Subaru 2002 IMPREZA Service Manual page 506

DIAGNOSTICS FOR ENGINE STARTING FAILURE
ENGINE (DIAGNOSTICS)
Step
7 CHECK INPUT SIGNAL FOR IGNITION COIL
& IGNITOR ASSEMBLY.
Check if the voltage varies synchronously with
engine speed when cranking, while monitoring
voltage between ignition coil & ignitor assem-
bly connector and engine ground.
Connector & terminal
• 2.0 L and 2.5 L
(E12) No. 4 (+) — Engine ground (–):
• 1.6 L
(E12) No. 2 (+) — Engine ground ( − − − − ):
8 CHECK HARNESS BETWEEN ECM AND IG-
NITION COIL & IGNITOR ASSEMBLY CON-
NECTOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from ECM.
3)Disconnect the connector from ignition coil &
ignitor assembly.
4)Measure the resistance of harness between
ECM and ignition coil & ignitor assembly con-
nector.
Connector & terminal
• 2.0 L and 2.5 L
(B134) No. 25 — (E12) No. 1:
• 1.6 L
(B134) No. 25 — (E12) No. 4:
9 CHECK HARNESS BETWEEN ECM AND IG-
NITION COIL & IGNITOR ASSEMBLY CON-
NECTOR.
Measure the resistance of harness between
ECM and ignition coil & ignitor assembly con-
nector.
Connector & terminal
• 2.0 L and 2.5 L
(B134) No. 26 — (E12) No. 4:
• 1.6 L
(B134) No. 26 — (E12) No. 2:
10 CHECK HARNESS BETWEEN ECM AND IG-
NITION COIL & IGNITOR ASSEMBLY CON-
NECTOR.
Measure the resistance of harness between
ECM and engine ground.
Connector & terminal:
(B134) No. 25 — Engine ground:
11 CHECK HARNESS BETWEEN ECM AND IG-
NITION COIL & IGNITOR ASSEMBLY CON-
NECTOR.
Measure the resistance of harness between
ECM and engine ground.
Connector & terminal
(B134) No. 26 — Engine ground:
Check
Is the voltage more than 10 V? Go to step 8.
Is the resistance less than 1
Ω?
Is the resistance less than 1
Ω?
Is the resistance more than 1
MΩ?
Is the resistance more than 1
MΩ?
EN-74
Yes
Replace the igni-
tion coil & ignitor
assembly. <Ref. to
IG-8, Ignition Coil
and Ignitor Assem-
bly.>
Go to step 9. Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ECM and ignition
coil & ignitor
assembly connec-
tor
• Poor contact in
coupling connector
(B22)
Go to step 10. Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ECM and ignition
coil & ignitor
assembly connec-
tor
• Poor contact in
coupling connector
(B22)
Go to step 11. Repair the ground
short circuit in har-
ness between
ECM and ignition
coil & ignitor
assembly connec-
tor.
Go to step 12. Repair the ground
short circuit in har-
ness between
ECM and ignition
coil & ignitor
assembly connec-
tor.
No