Subaru Legacy IV (2008 year). Manual - part 369

EN(H4DOTC)(diag)-297

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DH:DTC P2017 INTAKE MANIFOLD RUNNER POSITION SENSOR / SWITCH 

CIRCUIT HIGH (BANK 1)

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-196, DTC P2017 INTAKE MANIFOLD RUNNER PO-
SITION SENSOR / SWITCH CIRCUIT HIGH (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
• Improper idling
• Engine stalls.
• Poor driving performance

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-05686

E55

1 2 3

4 5

B21

E2

B21

3

1

2

B134

19

29

26

28

6

16

E55

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

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

TUMBLE GENERATOR 

VALVE ASSY RH

(WITH BUILT-IN SENSOR)

POSITION SENSOR

ECM

EN(H4DOTC)(diag)-298

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of tumble generator valve 
position sensor signal (RH) 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(H4DOTC)(diag)-34, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedures, refer to the
general scan tool operation manual.

Is the voltage 5 V or more?

Go to step 2.

Even if DTC is 
detected, the cir-
cuit has returned to 
a normal condition 
at this time. Repro-
duce the failure, 
and then perform 
the diagnosis 
again.

NOTE:
In this case, tem-
porary poor con-
tact of connector
may be the cause.

2

CHECK HARNESS BETWEEN ECM AND 
TUMBLE GENERATOR VALVE ASSEMBLY 
RH CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from tumble gen-
erator valve assembly RH.
3) Start the engine.
4) Read the data of tumble generator valve 
position sensor signal (RH) 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(H4DOTC)(diag)-34, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedures, refer to the
general scan tool operation manual.

Is the voltage 5 V or more?

Repair the short 
circuit to power in 
harness between 
ECM and tumble 
generator valve 
assembly RH con-
nector.

Go to step 3.

3

CHECK HARNESS BETWEEN ECM AND 
TUMBLE GENERATOR VALVE ASSEMBLY 
RH CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness between 
tumble generator valve assembly RH connector 
and engine ground.

Connector & terminal

(E55) No. 2 — Engine 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 in
harness between
ECM and tumble
generator valve
assembly RH con-
nector
• Poor contact in
ECM connector
• Poor contact of
coupling connector

4

CHECK POOR CONTACT.
Check for poor contact of tumble generator 
valve assembly RH connector.

Is there poor contact in the tum-
ble generator valve assembly 
RH connector?

Repair the poor 
contact of tumble 
generator valve 
assembly RH con-
nector.

Replace the tum-
ble generator valve 
assembly RH. 
<Ref. to 
FU(H4DOTC)-41, 
Tumble Generator 
Valve Assembly.>

EN(H4DOTC)(diag)-299

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DI: DTC P2021 INTAKE MANIFOLD RUNNER POSITION SENSOR / SWITCH 

CIRCUIT LOW (BANK 2)

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-197, DTC P2021 INTAKE MANIFOLD RUNNER PO-
SITION SENSOR / SWITCH CIRCUIT LOW (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
• Improper idling
• Engine stalls.
• Poor driving performance

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-05687

E51

B21

E2

B21

3

1

2

B134

19

29

16

28

6

27

E51

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

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

1 2 3

4 5

POSITION SENSOR

TUMBLE GENERATOR 

VALVE ASSY LH

(WITH BUILT-IN SENSOR)

ECM

EN(H4DOTC)(diag)-300

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of tumble generator valve 
position sensor signal (LH) 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(H4DOTC)(diag)-34, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedures, refer to the
general scan tool operation manual.

Is the voltage less than 0.2 V?

Go to step 2.

Even if DTC is 
detected, the cir-
cuit has returned to 
a normal condition 
at this time. Repro-
duce the failure, 
and then perform 
the diagnosis 
again.

NOTE:
In this case, tem-
porary poor con-
tact of connector
may be the cause.

2

CHECK POWER SUPPLY OF TUMBLE GEN-
ERATOR VALVE ASSEMBLY LH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from tumble gen-
erator valve assembly LH.
3) Turn the ignition switch to ON.
4) Measure the voltage between tumble gener-
ator valve assembly LH connector and engine 
ground.

Connector & terminal

(E51) No. 3 (+) — Engine ground (–):

Is the voltage 4.5 V or more?

Go to step 3.

Repair the harness 
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and tumble
generator valve
assembly LH con-
nector
• Poor contact in
ECM connector
• Poor contact of
coupling connector

3

CHECK HARNESS BETWEEN ECM AND 
TUMBLE GENERATOR VALVE ASSEMBLY 
LH CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance of harness between 
ECM and tumble generator valve assembly LH.

Connector & terminal

(B134) No. 16 — (E51) No. 1:

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 tumble
generator valve
assembly LH con-
nector
• Poor contact of
coupling connector

4

CHECK HARNESS BETWEEN ECM AND 
TUMBLE GENERATOR VALVE ASSEMBLY 
LH CONNECTOR.
Measure the resistance between ECM and 
chassis ground.

Connector & terminal

(B134) No. 16 — Chassis ground:

Is the resistance 1 M

: or 

more?

Go to step 5.

Repair the short 
circuit to ground in 
harness between 
ECM and tumble 
generator valve 
assembly LH con-
nector.

5

CHECK POOR CONTACT.
Check for poor contact of tumble generator 
valve assembly LH connector.

Is there poor contact in ECM or 
the tumble generator valve 
assembly LH connector?

Repair the poor 
contact in ECM or 
tumble generator 
valve assembly LH 
connector.

Replace the tum-
ble generator valve 
assembly LH. 
<Ref. to 
FU(H4DOTC)-41, 
Tumble Generator 
Valve Assembly.>