Subaru Legacy IV (2008 year). Service manual — part 711

4AT(diag)-65

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

R: DTC P0758 SHIFT SOLENOID “B” ELECTRICAL

DTC DETECTING CONDITION:
Output signal circuit of 2-4 brake duty solenoid is open or shorted.
TROUBLE SYMPTOM:
Excessive shift shock
WIRING DIAGRAM:

AT-04771

TCM

B11

1

2

3 4

5

6 7

8

9

13

14 15

20

19

17

16

10

11 12

18

4

B55

B11

AT 2

T4

3

8

B55

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

AT2

10

9

8

7

6

5

4

3

2

1

CONTROL VALVE BODY

2-4 BRAKE
DUTY
SOLENOID

4AT(diag)-66

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

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 transmission connector.

Connector & terminal

(B55) No. 4 — (B11) No. 3:

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 of harness between
TCM connector and chassis ground.

Connector & terminal

(B55) No. 4 — 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 2-4 BRAKE DUTY SOLENOID.
Measure the resistance between transmission
connector terminals.

Connector & terminal

(T4) No. 3 — No. 20:

Is the resistance 2.0 — 6.0

:? Go to step 4.

Go to step 7.

4

CHECK OUTPUT SIGNAL FROM TCM US-
ING SUBARU SELECT MONITOR.
1) Connect all connectors.
2) Connect the Subaru Select Monitor to data
link connector.
3) Start the engine, and run the Subaru Select
Monitor.
4) Warm up the transmission until the ATF
temperature exceeds approximately 80°C
(176°F).

NOTE:
If the ambient temperature falls below 0°C
(32°F), drive the vehicle until the ATF reaches
its operating temperature.
5) Stop the engine and turn the ignition switch
to ON (with engine OFF).
6) Shift the select lever to “N” range, and
depress the accelerator pedal.
7) Read the data of “Brake Clutch Duty Ratio”
using Subaru Select Monitor.
2-4 brake duty solenoid is indicated in “%”.

Is the measured value 100%?

Go to step 5.

Go to step 6.

5

CHECK OUTPUT SIGNAL FROM TCM US-
ING SUBARU SELECT MONITOR.
Shift the select lever to 2nd on manual mode.

Is the measured value 0%?

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 6.

6

CHECK POOR CONTACT.

Is there poor contact in 2-4
brake duty solenoid circuit?

Repair the poor
contact.

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

4AT(diag)-67

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

7

CHECK 2-4 BRAKE DUTY SOLENOID (IN
TRANSMISSION).
1) Remove the transmission connector from
bracket.
2) Drain the automatic transmission fluid.

CAUTION:
Do not drain ATF until it cools down.
3) Remove the oil pan, and disconnect the
connector from 2-4 brake duty solenoid.
4) Measure the resistance of harness between
2-4 brake duty solenoid connector and trans-
mission ground.

Connector & terminal

(AT2) No. 8 — Transmission ground:

Is the resistance 2.0 — 6.0

:? Go to step 8.

Replace the con-
trol valve body.
<Ref. to 4AT-56,
Control Valve
Body.>

8

CHECK HARNESS CONNECTOR BETWEEN
2-4 BRAKE DUTY SOLENOID AND TRANS-
MISSION.
Measure the resistance of harness between 2-4
brake duty solenoid and transmission connec-
tor.

Connector & terminal

(T4) No. 3 — (AT2) No. 8:

Is the resistance less than 1

:? Go to step 9.

Repair the open
circuit of harness
between 2-4 brake
duty solenoid and
transmission con-
nector.

9

CHECK HARNESS CONNECTOR BETWEEN
2-4 BRAKE DUTY SOLENOID AND TRANS-
MISSION.
Measure the resistance of harness between
transmission connector and transmission
ground.

Connector & terminal

(T4) No. 3 — Transmission ground:

Is the resistance 1 M

: or

more?

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 2-4 brake
duty solenoid and
transmission.

Repair the short
circuit of harness
between 2-4 brake
duty solenoid and
transmission con-
nector.

Step

Check

Yes

No

4AT(diag)-68

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

S: DTC P0763 SHIFT SOLENOID “C” ELECTRICAL

DTC DETECTING CONDITION:
Output signal circuit of high clutch duty solenoid is open or shorted.
TROUBLE SYMPTOM:
Excessive shift shock
WIRING DIAGRAM:

AT-04772

B11

1

2

3 4

5

6 7

8

9

13

14 15

20

19

17

16

10

11 12

18

6

B55

B11

AT 2

T4

7

3

B55

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

AT2

10

9

8

7

6

5

4

3

2

1

TCM

CONTROL VALVE BODY

HIGH
CLUTCH
DUTY
SOLENOID