Subaru IMPREZA GD 2007 Series Manual page 1483

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Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK POWER SUPPLY CIRCUIT TO FUEL
PUMP CONTROL UNIT.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel pump
control unit.
3) Turn the ignition switch to ON.
4) Measure the voltage between fuel pump
control unit and chassis ground.
Connector & terminal
(R122) No. 3 (+) — Chassis ground (–):
2 CHECK GROUND CIRCUIT OF FUEL PUMP
CONTROL UNIT.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness between
fuel pump control unit and chassis ground.
Connector & terminal
(R122) No. 1 — Chassis ground:
3 CHECK HARNESS BETWEEN FUEL PUMP
CONTROL UNIT AND FUEL PUMP CONNEC-
TOR.
1) Disconnect the connector from fuel pump.
2) Measure the resistance of harness between
fuel pump control unit and fuel pump connector.
Connector & terminal
(R122) No. 6 — (R58) No. 1:
(R122) No. 4 — (R58) No. 4:
4 CHECK HARNESS BETWEEN FUEL PUMP
CONTROL UNIT AND FUEL PUMP CONNEC-
TOR.
Measure the resistance between fuel pump
control unit and chassis ground.
Connector & terminal
(R122) No. 6 — Chassis ground:
(R122) No. 4 — Chassis ground:
5 CHECK HARNESS BETWEEN ECM AND
FUEL PUMP CONTROL UNIT.
1) Disconnect the connectors from the ECM.
2) Measure the resistance of the harness
between the ECM and fuel pump control unit.
Connector & terminal
(B135) No. 33 — (R122) No. 5:
(B136) No. 12 — (R122) No. 2:
Check
Is the voltage 10 V or more?
Is the resistance less than 5 Ω? Go to step 3.
Is the resistance less than 1 Ω? Go to step 4.
Is the resistance 1 MΩ or more? Go to step 5.
Is the resistance less than 1 Ω? Go to step 6.
EN(STI)(diag)-152
Yes No
Go to step 2. Repair the power
supply circuit.
NOTE:
In this case, repair
the following item:
• Open or ground
short circuit of har-
ness between fuel
pump relay and
fuel pump control
unit
• Poor contact of
fuel pump control
unit connector
• Poor contact of
fuel pump relay
connector
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit be-
tween fuel pump
control unit and
chassis ground
• Poor contact of
fuel pump control
unit connector
Repair the open
circuit between fuel
pump control unit
and fuel pump.
Repair the ground
short circuit of har-
ness between fuel
pump control unit
and fuel pump.
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit be-
tween the ECM
and fuel pump con-
trol unit
• Poor contact be-
tween ECM and
fuel pump control
unit