Subaru Legacy IV (2008 year). Manual — part 706

4AT(diag)-45

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK TORQUE CONVERTER TURBINE
SPEED SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from transmis-
sion.
3) Measure the resistance between transmis-
sion connector receptacle’s terminals.

Connector & terminal

(T4) No. 5 — No. 10:

Is the resistance 450 — 650

:? Go to step 2.

Replace the torque
converter turbine
speed sensor.
<Ref. to 4AT-53,
Torque Converter
Turbine Speed
Sensor.>

2

CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
1) Disconnect the connector from TCM.
2) Measure the resistance of harness between
TCM connector and transmission connector.

Connector & terminal

(B54) No. 1 — (B11) No. 5:

Is the resistance less than 1

:? Go to step 3.

Repair the open
circuit of harness
between TCM and
transmission con-
nector.

3

CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM connector and transmission connector.

Connector & terminal

(B54) No. 2 — (B11) No. 10:

Is the resistance less than 1

:? Go to step 4.

Repair the open
circuit of harness
between TCM and
transmission con-
nector, and poor
contact of the con-
nector.

4

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

Connector & terminal

(B54) No. 2 — Chassis ground:

Is the resistance 1 M

: or

more?

Go to step 5.

Repair the short
circuit of harness
between TCM and
transmission con-
nector.

5

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

Connector & terminal

(B54) No. 1 — Chassis ground:

Is the resistance 1 M

: or

more?

Go to step 6.

Repair the short
circuit of the har-
ness between
TCM and transmis-
sion connector,
and poor contact of
connector.

6

CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connectors to TCM and trans-
mission.
2) Connect the Subaru Select Monitor to data
link connector.
3) Turn the ignition switch to ON and run the
Subaru Select Monitor.
4) Start the engine.
5) Shift the select lever to “P” or “N” range.
6) Read the data of “Turbine Revolution
Speed” using Subaru Select Monitor.
• Compare the tachometer with Subaru Select
Monitor indications.

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

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 7.

7

CHECK POOR CONTACT.

Is there poor contact in torque
converter turbine speed sensor
circuit?

Repair the poor
contact.

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

4AT(diag)-46

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

E: DTC P0719 BRAKE SWITCH CIRCUIT LOW

DTC DETECTING CONDITION:
Brake switch malfunction, open input signal circuit
TROUBLE SYMPTOM:
Gear is not shifted down when driving a down hill.
WIRING DIAGRAM:

1

*

2

*

B159

2

1

3 4
8 9

7

6

5

B280

B281

C:

B:

B159

B280

B:

B281

C:

C23

B20

B30

3

5

9

M

AIN SBF

SBF-2

N

o

.8

E

18

17

TCM

B54

B365

2

4

3

B65

1

2

3

4

B65

B365

9

8

7

6

5

4

3

2

1

10

11 12 13 14 15 16 17 18 19

B225

1

*

2

*

1

*

2

*

7.5A

B54

B225

13
14

15 16

17

27

24

25
26

20

21
22

23

29
30

31

28

32

35

33
34

37
38

39

36

40

8

9

10

11 12

1

2

5

3

4

7

6

19

18

CAN JOINT
CONNECTOR

20

5

4

6 7

8

2

1

9

3

10

22

23

11 12 13 14 15

24 25

26 27

16 17 18

28 29

19 20

21

30

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

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

AT-04331

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

BODY INTEGRATED UNIT

FUSE & RELAY
BOX (F/B)

FUSE
(RELAY BLOCK)

B

A

TTER

Y

STOP LIGHT
SWITCH

(BLACK)

4AT(diag)-47

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK DTC.

Is DTC of CAN communication
displayed?

Perform the diag-
nosis according to
DTC.

Go to step 2.

2

CHECK FUSE (NO. 8).
1) Turn the ignition switch to OFF.
2) Remove the fuse (No. 8).

Is the fuse (No. 8) blown out?

Replace the fuse
(No. 8). If the
replaced fuse (No.
8) has blown out
easily, repair the
short circuit of har-
ness between fuse
(No. 8) and stop
light switch.

Go to step 3.

3

CHECK FUSE (RELAY BLOCK) (7.5A).
Remove the fuse (relay block) (7.5 A).

Is the fuse (7.5A) blown out?

Replace the fuse
(7.5A). If the
replaced fuse
(7.5A) blows out
easily, repair the
short circuit of har-
ness between fuse
(7.5A) and TCM.

Go to step 4.

4

CHECK BODY INTEGRATED UNIT.
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) Run the Subaru Select Monitor.
5) Depress the brake pedal.
6) Read the data of “Stop Light Switch” using
Subaru Select Monitor. <Ref. to LAN(diag)-12,
OPERATION, Subaru Select Monitor.>

Is ON displayed?

Go to step 5.

Go to step 6.

5

CHECK TCM.
Read the data of “Stop Light Switch” using Sub-
aru Select Monitor. <Ref. to 4AT(diag)-16,
OPERATION, Subaru Select Monitor.>

Is ON displayed?

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

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

6

CHECK BODY INTEGRATED UNIT INPUT
SIGNAL.
1) Disconnect the connector from body inte-
grated unit.
2) Depress the brake pedal.
3) Measure the voltage of harness between
the body integrated unit and chassis ground.

Connector & terminal

(B281) No. 23 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step 9.

Go to step 7.

7

CHECK HARNESS CONNECTOR BETWEEN
BODY INTEGRATED UNIT AND 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
body integrated unit and stop light switch.

Connector & terminal

(B281) No. 23 — (B65) No. 3:

Is the resistance less than 1

:? Go to step 8.

Repair the open
circuit of harness
between body inte-
grated unit and
stop light switch.

4AT(diag)-48

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

8

CHECK HARNESS CONNECTOR BETWEEN
BODY INTEGRATED UNIT AND STOP LIGHT
SWITCH.
Measure the resistance of harness between
body integrated unit and stop light switch.

Connector & terminal

(B281) No. 23 — Chassis ground:

Is the resistance 1 M

: or

more?

Go to step 9.

Repair the short
circuit of harness
between body inte-
grated unit and
stop light switch.

9

CHECK POOR CONTACT.

Is there poor contact in input
signal of brake switch?

Repair the poor
contact.

Check the body
integrated unit.

Step

Check

Yes

No