Subaru Legacy 2005 Service Manual page 786

ENGINE (DIAGNOSTICS)
Step
6 CHECK INPUT SIGNAL OF IGNITION COIL
AND IGNITOR ASSEMBLY.
1) Connect the connector to ignition coil and
ignitor assembly.
2) Check if the voltage varies synchronously
with engine speed when cranking, while moni-
toring voltage between ignition coil and ignitor
assembly connector and engine ground.
Connector & terminal
(E12) No. 1 (+) — Engine ground (
(E12) No. 4 (+) — Engine ground (
7 CHECK HARNESS BETWEEN ECM AND IG-
NITION COIL AND IGNITOR ASSEMBLY
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connector from ignition coil
and ignitor assembly.
4) Measure the resistance of harness
between ECM and ignition coil and ignitor
assembly connector.
Connector & terminal
(B135) No. 18 — (E12) No. 1:
(B135) No. 17 — (E12) No. 4:
8 CHECK HARNESS BETWEEN ECM AND IG-
NITION COIL AND IGNITOR ASSEMBLY
CONNECTOR.
Measure the resistance of harness between
ECM and engine ground.
Connector & terminal:
(B135) No. 18 — Engine ground:
(B135) No. 17 — Engine ground:
9 CHECK POOR CONTACT.
Check poor contact in ECM connector.
Diagnostics for Engine Starting Failure
Does the voltage vary more
than 10 V?
−
):
−
):
Is the resistance less than 1
Ω?
Is the resistance more than 1
MΩ?
Is there poor contact in ECM
connector?
EN(H4SO 2.5)(diag)-62
Check
Go to step 7.
Go to step 8.
Go to step 9.
Repair the poor
contact in ECM
connector.
Yes No
Replace the igni-
tion coil and ignitor
assembly. <Ref. to
IG(H4SO 2.0)-8,
Ignition Coil and
Ignitor Assembly.>
Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit of
harness between
ECM and ignition
coil and ignitor
assembly connec-
tor
• Poor contact in
coupling connector
Repair the ground
short circuit of har-
ness between
ECM and ignition
coil and ignitor
assembly connec-
tor.
Check the fuel
pump circuit. <Ref.
to EN(H4SO
2.5)(diag)-63,
FUEL PUMP CIR-
CUIT, Diagnostics
for Engine Start-
ing Failure.>