Subaru Legacy IV (2008 year). Manual - part 170

EN(H4SO)(diag)-283

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DC:DTC P2103 THROTTLE ACTUATOR CONTROL MOTOR CIRCUIT HIGH

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4SO)-184, 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(H4SO)(diag)-50,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4SO)(diag)-41, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

EN-06838

SBF-7

B134

A:

B137

B136

D:

B362

C:

E

C1

C21

D4

D5

A29

A19

D3

D7

D1

D2

A5

A28

A18

C6

ECM

5

8

7

6

B362

B47

B21

E57

B122

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

B134

A:

B136

C:

B137

D:

BATTERY

ELECTRONIC 
THROTTLE 
CONTROL RELAY

MAIN RELAY

1 2 3 4 5 6

E2

B21

B122

E

E

E

39

20

E57

4

6

1

2

3

5

34

35

36

37

52

*
*

ELECTRONIC 
THROTTLE CONTROL

: TERMINAL No. OPTIONAL ARRANGEMENT

*

18

17

38

19

8

5

6

10 11 12 13 14 15

7

2

1

3

4

16

30

19 20

22

28 29

9

17

18

25

21

23 24

32

31

26 27
33 34

3

4

1

2

5

6

6

4

B47

EN(H4SO)(diag)-284

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

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

PERFORMANCE

NOTE:
For the diagnostic procedure, refer to DTC P2101. <Ref. to EN(H4SO)(diag)-276, DTC P2101 THROTTLE
ACTUATOR CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Procedure with Diagnos-
tic 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. 8 — No. 7:

Is the resistance 1 M

: or 

more?

Go to step 2.

Replace the elec-
tronic throttle con-
trol relay. <Ref. to 
FU(H4SO)-42,
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. 7 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the short 
circuit to power in 
the harness 
between ECM and 
electronic throttle 
control relay con-
nector.

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 short 
circuit in harness 
to ground between 
ECM and elec-
tronic throttle con-
trol relay 
connector.

EN(H4SO)(diag)-285

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

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

LOW INPUT

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4SO)-186, DTC P2122 THROTTLE/PEDAL POSITION SEN-
SOR/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(H4SO)(diag)-50,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4SO)(diag)-41, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

EN-06844

B315

E

C:

ECM

B136

B137

D:

B83

B315

*

*

4

6

5

1

3

2

D1

D2

1 2 3 4 5 6

B21

E2

D3

B122

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:

B134

A:

C:

D:

B83

A5

B: B135

A: B134

D7

36

34

52

35

37

B122

ACCELERATOR 

PEDAL 

POSITION

SENSOR

E

*

*

 : TERMINAL No. OPTIONAL 
 ARRANGEMENT

*

B21

B23

B29

B22

B31

B30

C6

8

5

6

10 11 12 13 14 15

7

2

1

3

4

16

30

19 20

22

28 29

9

17

18

25

21

23 24

32

31

26 27
33 34

EN(H4SO)(diag)-286

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 connector to 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(H4SO)-39,
Engine Control 
Module (ECM).>