Subaru Legacy IV (2008 year). Manual - part 169

 

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Subaru Legacy IV (2008 year). Manual - part 169

 

 

EN(H4SO)(diag)-279

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

12

CHECK SENSOR OUTPUT.
1) Connect all connectors.
2) Turn the ignition switch to ON.
3) Read the data of main throttle sensor signal 
using Subaru Select Monitor.

NOTE:
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4SO)(diag)-33, Subaru Select Moni-
tor.>

Is the voltage 0.81 — 0.87 V?

Go to step 13.

Repair poor con-
tact of the elec-
tronic throttle 
control connector. 
Replace the elec-
tronic throttle con-
trol if defective. 
<Ref. to 
FU(H4SO)-12,
Throttle Body.>

13

CHECK SENSOR OUTPUT.
Read the data of sub throttle sensor signal 
using Subaru Select Monitor.

NOTE:
SUBARU SELECT MONITOR
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4SO)(diag)-33, Subaru Select Moni-
tor.>

Is the voltage 1.64 — 1.70 V?

Go to step 14.

Repair poor con-
tact of the elec-
tronic throttle 
control connector. 
Replace the elec-
tronic throttle con-
trol if defective. 
<Ref. to 
FU(H4SO)-12,
Throttle Body.>

14

CHECK HARNESS BETWEEN ECM AND 
ELECTRONIC THROTTLE CONTROL MO-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and 
electronic throttle control.
3) Measure the resistance between ECM and 
electronic throttle control connector.

Connector & terminal

(B137) No. 5 — (E57) No. 2:
(B137) No. 4 — (E57) No. 1:

Is the resistance less than 1 

:? Go to step 15.

Repair the harness 
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and electron-
ic throttle control
connector
• Poor contact of
coupling connector

15

CHECK HARNESS BETWEEN ECM AND 
ELECTRONIC THROTTLE CONTROL MO-
TOR.
1) Connect the connector to ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic 
throttle control connector and engine ground.

Connector & terminal

(E57) No. 2 (+) — Engine ground (–):
(E57) No. 1 (+) — Engine ground (–):

Is the voltage 5 V or more?

Repair the short 
circuit to power in 
the harness 
between ECM and 
electronic throttle 
control.

Go to step 16.

16

CHECK HARNESS BETWEEN ECM AND 
ELECTRONIC THROTTLE CONTROL MO-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance between electronic 
throttle control connector and engine ground.

Connector & terminal

(E57) No. 2 — Engine ground:
(E57) No. 1 — Engine ground:

Is the resistance 1 M

: or 

more?

Go to step 17.

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

17

CHECK ELECTRONIC THROTTLE CON-
TROL MOTOR HARNESS.
Measure the resistance between the electronic 
throttle control connector terminals.

Connector & terminal

(E57) No. 2 — (E57) No. 1:

Is the resistance 1 M

: or 

more?

Go to step 18.

Repair the short 
circuit of harness 
between ECM and 
electronic throttle 
control.

Step

Check

Yes

No

EN(H4SO)(diag)-280

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

18

CHECK ELECTRONIC THROTTLE CON-
TROL GROUND CIRCUIT.
Measure the resistance between ECM and 
chassis ground.

Connector & terminal

(B134) No. 5 — Chassis ground:
(B137) No. 1 — Chassis ground:
(B137) No. 2 — Chassis ground:
(B137) No. 3 — Chassis ground:
(B137) No. 7 — Chassis ground:

Is the resistance less than 5 

:? Go to step 19.

Repair the harness 
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and engine
ground
• Poor contact of
coupling connector

19

CHECK ELECTRONIC THROTTLE CON-
TROL.
Measure the resistance between electronic 
throttle control terminals.

Terminals

No. 2 — No. 1:

Is the resistance 50 

: or less? Go to step 20.

Replace the elec-
tronic throttle con-
trol. <Ref. to 
FU(H4SO)-12,
Throttle Body.>

20

CHECK ELECTRONIC THROTTLE CON-
TROL.
Move the throttle valve to the fully open and fully 
closed positions with fingers.
Check that the valve returns to the specified 
position when releasing fingers.

Does the valve return to the 
specified position? Standard 
value: 3 mm (0.12 in) from fully 
closed position

Repair the poor 
contact of ECM 
connector.

Replace the elec-
tronic throttle con-
trol. <Ref. to 
FU(H4SO)-12,
Throttle Body.>

Step

Check

Yes

No

EN(H4SO)(diag)-281

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DB:DTC P2102 THROTTLE ACTUATOR CONTROL MOTOR CIRCUIT LOW

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4SO)-183, DTC P2102 THROTTLE ACTUATOR CONTROL
MOTOR CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
• Improper idling
• Poor driving performance
• Engine stalls.

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)-282

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

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) Connect the battery to terminals No. 5 and 
No. 6 of electronic throttle control relay.
4) Measure the resistance between electronic 
throttle control relay terminals.

Terminals

No. 8 — No. 7:

Is the resistance less than 1 

:? Go to step 2.

Replace the elec-
tronic throttle con-
trol relay. <Ref. to 
FU(H4SO)-42,
Electronic Throttle 
Control Relay.>

2

CHECK POWER SUPPLY OF ELECTRONIC 
THROTTLE CONTROL RELAY.
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?

Go to step 3.

Repair the open or 
ground short circuit 
of power supply 
circuit.

3

CHECK HARNESS BETWEEN ECM AND 
ELECTRONIC THROTTLE CONTROL RE-
LAY.
1) Disconnect the connectors from ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic 
throttle control relay connector and chassis 
ground.

Connector & terminal

(B362) No. 6 (+) — 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 4.

4

CHECK HARNESS BETWEEN ECM AND 
ELECTRONIC THROTTLE CONTROL RE-
LAY.
1) Turn the ignition switch to OFF.
2) Measure the resistance between electronic 
throttle control relay connector and chassis 
ground.

Connector & terminal

(B362) No. 6 — Chassis ground:
(B362) No. 7 — Chassis ground:

Is the resistance 1 M

: or 

more?

Go to step 5.

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

5

CHECK HARNESS BETWEEN ECM AND 
ELECTRONIC THROTTLE CONTROL RE-
LAY.
Measure the resistance between ECM and 
electronic throttle control relay connector.

Connector & terminal

(B136) No. 21 — (B362) No. 6:
(B136) No. 1 — (B362) No. 7:

Is the resistance less than 1 

:? Repair the poor 

contact of ECM 
connector.

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

 

 

 

 

 

 

 

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