Subaru 2009 IMPREZA Service Manual page 1502

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
10 CHECK OUTPUT SIGNAL OF ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground on faulty cylinders.
Connector & terminal
#1 (B137) No. 8 (+) — Chassis ground (–):
#2 (B137) No. 9 (+) — Chassis ground (–):
#3 (B137) No. 10 (+) — Chassis ground (–):
#4 (B137) No. 11 (+) — Chassis ground (–):
11 CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel injector
on faulty cylinders.
3) Measure the resistance between fuel injec-
tor connector and engine ground on faulty cylin-
ders.
Connector & terminal
#1 (E5) No. 1 — Engine ground:
#2 (E16) No. 1 — Engine ground:
#3 (E6) No. 1 — Engine ground:
#4 (E17) No. 1 — Engine ground:
12 CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR CONNECTOR.
Measure the resistance of harness between
ECM and fuel injector connector on faulty cylin-
ders.
Connector & terminal
#1 (B137) No. 8 — (E5) No. 1:
#2 (B137) No. 9 — (E16) No. 1:
#3 (B137) No. 10 — (E6) No. 1:
#4 (B137) No. 11 — (E17) No. 1:
13 CHECK FUEL INJECTOR.
Measure the resistance between fuel injector
terminals on faulty cylinder.
Terminals
No. 1 — No. 2:
14 CHECK POWER SUPPLY LINE.
1) Turn the ignition switch to ON.
2) Measure the voltage between fuel injector
and engine ground on faulty cylinders.
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 (–):
Check
Is the voltage 10 V or more?
Is the resistance 1 M or
more?
Is the resistance less than 1 ? Go to step 13.
Is the resistance 5 — 20 ?
Is the voltage 10 V or more?
EN(H4DOTC)(diag)-281
ENGINE (DIAGNOSTICS)
Yes No
Go to step 15. Go to step 11.
Go to step 12. Repair the short
circuit to ground in
harness between
ECM and fuel
injector 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
Go to step 14. Replace the faulty
fuel injector. <Ref.
to FU(H4DOTC)-
41, Fuel Injector.>
Repair the poor Repair the harness
contact of all con- and connector.
nectors in fuel
NOTE:
injector circuit.
In this case, repair
the following item:
• Open circuit in
harness between
the main relay con-
nector and fuel in-
jector connector on
faulty cylinders
• Poor contact of
coupling connector
• Poor contact of
main relay connec-
tor