Subaru Legacy IV (2008 year). Manual - part 703

4AT(diag)-33

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

WIRING DIAGRAM:

AT-04898

MAIN  SBF

SBF-6

No.

 5

E

P

R

N

D

17

18

10

14

11

T7

B54

B12

T3

T3

B12

1

4

P

R

N

D

E

TCM

2

5

3

4

2

8

3

1

13

3

21

22

i10

i84

A:

B280

B:

A26

A27

B30

B20

B365

1

*

2

*

1

*

2

*

WN

WN

ON

i107

i106

*

*

*

*

ON

WN

WN

ON

ON

 :

 :

1

*

2

*

 :

*

 :

WN

 :

ON

B54

B12

T7

9

8

7

6

5

4

3

2

1

10

9

12

11

8

7

6

5

4

3

2

1

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

i10

i84

B280

2

1

3 4

6 7 8 9 10

22

21

20

19

18

17

16

15

14

13

12

11

5

8

7

6

5

4

3

2

1

22 23

21

20

19

16

15

14

13

12

11

10

9

34 35

33

32

17
30

18
31

29

28

27

26

25

24

8

7

6

5

4

3

2

1

22

23

21

20

19

16

15

14

13

12

11

10

9

17

30

18

29

28

27

26

25

24

A:

B:

i107

i106

1 2 3 4 5 6 7 8 9 10

11 12 13 14 15 16 17 18 19 20

1 2 3 4

B365

WITH NAVIGATION

WITHOUT NAVIGATION

TERMINAL No. OPTIONAL ARRANGEMENT
AMONG 1, 2, 3, 11, 12 AND 13

TERMINAL No. OPTIONAL ARRANGEMENT

TERMINAL No. OPTIONAL ARRANGEMENT
AMONG 8, 9, 10, 18, 19 AND 20

CAN
JOINT
CONNECTOR

BODY INTEGRATED UNIT

COMBINATION
METER

IGNITION

SWITCH

CAN TRANSCEIVER  &  RECEIVER

MICRO COMPUTER

INHIBITOR
SWITCH

B

A

TTER

Y

CAN

JOINT

CONNECTOR

CAN

JOINT

CONNECTOR

4AT(diag)-34

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK INDICATOR LIGHT.
1) Turn the ignition switch to ON.
2) Shift the select lever to “P” range.

Does the “P” range indicator 
light on combination meter illu-
minate?

Go to step 2.

Go to step 12.

2

CHECK INDICATOR LIGHT.

Does the “R” range indicator 
light on combination meter illu-
minate?

Go to step 26.

Go to step 3.

3

CHECK INDICATOR LIGHT.

Does the “N” range indicator 
light on combination meter illu-
minate?

Go to step 33.

Go to step 4.

4

CHECK INDICATOR LIGHT.

Does the “D” range indicator 
light on combination meter illu-
minate?

Go to step 40.

Go to step 5.

5

CHECK “P” RANGE SWITCH.
Read the data of “P range” using Subaru Select 
Monitor.

Is ON displayed?

Go to step 19.

Go to step 6.

6

CHECK INDICATOR LIGHT.
Shift the select lever to “R” range.

Does the “R” range indicator 
light on combination meter illu-
minate?

Go to step 8.

Go to step 7.

7

CHECK “R” RANGE SWITCH.
Read the data of “R range” using Subaru Select 
Monitor.

Is ON displayed?

Go to step 23.

Go to step 20.

8

CHECK INDICATOR LIGHT.
Shift the select lever to “N” range.

Does the “P” range indicator 
light on combination meter illu-
minate?

Go to step 10.

Go to step 9.

9

CHECK “N” RANGE SWITCH.
Read the data of “N range” using Subaru Select 
Monitor.

Is ON displayed?

Go to step 30.

Go to step 27.

10

CHECK INDICATOR LIGHT.
Shift the select lever to “D” range.

Does the “D” range indicator 
light on combination meter illu-
minate?

Even if the ATF 
temperature warn-
ing light blinks, the 
circuit is in normal 
condition at this 
time. A temporary 
poor contact of 
connector or har-
ness may be the 
cause. Repair the 
harness or con-
nector in TCM and 
transmission.

Go to step 11.

11

CHECK “D” RANGE SWITCH.
Read the data of “D range” using Subaru Select 
Monitor.

Is ON displayed?

Go to step 37.

Go to step 34.

12

CHECK HARNESS CONNECTOR BETWEEN 
INHIBITOR SWITCH AND CHASSIS 
GROUND.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from inhibitor 
switch.
3) Measure the resistance of harness between 
inhibitor switch and chassis ground.

Connector & terminal

(T7) No. 5 — Chassis ground:

Is the resistance 1 

: or more? Go to step 13.

Repair the open 
circuit of harness 
between inhibitor 
switch and chassis 
ground, and poor 
contact of the con-
nector.

4AT(diag)-35

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

13

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and 
inhibitor switch.
3) Measure the resistance of the harness 
between TCM and inhibitor switch connector.

Connector & terminal

(B54) No. 14 — (T7) No. 2:

Is the resistance less than 1 

:? Go to step 14.

Repair the open 
circuit of harness 
between TCM and 
inhibitor switch 
connector, and 
poor contact of the 
connector.

