Subaru IMPREZA GD 2007 Series Manual page 177

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ENGINE (DIAGNOSTICS)
Step
1 CHECK OPERATING SOUND OF FUEL
PUMP.
Make sure that the fuel pump operates for two
seconds when turning the ignition switch to ON.
NOTE:
Fuel pump operation can be executed using the
Subaru Select Monitor.
Regarding the procedures, refer to "Compulso-
ry Valve Operation Check Mode". <Ref. to
EN(H4SO)(diag)-48, Compulsory Valve Opera-
tion Check Mode.>
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:
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 (–):
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:
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:
Diagnostics for Engine Starting Failure
Does the fuel pump emit oper-
ating sound?
Is the resistance less than 5 Ω? Go to step 3.
Is the voltage 10 V or more?
Is the resistance less than 1 Ω? Go to step 5.
Is the resistance 1 MΩ or
more?
EN(H4SO)(diag)-68
Check Yes
Check the fuel
injector circuit.
<Ref. to
EN(H4SO)(diag)-
70, FUEL INJEC-
TOR CIRCUIT,
Diagnostics for
Engine Starting
Failure.>
Replace the fuel
pump. <Ref. to
FU(H4SO)-51,
Fuel Pump.>
Go to step 6.
No
Go to step 2.
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
fuel pump connec-
tor and chassis
grounding terminal
• Poor contact of
coupling connector
Go to step 4.
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• OPEN CIRCUIT
OF HARNESS BE-
TWEEN FUEL
PUMP AND FUEL
PUMP RELAY
CONNECTOR.
• Poor contact of
coupling connector
Repair the short
circuit of harness
between fuel pump
and fuel pump
relay connector.