Subaru Legacy IV (2008 year). Manual - part 710

 

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Subaru Legacy IV (2008 year). Manual - part 710

 

 

4AT(diag)-61

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 connector from transmission 
and TCM.
3) Measure the resistance of harness between 
TCM connector and transmission connector.

Connector & terminal

(B54) No. 3 — (B11) No. 2:
(B54) No. 4 — (B11) No. 1:

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

(B54) No. 3 — Chassis ground:
(B54) 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 LINE PRESSURE LINEAR SOLE-
NOID.
Measure the resistance between transmission 
connector receptacle’s terminals.

Connector & terminal

(T4) No. 1 — No. 2:

Is the resistance 4 — 8 

:?

Go to step 5.

Go to step 4.

4

CHECK LINE PRESSURE LINEAR SOLE-
NOID (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 control valve body.
4) Measure the resistance of line pressure lin-
ear solenoid connector terminals.

Connector & terminal

(AT2) No. 5 — No. 10:

Is the resistance 4 — 8 

:?

Go to step 5.

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

5

CHECK HARNESS CONNECTOR BETWEEN 
TRANSMISSION AND LINE PRESSURE LIN-
EAR SOLENOID.
Measure the resistance of harness between 
line pressure linear solenoid and transmission 
connector.

Connector & terminal

(T4) No. 2 — (AT2) No. 10:
(T4) No. 1 — (AT2) No. 5:

Is the resistance less than 1 

:? Go to step 6.

Repair the open 
circuit of harness 
between line pres-
sure linear sole-
noid and 
transmission con-
nector.

6

CHECK HARNESS CONNECTOR BETWEEN 
TRANSMISSION AND LINE PRESSURE LIN-
EAR SOLENOID.
Measure the resistance of harness between 
transmission connector and transmission 
ground.

Connector & terminal

(T4) No. 1 — Transmission ground:
(T4) No. 2 — 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 line pres-
sure linear 
solenoid and trans-
mission.

Repair the short 
circuit of harness 
between line pres-
sure linear sole-
noid and 
transmission con-
nector.

4AT(diag)-62

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

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-04770

TCM

B11

1

2

3 4

5

6 7

8

9

13

14 15

20

19

17

16

10

11 12

18

7

B55

B11

AT 2

T4

4

2

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

LOW  
CLUTCH
DUTY
SOLENOID

4AT(diag)-63

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 and transmission connector.

Connector & terminal

(B55) No. 7 — (B11) No. 4:

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 TRANSMISSION.
Measure the resistance of harness between 
TCM connector and transmission ground.

Connector & terminal

(B55) No. 7 — 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 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 

:? Go to step 4.

Go to step 7.

4

CHECK OUTPUT SIGNAL FROM TCM US-
ING 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 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 “P” or “N” range, and 
depress the accelerator pedal.
7) Read the data of “Low Clutch Duty” using 
Subaru Select Monitor.
• Low clutch 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.
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”.

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 transmis-
sion.

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-61, 
Transmission Con-
trol Module 
(TCM).>

4AT(diag)-64

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

7

CHECK LOW CLUTCH 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 control valve body.
4) Measure the resistance between low clutch 
duty solenoid connector and transmission 
ground.

Connector & terminal

(AT2) No. 2 — 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 
TRANSMISSION AND LOW CLUTCH DUTY 
SOLENOID.
Measure the resistance of harness between low 
clutch duty solenoid and transmission connec-
tor.

Connector & terminal

(T4) No. 4 — (AT2) No. 2:

Is the resistance less than 1 

:? 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 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 of the low 
clutch duty sole-
noid and transmis-
sion.

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

Step

Check

Yes

No

 

 

 

 

 

 

 

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