Subaru Legacy (2005 year). Manual - part 615

5AT(diag)-51

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

(B54) No. 16 — (B11) No. 7:
(B55) No. 7 — (B11) No. 1:

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 chassis ground.

Connector & terminal

(B54) No. 16 — Chassis ground:
(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 
chassis ground.

3

CHECK TCM POWER SUPPLY OUTPUT.
1) Connect the connector to TCM. (Transmis-
sion connector is disconnected)
2) Turn the ignition switch to ON. (engine 
OFF)
3) Measure the voltage between TCM con-
nector and chassis ground.

Connector & terminal

(B54) No. 16 (+) — Chassis ground (

−

):

Is the voltage 10 — 13 V?

Go to step 4.

Go to step 5.

4

CHECK TURBINE SPEED SENSOR INPUT 
CIRCUIT OF TCM.
Measure the voltage between TCM connector 
terminals.

Connector & terminal

(B55) No. 7 (+) — (B54) No. 19 (

−

):

Is the voltage 4 — 6 V?

Go to step 6.

Go to step 5.

5

CHECK TCM I/O SIGNAL.
Check I/O signal of power supply, ground and 
PVIGN power supply relay.
<Ref. to 5AT(diag)-13, ELECTRICAL SPECIFI-
CATION, Transmission Control Module (TCM) 
I/O Signal.>

Is TCM I/O signal OK?

Replace the TCM. 
<Ref. to 5AT-61, 
Transmission Con-
trol Module 
(TCM).>

Repair the open or 
short circuit for 
power supply and 
ground. Perform 
the diagnosis 
according to DTC 
for PVIGN power 
supply relay.

6

CHECK INPUT SIGNAL FOR TCM USING 
SUBARU SELECT MONITOR.
1) Connect all the connectors.
2) Jack-up the vehicle and support with rigid 
racks.

NOTE:

Raise all wheels off floor.

3) Start the engine, and drive it.
4) Read the current data of front wheel speed 
using Subaru Select Monitor. <Ref. to 
5AT(diag)-17, READ CURRENT DATA, OPER-
ATION, Subaru Select Monitor.>

NOTE:

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

Does the value of the front 
wheel speed depending on the 
acceleration and deceleration 
of the vehicle?

Even if the SPORT 
indicator lights 
blinks, the system 
is in normal condi-
tion. A temporary 
poor contact of 
connector or har-
ness may be the 
cause. Repair the 
poor contact of 
harness between 
ATF temperature 
sensor and trans-
mission connector.

Go to step 7.

5AT(diag)-52

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

7

CHECK HARNESS CONNECTOR BETWEEN 
TRANSMISSION AND CONTROL VALVE 
BODY.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from transmis-
sion.
3) Remove the transmission connector from 
bracket.
4) Jack-up the vehicle and place it on rigid 
racks.

NOTE:

Raise all wheels off floor.

5) Drain the ATF.

CAUTION:

Do not drain the ATF until it cools down.

6) Remove the oil pan, and disconnect the 
connector from control valve body connector.
7) Measure the resistance between transmis-
sion connector and control valve body connec-
tor.

Connector & terminal

(B11) No. 7 — (T10) No. 15:
(B11) No. 1 — (T10) No. 14:

Is the resistance less than 1 
Ω?

Go to step 8.

Repair the open 
circuit of harness 
between control 
valve body con-
nector and trans-
mission connector.

8

CHECK HARNESS CONNECTOR BETWEEN 
TRANSMISSION AND CONTROL VALVE 
BODY.
Measure the resistance between transmission 
ground and control valve body connector.

Connector & terminal

(T10) No. 15 — Transmission ground:
(T10) No. 14 — Transmission ground:

Is the resistance more than 1 
M

Ω?

Go to step 9.

Repair the short 
circuit of harness 
between transmis-
sion connector 
and transmission 
ground.

9

CHECK HARNESS CONNECTOR BETWEEN 
CONTROL VALVE BODY AND VEHICLE 
SPEED SENSOR.
1) Disconnect the connector from vehicle 
speed sensor.
2) Measure the resistance of harness 
between control valve body connector and 
vehicle speed sensor connector.

Connector & terminal

(T10) No. 15 — (T7) No. 3:
(T10) No. 14 — (T7) No. 2:
(T7) No. 1 — Transmission ground:

Is the resistance less than 1 
Ω?

Go to step 10.

