Subaru Legacy IV (2008 year). Manual — part 359

EN(H4DOTC)(diag)-257

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CO:DTC P1153 O2 SENSOR CIRCUIT RANGE/PERFORMANCE (HIGH) (BANK1

SENSOR1)

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-168, DTC P1153 O2 SENSOR CIRCUIT RANGE/
PERFORMANCE (HIGH) (BANK1 SENSOR1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
52, OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-43, PRO-
CEDURE, Inspection Mode.>.
WIRING DIAGRAM:

EN-05669

SBF-5

B47

B21

E2

B21

E2

1

2

4

6

3

5

E

E

C2

C3

B8

B9

B1

B134

4

3

2

1

E79

3 4

1 2

3

4

1

2

5

6

B21

B47

E79

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

A:

B135

B:

B136

C:

B137

D:

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

A:

D2

A5

D3

E2

B21

E

35

34

40

D7

36

D1

37

B138

*

*

*

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:

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

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

B:

D:

1 2 3 4
5 6 7 8

B138

42

26

43

15

MAIN RELAY

BATTERY

FRONT
OXYGEN (A/F)
SENSOR

ECM

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

EN(H4DOTC)(diag)-258

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CP:DTC P1160 RETURN SPRING FAILURE

NOTE:
For the diagnostic procedure, refer to DTC P2101. <Ref. to EN(H4DOTC)(diag)-318, DTC P2101 THROT-
TLE ACTUATOR CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Procedure with Di-
agnostic Trouble Code (DTC).>

Step

Check

Yes

No

1

CHECK FRONT OXYGEN (A/F) SENSOR
CONNECTOR AND COUPLING CONNEC-
TOR.

Has water entered the connec-
tor?

Completely
remove any water
inside.

Go to step 2.

2

CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance between ECM and
chassis ground.

Connector & terminal

(B135) No. 9 — Chassis ground:
(B135) No. 8 — Chassis ground:

Is the resistance 1 M

: or

more?

Go to step 3.

Repair the ground
short circuit of har-
ness between
ECM and front oxy-
gen (A/F) sensor
connector.

3

CHECK OUTPUT SIGNAL FOR ECM.
1) Connect the connector to ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM and
chassis ground.

Connector & terminal

(B135) No. 9 (+) — Chassis ground (–):

Is the voltage 4.5 V or more?

Go to step 5.

Go to step 4.

4

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

Connector & terminal

(B135) No. 8 (+) — Chassis ground (–):

Is the voltage 4.95 V or more?

Go to step 5.

Replace the front
oxygen (A/F) sen-
sor. <Ref. to
FU(H4DOTC)-46,
Front Oxygen (A/F)
Sensor.>

5

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

Connector & terminal

(B135) No. 9 (+) — Chassis ground (–):
(B135) No. 8 (+) — Chassis ground (–):

Is the voltage 8 V or more?

Repair the short
circuit to power in
the harness
between ECM and
front oxygen (A/F)
sensor connector.
After repair,
replace the ECM.
<Ref. to
FU(H4DOTC)-52,
Engine Control
Module (ECM).>

Repair the poor
contact of ECM
connector.

EN(H4DOTC)(diag)-259

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CQ:DTC P1400 FUEL TANK PRESSURE CONTROL SOLENOID VALVE CIRCUIT

LOW

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-172, DTC P1400 FUEL TANK PRESSURE CONTROL
SOLENOID VALVE CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
52, OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-43, PRO-
CEDURE, Inspection Mode.>.
WIRING DIAGRAM:

EN-05679

SBF-7

E4

B47

E

5
3

6
4

2
1

2

1

C17

C28

D29

C7

R15

R213

R68

R144

R1

B97

14

15

2

2

1

1

7

1

5

E52

2

1

E52

R144

E4

B47

R67

B97

R213

R68

1 2

3

4

1

2

5

6

B21

1 2

1 2

3

4 5 6 7 8

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

1

2

3 4 5 6

1 2 3 4

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20

R46

R67

6

B21

E2

11

48

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:

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

D:

B136

C:

B137

D:

44

MAIN RELAY

ECM

BATTERY

DRAIN VALVE

PRESSURE

CONTROL

SOLENOID VALVE

PURGE CONTROL

SOLENOID VALVE 1

PURGE CONTROL

SOLENOID VALVE 2

EN(H4DOTC)(diag)-260

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

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

Connector & terminal

(B136) No. 28 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the poor
contact of ECM
connector.

Go to step 2.

2

CHECK HARNESS BETWEEN ECM AND
PRESSURE CONTROL SOLENOID VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the ECM
and pressure control solenoid valve.
3) Measure the resistance between pressure
control solenoid valve and chassis ground.

Connector & terminal

(R68) No. 2 — Chassis ground:

Is the resistance 1 M

: or

more?

Go to step 3.

Repair the ground
short circuit of har-
ness between
ECM and pressure
control solenoid
valve connector.

3

CHECK HARNESS BETWEEN ECM AND
PRESSURE CONTROL SOLENOID VALVE.
Measure the resistance of harness between
ECM and pressure control solenoid valve con-
nector.

Connector & terminal

(B136) No. 28 — (R68) No. 2:

Is the resistance less than 1

:? Go to step 4.

Repair the harness
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and pressure
control solenoid
valve connector
• Poor contact of
coupling connector

4

CHECK PRESSURE CONTROL SOLENOID
VALVE.
Measure the resistance between pressure con-
trol solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance between 10 —
100

:?

Go to step 5.

Replace the pres-
sure control sole-
noid valve. <Ref. to
EC(H4DOTC)-16,
Pressure Control
Solenoid Valve.>

5

CHECK POWER SUPPLY TO THE PRES-
SURE CONTROL SOLENOID VALVE.
1) Turn the ignition switch to ON.
2) Measure the voltage between pressure con-
trol solenoid valve and chassis ground.

Connector & terminal

(R68) No. 1 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the poor
contact of pressure
control solenoid
valve connector.

Repair the harness
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
main relay and
pressure control
solenoid valve
connector
• Poor contact of
coupling connector
• Poor contact of
main relay connec-
tor