Subaru Legacy III (2000-2003 year). Service manual — part 584

AT-70

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

H: DTC 45 INTAKE MANIFOLD PRESSURE SIGNAL (NON-TURBO MODEL)

DIAGNOSIS:
Input signal circuit of TCM from ECM is open or shorted.
TROUBLE SYMPTOM:
Excessive shift shock.
WIRING DIAGRAM:

Step

Value

Yes

No

1

CHECK ENGINE GROUND TERMINALS AND
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 2.

2

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

2.0 L and 2.5 L without OBD model:

(B54) No. 1 — (B136) No. 11:

2.0 L and 2.5 L with OBD model:

(B54) No. 1 — (B137) No. 2:

3.0 L model:

(B54) No. 1 — (B135) No. 28:

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

1

Ω

Go to step 3.

Repair open circuit
in harness
between TCM and
ECM connector.

AT-00782

2

WO

11

28

OO

H6

1

B54

B54

B137

WO

:

B136

TCM

ECM

B137 :

WO

B136

B135 :

:

OO

H6

H6

: 3.0L MODEL

OO : 2.0L AND 2.5L MODEL WITHOUT OBD

WO : 2.0L AND 2.5L MODEL WITH OBD

B135

H6

:

OO

:

1 2

7

8

9

5 6

3 4

10 11 12
19 20 21

13

14 15

16

17

18

22

23

24

5

4

6 7

8

2

1

9

3

10

22

23

11 12 13 14 15

24 25

26 27

16 17 18

28 29

19 20

21

30

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

1 2

3 4

9

8

7

6

5

10 11 12 13

14 15

16 17 18

19 20

AT-71

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

3

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

Connector & terminal

(B54) No. 1 — Chassis ground:

Is the measured value less than the specified
value?

1 M

Ω

Go to step 4.

Repair short circuit
in harness
between TCM and
ECM connector.

4

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

Subaru Select Monitor is avail-
able.

Go to step 6.

Go to step 5.

5

CHECK INPUT SIGNAL FOR TCM.
1) Connect connectors to TCM and ECM.
2) Start the engine, and warm-up the trans-

mission until ATF temperature 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.

3) Engine idling.
4) Measure voltage between TCM connector

and chassis ground.

Connector & terminal

(B54) No. 1 (+) — Chassis ground (

−−−−

):

Is the measured value within the specified
range?

0.4 — 1.6 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 7.

6

CHECK INPUT SIGNAL FOR TCM USING
SUBARU SELECT MONITOR.
1) Connect connectors to TCM and ECM.
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 engine until engine coolant

temperature is above 80

°

C (176

°

F).

5) Engine idling.
6) Read data of intake manifold pressure sig-

nal using Subaru Select Monitor.

•Display shows intake manifold pressure signal
value sent from ECM.

Is intake manifold pressure data within the
specified range?

0.4 — 1.6 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 7.

7

CHECK POOR CONTACT.
Is there poor contact in intake manifold pres-
sure signal 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-72

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

I:

DTC 71 SHIFT SOLENOID 1

DIAGNOSIS:
Output signal circuit of shift solenoid 1 is open or shorted.
TROUBLE SYMPTOM:
Does not shift.
WIRING DIAGRAM:

AT-00583

22

TRANSMISSION

B54

TCM

AT5

1

T4

B11

SHIFT

SOLENOID 1

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-73

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 shift solenoid 1 connector.

Connector & terminal

(B54) No. 22 — (B11) No. 1:

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
connector and chassis ground.

Connector & terminal

(B54) No. 22 — 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
transmission con-
nector.

3

CHECK SHIFT SOLENOID 1.
Measure resistance between transmission
connector terminals.

Connector & terminal

(T4) No. 1 — No. 16:

Is the measured value within the specified
range?

10 — 16

Ω

Go to step 4.

Go to step 7.

4

CHECK OUTPUT SIGNAL EMITTED FROM
TCM.
1) Connect connectors to TCM and transmis-

sion.

2) Turn ignition switch to ON (engine OFF).
3) Move select lever to “D” range.
4) Measure voltage between TCM connector

and chassis ground.

Connector & terminal

(B54) No. 22 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

9V

Go to step 5.

Go to step 6.

5

CHECK OUTPUT SIGNAL EMITTED FROM
TCM.
1) Hold switch to ON.
2) Measure voltage between TCM connector

and chassis ground.

Connector & terminal

(B54) No. 22 (+) — Chassis ground (

−−−−

):

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

1V

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-
tact in the TCM.

Go to step 6.

6

CHECK POOR CONTACT.
Is there poor contact in shift solenoid 1 circuit?

There is poor contact.

Repair poor con-
tact.

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