

*

2

3

3

1

6 5 4

2

: RHD

: LHD

LHD : 1

RHD : 4

LHD : 2

RHD : 6

EN(H4SO 2.0)(diag)-75

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

2

CHECK FRONT OXYGEN (A/F) SENSOR 
HEATER CURRENT.
1) Turn the ignition switch to OFF.
2) Repair the battery short circuit of harness 
between ECM and front oxygen (A/F) sensor 
connector.
3) Turn the ignition switch to ON.
4) Read the data of front oxygen (A/F) sensor 
heater current using Subaru Select Monitor or 
general scan tool.

NOTE:

• Subaru Select Monitor
For detailed operation procedure, refer to 
“READ CURRENT DATA FOR ENGINE”. <Ref. 
to EN(H4SO 2.0)(diag)-25, Subaru Select 
Monitor.>
• General scan tool
For detailed operation procedure, refer to the 
general scan tool operation manual.

Is the current more than 2.3 A? Replace the ECM. 

<Ref. to FU(H4SO 
2.0)-34, Engine 
Control Module 
(ECM).>

Finish the diagno-
sis.

3

CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector 
and chassis ground.

Connector & terminal

(B135) No. 2 (+) — Chassis ground (

−

):

(B135) No. 3 (+) — Chassis ground (

−

):

Does the voltage change by 
shaking the ECM harness and 
connector?

Repair the battery 
short circuit of har-
ness between 
ECM and front 
oxygen (A/F) sen-
sor connector.

Finish the diagno-
sis.

Step

Check

Yes

No

EN(H4SO 2.0)(diag)-76

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

D: DTC P0037 HO2S HEATER CONTROL CIRCUIT LOW (BANK 1 SENSOR 2)

DTC DETECTING CONDITION:
Detects when malfunction occurs in 2 continuous driving cycles.

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

 

 

 

 

 

 

 

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