Subaru Legacy (2005 year). Manual — part 560

4AT(diag)-77

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

7

CHECK HIGH 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
control valve body connector.
4) Measure the resistance between high
clutch duty solenoid connector and transmis-
sion ground.

Connector & terminal

(AT3) No. 3 — 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
HIGH CLUTCH DUTY SOLENOID AND
TRANSMISSION.
Measure the resistance of harness between
high clutch duty solenoid and transmission
connector.

Connector & terminal

(T4) No. 7 — (AT3) No. 3:

Is the resistance less than 1
Ω?

Go to step 9.

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

9

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

Connector & terminal

(T4) No. 7 — 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 high clutch duty
solenoid and
transmission.

Repair the short
circuit of harness
between high
clutch duty sole-
noid and transmis-
sion connector.

Step

Check

Yes

No

4AT(diag)-78

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

T: DTC P0768 SHIFT SOLENOID “D” ELECTRICAL

DTC DETECTING CONDITION:
The output signal circuit of low & reverse duty solenoid is open or shorted.
TROUBLE SYMPTOM:
Gear is not changed.
WIRING DIAGRAM:

Step

Check

Yes

No

1

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

Connector & terminal

(B55) No. 7 — (B11) No. 6:

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. 7 — 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 & REVERSE DUTY SOLENOID.
Measure the resistance between transmission
connector terminals.

Connector & terminal

(T4) No. 6 — No. 20:

Is the resistance 2.0 — 6.0

Ω? Go to step 4.

Go to step 7.

AT-01490

7

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

16

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

LOW & REVERSE
DUTY
SOLENOID

4AT(diag)-79

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

4

CHECK OUTPUT SIGNAL EMITTED FROM
TCM USING SUBARU SELECT MONITOR.
1) Connect all the connectors.
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 “N” range.
7) Read the data of low & reverse duty sole-
noid using Subaru Select Monitor.
• Low & reverse duty solenoid is indicated in
“%”.

Is the value 100%?

Go to step 5.

Go to step 6.

5

CHECK OUTPUT SIGNAL EMITTED FROM
TCM USING SUBARU SELECT MONITOR.
1) Lift-up the vehicle.

NOTE:

Raise all wheels off floor.

2) Shift the select lever to manual mode, and
then hold it on 1st. Slowly increase the vehicle
speed up to 15 km/h (9 MPH), and then return
the accelerator pedal.

NOTE:

The speed difference between front and rear
wheels may light the ABS warning light or VDC
warning light, but this indicates no malfunction.
When AT control diagnosis is finished, perform
the ABS memory clearance procedure or VDC
memory clearance procedure of on-board diag-
nostics system. <Ref. to ABS(diag)-26, Clear
Memory Mode.> <Ref. to VDC(diag)-25, Clear
Memory Mode.>

3) Read the data of low & reverse duty sole-
noid.

Is the value 55%?

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 TCM and trans-
mission.

Go to step 6.

6

CHECK POOR CONTACT.

Is there poor contact in low &
reverse duty solenoid circuit?

Repair the poor
contact.

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

Step

Check

Yes

No

4AT(diag)-80

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

7

CHECK LOW & REVERSE 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 &
reverse duty solenoid connector and transmis-
sion ground.

Connector & terminal

(AT3) No. 1 — 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 & REVERSE
DUTY SOLENOID.
Measure the resistance of harness between
low & reverse duty solenoid and transmission
connector.

Connector & terminal

(T4) No. 6 — (AT3) No. 1:

Is the resistance less than 1
Ω?

Go to step 9.

Repair the open
circuit of harness
between low &
reverse duty sole-
noid and transmis-
sion connector.

9

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

Connector & terminal

(T4) No. 6 — 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 & reverse
duty solenoid and
transmission.

Repair the short
circuit of harness
between low &
reverse brake
solenoid and
transmission con-
nector.

Step

Check

Yes

No