Subaru Impreza 2004 - Page 376

EN(H4SO)(diag)-70
ENGINE (DIAGNOSTICS)
Diagnostics for Engine Starting Failure
Step Check Yes No
1 CHECK OPERATING SOUND OF FUEL
PUMP.
Make sure that fuel pump is in operation for
two seconds when turning the ignition switch to
ON.
N
O
TE:
Fuel pump operation can also be executed us-
ing Subaru Select Monitor.
For the procedure, refer to “Compulsory Valve
Operation Check Mode”. <Ref. to
EN(H4SO)(diag)-48, Compulsory Valve Oper-
ation Check Mode.>
Does the fuel pump produce
operating sound?
Check fuel injec-
tor circuit. <Ref. to
EN(H4SO)(diag)-
72, FUEL INJEC-
TOR CIRCUIT,
Diagnostics for
Engine Starting
Failure.>
Go to step 2.
2 CHECK GROUND CIRCUIT OF FUEL PUMP.
1)Turn the ignition switch to OFF.
2)Remove the fuel pump access hole lid.
3)Disconnect the connector from fuel pump.
4)Measure the resistance of harness connec-
tor between fuel pump and chassis ground.
Connector & terminal
(R58) No. 4 — Chassis ground:
Is the resistance less than 5
Ω?
Go to step 3. Repair harness
and connector.
N
O
TE:
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 the ignition switch to ON.
2)Measure the voltage of power supply circuit
between fuel pump connector and chassis
ground.
Connector & terminal
(R58) No. 1 (+) — Chassis ground (
−
−−
−
):
Is the voltage more than 10 V? Replace the fuel
pump. <Ref. to
FU(H4SO)-57,
Fuel Pump.>
Go to step 4.
4 CHECK HARNESS BETWEEN FUEL PUMP
AND FUEL PUMP RELAY CONNECTOR.
1)Turn the ignition switch to OFF.
2)Measure the resistance of harness connec-
tor between fuel pump and fuel pump relay.
Connector & terminal
(R58) No. 1 — (B46) No. 4:
Is the resistance less than 1
Ω?
Go to step 5. Repair harness
and connector.
N
O
TE:
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 the resistance of harness between
fuel pump and fuel pump relay connector.
Connector & terminal
(R58) No. 1 — Chassis ground:
Is the resistance more than 1
MΩ?
Go to step 6. Repair short circuit
in harness
between fuel pump
and fuel pump
relay connector.