Subaru Legacy (2005 year). Service manual — part 556

4AT(diag)-61

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

I:

DTC P0731 GEAR 1 INCORRECT RATIO

NOTE:
Refer to DTC P0736 for diagnostic procedure. <Ref. to 4AT(diag)-62, DTC P0736 REVERSE INCORRECT
RATIO, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

J: DTC P0732 GEAR 2 INCORRECT RATIO

NOTE:
Refer to DTC P0736 for diagnostic procedure. <Ref. to 4AT(diag)-62, DTC P0736 REVERSE INCORRECT
RATIO, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

K: DTC P0733 GEAR 3 INCORRECT RATIO

NOTE:
Refer to DTC P0736 for diagnostic procedure. <Ref. to 4AT(diag)-62, DTC P0736 REVERSE INCORRECT
RATIO, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

L: DTC P0734 GEAR 4 INCORRECT RATIO

NOTE:
Refer to DTC P0736 for diagnostic procedure. <Ref. to 4AT(diag)-62, DTC P0736 REVERSE INCORRECT
RATIO, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

4AT(diag)-62

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

M: DTC P0736 REVERSE INCORRECT RATIO

DTC DETECTING CONDITION:
Vehicle sensor, torque converter turbine speed sensor or control valve malfunction
TROUBLE SYMPTOM:
• Shift point is too high or too low.
• Excessive shift shock
• Tight corner braking phenomenon is occurred.
• Gear is not shifted to reverse.
• Gear position is held by fail safe function.

Step

Check

Yes

No

1

CHECK ACCELERATOR PEDAL POSITION
SENSOR.
1) Connect the Subaru Select Monitor to data
link connector.
2) Turn the ignition switch to ON.
3) Read the value of accelerator pedal posi-
tion sensor on Subaru Select Monitor display.

Does the value of accelerator
pedal position sensor change
from 0% to 100% smoothly
when throttle was operated
from fully closing to fully open-
ing?

Go to step 2.

Check the acceler-
ator pedal position
sensor circuit.
<Ref. to 4AT(diag)-
89, DTC P1708
THROTTLE POSI-
TION SENSOR
CIRCUIT LOW
INPUT, Diagnostic
Procedure with
Diagnostic Trou-
ble Code (DTC).>

2

CHECK FRONT VEHICLE SPEED SENSOR.
1) Lift-up the vehicle.
2) Start the engine.
3) Shift the select lever “D” range and slowly
increase vehicle speed.

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.>

Does the vehicle speed dis-
played by Subaru Select Moni-
tor almost correspond with
vehicle speed indicated by
combination meter?

Go to step 3.

Check front vehi-
cle speed sensor
circuit.

3

CHECK TORQUE CONVERTER TURBINE
SPEED SENSOR.
1) Shift the select lever to “P” or “N” range.
2) Idle the engine.

Does the turbine speed sen-
sor revolution displayed by
Subaru Select Monitor almost
correspond with engine revolu-
tion indicated by tachometer?

There are mal-
functions in TCM,
TCM connector
poor contact, or
transmission
assembly mechan-
ical malfunction.

Check torque con-
verter turbine
speed sensor cir-
cuit.

4AT(diag)-63

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

N: DTC P0741 TORQUE CONVERTER CLUTCH CIRCUIT PERFORMANCE OR

STUCK OFF

DTC DETECTING CONDITION:
• Lock up clutch malfunction
• Valve anchoring
TROUBLE SYMPTOM:
No lock-up occurs.

Step

Check

Yes

No

1

CHECK LOCK-UP DUTY SOLENOID CIR-
CUIT.
Diagnose according to DTC P0743 procedure.

Is there any trouble?

Repair or replace
the lock-up duty
solenoid circuit.

Go to step 2.

2

CHECK INHIBITOR SWITCH CIRCUIT.
Diagnose according to DTC P0705 procedure.

Is there any trouble?

Repair or replace
the inhibitor switch
circuit.

Go to step 3.

3

CHECK STOP LIGHT SWITCH CIRCUIT.
Diagnose according to DTC P0719 and P0724
procedure.

Is there any trouble?

Repair or replace
the stop light
switch circuit.

Go to step 4.

4

CHECK ATF TEMPERATURE SENSOR CIR-
CUIT.
Diagnose according to DTC P0712 AND
P0713 procedure.

Is there any trouble?

Repair or replace
the ATF tempera-
ture sensor circuit.

Go to step 5.

5

CHECK ACCELERATOR PEDAL POSITION
SENSOR.
1) Connect the Subaru Select Monitor to data
link connector.
2) Turn the ignition switch to ON.
3) Read the value of accelerator pedal posi-
tion sensor on Subaru Select Monitor display.

Does the value of accelerator
pedal position sensor change
from 0% to 100% smoothly
when throttle was operated
from fully closing to fully open-
ing?

Go to step 6.

Check the acceler-
ator pedal position
sensor circuit.

6

CHECK TORQUE CONVERTER TURBINE
SPEED SENSOR.
1) Shift the select lever to “P” or “N” range.
2) Idle the engine.

Does the turbine speed dis-
played by Subaru Select Moni-
tor almost correspond with
turbine speed indicated by
tachometer?

Go to step 7.

Check torque con-
verter turbine
speed sensor cir-
cuit.

7

CHECK ENGINE SPEED SIGNAL.
Idle the engine.

Does the engine speed dis-
played by Subaru Select Moni-
tor almost correspond with
engine speed indicated by
tachometer?

There is transmis-
sion assembly
mechanical mal-
function.

Check engine
speed signal cir-
cuit.

4AT(diag)-64

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

O: DTC P0743 TORQUE CONVERTER CLUTCH CIRCUIT ELECTRICAL

DTC DETECTING CONDITION:
Output signal circuit of lock-up duty solenoid is open or shorted.
TROUBLE SYMPTOM:
No lock-up occurs. (After engine is warmed-up)
WIRING DIAGRAM:

Step

Check

Yes

No

1

CHECK ANY OTHER DTC ON DISPLAY.

Is any other DTC displayed?

Perform the diag-
nosis according to
DTC.

Go to step 2.

AT-01485

B11

B55

AT3

1

2

3 4

5

6 7

8

9

13

14 15

20

19

17

16

10

11 12

18

5

B55

B11

AT3

T4

TCM

12

4

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

LOCK-UP
DUTY
SOLENOID

TRANSMISSION