Subaru Legacy (2005 year). Manual - part 226

EN(H4SO 2.5)(diag)-189

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

2. MT MODEL

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(H4SO 2.5)(diag)-
40, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4SO 2.5)(diag)-33, Inspection Mode.>.
WIRING DIAGRAM:
• EC, EK, EH, ER and K4 model

• KA and KS model

NOTE:
Fuel injection system for KA and KS model is the same as 2.0 L model. Refer to EN(H4SO 2.0) section.

EN-03515

B12

T7

1 2 3 4 5 6
7 8 9 10 11 12

1 2 3 4
5 6 7 8
9 10 11 12

B137

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

B25

1 2

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

B122

B138

B12

T3

T7

P

R

N

D

3

2

1

12

7

12

11

B137

9

E

E

1

B25

T2

T2

B25

2

AT

MT

E2

B21

B138

*

*

36

B122

LHD :

RHD :

INHIBITOR SWITCH

ECM

NEUTRAL
POSITION
SWITCH

*

: TERMINAL No. RANDOM ARRANGEMENT

EN(H4SO 2.5)(diag)-190

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK OPTION CODE.

Is the option code EC, EK, EH, 
ER or K4?

Go to step 2.

Refer to EN(H4SO 
2.0) section. <Ref. 
to EN(H4SO 
2.0)(diag)-64, List 
of Diagnostic Trou-
ble Code (DTC).>

NOTE:
Fuel injection sys-
tem for KA and KS
model is the same
as 2.0 L model.

2

CHECK INPUT SIGNAL OF ECM.
1) Turn the ignition switch to ON.
2) Place the shift lever except in neutral.
3) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B137) No. 9 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Go to step 3.

Go to step 5.

3

CHECK INPUT SIGNAL OF ECM.
1) Place the shift lever in neutral.
2) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B137) No. 9 (+) — Chassis ground (

−

):

Is the voltage less than 1 V?

Go to step 4.

Go to step 5.

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(H4SO 
2.5)-37, Engine 
Control Module 
(ECM).>

5

CHECK NEUTRAL POSITION SWITCH.
1) Place the shift lever in neutral.
2) Measure the resistance between transmis-
sion harness connector terminals.

Connector & terminal

(T2) No. 1 — No. 2:

Is the resistance less than 1 
Ω?

Go to step 6.

Repair the open 
circuit in transmis-
sion harness or 
replace the neu-
tral position switch.

6

CHECK HARNESS BETWEEN ECM AND 
NEUTRAL POSITION SWITCH CONNEC-
TOR.
1) Disconnect the connector from ECM.
2) Measure the resistance of harness 
between ECM and transmission harness con-
nector.

Connector & terminal

(B137) No. 9 — (B25) No. 2:

Is the resistance less than 1 
Ω?

Go to step 7.

Repair the open 
circuit of harness 
between ECM and 
transmission har-
ness connector.

7

CHECK HARNESS BETWEEN ECM AND 
NEUTRAL POSITION SWITCH CONNEC-
TOR.
Measure the resistance of harness between 
ECM and transmission harness connector.

Connector & terminal

(B25) No. 1 — Engine ground:

Is the resistance less than 5 
Ω?

Go to step 8.

Repair the har-
ness and connec-
tor.

NOTE:
In this case, repair
the following:
• Open circuit of 
harness between 
ECM and trans-
mission harness 
connector
• Poor contact in 
coupling connector

EN(H4SO 2.5)(diag)-191

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

BC:DTC P1152 O2 SENSOR CIRCUIT RANGE/PERFORMANCE (LOW) (BANK1 

SENSOR1)

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

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4SO 2.5)(diag)-
40, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4SO 2.5)(diag)-33, Inspection Mode.>.
WIRING DIAGRAM:

8

CHECK POOR CONTACT.
Check poor contact in transmission harness 
connector.

Is there poor contact in trans-
mission harness connector?

Repair the poor 
contact in trans-
mission harness 
connector.

Replace the ECM. 
<Ref. to FU(H4SO 
2.5)-37, Engine 
Control Module 
(ECM).>

Step

Check

Yes

No

EN-03457

3

4

1

2

5

6

B327

SBF-5

E

E

B327

E24

6
4

5
3

2
1

25

33

26

3

2

6

7

52

B134

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

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

ECM

BATTERY

FRONT OXYGEN

(A/F) SENSOR

OXYGEN (A/F) 
SENSOR RELAY

1

3

4 5 6

2

3

4

1

6

EN(H4SO 2.5)(diag)-192

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK HARNESS BETWEEN ECM AND 
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and 
front oxygen (A/F) sensor connector.
3) Measure the resistance of harness 
between ECM and front oxygen (A/F) sensor 
connector.

Connector & terminal

(B134) No. 26 — (E24) No. 1:
(B134) No. 33 — (E24) No. 3:

Is the resistance less than 1 
Ω?

Go to step 2.

Repair the har-
ness and connec-
tor.

NOTE:
In this case, repair
the following:
• Open circuit of 
harness between 
ECM and front 
oxygen (A/F) sen-
sor connector
• Poor contact in 
front oxygen (A/F) 
sensor connector
• Poor contact in 
ECM connector

2

CHECK POOR CONTACT.
Check poor contact in front oxygen (A/F) sen-
sor connector.

Is there poor contact in front 
oxygen (A/F) sensor connec-
tor?

Repair the poor 
contact in front 
oxygen (A/F) sen-
sor connector.

Replace the front 
oxygen (A/F) sen-
sor. <Ref. to 
FU(H4SO 2.5)-35, 
Front Oxygen (A/
F) Sensor.>