Subaru Legacy IV (2008 year). Manual - part 715

4AT(diag)-81

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Y: DTC P1817 SPORT MODE SWITCH CIRCUIT

DTC DETECTING CONDITION:
Input signal circuit of SPORT/manual mode switch is shorted.
TROUBLE SYMPTOM:
• Manual mode can not be set.
• The SPORT indicator light does not illuminate.
• No SPORT mode occurs.
WIRING DIAGRAM:

Step

Check

Yes

No

1

CHECK BODY INTEGRATED UNIT.
1) Connect the Subaru Select Monitor to data 
link connector.
2) Turn the ignition switch to ON. (engine OFF)
3) Read the DTC of the body integrated unit 
using the Subaru Select Monitor. <Ref. to 
LAN(diag)-12, OPERATION, Subaru Select 
Monitor.>

Is DTC displayed?

Perform the diag-
nosis according to 
DTC.

Go to step 2.

2

CHECK BODY INTEGRATED UNIT INPUT 
SIGNAL.
1) Shift the AT select lever to “P” range.
2) Read the “Tiptronic Mode Switch” data of 
the body integrated unit using the Subaru 
Select Monitor. <Ref. to LAN(diag)-12, OPERA-
TION, Subaru Select Monitor.>

Is OFF displayed?

Go to step 3.

Go to step 7.

AT-04343

1

*

1

*

2

*

1

*

2

*

2

*

B281

C:

B280

B:

B20

B30

C25

C15

18

17

B116

TCM

B54

10

11

6

7

B280

B281

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

8

7

6

5

4

3

2

1

22 23

21

20

19

16

15

14

13

12

11

10

9

17 18

28

27

26

25

24

B116

E

B:

C:

B365

B365

B54

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

8

9

C26

UP

DO

WN

1 2

3 4 5

6 7 8 9 10 11 12

9

8

7

6

5

4

3

2

1

10

11 12 13 14 15 16 17 18 19 20

BODY INTEGRATED UNIT

AT SELECT LEVER

JOINT

CONNECTOR

SPORT/
MANUAL 
MODE SWITCH

: TERMINAL No. OPTIONAL  
  ARRANGEMENT 
  AMONG 1, 2, 3, 11, 12  AND 13
: TERMINAL No. OPTIONAL 
  ARRANGEMENT 
  AMONG 8, 9, 10, 18, 19  AND 20

4AT(diag)-82

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

3

CHECK BODY INTEGRATED UNIT INPUT 
SIGNAL.
1) Shift the AT select lever from “P” to “D” 
range.
2) Read the “Tiptronic Mode Switch” data of 
the body integrated unit using the Subaru 
Select Monitor. <Ref. to LAN(diag)-12, OPERA-
TION, Subaru Select Monitor.>

Is the indication on each range 
OFF?

Go to step 4.

Replace the select 
lever assembly. 
<Ref. to CS-23, 
Select Lever.>

4

CHECK BODY INTEGRATED UNIT INPUT 
SIGNAL.
1) Shift the AT select lever to SPORT mode.
2) Read the “Tiptronic Mode Switch” data of 
the body integrated unit using the Subaru 
Select Monitor. <Ref. to LAN(diag)-12, OPERA-
TION, Subaru Select Monitor.>

Is ON displayed?

Go to step 5.

Replace the select 
lever assembly. 
<Ref. to CS-23, 
Select Lever.>

5

CHECK INHIBITOR SWITCH.
Shift the AT select lever from “P” to “D” range.

Is the indication of range posi-
tion indicator light in combina-
tion meter synchronized with 
position of select lever?

Go to step 6.

Adjust the inhibitor 
switch and select 
cable. <Ref. to 
4AT-46, ADJUST-
MENT, Inhibitor 
Switch.> <Ref. to 
CS-32, ADJUST-
MENT, Select 
Cable.>

6

CHECK INPUT SIGNAL FROM TCM.
1) Shift the AT select lever from “P” to “D” 
range.
2) Read the “Tiptronic Mode Switch” data of 
the TCM using the Subaru Select Monitor. <Ref. 
to 4AT(diag)-16, OPERATION, Subaru Select 
Monitor.>

Is the indication on each range 
OFF?

Even if the ATF 
temperature warn-
ing light is blinking, 
the circuit is in nor-
mal condition. A 
temporary short 
circuit of connector 
or harness may be 
the cause. Repair 
the harness or 
connector.

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

7

CHECK HARNESS BETWEEN BODY INTE-
GRATED UNIT AND SPORT/MANUAL MODE 
SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the harness connector from 
body integrated unit and AT select lever.
3) Measure the resistance between the body 
integrated unit and chassis ground.

Connector & terminal

(B281) No. 26 — Chassis ground:

Is the resistance 1 M

: or 

more?

Go to step 8.

Repair the short 
circuit of harness 
between body inte-
grated unit and 
sport/manual 
mode switch.

8

CHECK SPORT SHIFT SWITCH.
1) Shift the AT select lever to “P” range.
2) Measure the resistance of SPORT/manual 
mode switch connector terminals.

Terminals

No. 9 — No. 8:

Is the resistance 1 M

: or 

more?

