Subaru Legacy III (2000-2003 year). Manual - part 601

AT-138

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE FOR NO-DIAGNOSTIC TROUBLE CODE (DTC)

41

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

inhibitor switch.

3) Measure resistance of harness between 

TCM and inhibitor switch connector.

Connector & terminal

(B55) No. 4 — (T7) No. 3:

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

1 

Ω

Go to step 42.

Repair open circuit 
in harness 
between TCM and 
inhibitor switch 
connector, and 
poor contact in 
coupling connec-
tor.

42

CHECK INPUT SIGNAL FOR TCM.
1) Turn ignition switch to OFF.
2) Connect connector to TCM and inhibitor 

switch.

3) Turn ignition switch to ON.
4) Move select lever to D range.
5) Measure voltage between TCM and chas-

sis ground.

Connector & terminal

(B55) No. 4 (+) — Chassis ground (–):

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

1 V

Go to step 43.

Go to step 65.

43

CHECK INPUT SIGNAL FOR TCM.
1) Position select lever to any other than D 

range.

2) Measure voltage between TCM and chas-

sis ground.

Connector & terminal

(B55) No. 4 (+) — Chassis ground (–):

Does the measured value exceed the spec-
ified value?

8 V

Go to step 65.

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

44

CHECK “D” RANGE INDICATOR LIGHT 
BULB.
1) Turn ignition switch to OFF.
2) Remove combination meter.
3) Remove “D” range indicator light bulb from 

combination meter.
Is “D” range indicator light bulb OK?

Bulb is normal.

Go to step 45.

Replace “D” range 
indicator light bulb. 
<Ref. to IDI-14, 
Combination 
Meter Assembly.>

45

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND COMBINATION METER.
1) Disconnect connectors from TCM and com-

bination meter.

2) Measure resistance of harness between 

TCM and combination meter.

Connector & terminal

Except 3.0 L model and TURBO model:

(B55) No. 4 — (i11) No. 4:

3.0 L model and TURBO model:

(B55) No. 4 — (i10) No. 20:

Does the measured value exceed the spec-
ified value?

1 

Ω

Go to step 65.

Repair open circuit 
in harness 
between inhibitor 
switch connector 
and combination 
meter.

Step

Value

Yes

No

AT-139

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE FOR NO-DIAGNOSTIC TROUBLE CODE (DTC)

46

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND INHIBITOR SWITCH.
1) Turn ignition switch to OFF.
2) Disconnect connectors from TCM, inhibitor 

switch and combination meter.

3) Measure resistance of harness between 

TCM and chassis ground.

Connector & terminal

(B55) No. 4 — Chassis ground:

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 47.

Repair ground 
short circuit in “D” 
range circuit.

47

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

tor switch.

3) Measure resistance of harness between 

TCM and inhibitor switch connector.

Connector & terminal

(B55) No. 5 — (B12) No. 7:

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

1 

Ω

Go to step 48.

Repair open circuit 
in harness 
between TCM and 
inhibitor switch 
connector, and 
poor contact in 
coupling connec-
tor.

48

CHECK INPUT SIGNAL FOR TCM.
1) Turn ignition switch to OFF.
2) Connect connector to TCM and inhibitor 

switch.

3) Turn ignition switch to ON.
4) Move select lever to 3 range.
5) Measure voltage between TCM and chas-

sis ground.

Connector & terminal

(B55) No. 5 (+) — Chassis ground (–):

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

1 V 

Go to step 49.

Go to step 65.

49

CHECK INPUT SIGNAL FOR TCM.
1) Position select lever to any other than 3 

range.

2) Measure voltage between TCM and chas-

sis ground.

Connector & terminal

(B55) No. 5 (+) — Chassis ground (–):

Does the measured value exceed the spec-
ified value?

8 V

Go to step 65.

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

50

CHECK “3” RANGE INDICATOR LIGHT 
BULB.
1) Turn ignition switch to OFF.
2) Remove combination meter.
3) Remove “3” range indicator light bulb from 

combination meter.
Is “3” range indicator light bulb OK?

Bulb is normal.

Go to step 51.

Replace “3” range 
indicator light bulb. 
<Ref. to IDI-14, 
Combination 
Meter Assembly.>

Step

Value

Yes

No

AT-140

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE FOR NO-DIAGNOSTIC TROUBLE CODE (DTC)

51

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND COMBINATION METER.
1) Disconnect connectors from TCM and com-

bination meter.

