Subaru Legacy III (2000-2003 year). Manual — part 171

EN(H4SO)-296

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

CO:DTC P1698 — ENGINE TORQUE CONTROL CUT SIGNAL CIRCUIT MAL-

FUNCTION (LOW INPUT) —

• DTC DETECTING CONDITION:

• Two consecutive driving cycles with fault

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-01139

B136 ECM

15

10

TCM

B55

B55

1 2 3 4

10 11 12
19 20 21

13

5 6

14 15

7

8

9

16

17

18

22

23

24

B136

1 2 3

4 5 6

9

7 8

10 11

15 16 17

12 13 14

18 19 20

21

25 26

22 23 24

EN(H4SO)-297

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK OUTPUT SIGNAL FROM ECM.
1) Start engine, and warm-up the engine.
2) Turn ignition switch to OFF.
3) Turn ignition switch to ON.
4) Measure voltage between ECM and chas-

sis ground.

Connector & terminal

(B136) No. 15 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

3 V

Repair poor con-
tact in ECM con-
nector.

Go to step 2.

2

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 chassis ground.

Connector & terminal

(B136) No. 15 — Chassis ground:

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 3.

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

3

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

Connector & terminal

(B136) No. 15 — (B55) No. 10:

Is the measured value less than the specified
value?

1

Ω

Repair poor con-
tact in ECM or
TCM connector.

Repair open circuit
in harness
between ECM and
TCM connector.

EN(H4SO)-298

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

CP:DTC P1699 — ENGINE TORQUE CONTROL CUT SIGNAL CIRCUIT MAL-

FUNCTION (HIGH INPUT) —

• DTC DETECTING CONDITION:

• Two consecutive driving cycles with fault

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-01139

B136 ECM

15

10

TCM

B55

B55

1 2 3 4

10 11 12
19 20 21

13

5 6

14 15

7

8

9

16

17

18

22

23

24

B136

1 2 3

4 5 6

9

7 8

10 11

15 16 17

12 13 14

18 19 20

21

25 26

22 23 24

EN(H4SO)-299

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK OUTPUT SIGNAL FROM ECM.
1) Start engine, and warm-up the engine.
2) Turn ignition switch to OFF.
3) Disconnect connector from TCM.
4) Turn ignition switch to ON.
5) Measure voltage between ECM and chas-

sis ground.

Connector & terminal

(B136) No. 15 (+) — Chassis ground (

−−−−

):

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

3 V

Go to step 2.

Repair battery
short circuit in har-
ness between
ECM and TCM
connector. After
repair, replace
ECM. <Ref. to
FU(H4SO)-45,
Engine Control
Module.>

2

CHECK HARNESS BETWEEN ECM AND
TCM CONNECTOR.
1) Turn ignition switch to OFF.
2) Measure voltage between ECM and chas-

sis ground.

Connector & terminal

(B136) No. 15 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value by shaking harness and connec-
tor of ECM while monitoring the value with
voltage meter?

10 V

Repair battery
short circuit in har-
ness between
ECM and TCM
connector. After
repair, replace
ECM. <Ref. to
FU(H4SO)-45,
Engine Control
Module.>

Contact SUBARU
distributor service.

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