Subaru Legacy III (2000-2003 year). Manual - part 583

AT-66

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

8

CHECK INPUT SIGNAL FOR TCM.
1) Connect connectors to TCM and transmis-

sion.

2) Start the engine and move select lever to 

“P” or “N” range.

3) Measure voltage between TCM connector 

terminals.

Connector & terminal

(B55) No. 8 (+) — No. 9 (

−−−−

):

Does the measured value exceed the spec-
ified value?

AC 1 V

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 the TCM 
and transmission.

Go to step 11.

9

CHECK INPUT SIGNAL FOR TCM USING 
SUBARU SELECT MONITOR.
1) Connect connectors to TCM and transmis-

sion.

2) Connect Subaru Select Monitor to data link 

connector.

3) Turn ignition switch to ON and turn Subaru 

Select Monitor switch to ON.

4) Start the engine.
5) Move select lever to “P” or “N” range.
6) Read data of turbine speed using Subaru 

Select Monitor.

•Compare tachometer with Subaru Select 
Monitor indications.

Is the revolution value same as the tachom-
eter reading shown on the combination 
meter?

Same as tachometer value.

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 the TCM 
and transmission.

Go to step 11.

10

CHECK INPUT SIGNAL FOR TCM USING 
OSCILLOSCOPE.
1) Connect connectors to TCM and transmis-

sion.

2) Set oscilloscope to TCM connector termi-

nals.

Connector & terminal

Positive probe; (B55) No. 8
Ground; (B55) No. 9

3) Start the engine and move select lever to 

“P” or “N” range.
Does the measured value exceed the spec-
ified value?

AC 1 V

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 the TCM 
and transmission.

Go to step 11.

11

CHECK POOR CONTACT.
Is there poor contact in torque converter tur-
bine speed sensor circuit?

There is poor contact.

Repair poor con-
tact.

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

Step

Value

Yes

No

AT-67

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

MEMO:

AT-68

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

G: DTC 38 TORQUE CONTROL SIGNAL

DIAGNOSIS:
• The signal circuit is open or shorted.
TROUBLE SYMPTOM:
Excessive shift shock.
WIRING DIAGRAM:

Step

Value

Yes

No

1

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND ECM.
1) Turn ignition switch to OFF.
2) Disconnect connectors from TCM and 

ECM.

3) Measure resistance of harness between 

TCM and ECM connector.

Connector & terminal

Non-TURBO without OBD model:

(B56) No. 14 — (B135) No. 17:
(B56) No. 5 — (B135) No. 16:

Non-TURBO with OBD model:

(B56) No. 14 — (B136) No. 18:
(B56) No. 15 — (B136) No. 1:

3.0 L model and TURBO model:

(B56) No. 14 — (B134) No. 18:
(B56) No. 5 — (B134) No. 19:

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

1 

Ω

Go to step 2.

Repair open circuit 
in harness 
between TCM and 
ECM connector.

AT-00781

14

5

B56

B134 :

H6T

B136

B135

B134

B135

B56

TCM

:

:

OO

WO

OO : NON-TURBO MODEL WITOUT OBD

WO

H6T

: NON-TURBO MODEL WITH OBD

: 3.0L MODEL AND TURBO MODEL

1 2 3 4

10 11 12

19 20 21

13

5

6

14 15

7

8 9

16 17

18

22

WO

: 

H6T

: 

OO

: 

1 2 3 4

10 11 12
19 20 21

13

5 6

14 15

7

8

9

16

17

18

22

23

24

5 6 7

8

2

1

9

4

3

10

24

22 23

25

11 12 13 14 15

26

27 28

16 17 18 19

20 21

5 6

7

2

1

9

8

4

3

22

20

23

21

24

10 11 12 13 14

25 26

15 16 17

18 19

B136

H6T

A19

A18

WO

C1

C18

OO

B16

B17

AT-69

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

2

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

Connector & terminal

(B56) No. 14 — Chassis ground:
(B56) No. 5 — Chassis ground:

Does the measured value exceed the specified 
value?

1 M

Ω

Go to step 3.

Repair short circuit 
in harness 
between TCM and 
ECM connector.

3

CHECK OUTPUT SIGNAL EMITTED FROM 
TCM.
1) Connect connectors to TCM and ECM.
2) Turn ignition switch to ON (engine OFF).
3) Measure voltage between TCM connector 

terminals.

Connector & terminal

(B56) No. 14 (+) — Chassis ground (

−−−−

):

(B56) No. 5 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

4.8 V

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 the TCM 
and ECM.

Go to step 4.

4

CHECK POOR CONTACT.
Is there poor contact in torque control signal 
circuit?

There is poor contact.

Repair poor con-
tact.

Go to step 5.

5

CHECK GROUND LINE BETWEEN TRANS-
MISSION AND BODY.
Check installing condition of ground line in 
transmission and body.
Is there any dirt or rust at ground line installing 
point?

Remove dirt and 
rust.

Go to step 6.

6

CHECK GROUND LINE BETWEEN TRANS-
MISSION AND BODY.
Check installing condition of ground line in 
transmission and body.
Is tightening torque value within specification?

10 — 16 N·m (1.0 — 1.6 kgf-m, 
7.2 — 11.6 ft-lb)

Go to step 7.

Tighten to speci-
fied torque.

7

CHECK GROUND LINE INSIDE TRANSMIS-
SION.
1) Drain AT fluid and remove oil pan.
2) Check tightening torque value of ground 

line installing bolt.
Is tightening torque value within specifica-
tion?

7 — 9 N·m (0.7 — 0.9 kgf-m, 
5.1 — 6.5 ft-lb)

Go to step 9.

Tighten to speci-
fied torque.

8

CHECK GROUND CIRCUIT OF ECM.
<Ref. to AT-52, DTC 31 THROTTLE POSI-
TION SENSOR, Diagnostic Procedure with 
Diagnostic Trouble Code (DTC).>
Is there any trouble?

Ground terminals and ground 
circuit has a problem.

Repair ground ter-
minal and/or 
ground circuit of 
ECM.

Go to step 9.

9

RECHECK OUTPUT SIGNAL EMITTED 
FROM TCM.
Measure voltage between TCM connector and 
chassis ground.

Connector & terminal

(B56) No. 14 (+) — Chassis ground (

−−−−

):

(B56) No. 5 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the specified 
value?

4.8 V

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

Replace ECM.

Step

Value

Yes

No