Subaru IMPREZA 2004 Service Manual page 75

Step
2 CHECK POWER SUPPLY TO EACH FUEL
INJECTOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from #1 cylinder
fuel injector.
3)Turn the ignition switch to ON.
4)Measure the power supply voltage between
the fuel injector terminal and 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)Disconnect the connector from ECM.
2)Measure the resistance of harness between
ECM and fuel injector connector.
Connector & terminal
#1 (B134) No. 34 — (E5) No. 1:
#2 (B134) No. 23 — (E16) No. 1:
#3 (B134) No. 22 — (E6) No. 1:
#4 (B134) No. 8 — (E17) No. 1:
4 CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR CONNECTOR.
Measure the resistance of harness between
ECM and fuel injector connector.
Connector & terminal
#1 (B134) No. 34 — Chassis ground:
#2 (B134) No. 23 — Chassis ground:
#3 (B134) No. 22 — Chassis ground:
#4 (B134) No. 8 — Chassis ground:
5 CHECK EACH FUEL INJECTOR.
1)Turn the ignition switch to OFF.
2)Measure the resistance between each fuel
injector terminals.
Terminals
No. 1 — No. 2:
6 CHECK POOR CONTACT.
Check poor contact in ECM connector.
Diagnostics for Engine Starting Failure
Is the voltage more than 10 V? Go to step 3.
Is the resistance less than 1
Ω?
Is the resistance more than 1
MΩ?
Is the resistance 5 — 20 Ω?
Is there poor contact in ECM
connector?
EN(H4SO)(diag)-73
Check
Go to step 4.
Go to step 5.
Go to step 6.
Repair poor con-
tact in ECM con-
nector.
ENGINE (DIAGNOSTICS)
Yes No
Repair harness
and connector.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
main relay and fuel
injector connector
• Poor contact in
main relay connec-
tor
• Poor contact in
coupling connector
(B22)
• Poor contact in
fuel injector con-
nector
Repair harness
and connector.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ECM and fuel
injector connector
• Poor contact in
coupling connector
Repair ground
short circuit in har-
ness between
ECM and fuel
injector connector.
Replace the faulty
fuel injector.
Inspection using
"General Diagnos-
tic Table". <Ref. to
EN(H4SO)(diag)-
260, INSPEC-
TION, General
Diagnostic Table.>