Subaru Legacy III (2000-2003 year). Manual — part 318

EN(H6DO)-74

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

7

CHECK INPUT VOLTAGE OF INHIBITOR
SWITCH.
1) Turn ignition switch to OFF.
2) Disconnect connector from inhibitor switch.
3) Connect connector to ignition switch.
4) Measure input voltage between inhibitor

switch connector terminal and engine
ground while turning ignition switch to ST.

Connector & terminal

(B12) No. 12 (+) — Engine ground (–):

Is the voltage more than 10 V? Go to step 8.

Repair open or
ground short cir-
cuit in harness
between inhibitor
switch and ignition
switch.

8

CHECK INHIBITOR SWITCH CIRCUIT.
1) Turn ignition switch to OFF.
2) Place the selector lever in the “P” or “N”

position.

3) Separate transmission harness connector.
4) Measure resistance between transmission

harness connector terminals.

Connector & terminal

(T3) No. 11 — No. 12:

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

1

Ω

Repair open or
short circuit in har-
ness between
starter motor and
inhibitor switch.

Go to step 9.

9

CHECK TRANSMISSION HARNESS.
1) Disconnect connector from inhibitor switch.
2) Measure resistance of harness between

transmission harness and inhibitor switch
connector.

Connector & terminal

(T3) No. 12 — (T7) No. 12:
(T3) No. 11 — (T7) No. 7:

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

1

Ω

Go to step 10.

Repair open or
short circuit in har-
ness between
transmission har-
ness and inhibitor
switch connector.

10

CHECK POOR CONTACT.
Check poor contact in inhibitor switch connec-
tor.
Is there poor contact in inhibitor switch connec-
tor?

There is poor contact.

Repair poor con-
tact in inhibitor
switch connector.

Replace inhibitor
switch.

Step

Value

Yes

No

EN(H6DO)-75

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

MEMO:

EN(H6DO)-76

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

C: CONTROL MODULE POWER SUPPLY AND GROUND LINE

CAUTION:
After repair or replacement of faulty parts, conduct CLEAR MEMORY MODE <Ref. to EN(H6DO)-54,
OPERATION, Clear Memory Mode.> and INSPECTION MODE. <Ref. to EN(H6DO)-47, OPERATION, In-
spection Mode.>
• WIRING DIAGRAM:

EN-01083

D10

A14

D2

A2

D3

E49

B252

D9

C8

D8

D31

D21

5

1

3

B47

BATTERY

MAIN RELAY

1

2

3

5

6

4

F44

B61

SBF-5

6

F46

B108

2

SBF-4

SBF-1

4

1

B72

IGNITION
SWITCH

ECM

B134

A:

B136

C:

B137

D:

A22

7

B137

B136

C:

D:

A: B134

B47

3

4

1

2

5

6

B72

F44

F46

3 4

1 2

B252

C18

C17

TO FRONT OXYGEN (A/F) SENSOR

6

1 2 3 4
5 6 7 8

3 4

1 2

1

2

7

8

9

5

6

3

4

10 11 12

19 20 21
29 30 31

13 14 15 16 17

27 28

18

22 23 24 25 26

1 2

7

8 9

5

6

3

4

10 11 12
19 20 21

13 14 15 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

1 2 3 4
5 6 7 8

LHD

RHD

RHD

RHD

RHD

LHD

LHD

LHD

EN(H6DO)-77

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

Step

Value

Yes

No

1

CHECK MAIN RELAY.
1) Turn the ignition switch to OFF.
2) Remove main relay.
3) Connect battery to main relay terminals No.

1 and No. 2.

4) Measure resistance between main relay

terminals.

Terminals

No. 3 — No. 5:
No. 4 — No. 6:

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

10

Ω

Go to step 2.

Replace main
relay.

2

CHECK GROUND CIRCUIT OF ECM.
1) Disconnect connector from ECM.
2) Measure resistance of harness between

ECM and chassis ground.

Connector & terminal

(B134) No. 22 — Chassis ground:
(B136) No. 8 — Chassis ground:
(B136) No. 17 — Chassis ground:
(B136) No. 18 — Chassis ground:
(B137) No. 8 — Chassis ground:
(B137) No. 9 — Chassis ground:
(B137) No. 21 — Chassis ground:
(B137) No. 31 — Chassis ground:

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

5

Ω

Go to step 3.

Repair open circuit
in harness
between ECM
connector and
engine grounding
terminal.

3

CHECK INPUT VOLTAGE OF ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM connector

and chassis ground.

Connector & terminal

(B137) No. 10 (+) — Chassis ground (–):
(B134) No. 14 (+) — Chassis ground (–):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 4.

Repair open or
ground short cir-
cuit of power sup-
ply circuit.

4

CHECK HARNESS BETWEEN ECM AND
MAIN RELAY CONNECTOR.
1) Turn ignition switch to OFF.
2) Measure resistance between ECM and

chassis ground.

Connector & terminal

(B134) No. 2 — Chassis ground:

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 5.

Repair ground
short circuit in har-
ness between
ECM connector
and main relay
connector, then
replace ECM.

5

CHECK OUTPUT VOLTAGE FROM ECM.
1) Connect connector to ECM.
2) Turn ignition switch to ON.
3) Measure voltage between ECM connector

and chassis ground.

Connector & terminal

(B134) No. 2 (+) — Chassis ground (–):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 6.

Replace ECM.