Subaru Legacy III (2000-2003 year). Manual - part 576

AT-38

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE FOR SELECT MONITOR COMMUNICATION

13.Diagnostic Procedure for Select Monitor Communication

A: COMMUNICATION FOR INITIALIZING IMPOSSIBLE

DIAGNOSIS:
• Faulty harness connector
TROUBLE SYMPTOM:
• Select monitor communication failure
WIRING DIAGRAM:

AT-00774

C19

A21

C24

C15

4

2

A24

A23

C1

3

N

O. 4

 

SBF-4 

SBF-1 

IGNITION 
SWITCH

BATTERY

NO

. 11 

F44

B61

B22

E3

B83

B252

E49

13

6

10

1

15

16

17

B40

B300

DATA LINK
CONNECTOR

LINE END
CHECK
CONNECTOR

SHIELD AND
SENSOR
GROUND JOINT
CONNECTOR

F2

B100

B11

1 2

5

6 7

8

13

14 15

16

9 10

11 12

3 4

17 18

19 20

B40

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16

TCM

B54

A:

B56

C:

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

B56

1 2

7

8

9

5 6

3 4

10 11 12
19 20 21

13

14 15

16

17

18

22

23

24

LHD

LHD

RHD

RHD

LHD

H4

RHD

LHD

H6

H4

H6

RHD

SBF-5

6

16

2

12

B11

T4

16

TRANSMISSION

1 2 3 4
5 6 7 8

F44

B22

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

B252

1 2 3 4
5 6 7 8

B300

1

3

4 5 6

2

B83

1 2 3 4

5 6 7 8 9 10

11 12

19

20

13 14 15 16 17 18

F2

1

12

9

8

7

6

17

5

4

3

2

14

13

15 16

18

21

20

19

22 23 24

11

10

AT-39

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE FOR SELECT MONITOR COMMUNICATION

Step

Value

Yes

No

1

CHECK SUBARU SELECT MONITOR POW-
ER SUPPLY CIRCUIT.
Measure voltage between data link connector 
and chassis ground.

Connector & terminal

(B40) No. 1 (+)  — Chassis ground (

−−−−

):

Does the measured value exceed the specified 
value?

10 V

Go to step 2.

Repair harness 
and connector 
between battery 
and data link con-
nector, and poor 
contact in cou-
pling connector.

2

CHECK SUBARU SELECT MONITOR 
GROUND CIRCUIT.
Measure resistance of harness between data 
link connector and chassis ground.

Connector & terminal

(B40) No. 12 — Chassis ground:
(B40) No. 13 — Chassis ground:

Is the measured value less than the specified 
value?

1 

Ω

Go to step 3.

Repair open circuit 
in harness 
between data link 
connector and 
ground terminal, 
and poor contact 
in coupling con-
nector.

3

CHECK COMMUNICATION OF SELECT 
MONITOR.
1) Turn ignition switch to ON.
2) Using the select monitor, check whether 

communication to engine systems can be 
executed normally.
Are the name and year of the system dis-
played on the select monitor?

Name and year are displayed. Go to step 6.

Go to step 4.

4

CHECK COMMUNICATION OF SELECT 
MONITOR.
1) Turn ignition switch to OFF.
2) Disconnect TCM connector.
3) Check whether communication to engine 

systems can be executed normally.
Are the name and year of the system dis-
played on the select monitor?

Name and year are displayed. Go to step 8.

Go to step 5.

5

CHECK COMMUNICATION OF SELECT 
MONITOR.
1) Turn ignition switch to OFF.
2) Connect TCM connector.
3) Disconnect ECM connector.
4) Check whether communication to transmis-

sion systems can be executed normally.
Are the name and year of the system dis-
played on the select monitor?

Name and year are displayed. Inspect ECM.

Go to step 6.

6

CHECK HARNESS CONNECTOR BETWEEN 
EACH CONTROL MODULE AND DATA LINK 
CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect TCM and ECM connectors.
3) Measure resistance between data link con-

nector and chassis ground.

Connector & terminal

(B40) No. 10 — Chassis ground:
(B40) No. 6 — Chassis ground:

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 7.

Repair harness 
and connector 
between each 
control module 
and data link con-
nector.

AT-40

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE FOR SELECT MONITOR COMMUNICATION

7

CHECK OUTPUT SIGNAL FOR TCM.
1) Turn ignition switch to ON.
2) Measure voltage between data link connec-

tor and chassis ground.

Connector & terminal

(B40) No. 10 (+)  — Chassis ground (

−−−−

):

(B40) No. 6 (+)  — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

1 V

Repair harness 
and connector 
between each 
control module 
and data link con-
nector.

A temporary poor 
contact of the con-
nector or harness 
may be the cause. 
Repair harness or 
connector in the 
circuit.

8

CHECK HARNESS/CONNECTOR BETWEEN 
TCM AND DATA LINK CONNECTOR.
Measure resistance between TCM connector 
and data link connector.

Connector & terminal

(B56) No. 15 — (B40) No. 10:

Is the measured value less than the specified 
value?

0.5 

Ω

Go to step 9.

Repair harness 
and connector 
between TCM and 
data link connec-
tor.

9

CHECK HARNESS/CONNECTOR BETWEEN 
TCM AND DATA LINK CONNECTOR.
Measure resistance between TCM connector 
and data link connector.

Connector & terminal

(B56) No. 24 — (B40) No. 6:

Does the measured value exceed the specified 
value?

1 M

Ω

Go to step 10.

Repair harness 
and connector 
between TCM and 
data link connec-
tor.

10

CHECK INSTALLATION OF TCM CONNEC-
TOR.
Turn ignition switch to OFF.
Is TCM connector inserted into TCM?

TCM connector is inserted cor-
rectly.

Go to step 11.

Insert TCM con-
nector into TCM.

11

CHECK POOR CONTACT IN CONNECTORS.
Is there poor contact in control module and 
data link connector?

There is poor contact.

Repair poor con-
tact.

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

Step

Value

Yes

No

AT-41

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE FOR SELECT MONITOR COMMUNICATION

MEMO: