Subaru Impreza 2003 Service Manual page 1340

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
Step
6 CHECK POWER SUPPLY LINE.
1)Turn the ignition switch to ON.
2)Measure the voltage between fuel injector
and engine ground on faulty cylinders.
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 ( − − − − ):
7 CHECK HARNESS BETWEEN FUEL INJEC-
TOR AND ECM CONNECTOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from fuel injector
on faulty cylinder.
3)Turn the ignition switch to ON.
4)Measure the voltage between ECM connec-
tor and chassis ground on faulty cylinders.
Connector & terminal
#1 (B84) No. 1 (+) — Chassis ground
( − − − − ):
#2 (B137) No. 6 (+) — Chassis ground
( − − − − ):
#3 (B137) No. 5 (+) — Chassis ground
( − − − − ):
#4 (B137) No. 4 (+) — Chassis ground
( − − − − ):
8 CHECK FUEL INJECTOR.
1)Turn the ignition switch to OFF.
2)Measure the resistance between fuel injector
terminals on faulty cylinder.
Terminals
No. 1 — No. 2:
9 CHECK INSTALLATION OF CAMSHAFT PO-
SITION SENSOR/CRANKSHAFT POSITION
SENSOR.
10 CHECK CRANKSHAFT SPROCKET.
Remove the timing belt cover.
Check
Is the voltage more than 10 V? Repair the poor
Is the voltage more than 10 V? Repair the battery
Is the resistance less than 1
Ω?
Is the camshaft position sensor
or crankshaft position sensor
loosely installed?
Is the crankshaft sprocket
rusted or does it have broken
teeth?
EN(H4DOTC)-164
Yes
Repair the har-
contact in all con- ness and connec-
nectors in fuel tor.
injector circuit.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
main relay and fuel
injector connector
on faulty cylinders
• Poor contact in
coupling connector
• Poor contact in
main relay con-
nector
• Poor contact in
fuel injector con-
nector on faulty
cylinders
Go to step 8.
short circuit in har-
ness between
ECM and fuel
injector. After
repair, replace the
ECM. <Ref. to
FU(H4DOTC)-49,
Engine Control
Module (ECM).>
Replace the faulty Go to step 9.
fuel injector <Ref.
to FU(H4DOTC)-
37, Fuel Injector.>
and ECM <Ref. to
FU(H4DOTC)-49,
Engine Control
Module (ECM).>
Tighten the cam- Go to step 10.
shaft position sen-
sor or crankshaft
position sensor.
Replace the crank- Go to step 11.
shaft sprocket.
<Ref. to
ME(H4DOTC)-71,
Crankshaft
Sprocket.>
No