Subaru Legacy 2003 Service Manual page 1984

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK SPARK PLUG CONDITION.
1) Remove the spark plug. <Ref. to
IG(H4DOSTC)-5, REMOVAL, Spark Plug.>
2) Check the spark plug condition. <Ref. to
IG(H4DOSTC)-6, INSPECTION, Spark
Plug.>
Is spark plug's status OK?
2 CHECK IGNITION SYSTEM FOR SPARKS.
1) Connect the spark plug to ignition coil.
2) Release the fuel pressure. <Ref. to
FU(H4DOSTC)-44, RELEASING OF FUEL
PRESSURE, OPERATION, Fuel.>
3) Contact the spark plug's thread portion on
engine.
4) While opening throttle valve fully, crank the
engine to check that spark occurs at each
cylinder.
Does the spark occur at each cylinder?
3 CHECK POWER SUPPLY CIRCUIT FOR IG-
NITION COIL & IGNITOR ASSEMBLY.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ignition coil
& ignitor assembly.
3) Turn the ignition switch to ON.
4) Measure the power supply voltage between
ignition coil & ignitor assembly connector
and engine ground.
Connector & terminal
(E31) No. 3 (+) — Engine ground ( − − − − ):
(E32) No. 3 (+) — Engine ground ( − − − − ):
(E33) No. 3 (+) — Engine ground ( − − − − ):
(E34) No. 3 (+) — Engine ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
4 CHECK HARNESS OF IGNITION COIL & IG-
NITOR ASSEMBLY GROUND CIRCUIT.
1) Turn the ignition switch to OFF.
2) Measure the resistance between ignition
coil & ignitor assembly connector and
engine ground.
Connector & terminal
(E31) No. 2 — Engine ground:
(E32) No. 2 — Engine ground:
(E33) No. 2 — Engine ground:
(E34) No. 2 — Engine ground:
Is the measured value less than the speci-
fied value?
Value
OK
Spark occurs.
10 V
5 Ω
EN(H4DOSTC)-145
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Replace the spark
plug.
Check the fuel Go to step 3.
pump system.
<Ref. to
EN(H4DOSTC)-
60, FUEL PUMP
CIRCUIT, Diag-
nostics for Engine
Starting Failure.>
Go to step 4. Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ignition coil & igni-
tor assembly, and
ignition switch
connector
• Poor contact in
coupling connec-
tors
Go to step 5. Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ignition coil & igni-
tor assembly con-
nector and engine
grounding terminal
No