Subaru Legacy IV (2008 year). Manual — part 756

5AT(diag)-39

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

B: DTC P0712 TRANSMISSION FLUID TEMPERATURE SENSOR CIRCUIT LOW

INPUT

DTC DETECTING CONDITION:
Input signal circuit to ATF temperature sensor is open.
TROUBLE SYMPTOM:
Excessive shift shock
WIRING DIAGRAM:

Step

Check

Yes

No

1

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

Connector & terminal

(B54) No. 17 — (B11) No. 5:
(B54) No. 18 — (B11) No. 12:

Is the resistance less than 1

:? Go to step 2.

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

2

CHECK ATF OIL TEMPERATURE SENSOR.
1) Turn the ignition switch to OFF.
2) Connect the connectors to transmission and
TCM.
3) Turn the ignition switch to ON and start
engine.
4) Warm up the transmission until the ATF
temperature exceeds 80°C (176°F).

NOTE:
If the ambient temperature is below 0°C (32°F),
drive the vehicle until the ATF reaches its oper-
ating temperature.
5) Disconnect the connector from transmis-
sion.
6) Measure the resistance between transmis-
sion connector terminals.

Connector & terminal

(T4) No. 5 — (T4) No. 12:

Is the resistance 300 — 800

:? Go to step 3.

Go to step 5.

TCM

B11

1

2

3 4

5

6 7

8

9

13

14 15

20

19

17

16

10

11 12

18

18

B54

B11

T10

T4

12

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

CONTROL VALVE BODY

T10

1 2 3 4
6 7 8 9

5

10

17

5

4

3

T20

A

TF TEMPERA

TURE

SENSOR

AT-04348

5AT(diag)-40

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

3

CHECK ATF OIL TEMPERATURE SENSOR.
Measure the resistance between transmission
connector terminals.

Connector & terminal

(T4) No. 5 — (T4) No. 12:

Does the resistance value
increase while the ATF temper-
ature decreases?

Go to step 4.

Go to step 5.

4

CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connector.
2) Turn the ignition switch to ON. (engine OFF)
3) Read the ATF temperature using Subaru
Select Monitor.

Does the ATF temperature
gradually decrease?

Even if the AT OIL
TEMP light blinks,
the system is in
normal condition.
A temporary poor
contact of connec-
tor or harness may
be the cause.
Repair the poor
contact of harness
between ATF oil
temperature sen-
sor and transmis-
sion connector.

Go to step 6.

5

CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND CONTROL VALVE
BODY.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from transmis-
sion.
3) Remove the transmission connector from
bracket.
4) Lift up the vehicle.

NOTE:
Raise all wheels off the floor.
5) Drain the ATF.

CAUTION:
Do not drain ATF until it cools down.
6) Remove the oil pan, and disconnect the
connector from control valve body connector.
7) Measure the resistance between transmis-
sion connector and control valve body connec-
tor.

Connector & terminal

(T4) No. 12 — (T10) No. 4:
(T4) No. 5 — (T10) No. 3:

Is the resistance less than 1

:? Replace the con-

trol valve body.
<Ref. to 5AT-57,
Control Valve
Body.>

Repair the open
circuit of harness
between transmis-
sion connector and
control valve body
connector.

6

CHECK POOR CONTACT.

Is there poor contact in ATF oil
temperature sensor circuit?

Repair the poor
contact.

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

Step

Check

Yes

No

5AT(diag)-41

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

C: DTC P0713 TRANSMISSION FLUID TEMPERATURE SENSOR CIRCUIT HIGH

INPUT

DTC DETECTING CONDITION:
Input signal circuit to ATF oil temperature sensor is shorted.
TROUBLE SYMPTOM:
Excessive shift shock
WIRING DIAGRAM:

Step

Check

Yes

No

1

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

Connector & terminal

(B54) No. 17 — Chassis ground:
(B54) No. 18 — Chassis ground:

Is the resistance 1 M

: or

more?

Go to step 2.

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

2

CHECK ATF OIL TEMPERATURE SENSOR.
1) Turn the ignition switch to OFF.
2) Connect the connectors to transmission and
TCM.
3) Turn the ignition switch to ON and start
engine.
4) Warm up the transmission until the ATF
temperature exceeds 80°C (176°F).

NOTE:
If the ambient temperature is below 0°C (32°F),
drive the vehicle until the ATF reaches its oper-
ating temperature.
5) Disconnect the connector from transmis-
sion.
6) Measure the resistance between transmis-
sion connector terminals.

Connector & terminal

(T4) No. 5 — (T4) No. 12:

Is the resistance 300 — 800

:? Go to step 3.

Go to step 5.

TCM

B11

1

2

3 4

5

6 7

8

9

13

14 15

20

19

17

16

10

11 12

18

18

B54

B11

T10

T4

12

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

CONTROL VALVE BODY

T10

1 2 3 4
6 7 8 9

5

10

17

5

4

3

T20

A

TF TEMPERA

TURE

SENSOR

AT-04348

5AT(diag)-42

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

3

CHECK ATF OIL TEMPERATURE SENSOR.
Measure the resistance between transmission
connector terminals.

Connector & terminal

(T4) No. 5 — (T4) No. 12:

Does the resistance value
increase while the ATF temper-
ature decreases?

Go to step 4.

Go to step 5.

4

CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connector.
2) Turn the ignition switch to ON. (engine OFF)
3) Read the ATF temperature using Subaru
Select Monitor.

Does the ATF temperature
gradually decrease?

Even if the AT OIL
TEMP light blinks,
the system is in
normal condition.
A temporary poor
contact of connec-
tor or harness may
be the cause.
Repair the poor
contact of harness
between ATF oil
temperature sen-
sor and transmis-
sion connector.

Go to step 6.

5

CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND CONTROL VALVE
BODY.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from transmis-
sion.
3) Remove the transmission connector from
bracket.
4) Lift up the vehicle.

NOTE:
Raise all wheels off the floor.
5) Drain the ATF.

CAUTION:
Do not drain ATF until it cools down.
6) Remove the oil pan, and disconnect the
connector from control valve body connector.
7) Measure the resistance between chassis
ground and control valve body connector.

Connector & terminal

(T10) No. 3 — Chassis ground:
(T10) No. 4 — Chassis ground:

Is the resistance 1 M

: or

more?

Replace the con-
trol valve body.
<Ref. to 5AT-57,
Control Valve
Body.>

Repair the short
circuit of harness
between transmis-
sion connector and
control valve body
connector.

6

CHECK POOR CONTACT.

Is there poor contact in ATF oil
temperature sensor circuit?

Repair the poor
contact.

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

Step

Check

Yes

No