Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 290

EN(H4DOTC)(diag)-384

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

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

Connector & terminal

(B135) No. 23 — (B315) No. 6:
(B135) No. 29 — (B315) No. 5:

Is the resistance less than 1 Ω? Go to step

2.

Repair the open
circuit of harness
between ECM con-
nector and accel-
erator pedal
position sensor
connector.

2

CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR
CONNECTOR.
1) Connect the connector to ECM.
2) Measure the resistance between accelera-
tor pedal position sensor connector and chassis
ground.

Connector & terminal

(B315) No. 5 — Chassis ground:

Is the resistance less than 5 Ω? Go to step

3.

Repair the harness
and connector.
NOTE:

In this case, repair
the following item:
• Open circuit of
harness between
ECM

connector

and engine ground
• Poor contact of
ECM connector
• Poor contact of
coupling connector

3

CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR
CONNECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between accelerator
pedal position sensor connector and chassis
ground.

Connector & terminal

(B315) No. 6 (+) — Chassis ground (–):

Is the voltage 5 V or more?

Repair the short
circuit to power
supply in harness
between ECM con-
nector and accel-
erator pedal
position sensor
connector.

Go to step

4.

4

CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance between ECM con-
nectors.

Connector & terminal

(B135) No. 21 — (B135) No. 23:

Is the resistance 1 MΩ or
more?

Repair the poor
contact of acceler-
ator pedal position
sensor connector.
Replace the accel-
erator pedal if
defective. <Ref. to
SP(STI)-4, Accel-
erator Pedal.>

Repair the short
circuit to power
supply in harness
between ECM con-
nector and accel-
erator pedal
position sensor
connector.

EN(H4DOTC)(diag)-385

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

ET:DTC P2127 THROTTLE/PEDAL POSITION SENSOR/SWITCH “E” CIRCUIT

LOW INPUT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-259, DTC P2127 THROTTLE/PEDAL POSITION

SENSOR/SWITCH “E” CIRCUIT LOW INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance
CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-63,

OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-49, PROCE-

DURE, Inspection Mode.>.

WIRING DIAGRAM:

• Engine electrical system, without SI-DRIVE <Ref. to WI-32, WITHOUT SI-DRIVE, WIRING DIAGRAM,

Engine Electrical System.>

• Engine electrical system, with SI-DRIVE <Ref. to WI-48, WITH SI-DRIVE, WIRING DIAGRAM, Engine

Electrical System.>

EN-08749

B315

C: B136

B137

D:

B83

B315

*

*

4

6

5

1

3

2

B21

B23

B29

B22

B31

B30

A4

B21

E2

D1

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

A6

C4

D3

B: B135

A: B134

A3

40

34

35

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:

*

6

4 5

3

2

1

E

ECM

: TERMINAL No.

OPTIONAL ARRANGEMENT

ACCELERATOR

PEDAL POSITION

SENSOR

EN(H4DOTC)(diag)-386

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

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

Connector & terminal

(B135) No. 22 — Chassis ground:
(B135) No. 31 — Chassis ground:

Is the resistance 1 MΩ or
more?

Go to step

2.

Repair the short
circuit to ground in
harness between
ECM connector
and accelerator
pedal position sen-
sor 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. 3 — Chassis ground:

Is the resistance 1 MΩ or
more?

Replace the accel-
erator pedal. <Ref.
to SP(STI)-4,
Accelerator
Pedal.>

Repair the short
circuit to ground in
harness between
ECM connector
and accelerator
pedal position sen-
sor connector.
Replace the ECM if
defective. <Ref. to
FU(STI)-59,
Engine Control
Module (ECM).>
<Ref. to FU(w/o
STI)-57, Engine
Control Module
(ECM).>

EN(H4DOTC)(diag)-387

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

EU:DTC P2128 THROTTLE/PEDAL POSITION SENSOR/SWITCH “E” CIRCUIT

HIGH INPUT

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-261, DTC P2128 THROTTLE/PEDAL POSITION

SENSOR/SWITCH “E” CIRCUIT HIGH INPUT, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

• Improper idling

• Poor driving performance
CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-63,

OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-49, PROCE-

DURE, Inspection Mode.>.

WIRING DIAGRAM:

• Engine electrical system, without SI-DRIVE <Ref. to WI-32, WITHOUT SI-DRIVE, WIRING DIAGRAM,

Engine Electrical System.>

• Engine electrical system, with SI-DRIVE <Ref. to WI-48, WITH SI-DRIVE, WIRING DIAGRAM, Engine

Electrical System.>

EN-08749

B315

C: B136

B137

D:

B83

B315

*

*

4

6

5

1

3

2

B21

B23

B29

B22

B31

B30

A4

B21

E2

D1

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

A6

C4

D3

B: B135

A: B134

A3

40

34

35

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:

*

6

4 5

3

2

1

E

ECM

: TERMINAL No.

OPTIONAL ARRANGEMENT

ACCELERATOR

PEDAL POSITION

SENSOR