Subaru Legacy III (2000-2003 year). Service manual — part 471

EN(H4DOSTC)-54

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

7

CHECK TRANSMISSION TYPE.
Is the target AT vehicle?

Target is AT vehicle.

Go to step 8.

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

8

CHECK INPUT VOLTAGE OF INHIBITOR
SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from inhibitor

switch.

3) Connect the connector to ignition switch.
4) Measure the input voltage between inhibitor

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

Connector & terminal

(B12) No. 12 (+) — Engine ground (–):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 9.

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

9

CHECK INHIBITOR SWITCH.
1) Place the selector lever in the “P” or “N”

position.

2) Measure the resistance between inhibitor

switch terminals.

Connector & terminal

(T3) No. 11 — No. 12:

Is the measured value less than specified
value?

1

Ω

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

Replace the inhibi-
tor switch. <Ref. to
AT-50,
REMOVAL, Inhibi-
tor Switch.>

Step

Value

Yes

No

EN(H4DOSTC)-55

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

MEMO:

EN(H4DOSTC)-56

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(H4DOSTC)-
35, Clear Memory Mode.> and INSPECTION MODE. <Ref. to EN(H4DOSTC)-33, Inspection Mode.>
• WIRING DIAGRAM:

EN-00931

B72

B137

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

BATTERY

IGNITION
SWITCH

MAIN RELAY

SBF-4

SBF-1

SBF-5

B72

TO FRONT OXYGEN(A/F) SENSOR

A2

D8

D9

A22

C17

C8

C18

A7

A15

E1

A12

D2

D3

D10

A14

No.11

B47

E3

B22

1

2

3

5

6

4

ECM

E

E

1

4

B134

B136

B137

A :

C :

D :

B84

E :

3

15

16

14

13

E

3

4

1

2

5

6

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

13 14 15 16

B134

B22

B47

B84

B136

1 2 3 4

10 11 12

19 20 21

13

5

6

14 15

7

8 9

16 17

18

22

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

8 9 10

4

11 12

13 14 15

16

5 6

7

17

EN(H4DOSTC)-57

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

Step

Value

Yes

No

1

CHECK MAIN RELAY.
1) Turn the ignition switch to OFF.
2) Remove the main relay.
3) Connect the battery to main relay terminals

No. 1 and No. 2.

4) Measure the 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 the main
relay.

2

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

between ECM and chassis ground.

Connector & terminal

(B134) No. 7 — Chassis ground:
(B134) No. 12 — Chassis ground:
(B134) No. 15 — Chassis ground:
(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:
(B84) No. 1 — Chassis ground:

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

5

Ω

Go to step 3.

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

3

CHECK INPUT VOLTAGE OF ECM.
Measure the voltage between ECM connector
and chassis ground.

Connector & terminal

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

Does the measured value exceed the specified
value?

10 V

Go to step 4.

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

4

CHECK INPUT VOLTAGE OF ECM.
1) Turn the ignition switch to ON.
2) Measure the resistance between ECM and

chassis ground.

Connector & terminal

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

Does the measured value exceed the spec-
ified value?

10 V

Go to step 5.

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

5

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 6.

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