Subaru Legacy (2005 year). Manual — part 558

4AT(diag)-69

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Q: DTC P0753 SHIFT SOLENOID “A” ELECTRICAL

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

AT-01487

B11

B55

AT3

1

2

3 4

5

6 7

8

9

13

14 15

20

19

17

16

10

11 12

18

9

B55

B11

AT3

T4

TCM

4

2

1

2

7

8

9

5

6

3

4

10 11 12

19 20 21

29 30 31

13 14 15 16 17

27 28

18

22 23 24 25 26

1

3

4 5 6

2

LOW CLUTCH
DUTY
SOLENOID

TRANSMISSION

4AT(diag)-70

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

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. 9 — (B11) No. 4:

Is the resistance less than 1
Ω?

Go to step 2.

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

2

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

Connector & terminal

(B55) No. 9 — Chassis ground:

Is the resistance more than 1
M

Ω?

Go to step 3.

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

3

CHECK LOW CLUTCH DUTY SOLENOID.
Measure the resistance between transmission
connector terminals.

Connector & terminal

(T4) No. 4 — No. 20:

Is the resistance 2.0 — 6.0

Ω? Go to step 5.

Go to step 4.

4

CHECK OUTPUT SIGNAL EMITTED FROM
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) Start the engine, and turn the Subaru
Select Monitor power switch to ON.
4) Warm-up the transmission until the ATF
temperature exceeds approx. 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) Stop the engine and turn the ignition switch
to ON (engine OFF).
6) Shift the select lever to “P” or “N” range,
and depress the accelerator pedal.
7) Read the data of low clutch duty solenoid
using Subaru Select Monitor.
• Low clutch duty solenoid is indicated in “%”.

Is the value 100%?

Go to step 5.

Go to step 7.

5

CHECK OUTPUT SIGNAL EMITTED FROM
TCM USING SUBARU SELECT MONITOR.
1) Turn the ignition switch to ON (engine
OFF).
2) Shift the select lever to “D” range.
3) Read the data of low clutch duty solenoid.

Is the value 0%?

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 transmission.

Go to step 6.

6

CHECK POOR CONTACT.

Is there poor contact in low
clutch duty solenoid circuit?

Repair the poor
contact.

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

4AT(diag)-71

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

7

CHECK LOW CLUTCH DUTY SOLENOID (IN
TRANSMISSION).
1) Remove the transmission connector from
bracket.
2) Drain the ATF.

CAUTION:

Do not drain ATF until it cools down.

3) Remove the oil pan, and disconnect the
connector from control valve body.
4) Measure the resistance between low clutch
duty solenoid connector and transmission
ground.

Connector & terminal

(AT3) No. 2 — Transmission ground:

Is the resistance 2.0 — 6.0

Ω? Go to step 8.

Replace the con-
trol valve body.
<Ref. to 4AT-62,
Control Valve
Body.>

8

CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND LOW CLUTCH DUTY
SOLENOID.
Measure the resistance of harness between
low clutch duty solenoid and transmission con-
nector.

Connector & terminal

(T4) No. 4 — (AT3) No. 2:

Is the resistance less than 1
Ω?

Go to step 9.

Repair the open
circuit of harness
between low clutch
duty solenoid and
transmission con-
nector.

9

CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND LOW CLUTCH DUTY
SOLENOID.
Measure the resistance of harness between
transmission connector and transmission
ground.

Connector & terminal

(T4) No. 4 — Transmission ground:

Is the resistance more than 1
M

Ω?

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 low clutch duty
solenoid and
transmission.

Repair the short
circuit of harness
between low clutch
duty solenoid and
transmission con-
nector.

Step

Check

Yes

No

4AT(diag)-72

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

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:

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. 6 — (B11) No. 3:

Is the resistance less than 1
Ω?

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. 6 — Chassis ground:

Is the resistance more than 1
M

Ω?

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

Ω? Go to step 4.

Go to step 7.

AT-01488

6

B55

B11

AT3

T4

TCM

B11

1

2

3 4

5

6 7

8

9

13

14 15

20

19

17

16

10

11 12

18

3

6

B55

AT3

1

2

7

8

9

5

6

3

4

10 11 12

19 20 21

29 30 31

13 14 15 16 17

27 28

18

22 23 24 25 26

1

3

4 5 6

2

TRANSMISSION

2-4 BRAKE
DUTY
SOLENOID