Subaru Legacy (2005 year). Service manual — part 555

4AT(diag)-57

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

• RHD model

AT-03159

B64

B159

B280

B:

B281

C:

C23

B20

B30

8

B352

2

4

B53

B352

B53

10

9

8

7

6

5

4

3

2

1

20

19

18

17

16

15

14

13

12

11

B54

8

3

4

5

6

7

2

1

18 19 20

17

16

15

14

13

12

11

10

9

24

23

22

21

2

5

1

9

3

12

TCM

B54

MAIN SBF

SBF-2

No.8

E

B

A

TTER

Y

STOP LIGHT
SWITCH

JOINT
CONNECTOR

JOINT
CONNECTOR

JOINT
CONNECTOR

BODY INTEGRATED
MODULE

2

1

3 4

8

7

6

5

B159

2

1

3 4
8 9

7

6

5

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

B281

8

7

6

5

4

3

2

1

21

22

20

19

16

15

14

13

12

11

10

9

17 18

28

27

26

25

24

23

B64

2

1

C:

B:

6

2

*

2

*

1

*

1

*

1

*

: TERMINAL No. RANDOM ARRANGEMENT
AMONG 8,18, AND 19

2

*

: TERMINAL No. RANDOM ARRANGEMENT
AMONG 9,10, AND 20

4AT(diag)-58

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK DTC.

Does the DTC of CAN commu-
nication appear in the on-board
diagnostics test mode?

Perform the diag-
nosis according to
DTC.

Go to step 2.

2

CHECK BODY INTEGRATED MODULE.
1) Turn the ignition switch to OFF.
2) Connect the Subaru Select Monitor to data
link connector.
3) Turn the ignition switch to ON. (engine
OFF)
4) Turn the Subaru Select Monitor power
switch to ON.
5) Read the data of brake pedal switch using
Subaru Select Monitor. <Ref. to 4AT(diag)-16,
OPERATION, Subaru Select Monitor.>

Is OFF displayed?

Go to step 3.

Go to step 4.

3

CHECK TCM.
Read the data of brake pedal switch using
Subaru Select Monitor. <Ref. to 4AT(diag)-16,
OPERATION, Subaru Select Monitor.>

Is OFF displayed?

A temporary poor
contact of connec-
tor or harness may
be the cause.
Check the poor
contact.

Replace the TCM.
<Ref. to 4AT-66,
Transmission Con-
trol Module
(TCM).>

4

CHECK BODY INTEGRATED MODULE IN-
PUT SIGNAL.
1) Disconnect the harness connector of body
integrated module.
2) Measure the voltage of harness between
body integrated module and stop light switch.

Connector & terminal

(B281) No. 23 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Go to step 5.

Go to step 7.

5

CHECK STOP LIGHT SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from stop light
switch.
3) Measure the resistance of harness
between stop light switch terminals.

Terminal

LHD model (With cruise control)

No. 2 — No. 3:

LHD model (Without cruise control)

No. 1 — No. 2:

RHD model

No. 1 — No. 2:

Is the resistance more than 1
M

Ω?

Go to step 6.

Replace the stop
light switch.

6

CHECK HARNESS CONNECTOR BETWEEN
BODY INTEGRATED MODULE AND STOP
LIGHT SWITCH.
1) Turn the ignition switch to ON.
2) Measure the voltage of harness between
body integrated module and chassis ground.

Connector & terminal

(B281) No. 23 (+) — Chassis ground (

−

):

Is the voltage less than 1 V?

Go to step 7.

Repair the short
circuit of harness
between TCM and
stop light switch.

7

CHECK POOR CONTACT.

Is there poor contact in input
signal of brake switch?

Repair the poor
contact.

Check the body
integrated module.

4AT(diag)-59

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

H: DTC P0725 ENGINE SPEED INPUT CIRCUIT

DTC DETECTING CONDITION:
Engine speed input signal circuit is open or shorted.
TROUBLE SYMPTOM:
• No lock-up occurs. (After engine is warmed-up)
• SPORT indicator light remains on when the vehicle speed is “0”.
WIRING DIAGRAM:

AT-01892

27

13

B134

ECM

B54

TCM

23

ND

HU

B54

1 2

7

8 9

5

6

3

4

10 11 12
19 20 21

13 14 15 16

17 18

22 23 24

B135

B134

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

:

:

:

:

ND

HU

B135

ND

HU

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

: 2.5 L EK AND 2.5 L K4 MODEL

: EXCEPT 2.5 L EK AND 2.5 L K4 MODEL

ND

HU

4AT(diag)-60

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

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

Connector & terminal

2.5 L EK and 2.5 L K4 model

(B54) No. 13 — (B134) No. 23:

Except for 2.5 L EK and 2.5 L K4 model

(B54) No. 13 — (B135) No. 27:

Is the resistance less than 1
Ω?

Go to step 2.

Repair the open
circuit of harness
between TCM and
ECM connector.

2

CHECK HARNESS CONNECTOR BETWEEN
TCM AND ECM.
Measure the resistance of harness between
TCM connector and chassis ground.

Connector & terminal

(B54) No. 13 — Chassis ground:

Is the resistance more than 1
M

Ω?

Go to step 3.

Repair the short
circuit of harness
between TCM and
ECM connector.

3

CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connectors to TCM and ECM.
2) Connect the Subaru Select Monitor to data
link connector.
3) Start the engine, and turn the Subaru
Select Monitor power switch to ON.
4) Run the engine at idle.
5) Read the data of engine speed using Sub-
aru Select Monitor.
• Display shows engine speed signal value
sent from ECM.

Is the revolution value same as
the tachometer reading shown
on the combination meter?

Even if the SPORT
indicator light is
blinking, the cir-
cuit has returned
to normal condi-
tion at this time. A
temporary poor
contact of connec-
tor or harness may
be the cause.
Repair the har-
ness or connector
in the TCM and
ECM.

Go to step 4.

4

CHECK POOR CONTACT.

Is there poor contact in engine
speed signal circuit?

Repair the poor
contact.

Go to step 5.

5

CONFIRM DTC P0725.
Replace the ECM with a new one.

Does the DTC appear again,
after the memory has been
cleared?

Replace the TCM.
<Ref. to 4AT-66,
Transmission Con-
trol Module
(TCM).>

Replace the ECM.
<Ref. to FU(H4SO
2.0)-34, Engine
Control Module
(ECM).>