Subaru Legacy (2005 year). Manual - part 552

4AT(diag)-45

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND ATF TEMPERATURE SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM.
3) Measure the resistance between TCM con-
nector terminals.

Connector & terminal

(B54) No. 21 — No. 9:

Is the resistance more than 
500 

Ω?

Go to step 2.

Go to step 4.

2

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND ATF TEMPERATURE SENSOR.
Measure the resistance of harness between 
TCM connector and chassis ground.

Connector & terminal

(B54) No. 21 — Chassis ground:

Is the resistance more than 1 
M

Ω?

Go to step 3.

Go to step 4.

3

CHECK HARNESS.
Measure the resistance between TCM connec-
tor terminals while shaking the harness.

Connector & terminal

(B54) No. 21 — No. 9:

Does the resistance change?

Go to step 4.

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

4

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

Connector & terminal

(B54) No. 21 — Chassis ground:

Is the resistance more than 1 
M

Ω?

Go to step 5.

Repair the short 
circuit of harness 
between TCM and 
transmission har-
ness. 

5

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND ATF TEMPERATURE SENSOR.
Measure the resistance of harness between 
TCM connector and chassis ground.

Connector & terminal

(B54) No. 9 — Chassis ground:

Is the resistance more than 1 
M

Ω?

Go to step 6.

Repair the short 
circuit of harness 
between TCM and 
transmission har-
ness. 

6

CHECK ATF TEMPERATURE SENSOR.
Measure the resistance between transmission 
connector terminals.

Connector & terminal

(T4) No. 11 — No. 15:

Is the resistance more than 
500 

Ω?

Even if the SPORT 
indicator light is 
blinking, the cir-
cuit has returned 
to normal condi-
tion at this time. A 
temporary short 
circuit of connector 
or harness may be 
the cause. Repair 
the harness or 
connector.

Go to step 7.

4AT(diag)-46

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

7

CHECK TRANSMISSION HARNESS.
1) Lift-up the vehicle.
2) Drain the ATF.

CAUTION:

Do not drain ATF until it cools down.

3) Remove the oil pan.
4) Disconnect the harness connector from 
control valve.
5) Measure the resistance between ATF tem-
perature sensor connector terminals
6) Measure the resistance between transmis-
sion connector and transmission ground.

Connector & terminal

(T4) No. 11 — Transmission ground:

Is the resistance more than 1 
M

Ω?

Go to step 8.

Replace the trans-
mission harness. 

8

CHECK TRANSMISSION HARNESS.
Measure the resistance between transmission 
connector and transmission ground.

Connector & terminal

(T4) No. 15 — Transmission ground:

Is the resistance more than 1 
M

Ω?

Go to step 9.

Replace the trans-
mission harness. 

9

CHECK ATF TEMPERATURE SENSOR.
Measure the resistance between control valve 
connector terminals

Terminal

No. 1 — No. 3:

Is the resistance more than 
500 

Ω?

Even if the SPORT 
indicator light is 
blinking, the cir-
cuit has returned 
to normal condi-
tion at this time. A 
temporary short 
circuit of connector 
or harness may be 
the cause. Repair 
the harness or 
connector.

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

Step

Check

Yes

No

4AT(diag)-47

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

D: DTC P0715 INPUT/TURBINE SPEED SENSOR CIRCUIT

DTC DETECTING CONDITION:
Input signal circuit of TCM is open or shorted.
TROUBLE SYMPTOM:
Excessive shift shock
WIRING DIAGRAM:

AT-03157

RH LH

RH

LH

5

10

B11

T4

TCM

B54

7

B11

1

2

3 4

5

6 7

8

9

13

14 15

20

19

17

16

10

11 12

18

B54

      TORQUE
   CONVERTER
TURBINE SPEED
      SENSOR

1 2

7

8 9

5

6

3

4

10 11 12
19 20 21

13 14 15 16

17 18

22 23 24

B53

1 2 3 4 5 6 7 8 9 10

11 12 13 14 15 16 17 18 19 20

16

B53

JOINT
CONNECTOR

 : LHD MODEL

RH

LH

 : RHD MODEL

*

: TERMINAL No. RANDOM ARRANGEMENT
  AMONG 2,3, AND 13

* *

*

*

*

*

4AT(diag)-48

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK TORQUE CONVERTER TURBINE 
SPEED SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from transmis-
sion.
3) Measure the resistance between transmis-
sion connector receptacle’s terminals.

Connector & terminal

(T4) No. 5 — No. 10:

Is the resistance 450 — 650 
Ω?

Go to step 2.

Replace the 
torque converter 
turbine speed sen-
sor. <Ref. to 4AT-
59, Torque Con-
verter Turbine 
Speed Sensor.>

2

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND TRANSMISSION.
1) Disconnect the connector from TCM.
2) Measure the resistance of harness 
between TCM and transmission connector.

Connector & terminal

(B54) No. 7 — (B11) No. 5:

Is the resistance less than 1 
Ω?

Go to step 3.

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

3

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

Connector & terminal

(B54) No. 16 — (B11) No. 10:

Is the resistance less than 1 
Ω?

Go to step 4.

Repair the open 
circuit of harness 
between TCM and 
transmission con-
nector, and poor 
contact in connec-
tor.

4

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:

Is the resistance more than 1 
M

Ω?

Go to step 5.

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

5

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

Connector & terminal

(B54) No. 7 — Chassis ground:

Is the resistance more than 1 
M

Ω?

Go to step 6.

Repair the short 
circuit of harness 
between TCM and 
transmission con-
nector, and poor 
contact in connec-
tor.

6

CHECK INPUT SIGNAL FOR 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) Turn the ignition switch to ON and the Sub-
aru Select Monitor power switch to ON.
4) Start the engine.
5) Shift the select lever to “P” or “N” range.
6) Read the data of turbine speed using Sub-
aru Select Monitor.
• Compare the tachometer with Subaru Select 
Monitor indications.

Is the revolution value same as 
the tachometer reading shown 
on the combination meter?

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 7.

7

CHECK POOR CONTACT.

Is there poor contact in torque 
converter turbine speed sensor 
circuit?

Repair the poor 
contact.

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