2) Measure resistance of harness between 

TCM and combination meter.

Connector & terminal

Except 3.0 L model and TURBO model:

(B55) No. 5 — (i11) No. 11:

3.0 L model and TURBO model:

(B55) No. 5 — (i10) No. 19:

Does the measured value exceed the spec-
ified value?

1 

Ω

Go to step 65.

Repair open circuit 
in harness 
between TCM 
connector and 
combination 
meter, and poor 
contact in TCM 
connector.

52

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND INHIBITOR SWITCH.
1) Turn ignition switch to OFF.
2) Disconnect connectors from TCM, inhibitor 

switch and combination meter.

3) Measure resistance of harness between 

TCM and chassis ground.

Connector & terminal

(B55) No. 5 — Chassis ground:

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 53.

Repair ground 
short circuit in “3” 
range circuit.

53

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

tor switch.

3) Measure resistance of harness between 

TCM and inhibitor switch connector.

Connector & terminal

(B55) No. 6 — (T7) No. 4:

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

1 

Ω

Go to step 54.

Repair open circuit 
in harness 
between TCM and 
inhibitor switch 
connector, and 
poor contact in 
coupling connec-
tor.

54

CHECK INPUT SIGNAL FOR TCM.
1) Turn ignition switch to OFF.
2) Connect connector to TCM and inhibitor 

switch.

3) Turn ignition switch to ON.
4) Move select lever to 2 range.
5) Measure voltage between TCM and chas-

sis ground.

Connector & terminal

(B55) No. 6 (+) — Chassis ground (–):

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

1 V

Go to step 55.

Go to step 65.

55

CHECK INPUT SIGNAL FOR TCM.
1) Position select lever to any other than 2 

range.

2) Measure voltage between TCM and chas-

sis ground.

Connector & terminal

(B55) No. 6 (+) — Chassis ground (–):

Does the measured value exceed the spec-
ified value?

8 V

Go to step 65.

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

Step

Value

Yes

No

AT-141

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE FOR NO-DIAGNOSTIC TROUBLE CODE (DTC)

56

CHECK “2” RANGE INDICATOR LIGHT 
BULB.
1) Turn ignition switch to OFF.
2) Remove combination meter.
3) Remove “2” range indicator light bulb from 

combination meter.
Is “2” range indicator light bulb OK?

Bulb is normal.

Go to step 57.

Replace “2” range 
indicator light bulb. 
<Ref. to IDI-14, 
Combination 
Meter Assembly.>

57

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND COMBINATION METER.
1) Disconnect connectors from TCM and com-

bination meter.

2) Measure resistance of harness between 

TCM and combination meter.

Connector & terminal

Except 3.0 L model and TURBO model:

(B55) No. 6 — (i11) No. 12:

3.0 L model and TURBO model:

(B55) No. 6 — (i10) No. 16:

Does the measured value exceed the spec-
ified value?

1 

Ω

Go to step 65.

Repair open circuit 
in harness 
between TCM and 
combination 
meter, and poor 
contact in TCM 
connector.

58

CHECK HARNESS CONNECTOR BETWEEN 
TCM AND INHIBITOR SWITCH.
1) Turn ignition switch to OFF.
2) Disconnect connectors from TCM, inhibitor 

switch and combination meter.

3) Measure resistance of harness between 

TCM and chassis ground.

Connector & terminal

(B55) No. 6 — Chassis ground:

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 59.

Repair ground 
short circuit in “2” 
range circuit.

59

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

inhibitor switch.

3) Measure resistance of harness between 

TCM and inhibitor switch connector.

Connector & terminal

(B55) No. 7 — (T7) No. 6:

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

1 

Ω

Go to step 60.

Repair open circuit 
in harness 
between TCM and 
inhibitor switch 
connector, and 
poor contact in 
coupling connec-
tor.

60

CHECK INPUT SIGNAL FOR TCM.
1) Turn ignition switch to OFF.
2) Connect connector to TCM and inhibitor 

switch.

3) Turn ignition switch to ON.
4) Move select lever to 1 range.
5) Measure voltage between TCM and chas-

sis ground.

Connector & terminal

(B55) No. 7 (+) — Chassis ground (–):

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

1 V

Go to step 61.

Go to step 65.

Step

Value

Yes

No