Subaru Legacy III (2000-2003 year). Manual - part 172

EN(H4SO)-300

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

CQ:DTC P1711 — ENGINE TORQUE CONTROL SIGNAL #1 CIRCUIT MALFUNC-

TION —

• DTC DETECTING CONDITION:

• Two consecutive driving cycles with fault

• TROUBLE SYMPTOM:

• Excessive shift shock

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode<Ref. to EN(H4SO)-47, OPER-
ATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4SO)-40, OPERATION, Inspection 
Mode.> .
• WIRING DIAGRAM:

EN-01140

15

B136 ECM

TCM

B56

B136

5 6

7

2

1

9

8

4

3

23

21 22

24

10 11 12 13 14

25 26

15 16 17

18 19 20

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

EN(H4SO)-301

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK INPUT SIGNAL FOR ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM and chas-

sis ground.

Connector & terminal

(B136) No. 1 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

4.5 V

Go to step 2.

Go to step 4.

2

CHECK INPUT SIGNAL FOR ECM.
Measure voltage between ECM and chassis 
ground.

Connector & terminal

(B136) No. 1 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the specified 
value?

10 V

Repair battery 
short circuit in har-
ness between 
ECM and TCM 
connector.

Go to step 3.

3

CHECK POOR CONTACT.
Check poor contact in ECM connector.
Is there poor contact in ECM connector?

There is poor contact.

Repair poor con-
tact in ECM con-
nector.

Contact SUBARU 
distributor service.

NOTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.

4

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

TCM.

3) Measure resistance of harness between 

ECM and TCM connector.

Connector & terminal

(B136) No. 1 — (B56) No. 5:

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

1 

Ω

Go to step 5.

Repair open circuit 
in harness 
between ECM and 
TCM connector.

5

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

Connector & terminal

(B136) No. 1 — Chassis ground:

Does the measured value exceed the specified 
value?

1 M

Ω

Go to step 6.

Repair ground 
short circuit in har-
ness between 
ECM and TCM 
connector.

6

CHECK POOR CONTACT.
Check poor contact in TCM connector.
Is there poor contact in TCM connector?

There is poor contact.

Repair poor con-
tact in TCM con-
nector.

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

EN(H4SO)-302

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

CR:DTC P1712 — ENGINE TORQUE CONTROL SIGNAL #2 CIRCUIT MALFUNC-

TION —

• DTC DETECTING CONDITION:

• Two consecutive driving cycles with fault

• TROUBLE SYMPTOM:

• Excessive shift shock

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode<Ref. to EN(H4SO)-47, OPER-
ATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4SO)-40, OPERATION, Inspection 
Mode.> .
• WIRING DIAGRAM:

EN-01141

18

14

B136 ECM

TCM

B56

B136

5 6

7

2

1

9

8

4

3

23

21 22

24

10 11 12 13 14

25 26

15 16 17

18 19 20

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

EN(H4SO)-303

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK INPUT SIGNAL FOR ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM and chas-

sis ground.

Connector & terminal

(B136) No. 18 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

4.5 V

Go to step 2.

Go to step 4.

2

CHECK INPUT SIGNAL FOR ECM.
Measure voltage between ECM and chassis 
ground.

Connector & terminal

(B136) No. 18 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the specified 
value?

10 V

Repair battery 
short circuit in har-
ness between 
ECM and TCM 
connector.

Go to step 3.

3

CHECK POOR CONTACT.
Check poor contact in ECM connector. 
Is there poor contact in ECM connector?

There is poor contact.

Repair poor con-
tact in ECM con-
nector.

Contact SUBARU 
distributor service.

NOTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.

4

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

TCM.

3) Measure resistance of harness between 

ECM and TCM connector.

Connector & terminal

(B136) No. 18 — (B56) No. 14:

1 

Ω

Go to step 5.

Repair open circuit 
in harness 
between ECM and 
TCM connector.

5

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

Connector & terminal

(B136) No. 18 — Chassis ground:

Is the measured value less than the specified 
value?

10 

Ω

Go to step 6.

Repair ground 
short circuit in har-
ness between 
ECM and TCM 
connector.

6

CHECK POOR CONTACT.
Check poor contact in TCM connector. 
Is there poor contact in TCM connector?

There is poor contact.

Repair poor con-
tact in TCM con-
nector.

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