Subaru Legacy IV (2008 year). Service manual — part 765

5AT(diag)-75

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

X: DTC P0768 SHIFT SOLENOID “D” ELECTRICAL

DTC DETECTING CONDITION:
The output signal circuit of direct clutch linear solenoid is open or shorted.
TROUBLE SYMPTOM:
Locked to 1st or 4th gear.
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

(B55) No. 22 — Chassis ground:
(B55) No. 23 — Chassis ground:
(B54) No. 1 — (B11) No. 16:

Is the resistance less than 1

:? Go to step 2.

Repair the open
circuit of harness
between TCM con-
nector and trans-
mission connector.

2

CHECK HARNESS CONNECTOR BETWEEN
TCM AND CHASSIS GROUND.
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 3.

Repair the short
circuit of harness
between TCM con-
nector and trans-
mission connector.

AT-04361

A1

B11

T11

T4

16

4

CONTROL VALVE BODY

DIRECT CLUTCH

LINEAR SOLENOID

B11

1

2

3 4

5

6 7

8

9

13

14 15

20

19

17

16

10

11 12

18

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

1 2 3 4
5 6 7 8

T11

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

TCM

B54

A:

B55

B:

B22

B23

E

B54

A:

B55

B:

5AT(diag)-76

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

3

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
control valve body connector.
7) Measure the resistance between transmis-
sion connector and control valve body connec-
tor.

Connector & terminal

(T4) No. 16 — (T11) No. 4:

Is the resistance less than 1

:? Go to step 4.

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

4

CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND CONTROL VALVE
BODY.
Measure the resistance between transmission
ground and control valve body connector.

Connector & terminal

(T11) No. 4 — Transmission ground:

Is the resistance 1 M

: or

more?

Repair the open
circuit of harness
between control
valve body con-
nector and trans-
mission ground.

Go to step 5.

5

CHECK DIRECT CLUTCH LINEAR SOLE-
NOID.
Measure the resistance of harness connector
between control valve body connector and
transmission ground.

Connector & terminal

(T11) No. 4 — Transmission ground:

Is the resistance 3 — 9

:?

Go to step 6.

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

6

CHECK POOR CONTACT.
Check that there are no poor contact in TCM
connector, transmission connector and control
valve body connector.

Is there any loosing terminal,
entering foreign matter, damag-
ing connector body?

Repair the poor
contact.

Go to step 7.

7

CHECK AFTER REPAIR.
1) Perform the Clear Memory Mode.
2) Drive for a while, read the DTC, and check
that there is no faulty.

Is DTC displayed?

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

Temporary poor
contact or open cir-
cuit occurs.
Recheck that the
harness connector
has no faulty.

Step

Check

Yes

No

5AT(diag)-77

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Y: DTC P0771 SHIFT SOLENOID “E” PERFORMANCE OR STUCK OFF

DTC DETECTING CONDITION:
Output signal of forward brake linear solenoid does not match the oil pressure.
TROUBLE SYMPTOM:
Locked to 2nd, 3rd, 4th gear.
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

(B55) No. 22 — Chassis ground:
(B55) No. 23 — Chassis ground:
(B54) No. 19 — (B11) No. 13:
(B54) No. 21 — (B11) No. 9:

Is the resistance less than 1

:? Go to step 2.

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

2

CHECK HARNESS CONNECTOR BETWEEN
TCM AND CHASSIS GROUND.
Measure the resistance between TCM connec-
tor and chassis ground.

Connector & terminal

(B54) No. 21 — Chassis ground:

Is the resistance 1 M

: or

more?

Go to step 3.

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

3

CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect all connectors.
2) Turn the ignition switch to ON. (engine OFF)
3) Check input signal of “Fwd/B hydraulic pres-
sure SW”.

Is OFF displayed?

Go to step 4.

Go to step 6.

AT-04362

A21

A1

9

CONTROL VALVE BODY

B11

T4

7

T10

T11

9

13

10

FORWARD

BRAKE

OIL PRESSURE

SWITCH

FORWARD
BRAKE
LINEAR
SOLENOID

B11

1 2

5

6 7

8

13

14 15

16

9 10

11 12

3 4

17 18

19 20

T11

1 2 3 4
5 6 7 8

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

T10

1 2 3 4
6 7 8 9

5

10

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

TCM

B54

A:

B55

B:

B22

B23

E

B54

A:

B55

B:

5AT(diag)-78

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

4

CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Turn the ignition switch to OFF.
2) Turn the ignition switch to ON. (Engine ON)
3) Drive the vehicle on 2nd speed of manual
mode 15 km/h (9 MPH) with checking current
gear position using Subaru Select Monitor.
4) Check input signal of “Fwd/B hydraulic pres-
sure SW”.

Is ON displayed?

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
in the solenoid out-
put and oil pres-
sure SW input.

Go to step 5.

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
control valve body connector.
7) Measure the resistance between transmis-
sion connector and control valve body connec-
tor.

Connector & terminal

(T4) No. 13 — (T11) No. 7:
(T4) No. 9 — (T10) No. 10:

Is the resistance less than 1

:? Replace the con-

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

Replace the trans-
mission harness
assembly.

6

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
control valve body connector.
7) Check the insulation of transmission har-
ness assembly.

Connector & terminal

(T10) No. 10 — Transmission 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.

Step

Check

Yes

No