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: