Subaru Legacy IV (2008 year). Service 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.>