Replace the con-
trol valve body. 
<Ref. to 5AT-58, 
Control Valve 
Body.>

10

CHECK HARNESS CONNECTOR BETWEEN 
CONTROL VALVE BODY AND VEHICLE 
SPEED SENSOR.
Measure the resistance of harness between 
control valve body connector and transmission 
ground.

Connector & terminal

(T10) No. 15 — Transmission ground:
(T10) No. 14 — Transmission ground:

Is the resistance more than 1 
M

Ω?

Replace the vehi-
cle speed sensor.

Replace the con-
trol valve body. 
<Ref. to 5AT-58, 
Control Valve 
Body.>

Step

Check

Yes

No

5AT(diag)-53

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

G: DTC P0724 TORQUE CONVERTER/BRAKE SWITCH “B” CIRCUIT HIGH

DTC DETECTING CONDITION:
Brake switch malfunction, open input signal circuit
TROUBLE SYMPTOM:
Gear is not shifted down when climbing a hill.
WIRING DIAGRAM:

AT-03175

B159

B280

B:

B281

C:

C23

B20

B30

B159

2

1

3 4
8 9

7

6

5

B280

8

7

6

5

4

3

2

1

22

23

21

20

19

16

15

14

13

12

11

10

9

17

30

18

29

28

27

26

25

24

B281

8

7

6

5

4

3

2

1

21

22

20

19

16

15

14

13

12

11

10

9

17 18

28

27

26

25

24

23

B54

4

3

TCM

B54

FUSE & RELAY
BOX (F/B)

BODY INTEGRATED
MODULE

C:

B:

1 2

7

8

9

5 6

3 4

10 11 12
19 20 21

13

14 15

16

17

18

22

23

24

MAIN SBF

SBF-2

No.8

E

B

A

TTER

Y

B65

1 2

B64

1

2

3

4

WC

OC :

:

B65

WC

B64

OC :

:

STOP LIGHT
SWITCH

32

WC

WC

12

OC

OC

5

9

OC

WC : WITH CRUISE CONTROL

: WITHOUT CRUISE CONTROL

5AT(diag)-54

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK DTC.

Is any of following DTC 
detected? / AT CAN Communi-
cation Circuit / Output Speed 
Sensor Circuit / AT Vehicle 
Speed Sensor Circuit Malfunc-
tion (Rear Wheel)

Perform the diag-
nosis according to 
DTC.

Go to step 2.

2

CHECK BODY INTEGRATED MODULE.
1) Turn the ignition switch to OFF.
2) Connect the Subaru Select Monitor to data 
link connector.
3) Turn the ignition switch to ON. (engine 
OFF)
4) Turn the Subaru Select Monitor power 
switch to ON.
5) Read the data of brake pedal switch using 
Subaru Select Monitor. <Ref. to 5AT(diag)-17, 
OPERATION, Subaru Select Monitor.>

Is OFF displayed?

Go to step 3.

Go to step 4.

3

CHECK TCM.
Read the data of brake pedal switch using 
Subaru Select Monitor. <Ref. to 5AT(diag)-17, 
OPERATION, Subaru Select Monitor.>

Is OFF displayed?

A temporary poor 
contact of connec-
tor or harness may 
be the cause. 
Check the poor 
contact.

Replace the TCM. 
<Ref. to 5AT-61, 
Transmission Con-
trol Module 
(TCM).>

4

CHECK BODY INTEGRATED MODULE IN-
PUT SIGNAL.
1) Disconnect the connector from body inte-
grated module.
2) Measure the voltage between body inte-
grated module connector and chassis ground.

Connector & terminal

(B281) No. 23 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Go to step 5.

Go to step 7.

5

CHECK STOP LIGHT SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from stop light 
switch.
3) Measure the resistance of stop light switch 
terminals.

Terminal

With cruise control

(B65) No. 2 — No. 3:

Without cruise control

(B64) No. 1 — No. 2:

Is the resistance more than 1 
M

Ω?

Go to step 6.

Replace the stop 
light switch.

6

CHECK HARNESS CONNECTOR BETWEEN 
BODY INTEGRATED MODULE AND STOP 
LIGHT SWITCH.
1) Turn the ignition switch to ON.
2) Measure the voltage of harness between 
body integrated module connector and chassis 
ground.

Connector & terminal

(B281) No. 23 (+) — Chassis ground (

−

):

Is the voltage less than 1 V?

Go to step 7.

Repair the short 
circuit of harness 
between TCM and 
stop light switch.

7

CHECK POOR CONTACT.

Is there poor contact in input 
signal of brake switch?

Repair the poor 
contact.

Check the body 
integrated module.