Subaru Legacy (2005 year). 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