Subaru Legacy IV (2008 year). Service manual — part 566

EN(H6DO)(diag)-237

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

6

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 connector.

Connector & terminal

(B135) No. 4 — (E61) No. 3:
(B135) No. 30 — (E61) No. 4:
(B135) No. 15 — (E25) No. 3:
(B135) No. 30 — (E25) No. 4:

Is the resistance less than 1

:? Go to step 7.

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

7

CHECK HARNESS BETWEEN ECM AND
REAR OXYGEN SENSOR CONNECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between rear oxygen
sensor connector and chassis ground.

Connector & terminal

(E61) No. 3 (+) — Chassis ground (–):
(E25) No. 3 (+) — Chassis ground (–):

Is the voltage 0.2 — 0.5 V?

Go to step 8.

Repair the harness
and connector.

NOTE:
Repair the follow-
ing locations.
• Open circuit of
harness between
the ECM and rear
oxygen sensor
• Poor contact in
ECM and rear oxy-
gen sensor
• Poor contact in
ECM connector

8

CHECK REAR OXYGEN SENSOR SHIELD.
1) Turn the ignition switch to OFF.
2) Expose the rear oxygen sensor connector
body side harness sensor shield.
3) Measure the resistance between the sensor
shield and chassis ground.

Is the resistance less than 1

:? Replace the rear

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

Repair the open
circuit in the rear
oxygen sensor har-
ness.

Step

Check

Yes

No

EN(H6DO)(diag)-238

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CD:DTC P0442 EVAPORATIVE EMISSION CONTROL SYSTEM LEAK DETECTED

(SMALL LEAK)

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H6DO)-108, DTC P0442 EVAPORATIVE EMISSION CONTROL
SYSTEM LEAK DETECTED (SMALL LEAK), Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
• Fuel odor
• There is a hole of more than 1.0 mm (0.04 in) dia. in evaporation system or fuel tank.

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:

SBF-7

E4

B47

E

5
3

6
4

2
1

ECM

2

1

C17

C28

D29

R15

R213

R68

R144

R1

B97

14

7

2

2

1

1

15

1

5

PURGE CONTROL

SOLENOID VALVE

DRAIN VALVE

PRESSURE CONTROL

SOLENOID VALVE

MAIN RELAY

R68

E4

1 2

B47

3

4

1

2

5

6

R144

1 2

R213

1 2

3

4 5 6 7 8

R67

1

2

3 4 5 6

B97

1 2 3 4

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20

R46

R67

6

BATTERY

B21

E2

E76

E77

41

48

2

10

E77

1

3

4 5 6

2

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:

EN-06878

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

EN(H6DO)(diag)-239

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK FUEL FILLER CAP.
1) Turn the ignition switch to OFF.
2) Check the fuel filler cap.

NOTE:
The DTC is stored in memory if fuel filler cap is
or was loose or if the cap chain has caught while
tightening.

Is the fuel filler cap tightened
securely?

Go to step 2.

Tighten fuel filler
cap securely.

2

CHECK FUEL FILLER CAP.

Is the fuel filler cap genuine?

Go to step 3.

Replace with a
genuine fuel filler
cap.

3

CHECK FUEL FILLER PIPE GASKET.

Is there any damage to the seal
between fuel filler cap and fuel
filler pipe?

Repair or replace
the fuel filler cap
and fuel filler pipe.
<Ref. to
FU(H6DO)-52,
Fuel Filler Pipe.>

Go to step 4.

4

CHECK DRAIN VALVE.
1) Connect the delivery (test) mode connector.
2) Turn the ignition switch to ON.
3) Operate the drain valve using the Subaru
Select Monitor.

NOTE:
The drain valve can be operated using Subaru
Select Monitor. For the procedures, refer to
“Compulsory Valve Operation Check Mode”.
<Ref. to EN(H6DO)(diag)-53, Compulsory
Valve Operation Check Mode.>

Does the drain valve operate?

Go to step 5.

Replace the drain
valve. <Ref. to
EC(H6DO)-16,
Drain Valve.>

5

CHECK PURGE CONTROL SOLENOID
VALVE.
Operate the purge control solenoid valve using
the Subaru Select Monitor.

NOTE:
Purge control solenoid valve operation can be
executed using Subaru Select Monitor. For the
procedures, refer to “Compulsory Valve Opera-
tion Check Mode”. <Ref. to EN(H6DO)(diag)-
53, Compulsory Valve Operation Check
Mode.>

Does the purge control sole-
noid valve operate?

Go to step 6.

Replace the purge
control solenoid
valve. <Ref. to
EC(H6DO)-8,
Purge Control
Solenoid Valve.>

6

CHECK PRESSURE CONTROL SOLENOID
VALVE.
Operate the pressure control solenoid valve
using the Subaru Select Monitor.

NOTE:
The pressure control solenoid valve operation
can be executed using the Subaru Select Mon-
itor. For the procedures, refer to “Compulsory
Valve Operation Check Mode”. <Ref. to
EN(H6DO)(diag)-53, Compulsory Valve Opera-
tion Check Mode.>

Does the pressure control sole-
noid valve operate?

Go to step 7.

Replace the pres-
sure control sole-
noid valve. <Ref. to
EC(H6DO)-13,
Pressure Control
Solenoid Valve.>

7

CHECK EVAPORATIVE EMISSION CON-
TROL SYSTEM LINE.
1) Turn the ignition switch to OFF.
2) Disconnect the delivery (test) mode connec-
tor.

Is there any hole of more than
1.0 mm (0.04 in) dia. on evapo-
ration line?

Repair or replace
the evaporation
line. <Ref. to
FU(H6DO)-65,
Fuel Delivery and
Evaporation
Lines.>

Go to step 8.

EN(H6DO)(diag)-240

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

8

CHECK CANISTER.

Is the canister damaged or is
there a hole of more than
1.0 mm (0.04 in) dia. in it?

Repair or replace
the canister. <Ref.
to EC(H6DO)-6,
Canister.>

Go to step 9.

9

CHECK FUEL TANK.
Remove the fuel tank. <Ref. to FU(H6DO)-45,
Fuel Tank.>

Is the fuel tank damaged or is
there any hole of more than
1.0 mm (0.04 in) dia. in it?

Repair or replace
the fuel tank. <Ref.
to FU(H6DO)-45,
Fuel Tank.>

Go to step 10.

10

CHECK ANY OTHER MECHANICAL TROU-
BLE IN EVAPORATIVE EMISSION CON-
TROL SYSTEM.

Is there any hole of more than
1.0 mm (0.04 in) dia., crack,
clogging, or disconnections,
bend, misconnection of hoses
or pipes in evaporative emis-
sion control system?

Repair or replace
the hoses or pipes.

Repair the poor
contact of ECM
connector.

Step

Check

Yes

No