Subaru Legacy (2005 year). Service manual — part 629

5AT(diag)-107

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

(B55) No. 22 — (B12) No. 6:
(B54) No. 16 — (B11) No. 7:

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

(B55) No. 22 — Chassis ground:
(B54) No. 16 — 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 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. 22 (+) — (B54) No. 19 (

−

):

Is the voltage 4 — 6 V?

Go to step 6.

Go to step 5.

5

CHECK TCM I/O SIGNAL.
Check TCM 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 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.

5AT(diag)-108

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

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 set the vehicle in 1st
speed driving condition of manual mode.
4) Read the current data of torque converter
turbine speed 2 using Subaru Select Monitor.
<Ref. to 5AT(diag)-17, OPERATION, 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 turbine
speed sensor 2 change
depending on the acceleration,
deceleration and shifting gear
of the vehicle? Also, is the
value of turbine speed sensor
2 between 1,300 — 1,400 rpm
when the value of torque con-
verter turbine speed sensor is
2,000 rpm?

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 in
harness of turbine
speed sensor 2
and transmission
connector.

Go to step 7.

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

(T3) No. 6 — (T11) No. 3:
(T4) No. 7 — (T10) No. 15:

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

(T11) No. 3 — Transmission ground:
(T10) No. 15 — Transmission ground:

Is the resistance more than 1
M

Ω?

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

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

Step

Check

Yes

No

5AT(diag)-109

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

AK:DTC P1716 ATF TEMP. SENSOR 2 CIRCUIT LOW

DTC DETECTING CONDITION:
Input signal circuit of TCM to ATF temperature sensor 2 is open or shorted.
TROUBLE SYMPTOM:
Excessive shift shock
WIRING DIAGRAM:

AT-03196

1 2 3

6

8 9 10 11 12 13 14

4 5

15 16

T10

7

1 2
5

8

6

9 10 11

3 4

12

T11

7

B54

TCM

B54

TRANSMISSION

1 2

7

8

9

5 6

3 4

10 11 12
19 20 21

13

14 15

16

17

18

22

23

24

B11

1 2

5

6 7

8

13

14 15

16

9 10

11 12

3 4

17 18

19 20

11

B11

T4

13

6

12

T10

T11

2

1

5AT(diag)-110

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. 13 — (B11) No. 12:
(B54) No. 11 — (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 ATF TEMPERATURE SENSOR.
1) Turn the ignition switch to OFF.
2) Connect the connectors to transmission
and TCM.
3) Turn the ignition switch to ON and start
engine.
4) Warm-up the transmission until the ATF
temperature exceeds 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) Disconnect the connector from transmis-
sion.
6) Measure the resistance between transmis-
sion connector terminals.

Connector & terminal

(T4) No. 6 — (T4) No. 12:

Is the resistance 300 — 700

Ω Go to step 3.

Go to step 5.

3

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

Connector & terminal

(T4) No. 6 — (T4) No. 12:

Does the resistance value
increase while the ATF temper-
ature decreases?

Go to step 4.

Go to step 5.

4

CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect the connector.
2) Turn the ignition switch to ON. (engine
OFF)
3) Read the ATF temperature using Subaru
Select Monitor.

Does the ATF temperature
gradually decrease?

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
harness or con-
tact in the ATF
temperature sen-
sor and transmis-
sion connector.

Go to step 6.