Subaru Legacy IV (2008 year). Manual - part 376

EN(H4DOTC)(diag)-325

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DS:DTC P2103 THROTTLE ACTUATOR CONTROL MOTOR CIRCUIT HIGH

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-210, DTC P2103 THROTTLE ACTUATOR CONTROL
MOTOR CIRCUIT HIGH, 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-05673

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

7 8

3
4

5
6

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

34 35

36 37 38 39 40 41

48 49

50 51 52 53 54

42 43

44 45

46 47

26 27 28 29 30 31 32 33

1 2 3 4
5 6 7 8

1

2

7

8 9

5

6

3

4

10 11 12

19 20 21

29

30 31

13 14 15 16 17

27

28

18

22 23

24 25

26

1

2

8 9

5

6

3

4

10 11 12

19 20 21

29 30

31

13 14 15 16

17

27

28

18

22 23 24 25 26

7

32 33 34 35

1 2 3 4 5 6

E57

B47

B137

D:

B21

B122

B136

C:

B362

B134

A:

36

40

34

35

37

E2

B21

C21

C1

A29

6

A18

C6

A28

6

4

25

*

*

B122

24

E

38

39

28

D5

D4

A19

A5

D7

D1

D2

D3

3

E57

2

1

5

B134

B362

B47

5

7

6

A:

B137

B136

D:

C:

*

E

SBF-7

8

6

4

E

3

4

1

2

5

6

ELECTRONIC
THROTTLE 
CONTROL RELAY

MAIN RELAY

BATTERY

ECM

ELECTRONIC THROTTLE 
CONTROL

: TERMINAL No. OPTIONAL 
  ARRANGEMENT

EN(H4DOTC)(diag)-326

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DT:DTC P2109 THROTTLE/PEDAL POSITION SENSOR “A” MINIMUM STOP 

PERFORMANCE

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 ELECTRONIC THROTTLE CON-
TROL RELAY.
1) Turn the ignition switch to OFF.
2) Remove the electronic throttle control relay.
3) Measure the resistance between electronic 
throttle control relay terminals.

Terminals

No. 7 — No. 8:

Is the resistance 1 M

: or 

more?

Go to step 2.

Replace the elec-
tronic throttle con-
trol relay. <Ref. to 
FU(H4DOTC)-55, 
Electronic Throttle 
Control Relay.>

2

CHECK SHORT CIRCUIT OF ELECTRONIC 
THROTTLE CONTROL RELAY POWER SUP-
PLY.
1) Turn the ignition switch to ON.
2) Measure the voltage between electronic 
throttle control relay connector and chassis 
ground.

Connector & terminal

(B362) No. 8 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the short 
circuit to power in 
harness between 
ECM and elec-
tronic throttle con-
trol relay.

Go to step 3.

3

CHECK HARNESS BETWEEN ECM AND 
ELECTRONIC THROTTLE CONTROL RE-
LAY.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance between ECM and 
chassis ground.

Connector & terminal

(B136) No. 21 — Chassis ground:

Is the resistance 1 M

: or 

more?

Repair the poor 
contact of ECM 
connector.

Repair the ground 
short circuit of har-
ness between 
ECM and elec-
tronic throttle con-
trol relay.

EN(H4DOTC)(diag)-327

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DU:DTC P2122 THROTTLE/PEDAL POSITION SENSOR/SWITCH “D” CIRCUIT 

LOW INPUT

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-214, DTC P2122 THROTTLE/PEDAL POSITION
SENSOR/SWITCH “D” CIRCUIT LOW INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
• Improper idling
• 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-05690

B315

C: B136

B137

D:

B83

B315

*

*

4

6

5

1

3

2

B21

B23

B29

B22

B31

B30

D2

B21

E2

D1

1 2 3 4
5 6 7 8

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

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

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

B:

C:

D:

B122

B83

D3

A5

C6

B: B135

A: B134

D7

37

35

34

40

36

B122

1 2 3 4 5 6

*

*

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:

E

*

ACCELERATOR PEDAL 

POSITION SENSOR

ECM

: TERMINAL No. OPTIONAL 
  ARRANGEMENT

EN(H4DOTC)(diag)-328

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and 
accelerator pedal position sensor.
3) Measure the resistance between ECM and 
chassis ground.

Connector & terminal

(B135) No. 21 — Chassis ground:
(B135) No. 23 — Chassis ground:
(B135) No. 23 — (B136) No. 6:

Is the resistance 1 M

: or 

more?

Go to step 2.

Repair the ground 
short circuit of har-
ness between 
ECM and accelera-
tor pedal position 
sensor connector.

2

CHECK SHORT CIRCUIT INSIDE THE ECM.
1) Connect the ECM.
2) Measure the resistance between accelera-
tor pedal position sensor connector and chassis 
ground.

Connector & terminal

(B315) No. 6 — Chassis ground:

Is the resistance 1 M

: or 

more?

Replace the accel-
erator pedal. <Ref. 
to SP(H4SO)-3, 
Accelerator 
Pedal.>

Repair the ground 
short circuit of har-
ness between 
ECM and accelera-
tor pedal position 
sensor connector. 
Replace the ECM if 
defective. <Ref. to 
FU(H4DOTC)-52, 
Engine Control 
Module (ECM).>