Subaru Legacy 2003 Service Manual page 866

DIAGNOSTICS FOR ENGINE STARTING FAILURE
Step
1 CHECK IGNITION SYSTEM FOR SPARKS.
1) Remove plug cord cap from each spark
plug.
2) Install new spark plug on plug cord cap.
CAUTION:
Do not remove spark plug from engine.
3) Contact spark plug's thread portion on
engine.
4) Crank engine to check that spark occurs at
each cylinder.
Does spark occur at each cylinder?
2 CHECK POWER SUPPLY CIRCUIT FOR IG-
NITION COIL & IGNITOR ASSEMBLY.
1) Turn ignition switch to OFF.
2) Disconnect connector from ignition coil &
ignitor assembly.
3) Turn ignition switch to ON.
4) Measure power supply voltage between
ignition coil & ignitor assembly connector
and engine ground.
Connector & terminal
(E12) No. 2 (+) — Engine ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
3 CHECK HARNESS OF IGNITION COIL & IG-
NITOR ASSEMBLY GROUND CIRCUIT.
1) Turn ignition switch to OFF.
2) Measure resistance between ignition coil &
ignitor assembly connector and engine
ground.
Connector & terminal
(E12) No. 3 — Engine ground:
Is the measured value less than the speci-
fied value?
4 CHECK IGNITION COIL & IGNITOR ASSEM-
BLY.
1) Remove spark plug cords.
2) Measure resistance between spark plug
cord contact portions to check secondary
coil.
Terminals
No. 1 — No. 2:
Is the measured value within the specified
value?
5 CHECK IGNITION COIL & IGNITOR ASSEM-
BLY.
Measure resistance between spark plug cord
contact portions to check secondary coil.
Terminals
No. 3 — No. 4:
Is the measured value within the specified
value?
Value
Spark occurs.
10 V
5 Ω
10 — 15 Ω
10 — 15 Ω
EN(H4SOw/oOBD)-47
ENGINE (DIAGNOSTICS)
Yes
Check fuel pump Go to step 2.
system. <Ref. to
EN(H4SOw/
oOBD)-50, FUEL
PUMP CIRCUIT,
Diagnostics for
Engine Starting
Failure.>
Go to step 3. Repair harness
and connector.
NOTE:
In this case, repair
the following:
• Open circuit or
ground short in
harness between
ignition coil & igni-
tor assembly, and
ignition switch
connector
• Poor contact in
coupling connector
(B22)
Go to step 4. Repair harness
and connector.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ignition coil & igni-
tor assembly con-
nector and engine
grounding terminal
Go to step 5. Replace ignition
coil & ignitor
assembly.
Go to step 6. Replace ignition
coil & ignitor
assembly.
No