Subaru 2009 IMPREZA Service Manual page 1387

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
5 CHECK HARNESS BETWEEN ECM AND
FUEL PUMP CONTROL UNIT CONNECTOR.
1) Disconnect the connectors from ECM.
2) Measure the resistance of harness between
ECM and fuel pump control unit connector.
Connector & terminal
(B135) No. 33 — (R122) No. 9:
(B136) No. 12 — (R122) No. 8:
6 CHECK HARNESS BETWEEN ECM AND
FUEL PUMP CONTROL UNIT CONNECTOR.
Measure the resistance between fuel pump
control unit connector and chassis ground.
Connector & terminal
(R122) No. 9 — Chassis ground:
(R122) No. 8 — Chassis ground:
7 CHECK POOR CONTACT.
Check for poor contact of ECM and fuel pump
control unit connector.
8 CHECK EXPERIENCE OF RUNNING OUT OF
FUEL.
Check
Is the resistance less than 1 ? Go to step 6.
Is the resistance 1 M or
more?
Is there poor contact of ECM or
fuel pump control unit connec-
tor?
Has the vehicle experienced
running out of fuel?
EN(H4DOTC)(diag)-166
Yes No
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM
pump control unit
• Poor contact of
coupling connector
Go to step 7. Repair the short
circuit to ground in
harness between
ECM and fuel
pump control unit
connector.
Repair the poor Go to step 8.
contact of ECM or
fuel pump control
unit connector.
Finish the diagno- Replace the fuel
sis. pump control unit.
<Ref. to
NOTE:
FU(H4DOTC)-59,
DTC may be re-
Fuel Pump Control
corded as a result
Unit.>
of fuel pump idling
while running out
of fuel.
and fuel