Subaru Legacy III (2000-2003 year). Service manual — part 472

EN(H4DOSTC)-58

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

6

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

nector and chassis ground.

Connector & terminal

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

Does the measured value exceed the spec-
ified value?

10 V

Go to step 7.

Replace the ECM.
<Ref. to
FU(H4DOSTC)-
40, Engine Con-
trol Module.>

7

CHECK INPUT VOLTAGE OF MAIN RELAY.
Check the voltage between main relay connec-
tor and chassis ground.

Connector & terminal

(B47) No. 2 (+) — Chassis ground (–):

Does the measured value exceed the specified
value?

10 V

Go to step 8.

Repair the open
circuit in harness
between ECM
connector and
main relay con-
nector.

8

CHECK GROUND CIRCUIT OF MAIN RE-
LAY.
1) Turn the ignition switch to OFF.
2) Measure the resistance between main relay

connector and chassis ground.

Connector & terminal

(B47) No. 1 — Chassis ground:

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

5

Ω

Go to step 9.

Repair the open
circuit between
main relay and
chassis ground.

9

CHECK INPUT VOLTAGE OF MAIN RELAY.
Measure the voltage between main relay con-
nector and chassis ground.

Connector & terminal

(B47) No. 5 (+) — Chassis ground (

−−−−

):

(B47) No. 6 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the specified
value?

10 V

Go to step 10.

Repair the open or
ground short cir-
cuit in harness of
power supply cir-
cuit.

10

CHECK INPUT VOLTAGE OF ECM.
1) Connect the main relay connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM con-

nector and chassis ground.

Connector & terminal

(B137) No. 2 (+) — Chassis ground (–):
(B137) No. 3 (+) — Chassis ground (–):

Does the measured value exceed the spec-
ified value?

10 V

Check the fuel
pump circuit. <Ref.
to EN(H4DOSTC)-
60, FUEL PUMP
CIRCUIT, Diag-
nostics for Engine
Starting Failure.>

Repair the open or
ground short cir-
cuit in harness
between ECM
connector and
main relay con-
nector.

Step

Value

Yes

No

EN(H4DOSTC)-59

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

MEMO:

EN(H4DOSTC)-60

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

D: FUEL PUMP CIRCUIT

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-00932

B134

B136

B46

R122

E

E

M

10

7

6

FUEL PUMP
RELAY

FUEL PUMP
CONTROLLER

FUEL
PUMP

SBF-5

B46

R122

B134

A :

B136

C :

R15

R57

R58

R2

ECM

B98

B99

R58

B99

R3

BATTERY

1

3

5

4

A13

C16

3 4

1 2

8 9 10 11

12 13 14 15 16 17 18 19 20 21 22 23 24

5

6 7

3 4

1 2

1 2

3 4

5 6 7 8 9 10

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

2

4

2

1

9

8

5

14

16

1

2

3 4 5 6

R57

R3

R2

2 3 4 5

6 7 8 9

11 12 13 14

17 18 19 20

10

1

15 16

1 2
3 4
5 6

No.13

EN(H4DOSTC)-61

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

Step

Value

Yes

No

1

CHECK OPERATING SOUND OF FUEL
PUMP.
Make sure that the fuel pump is in operation for
2 seconds when turning ignition switch to ON.
Does the fuel pump produce operating sound?

NOTE:

Fuel pump operation can also be executed us-
ing the Subaru Select Monitor (Function mode:
FD01).
For the procedure, refer to “Compulsory Valve
Operation Check Mode”. <Ref. to
EN(H4DOSTC)-36, Compulsory Valve Opera-
tion Check Mode.>

Operating sound produced.

Go to step 2.

Record the DTC.
Repair the trouble
case. <Ref. to
EN(H4DOSTC)-
66, Diagnostic
Procedure with
Diagnostic Trou-
ble Code (DTC).>

2

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

There is poor contact.

Repair poor con-
tact in ECM con-
nectors.

Inspection using
“General Diagnos-
tic Table” <Ref. to
EN(H4DOSTC)-
246, INSPEC-
TION, General
Diagnostic Table.>