Subaru Legacy IV (2008 year). Manual - part 753

5AT(diag)-27

AT OIL TEMP Warning Light Display

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

B: INSPECTION

DIAGNOSIS:
AT OIL TEMP light circuit is open or shorted.
TROUBLE SYMPTOM:
When the ignition switch is turned to ON (engine OFF), AT OIL TEMP light does not illuminate.
WIRING DIAGRAM:

AT-04892

3

21

22

i10

i84

A:

B280

B:

A26

A27

B20

B30

21

20

TCM

B55

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:

B365

i107

i106

1 2 3 4 5 6 7 8 9 10

11 12 13 14 15 16 17 18 19 20

1

*

2

*

1

*

2

*

 :

 :

1

*

2

*

 :

*

1 2 3 4

MAIN  SBF

SBF-6

No.

 5

E

B365

B55

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

WITH NAVIGATION

WITHOUT NAVIGATION

 :

WN

 :

ON

WN

WN

ON

i107

i106

*

*

*

CAN
JOINT
CONNECTOR

*

ON

WN

WN

ON

ON

BODY INTEGRATED UNIT

IGNITION

SWITCH

B

A

TTER

Y

MICRO COMPUTER

CAN TRANSCEIVER  &  RECEIVER

COMBINATION
METER

CAN

JOINT

CONNECTOR

CAN
JOINT
CONNECTOR

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

AT OIL
TEMP

5AT(diag)-28

AT OIL TEMP Warning Light Display

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK AT OIL TEMP LIGHT.
Turn the ignition switch to ON.

Does the AT OIL TEMP light 
illuminate?

Go to step 2.

Perform the self-
diagnosis of com-
bination meter.

2

CHECK AT OIL TEMP LIGHT.
After the ignition switch is ON, wait for at least 2 
seconds.

Does the AT OIL TEMP light 
illuminate?

Go to step 3.

Go to step 4.

3

CHECK AT OIL TEMP LIGHT.
Start the engine.

Does the AT OIL TEMP light go 
off?

Normal. Go back to 
Basic Diagnostic 
Procedure. <Ref. 
to 5AT(diag)-2, 
Basic Diagnostic 
Procedure.>

Go to step 7.

4

CHECK SUBARU SELECT MONITOR COM-
MUNICATION.
Connect the Subaru Select Monitor to data link 
connector.

Is the communication between 
Subaru Select Monitor and 
TCM normal?

Go to step 5.

Check the power 
supply ground cir-
cuit of TCM and 
Subaru Select 
Monitor communi-
cation. <Ref. to 
5AT(diag)-29, 
Diagnostic Proce-
dure for Subaru 
Select Monitor 
Communication.>

5

CHECK TCM.
Display the current data of TCM using Subaru 
Select Monitor.

Is the “Diagnosis Light” output 
signal “ON”?

Go to step 6.

Replace the TCM. 
<Ref. to 5AT-60, 
Transmission Con-
trol Module 
(TCM).>

6

CHECK BODY INTEGRATED UNIT.
Display the current data of body integrated unit 
using Subaru Select Monitor. <Ref. to 
LAN(diag)-12, OPERATION, Subaru Select 
Monitor.>

Does the “AT OIL TEMP light” 
input signal “Illuminate”?

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

Check DTC of 
body integrated 
unit. <Ref. to 
LAN(diag)-12, 
OPERATION, Sub-
aru Select Moni-
tor.>

7

CHECK TCM.
1) Start the engine.
2) Display the current data of TCM using Sub-
aru Select Monitor. <Ref. to 5AT(diag)-18, 
OPERATION, Subaru Select Monitor.>

Is the “Diagnosis Light” output 
signal “ON”?

Replace the TCM. 
<Ref. to 5AT-60, 
Transmission Con-
trol Module 
(TCM).>

Go to step 8.

8

CHECK BODY INTEGRATED UNIT.
Display the current data of body integrated unit 
using Subaru Select Monitor. <Ref. to 
LAN(diag)-12, OPERATION, Subaru Select 
Monitor.>

Does the “AT OIL TEMP light” 
input signal “Illuminate”?

Check DTC of 
body integrated 
unit. Perform the 
diagnosis accord-
ing to DTC. <Ref. 
to LAN(diag)-12, 
OPERATION, Sub-
aru Select Moni-
tor.>

Perform the self-
diagnosis of com-
bination meter. 
<Ref. to IDI-5, 
INSPECTION,
Combination Meter 
System.>

5AT(diag)-29

Diagnostic Procedure for Subaru Select Monitor Communication

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

12.Diagnostic Procedure for Subaru Select Monitor Communication

A: COMMUNICATION FOR INITIALIZING IMPOSSIBLE

DIAGNOSIS:
Defective harness connector
TROUBLE SYMPTOM:
Subaru Select Monitor communication failure
WIRING DIAGRAM:

AT-04893

B40

M/B No.