Check the body 
integrated unit.

Replace the select 
lever assembly. 
<Ref. to CS-23, 
Select Lever.>

Step

Check

Yes

No

4AT(diag)-83

Diagnostic Procedure without Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

14.Diagnostic Procedure without Diagnostic Trouble Code (DTC)

A: CHECK FWD SWITCH

DIAGNOSIS:
• LED does not illuminate even with the fuse installed on FWD fuse holder.
• FWD signal circuit is open or shorted.
WIRING DIAGRAM:

AT-04899

i10

i84

F108

B361

A:

A:

B:

A1

8

A17

B10

TCM

B54

A:

B55

B:

F27

B361

F108

9

11

8

13

E

B365

B54

B55

i107

i106

1

4

3

2

F27

12

11

10

18
19

16

15

17

9

20 21 22

8

4 5

3

2

1

7

6

14

13

9

8

7

6

5

4

3

2

1

10

11 12 13 14 15 16 17 18 19 20

1
7

2 3

4 5 6

8 9 10 11 12 13 14

1
9

2 3

8

10

4

11 12 13 14 15 16

5 6 7

17 18

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

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

1 2

3 4

5 6

7 8

9 10 11 12

14 15 16 17 18 19 20 21 22 23

24 25

26 27 28 29

30 31 32 33

34 35

13

2

1

3 4

6 7 8 9 10

22

21

20

19

18

17

16

15

14

13

12

11

5

MAIN  SBF

SBF-6

No.

 5

E

3

21

22

i10

i84

A:

B280

B:

A26

A27

B20

B30

B365

1

*

2

*

1

*

2

*

WN

WN

ON

i107

i106

*

*

*

*

ON

WN

WN

ON

ON

 :

 :

1

*

2

*

 :

*

 :

WN

 :

ON

B280

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

B:

CAN
JOINT
CONNECTOR

BODY INTEGRATED UNIT

IGNITION

SWITCH

CAN TRANSCEIVER  &  RECEIVER

MICRO COMPUTER

B

A

TTER

Y

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

COMBINATION
METER

AWD
WARNING
LIGHT

CAN

JOINT

CONNECTOR

CAN

JOINT

CONNECTOR

THROUGH JOINT
CONNECTOR

RELAY HOLDER

FWD FUSE

HOLDER

4AT(diag)-84

Diagnostic Procedure without Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK SPARE FUSE.

Is the spare fuse OK?

Go to step 2.

Replace the fuse.

2

CHECK FWD FUSE HOLDER.
Connect the Subaru Select Monitor to data link 
connector.

When the fuse is inserted to 
FWD fuse holder, does the LED 
illuminate?

Go to step 3.

Go to step 4.

3

CHECK COMBINATION METER.

Does the AWD warning light 
illuminate?

Go to INSPEC-
TION FOR 
SPORT/MANUAL 
MODE SWITCH. 
<Ref. to 4AT(diag)-
86, CHECK 
SPORT SHIFT 
SWITCH, Diag-
nostic Procedure 
without Diagnostic 
Trouble Code 
(DTC).>

Go to step 9.

4

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND FWD FUSE HOLDER.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM.
3) Measure the resistance of harness between 
TCM and FWD fuse holder.

Connector & terminal

(B55) No. 10 — (F27) No. 8:

Is the resistance less than 1 

:? Go to step 5.

Repair the open 
circuit of harness 
between TCM and 
FWD fuse holder.

5

CHECK HARNESS CONNECTOR BETWEEN 
FWD FUSE HOLDER AND CHASSIS 
GROUND.
Measure the resistance of harness between 
FWD fuse holder and chassis ground.

Connector & terminal

(F27) No. 9 — Chassis ground:

Is the resistance less than 1 

:? Go to step 6.

Repair the open 
circuit of harness 
between FWD fuse 
holder and chassis 
ground.

6

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND FWD FUSE HOLDER.
Measure the resistance of harness connector 
between TCM and body to make sure that cir-
cuit does not short.

Connector & terminal

(B55) No. 10 — Chassis ground:

Is the resistance 1 M

: or 

more?

Go to step 7.

Repair the short 
circuit of harness 
between TCM and 
FWD fuse holder.

7

CHECK INPUT SIGNAL FOR TCM.
1) Turn the ignition switch to OFF.
2) Connect the connector to TCM.
3) Turn the ignition switch to ON.
4) Measure the signal voltage for TCM with the 
fuse installed to FWD fuse holder.

Connector & terminal

(B55) No. 10 (+) — Chassis ground (–):

Is the voltage less than 1 V?

Go to step 8.

Go to step 10.

8

CHECK INPUT SIGNAL FOR TCM.
Measure the signal voltage for TCM with the 
fuse removed from FWD fuse holder.

Connector & terminal

(B55) No. 10 (+) — Chassis ground (–):

Is the voltage 10.5 V or more?

Go to step 9.

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

9

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 10.

10

CHECK COMBINATION METER.
Check the AWD warning light. <Ref. to IDI-5, 
INSPECTION, Combination Meter System.>

Is the AWD warning light OK?

Go to step 11.

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