Subaru Legacy 2003 Service Manual page 870

DIAGNOSTICS FOR ENGINE STARTING FAILURE
Step
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
EN(H4SOw/oOBD)-29, OPERATION, Compul-
sory Valve Operation Check Mode.>
Does fuel pump produce operating sound?
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?
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?
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?
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?
CHECK MODE".<Ref.
EN(H4SOw/oOBD)-51
Value
Fuel pump produces operating
sound.
to
5 Ω
10 V
1 Ω
1 MΩ
ENGINE (DIAGNOSTICS)
Yes
Check fuel injec- Go to step 2.
tor circuit. <Ref. to
EN(H4SOw/
oOBD)-53, FUEL
INJECTOR CIR-
CUIT, Diagnostics
for Engine Start-
ing Failure.>
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)
Replace fuel Go to step 4.
pump.
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)
Go to step 6. Repair ground
short circuit in har-
ness between fuel
pump and fuel
pump relay con-
nector.
No