 12

16

5

7

4

E

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16

5

6

7

2

1

3

4

29

10 11 12 13 14 15

25

24

16

30

9

8

17 18 19

20
28

21 22 23

32

31

26 27

33

34 35

No. 13

MAIN  SBF

SBF-6

F/B No.

 12

B40

B55

TCM

25

19

18

8

E

27

26

23

22

B55

E

B134

A:

B136

C:

ECM

C6

A5

36

B21

C: B136

16

10 11 12 13 14 15

25

24

30

9

8

7

17 18 19 20
28

21 22 23

29

32

31

1

2

3

4

5

6

27

26

33 34 35

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

B134

A:

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 26 27 28 29 30 31 32 33

34

35

42

43

36

37

38

39

48

49

50

51

52

53

54

40

41

44

45

46

47

B21

E2

8

SBF-8

No. 4

IG2 RELAY

BATTERY

DATA LINK
CONNECTOR

IGNITION

SWITCH

5AT(diag)-30

Diagnostic Procedure for Subaru Select Monitor Communication

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK SUBARU SELECT MONITOR POW-
ER SUPPLY CIRCUIT.
Measure the voltage between data link connec-
tor and chassis ground.

Connector & terminal

(B40) No. 16 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step 2.

Repair harness 
connector between 
the battery and 
data link connec-
tor, and poor con-
tact of the 
connector.

2

CHECK SUBARU SELECT MONITOR 
GROUND CIRCUIT.
Measure the resistance of harness between 
data link connector and chassis ground.

Connector & terminal

(B40) No. 4 — Chassis ground:
(B40) No. 5 — Chassis ground:

Is the resistance less than 1 

:? Go to step 3.

Repair the open 
circuit of harness 
between data link 
connector and 
ground terminal, 
and poor contact of 
connector.

3

CHECK COMMUNICATION OF SUBARU SE-
LECT MONITOR.
1) Turn the ignition switch to ON.
2) Using the Subaru Select Monitor, check 
whether communication to the transmission 
system can be executed normally.

Is the name of system dis-
played on Subaru Select Moni-
tor?

Go to step 8.

Go to step 4.

4

CHECK COMMUNICATION OF SUBARU SE-
LECT MONITOR.
1) Turn the ignition switch to OFF.
2) Disconnect the TCM connector.
3) Turn the ignition switch to ON.
4) Check whether communication to engine 
system can be executed normally.

Is the name of system dis-
played on Subaru Select Moni-
tor?

Go to step 6.

Go to step 5.

5

CHECK COMMUNICATION OF SUBARU SE-
LECT MONITOR.
1) Turn the ignition switch to OFF.
2) Connect the TCM connector.
3) Disconnect the connector from ECM.
4) Turn the ignition switch to ON.
5) Check whether communication to transmis-
sion system can be executed normally.

Is the name of system dis-
played on Subaru Select Moni-
tor?

Inspect the ECM.

Go to step 6.

6

CHECK HARNESS CONNECTOR BETWEEN 
EACH CONTROL MODULE AND DATA LINK 
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the TCM and ECM connector.
3) Measure the resistance between TCM con-
nector and chassis ground.

Connector & terminal

(B40) No. 7 — Chassis ground:

Is the resistance 1 M

: or 

more?

Go to step 7.

Check harness 
and connector 
between each con-
trol module and 
data link connec-
tor.

7

CHECK OUTPUT SIGNAL OF TCM.
1) Turn the ignition switch to ON.
2) Measure the voltage between TCM and 
chassis ground.

Connector & terminal

(B40) No. 7 (+) — Chassis ground (–):

Is the voltage 1 V or more?

Check harness 
and connector 
between each con-
trol module and 
data link connec-
tor.

Go to step 8.

8

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND DATA LINK CONNECTOR.
Measure the resistance between TCM connec-
tor and data link connector.

Connector & terminal

(B55) No. 8 — (B40) No. 7:

Is the resistance less than 1 

:? Go to step 9.

Repair the harness 
and connector 
between TCM and 
data link connec-
tor.

9

CHECK INSTALLATION OF TCM CONNEC-
TOR.
Turn the ignition switch to OFF.

Is TCM connector connected to 
TCM?

Go to step 10.

Connect the TCM 
connector to TCM.