Subaru 2009 IMPREZA Service Manual page 1301

ENGINE (DIAGNOSTICS)
Step
1 CHECK OPERATION OF EACH FUEL INJEC-
TOR.
While cranking the engine, check each fuel
injector emits operating sound. Use a sound
scope or attach a screwdriver to the injector for
this check.
2 CHECK POWER SUPPLY TO EACH FUEL IN-
JECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel injector.
3) Turn the ignition switch to ON.
4) Measure the power supply voltage between
fuel injector connector and the engine ground.
Connector & terminal
#1 (E5) No. 2 (+) — Engine ground (–):
#2 (E16) No. 2 (+) — Engine ground (–):
#3 (E6) No. 2 (+) — Engine ground (–):
#4 (E17) No. 2 (+) — Engine ground (–):
3 CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance of harness between
ECM and fuel injector connector.
Connector & terminal
(B137) No. 8 — (E5) No. 1:
(B137) No. 9 — (E16) No. 1:
(B137) No. 10 — (E6) No. 1:
(B137) No. 11 — (E17) No. 1:
4 CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR CONNECTOR.
Measure the resistance of harness between
ECM and chassis ground.
Connector & terminal
(B137) No. 8 — Chassis ground:
(B137) No. 9 — Chassis ground:
(B137) No. 10 — Chassis ground:
(B137) No. 11 — Chassis ground:
5 CHECK EACH FUEL INJECTOR.
Measure the resistance between each fuel
injector terminals.
Terminals
No. 1 — No. 2:
6 CHECK POOR CONTACT.
Check for poor contact of ECM connector.
Diagnostics for Engine Starting Failure
Does the fuel injector emit
operating sound?
Is the voltage 10 V or more?
Is the resistance less than 1 ? Go to step 4.
Is the resistance 1 M or
more?
Is the resistance 5 — 20 ?
Is there poor contact of ECM
connector?
EN(H4DOTC)(diag)-80
Check Yes
Check the fuel
pressure. <Ref. to
ME(H4DOTC)-25,
INSPECTION,
Fuel Pressure.>
Go to step 3.
Go to step 5.
Go to step 6.
Repair the poor
contact of ECM
connector.
No
Go to step 2.
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
main relay connec-
tor and fuel injector
connector
• Poor contact of
main relay connec-
tor
• Poor contact of
coupling connector
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and fuel in-
jector connector
• Poor contact of
coupling connector
Repair the short
circuit to ground in
harness between
ECM and fuel
injector connector.
Replace the faulty
fuel injector. <Ref.
to FU(H4DOTC)-
41, Fuel Injector.>
Inspection using
"General Diagnostic
Table". <Ref. to
EN(H4DOTC)(diag)
-367, INSPEC-
TION, General
Diagnostic Table.>