Subaru Legacy III (2000-2003 year). Manual - part 590

AT-94

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

7

CHECK OUTPUT SIGNAL EMITTED FROM 
TCM USING SUBARU SELECT MONITOR.
1) Connect all connectors.
2) Connect Subaru Select Monitor to data link 

connector.

3) Start the engine, and turn Subaru Select 

Monitor switch to ON.

4) Warm-up the transmission until ATF tem-

perature is above 80

°

C (176

°

F).

NOTE:

If ambient temperature is below 0

°

C (32

°

F),

drive the vehicle until the ATF reaches its oper-
ating temperature.

5) Stop the engine and turn ignition switch to 

ON (engine OFF).

6) Move select lever to “N”.
7) Read data of 2-4 brake duty solenoid using 

Subaru Select Monitor.

•2-4 brake duty solenoid is indicated in “%”.
8) Throttle is fully closed.

Is 2-4 brake duty solenoid data within the 
specified value?

100%

Go to step 8.

Go to step 9.

8

CHECK OUTPUT SIGNAL EMITTED FROM 
TCM USING SUBARU SELECT MONITOR.
1) Turn ignition switch to ON (Engine OFF).
2) Throttle is fully open.
3) Read line pressure duty solenoid data 

using Subaru Select Monitor.
Is line pressure duty solenoid data less 
than the specified value?

25%

Even if “POWER” 
indicator lights up, 
the circuit has 
returned to a nor-
mal condition at 
this time. A tempo-
rary poor contact 
of the connector or 
harness may be 
the cause. Repair 
harness or con-
nector in TCM and 
transmission.

Go to step 9.

9

CHECK POOR CONTACT.
Is there poor contact in 2-4 brake duty solenoid 
circuit?

There is poor contact.

Repair poor con-
tact.

Replace TCM. 
<Ref. to AT-76, 
Transmission Con-
trol Module 
(TCM).>

10

CHECK 2-4 BRAKE DUTY SOLENOID (IN 
TRANSMISSION).
1) Remove transmission connector from 

bracket.

2) Drain automatic transmission fluid.

CAUTION:

Do not drain the automatic transmission flu-
id until it cools down.

3) Remove oil pan, and disconnect connector 

from 2-4 brake duty solenoid.

4) Measure resistance between 2-4 brake 

duty solenoid connector and transmission 
ground.

Terminal

No. 1 — Transmission ground:

Is the measured value within the specified 
range?

2.0 — 4.5 

Ω

Go to step 11.

Replace 2-4 brake 
duty solenoid. 
<Ref. to AT-67, 
Shift Solenoids, 
Duty Solenoids 
and ATF Temper-
ature Sensor.>

Step

Value

Yes

No

AT-95

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

11

CHECK HARNESS CONNECTOR BETWEEN 
TRANSMISSION AND 2-4 BRAKE DUTY SO-
LENOID.
Measure resistance of harness between 2-4 
brake duty solenoid and transmission connec-
tor.

Connector & terminal

(T4) No. 9 — (AT7) No. 1:

Is the measured value less than the specified 
value?

1 

Ω

Go to step 12.

Repair open circuit 
in harness 
between 2-4 brake 
duty solenoid and 
transmission con-
nector.

12

CHECK HARNESS CONNECTOR BETWEEN 
TRANSMISSION AND 2-4 BRAKE DUTY SO-
LENOID.
Measure resistance of harness between trans-
mission connector and transmission ground.

Connector & terminal

(T4) No. 9 — Transmission ground:

Does the measured value exceed the specified 
value?

1 M

Ω

Even if “POWER” 
indicator lights up, 
the circuit has 
returned to a nor-
mal condition at 
this time. A tempo-
rary poor contact 
of the connector or 
harness may be 
the cause. Repair 
harness or con-
nector in line pres-
sure duty solenoid 
and transmission.

Repair short circuit 
in harness 
between 2-4 brake 
duty solenoid and 
transmission con-
nector.

Step

Value

Yes

No

AT-96

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

O: DTC 77 LOCK-UP DUTY SOLENOID

DIAGNOSIS:
Output signal circuit of lock-up duty solenoid is open or shorted.
TROUBLE SYMPTOM:
No “lock-up” (after engine warm-up).
WIRING DIAGRAM:

AT-00589

 

7

TRANSMISSION

B54

TCM

AT3

13

T4

B11

LOCK-UP

DUTY

SOLENOID

B54

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

AT-97

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK DTC.
Do multiple trouble codes appear in the on-
board diagnostics test mode?

DTC is displayed.

Go to another 
Diagnostic trouble 
code (DTC).

Go to step 2.

2

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND TRANSMISSION.
1) Turn ignition switch to OFF.
2) Disconnect connector from TCM and trans-

mission.

3) Measure resistance of harness between 

TCM and transmission connector.

Connector & terminal

(B54) No. 7 — (B11) No. 13:

Is the measured value less than the speci-
fied value?

1 

Ω

Go to step 3.

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

3

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

Connector & terminal

(B54) No. 7 — Chassis ground:

Does the measured value exceed the specified 
value?

1 M

Ω

Go to step 4.

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

4

CHECK LOCK-UP DUTY SOLENOID.
Measure resistance between transmission 
connector receptacle's terminals.

Connector & terminal

(T4) No. 13 — No. 16:

Is the measured value within the specified 
range?

10 — 17 

Ω

Go to step 5.

Go to step 11.

5

PREPARE SUBARU SELECT MONITOR.
Do you have a Subaru Select Monitor?

Subaru Select Monitor is avail-
able.

Go to step 8.

Go to step 6.