Subaru Legacy III (2000-2003 year). Service manual — part 595

AT-114

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

8

CHECK INPUT SIGNAL FOR TCM USING
OSCILLOSCOPE.
1) Set oscilloscope to TCM connector termi-

nals.

Connector & terminal

Positive probe; (B56) No. 9
Ground; (B55) No. 9

2) Turn ignition switch to ON (engine OFF).

Check signal waveform pattern on oscillo-
scope. <Ref. to AT-20, WAVEFORM, MEA-
SUREMENT, Transmission Control Module
(TCM) I/O Signal.> Is waveform pattern
same as that shown in the figure?

Same wave form as shown in
figure.

Go to step 9.

Repair poor con-
tact in VDCCM.

9

CHECK INPUT SIGNAL FOR TCM USING
OSCILLOSCOPE.
1) Set oscilloscope to TCM connector termi-

nals.

Connector & terminal

Positive probe; (B56) No. 18
Ground; (B55) No. 9

2) Turn ignition switch to ON (engine OFF).

Check signal waveform pattern on oscillo-
scope. <Ref. to AT-20, WAVEFORM, MEA-
SUREMENT, Transmission Control Module
(TCM) I/O Signal.> Is waveform pattern
same as that shown in the figure?

Same wave form as shown in
figure.

Go to step 10.

Repair poor con-
tact in VDCCM.

10

CHECK POOR CONTACT.
Is there poor contact in TCM?

There is poor contact.

Repair poor con-
tact.

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

Step

Value

Yes

No

AT-115

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

MEMO:

AT-116

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

S: DTC 93 REAR VEHICLE SPEED SENSOR

DIAGNOSIS:
Input signal circuit of TCM is open or shorted.
TROUBLE SYMPTOM:
No lock-up or excessive tight corner “braking”.
WIRING DIAGRAM:

AT-00785

19

20

B24

A19

B11

T4

TCM

B54

A:

B55

B:

NT

TB

7
8
9

SHIELD AND
SENSOR GROUND
JOINT CONNECTOR

REAR VEHICLE

B55

B11

SPEED SENSOR

B54

1 2

5

6 7

8

13

14 15

16

9 10

11 12

3 4

17 18

19 20

1 2 3 4

10 11 12
19 20 21

13

5 6

14 15

7

8

9

16

17

18

22

23

24

1 2 3 4

10 11 12
19 20 21

13

5 6

14 15

7

8

9

16

17

18

22

23

24

1 2 3 4 5 6 7 8 9 10 11 12

B53

B300

1 2 3 4 5 6

: NT

: TB

B53

B330

: NT

: TB

1
2
3

: NON-TURBO MODEL

NT

: TURBO MODEL

TB

AT-117

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

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

(B55) No. 24 — (B11) 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
transmission con-
nector.

2

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

Connector & terminal

(B54) No. 19 — (B11) No. 20:

Is the measured value less than the specified
value?

1

Ω

Go to step 3.

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

3

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

Connector & terminal

(B55) No. 24 — 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 HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure resistance of harness between TCM
and chassis ground.

Connector & terminal

(B54) No. 19 — Chassis ground:

Does the measured value exceed the specified
value?

1 M

Ω

Go to step 5.

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

5

CHECK REAR VEHICLE SPEED SENSOR.
Measure resistance between transmission
connector receptacle's terminals.

Connector & terminal

(T4) No. 19 — No. 20:

Is the measured value within the specified
range?

450 — 650

Ω

Go to step 6.

Replace rear vehi-
cle speed sensor.
<Ref. to AT-58,
Rear Vehicle
Speed Sensor.>

6

PREPARE OSCILLOSCOPE.
Do you have oscilloscope?

Oscilloscope is available.

Go to step 10.

Go to step 7.

7

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

Subaru Select Monitor is avail-
able.

Go to step 9.

Go to step 8.