14

CHECK INPUT SIGNAL FOR TCM.
1) Turn the ignition switch to OFF.
2) Connect the connector to TCM and inhibitor 
switch.
3) Turn the ignition switch to ON.
4) Shift the select lever to “P” range.
5) Measure the voltage between TCM and 
chassis ground.

Connector & terminal

(B54) No. 14 (+) — Chassis ground (–):

Is the voltage less than 1 V?

Go to step 15.

Go to step 41.

15

CHECK INPUT SIGNAL FOR TCM.
1) Shift the select lever to any range other than 
“P”.
2) Measure the voltage between TCM and 
chassis ground.

Connector & terminal

(B54) No. 14 (+) — Chassis ground (–):

Is the voltage 8 V or more?

Go to step 16.

Replace the TCM. 
<Ref. to 4AT-61, 
Transmission Con-
trol Module 
(TCM).>

16

CHECK BODY INTEGRATED UNIT.
Read the data of “Inhibitor Switch” from Subaru 
Select Monitor. <Ref. to LAN(diag)-12, OPERA-
TION, Subaru Select Monitor.>

Is “7” displayed?

Go to step 17.

Check the body 
integrated unit.

17

CHECK BODY INTEGRATED UNIT.
Check DTC of body integrated unit.

Is DTC of CAN communication 
displayed?

Perform the diag-
nosis according to 
DTC.

Go to step 18.

18

CHECK COMBINATION METER.
Check the “P” range indicator light. <Ref. to IDI-
5, INSPECTION, Combination Meter System.>

Is the “P” range indicator light 
bulb OK?

Go to step 41.

Replace the com-
bination meter 
assembly. <Ref. to 
IDI-22, Combina-
tion Meter.>

19

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM, inhib-
itor switch and combination meter.
3) Measure the resistance of harness between 
TCM connector and chassis ground.

Connector & terminal

(B54) No. 14 — Chassis ground:

Is the resistance 1 M

: or 

more?

Go to step 42.

Repair ground 
short circuit in “P” 
range circuit.

20

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and 
inhibitor switch.
3) Measure the resistance of the harness 
between TCM and inhibitor switch connector.

Connector & terminal

(B54) No. 13 — (T7) No. 5:

Is the resistance less than 1 

:? Go to step 21.

Repair the open 
circuit of harness 
between TCM and 
inhibitor switch 
connector, and 
poor contact of the 
connector.

Step

Check

Yes

No

4AT(diag)-36

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

21

CHECK INPUT SIGNAL FOR TCM.
1) Turn the ignition switch to OFF.
2) Connect the connector to TCM and inhibitor 
switch.
3) Turn the ignition switch to ON.
4) Shift the select lever to “R” range.
5) Measure the voltage between TCM and 
chassis ground.

Connector & terminal

(B54) No. 13 (+) — Chassis ground (–):

Is the voltage less than 1 V?

Go to step 22.

Go to step 41.

22

CHECK INPUT SIGNAL FOR TCM.
1) Shift the select lever to other than “R” range.
2) Measure the voltage between TCM and 
chassis ground.

Connector & terminal

(B54) No. 13 (+) — Chassis ground (–):

Is the voltage 8 V or more?

Go to step 41.

Replace the TCM. 
<Ref. to 4AT-61, 
Transmission Con-
trol Module 
(TCM).>

23

CHECK BODY INTEGRATED UNIT.
Read the data of Shift Position from Subaru 
Select Monitor. <Ref. to LAN(diag)-12, OPERA-
TION, Subaru Select Monitor.>

Is “6” displayed?

Go to step 24.

Check the body 
integrated unit.

24

CHECK BODY INTEGRATED UNIT.
Check DTC of body integrated unit.

Is DTC of CAN communication 
displayed?

Perform the diag-
nosis according to 
DTC.

Go to step 25.

25

CHECK COMBINATION METER.
Check the “R” range indicator light. <Ref. to IDI-
5, INSPECTION, Combination Meter System.>

Is the “R” range indicator light 
OK?

Go to step 41.

Replace the com-
bination meter 
assembly. <Ref. to 
IDI-22, Combina-
tion Meter.>

26

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from TCM, inhib-
itor switch and combination meter.
3) Measure the resistance of harness between 
TCM connector and chassis ground.

Connector & terminal

(B54) No. 13 — Chassis ground:

Is the resistance 1 M

: or 

more?

Go to step 41.

Repair ground 
short circuit in “R” 
range circuit.

27

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND INHIBITOR SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and 
inhibitor switch.
3) Measure the resistance of the harness 
between TCM and inhibitor switch connector.

Connector & terminal

(B54) No. 11 — (T7) No. 3:

Is the resistance less than 1 

:? Go to step 28.

Repair the open 
circuit of harness 
between TCM and 
inhibitor switch 
connector, and 
poor contact of the 
connector.

28

CHECK INPUT SIGNAL FOR TCM.
1) Turn the ignition switch to OFF.
2) Connect the connector to TCM and inhibitor 
switch.
3) Turn the ignition switch to ON.
4) Shift the select lever to “N” range.
5) Measure the voltage between TCM and 
chassis ground.

Connector & terminal

(B54) No. 11 (+) — Chassis ground (–):

Is the voltage less than 1 V?

Go to step 29.

Go to step 41.

Step

Check

Yes

No