Subaru Legacy III (2000-2003 year). Manual - part 215

EN(H4SOw/oOBD)-50

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

E: FUEL PUMP CIRCUIT

CAUTION:
After repair or replacement of faulty parts, conduct CLEAR MEMORY and INSPECTION MODES. <Ref. 
to EN(H4SOw/oOBD)-28, OPERATION, Clear Memory Mode.>  and <Ref. to EN(H4SOw/oOBD)-26, OP-
ERATION, Inspection Mode.>
• WIRING DIAGRAM:

EN-01048

FUEL PUMP
RELAY

SBF-4

SBF-1

SBF-5

No. 13

4

1

B46

B72

IGNITION 
SWITCH

BATTERY

4

3

1

2

No. 11

B134

1 2

3 4

5 6

7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

24 25

26 27 28 29

30 31 32 33

34 35

B46

B97

B72

R3

R58

1

2

3 4 5 6

R57

3
5

2
1

R57

R15

FUEL PUMP

R58

*

B134

ECM

WITH IMMOBILIZER

LHD

LHD

1

R3

B99

B97

R1

3

RHD

RHD

3 4

1 2

1 2
3 4
5 6

1 2 3 4
5 6 7 8

1

2 3 4 5

6 7

9

8

10

11 12 13 14 15 16 17 18 19 20

WITHOUT IMMOBILIZER

: 29
: 16

*

3 4

1 2

EN(H4SOw/oOBD)-51

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

Step

Value

Yes

No

1

CHECK OPERATING SOUND OF FUEL 
PUMP.
Make sure that fuel pump is in operation for 
two seconds when turning ignition switch to 
ON.

NOTE:

Fuel pump operation check can also be execut-
ed using Subaru Select Monitor. For the proce-
dure, refer to the “COMPULSORY VALVE
OPERATION CHECK MODE”.<Ref. to
EN(H4SOw/oOBD)-29, OPERATION, Compul-
sory Valve Operation Check Mode.>

Does fuel pump produce operating sound?

Fuel pump produces operating 
sound.

Check fuel injec-
tor circuit. <Ref. to 
EN(H4SOw/
oOBD)-53, FUEL 
INJECTOR CIR-
CUIT, Diagnostics 
for Engine Start-
ing Failure.>

Go to step 2.

2

CHECK GROUND CIRCUIT OF FUEL PUMP.
1) Turn ignition switch to OFF.
2) Raise rear seat, and turn floor mat up.
3) Remove service hole cover.
4) Disconnect connector from fuel pump.
5) Measure resistance of harness connector 

between fuel pump and chassis ground.

Connector & terminal

(R58) No. 1 — Chassis ground:

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

5 

Ω

Go to step 3.

Repair harness 
and connector.

NOTE:
In this case, repair
the following:
• Open circuit in 
harness between 
fuel pump connec-
tor and chassis 
grounding terminal
• Poor contact in 
coupling connector 
(R57) and (R1)

3

CHECK POWER SUPPLY TO FUEL PUMP.
1) Turn ignition switch to ON.
2) Measure voltage of power supply circuit 

between fuel pump connector and chassis 
ground.

Connector & terminal

(R58) No. 2 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Replace fuel 
pump.

Go to step 4.

4

CHECK HARNESS BETWEEN FUEL PUMP 
AND FUEL PUMP RELAY CONNECTOR.
1) Turn ignition switch to OFF.
2) Measure resistance of harness between 

fuel pump and fuel pump relay connector.

Connector & terminal

(R58) No. 2 — (B46) No. 4:

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

1 

Ω

Go to step 5.

Repair harness 
and connector.

NOTE:
In this case, repair
the following:
• Open circuit in 
harness between 
fuel pump and fuel 
pump relay con-
nector
• Poor contact in 
coupling connec-
tors (R57) and 
(R1)

5

CHECK HARNESS BETWEEN FUEL PUMP 
AND FUEL PUMP RELAY CONNECTOR.
Measure resistance of harness between fuel 
pump and fuel pump relay connector.

Connector & terminal

(R58) No. 2 — 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 fuel 
pump and fuel 
pump relay con-
nector.

EN(H4SOw/oOBD)-52

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

6

CHECK FUEL PUMP RELAY.
1) Disconnect connector from fuel pump relay.
2) Remove fuel pump relay from bracket.
3) Connect battery to fuel pump relay connec-

tor terminals No. 1 and No. 3.

4) Measure resistance between connector ter-

minals of fuel pump relay.

Terminals

No. 2 — No. 4:

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

10 

Ω

Go to step 7.

Replace fuel pump 
relay.

7

CHECK HARNESS BETWEEN ECM AND 
FUEL PUMP RELAY CONNECTOR.
1) Disconnect connectors from ECM.
2) Measure resistance of harness between 

ECM and fuel pump relay connector.

Connector & terminal

With cruise control:

(B134) No. 29 — (B46) No. 3:

Without cruise control:

(B134) No. 16 — (B46) No. 3:

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

1 

Ω

Go to step 8.

Repair open circuit 
in harness 
between ECM and 
fuel pump relay 
connector.

8

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.

Check fuel injec-
tor circuit. <Ref. to 
EN(H4SOw/
oOBD)-53, FUEL 
INJECTOR CIR-
CUIT, Diagnostics 
for Engine Start-
ing Failure.>

Step

Value

Yes

No

EN(H4SOw/oOBD)-53

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

F: FUEL INJECTOR CIRCUIT

CAUTION:
• Check or repair only faulty parts.
• After repair or replacement of faulty parts, conduct CLEAR MEMORY and INSPECTION MODES.
<Ref. to EN(H4SOw/oOBD)-28, OPERATION, Clear Memory Mode.>  and <Ref. to EN(H4SOw/oOBD)-
26, OPERATION, Inspection Mode.>
• WIRING DIAGRAM:

Step

Value

Yes

No

1

CHECK OPERATION OF EACH FUEL INJEC-
TOR.
While cranking the engine, check that each 
fuel injector emits “operating” sound. Use a 
sound scope or attach a screwdriver to injector 
for this check.
Is the fuel injector emits “operating” sound?

Fuel injector emits “operating” 
sound.

Check fuel pres-
sure.  <Ref. to 
ME(H4SO)-28, 
INSPECTION, 
Fuel Pressure.>

Go to step 2.

EN-01049

B22

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

E6

E17

E5

E16

1 2

1

2

1

2

1

2

1

2

A14

A13

A4

A15

9

1

10

11

12

ECM

B136

C:

B134

A:

E5

E16

E6

E17

B22

E3

FUEL INJECTOR

No. 1

FUEL INJECTOR

No. 2

FUEL INJECTOR

No. 3

FUEL INJECTOR

No. 4

BATTERY

C1

C2

A: B134

1 2

3 4

5 6

7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

24 25

26 27 28 29

30 31 32 33

34 35

F44

B61

SBF-5

6

LHD

LHD

RHD

RHD

B47

MAIN RELAY

1

2

3

5

4

6

B47

3

4

1

2

5

6

F44

1 2 3 4
5 6 7 8

5

4

6 7

8

2

1

9

3

10

22

23

11 12 13 14 15

24 25

26 27

16 17 18

28 29

19 20

21

30

B136

C: