Subaru Legacy III (2000-2003 year). Manual — part 116

EN(H4SO)-76

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

E: FUEL PUMP CIRCUIT

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-01120

1

R3

B99

RHD

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

3
5

2
1

R57

R15

FUEL PUMP

R58

2

B134

ECM

B97

R1

3

B46

3 4

1 2

B72

3 4

1 2

R58

1 2
3 4
5 6

R57

1

2

3 4 5 6

B97

1 2 3 4
5 6 7 8

RHD

LHD

LHD

R3

2 3 4 5

6 7 8 9

11 12 13 14

17 18 19 20

10

1

15 16

EN(H4SO)-77

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.
Does fuel pump produce operating sound?

NOTE:

Fuel pump operation can also be executed us-
ing Subaru Select Monitor (Function mode:
FD01).
For the procedure, refer to “Compulsory Valve
Operation Check Mode”. <Ref. to EN(H4SO)-
48, Compulsory Valve Operation Check
Mode.>

Operating sound produced.

Check fuel injec-
tor circuit. <Ref. to
EN(H4SO)-80,
FUEL INJECTOR
CIRCUIT, Diag-
nostics for Engine
Starting Failure.>

Go to step 2.

2

CHECK GROUND CIRCUIT OF FUEL PUMP.
1) Turn ignition switch to OFF.
2) Remove fuel pump access hole lid located

on the right rear of trunk compartment floor
(Sedan) or luggage compartment floor
(Wagon).

3) Disconnect connector from fuel pump.
4) 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

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. <Ref. to
FU(H4SO)-62,
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 connector

between fuel pump and fuel pump relay.

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 connec-
tor and chassis
grounding terminal
• Poor contact in
coupling connec-
tors

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:

Is the measured value less than the specified
value?

1 M

Ω

Go to step 6.

Repair short circuit
in harness
between fuel
pump and fuel
pump relay con-
nector.

EN(H4SO)-78

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

6

CHECK FUEL PUMP RELAY.
1) Disconnect connectors from fuel pump

relay and main relay.

2) Remove fuel pump relay and main relay

with 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. <Ref. to
FU(H4SO)-47,
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

(B134) No. 11 — (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(H4SO)-80,
FUEL INJECTOR
CIRCUIT, Diag-
nostics for Engine
Starting Failure.>

Step

Value

Yes

No

EN(H4SO)-79

ENGINE (DIAGNOSTICS)

DIAGNOSTICS FOR ENGINE STARTING FAILURE

MEMO: