Subaru Legacy IV (2008 year). Manual — part 713

4AT(diag)-73

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

6

CHECK POOR CONTACT.

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

Repair the poor
contact.

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

7

CHECK LOW & REVERSE BRAKE DUTY SO-
LENOID (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 &
reverse duty solenoid connector and transmis-
sion ground.

Connector & terminal

(AT2) No. 1 — 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 & REVERSE
DUTY SOLENOID.
Measure the resistance of harness between low
& reverse duty solenoid and transmission con-
nector.

Connector & terminal

(T4) No. 6 — (AT2) No. 1:

Is the resistance less than 1

:? Go to step 9.

Repair 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 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 har-
ness or connector
in low & reverse
duty solenoid and
transmission.

Repair the short
circuit of the har-
ness between the
low & reverse duty
solenoid and the
transmission con-
nector.

Step

Check

Yes

No

4AT(diag)-74

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

U: DTC P0801 REVERSE INHIBIT CONTROL CIRCUIT

DTC DETECTING CONDITION:
Shift lock solenoid malfunction, open or short reverse inhibitor control circuit
TROUBLE SYMPTOM:
• Gear is shifted from “N” range to “P” range during driving at 20 km/h (12 MPH) or more.
• Gear cannot be shifted from “N” range to “R” range.
WIRING DIAGRAM:

Step

Check

Yes

No

1

CHECK SHIFT LOCK SOLENOID.
1) Start the integrated unit by force, and check
the operation of shift lock solenoid. <Ref. to
LAN(diag)-12, READ DIAGNOSTIC TROUBLE
CODE (DTC), OPERATION, Subaru Select
Monitor.>
2) Operate AT select lever without depressing
the brake pedal.

Does the AT select lever oper-
ate?

Go to step 2.

Go to step 3.

2

CHECK OUTPUT SIGNAL OF INTEGRATED
UNIT.
1) Display the following items using Subaru
Select Monitor.
• Key-lock warning SW
• Shift Position
• P SW
• 'Stop Light Switch
2) Step on the brake and shift the AT select
lever to “P” range.

Do the units of measure of
items displayed change?

Go to step 3.

Check the circuits
of the items whose
values do not
change.

3

CHECK HARNESS CONNECTOR BETWEEN
BODY INTEGRATED UNIT AND SHIFT LOCK
SOLENOID.
Measure the harness resistance between the
body integrated unit and chassis ground.

Connector & terminal

(B280) No. 6 — Chassis ground:

Is the resistance 1 M

: or

more?

Go to step 4.

Repair the short
circuit of harness
between body inte-
grated unit and
shift lock solenoid
connector.

6

E

B116

B116

3
4

B280

B280

1 2

3 4 5

6 7 8 9 10 11 12

5

4

6 7

8

2

1

9

3

10

22

23

11 12 13 14 15

24 25

26 27

16 17 18

28 29

19 20

21

30

AT-04340

BODY INTEGRATED UNIT

SHIFT LOCK
SOLENOID

4AT(diag)-75

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

4

CHECK HARNESS BETWEEN SHIFT LOCK
SOLENOID AND CHASSIS GROUND TERMI-
NAL.
Measure the resistance of harness between
shift lock solenoid and chassis ground.

Connector & terminal

(B116) No. 4 — Chassis ground:

Is the resistance less than 1

:? Go to step 5.

Repair the open
circuit of harness
between chassis
ground and shift
lock solenoid con-
nector.

5

CHECK SHIFT LOCK SOLENOID.
Measure the resistance of shift lock solenoid
terminals.

Connector & terminal

(B116) No. 3 — No. 4:

Is the resistance 12 — 18

:?

Go to step 6.

Replace the shift
lock solenoid.

6

CHECK OUTPUT SIGNAL OF BODY INTE-
GRATED UNIT.
1) Connect all connectors.
2) Turn the ignition switch to ON.
3) Shift the AT select lever to “D” range.
4) Measure the voltage between body inte-
grated unit and chassis ground.

Connector & terminal

(B280) No. 6 (+) — Chassis ground (–):

Is the voltage 10.5 V or more?

Go to step 7.

Go to step 8.

7

CHECK OUTPUT SIGNAL OF BODY INTE-
GRATED UNIT.
1) Lift up the vehicle.
2) Start the engine.
3) Shift the select lever to “D” range and slowly
increase vehicle speed to over 20 km/h (12
MPH).

NOTE:
The speed difference between front and rear
wheels may illuminate the ABS warning light,
but this does not indicate a malfunction. When
AT control diagnosis is finished, perform the
ABS or VDC clear memory of on-board diag-
nostics system. <Ref. to ABS(diag)-20, Clear
Memory Mode.> <Ref. to VDC(diag)-23, Clear
Memory Mode.>
4) Measure the voltage between body inte-
grated unit and chassis ground.

Connector & terminal

(B280) No. 6 (+) — Chassis ground (–):

Is the voltage less than 1 V?

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 the
reverse inhibitor
control circuit.

Go to step 8.

8

CHECK POOR CONTACT.

Is there poor contact in the
reverse inhibitor control circuit?

Repair the poor
contact.

Replace the body
integrated unit.
<Ref. to SL-56,
Body Integrated
Unit.>

Step

Check

Yes

No

4AT(diag)-76

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

V: DTC P1706 AT VEHICLE SPEED SENSOR CIRCUIT MALFUNCTION (REAR

WHEEL)

DTC DETECTING CONDITION:
Input signal circuit of TCM is open or shorted.
TROUBLE SYMPTOM:
No lock up or tight corner braking phenomenon is occurred.
WIRING DIAGRAM:

Step

Check

Yes

No

1

CHECK IGNITION POWER SUPPLY CIR-
CUIT.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from rear vehicle
speed sensor.
3) Turn the ignition switch to ON.
4) Measure the ignition power supply voltage
between rear vehicle speed sensor connector
and transmission ground.

Connector & terminal

(AT13) No. 3 (+) — Transmission ground
(–):

Is the voltage 10 V or more?

Go to step 2.

Check harness
between rear vehi-
cle speed sensor
and battery for
open circuit, short
or poor contact.
Repair the harness
if required.

2

CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness between
TCM connector and rear vehicle speed sensor
connector.

Connector & terminal

(B54) No. 15 — (AT13) No. 1:

Is the resistance less than 1

:? Go to step 3.

Repair the open
circuit or poor con-
tact of the connec-
tor in harness
between TCM and
rear vehicle speed
sensor connector.

3

CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM connector and rear vehicle speed sensor
connector.

Connector & terminal

(B54) No. 26 — (AT13) No. 2:

Is the resistance less than 1

:? Go to step 4.

Repair the open
circuit or poor con-
tact of the connec-
tor in harness
between TCM and
rear vehicle speed
sensor connector.

15

26

B11

AT13

T4

9

17

13

3

1

2

B54

E

MAIN SBF

SBF-6

No.12

B11

AT13

1 2 3

TCM

B54

AT-04341

1 2

5

6 7

8

13

14 15

16

9 10

11 12

3 4

17 18

19 20

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

BATTERY

IGNITION
SWITCH

REAR VEHICLE
SPEED SENSOR