Subaru 2009 IMPREZA Service Manual page 1503

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
15 CHECK HARNESS BETWEEN ECM AND
FUEL INJECTOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel injector
on faulty cylinders.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM and
chassis ground on faulty cylinders.
Connector & terminal
#1 (B137) No. 8 (+) — Chassis ground (–):
#2 (B137) No. 9 (+) — Chassis ground (–):
#3 (B137) No. 10 (+) — Chassis ground (–):
#4 (B137) No. 11 (+) — Chassis ground (–):
16 CHECK FUEL INJECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between fuel injec-
tor terminals on faulty cylinder.
Terminals
No. 1 — No. 2:
17 CHECK INSTALLATION OF CAMSHAFT PO-
SITION SENSOR/CRANKSHAFT POSITION
SENSOR.
18 CHECK CRANK SPROCKET.
Remove the timing belt cover. <Ref. to
ME(H4DOTC)-49, REMOVAL, Timing Belt
Cover.>
19 CHECK INSTALLATION CONDITION OF
TIMING BELT.
Turn the crankshaft using ST, and align the
alignment mark on crank sprocket with align-
ment mark on cylinder block.
ST 499987500
20 CHECK ELECTRONIC THROTTLE CON-
TROL RELAY.
1) Turn the ignition switch to OFF.
2) Remove the electronic throttle control relay.
3) Connect the battery to terminals No. 31 and
No. 32 of electronic throttle control relay.
4) Measure the resistance between electronic
throttle control relay terminals.
Terminals
No. 29 — No. 30:
21 CHECK POWER SUPPLY OF ELECTRONIC
THROTTLE CONTROL RELAY.
Measure the voltage between electronic throttle
control relay connector and chassis ground.
Connector & terminal
(B220) No. 29 (+) — Chassis ground (–):
22 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY CONNECTOR.
1) Disconnect the connectors from ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control relay connector and chassis
ground.
Connector & terminal
(B220) No. 32 (+) — Chassis ground (–):
Is the voltage 10 V or more?
Is the resistance less than 1 ? Replace the faulty
Is the camshaft position sensor
or crankshaft position sensor
loosely installed?
Is the crank sprocket rusted or
does it have broken teeth?
Is the timing belt dislocated
from its proper position?
CRANKSHAFT
SOCKET
Is the resistance less than 1 ? Go to step 21.
Is the voltage 10 V or more?
Is the voltage 10 V or more?
EN(H4DOTC)(diag)-282
Check Yes
Repair the short
circuit to power in
harness between
ECM and fuel
injector connector.
fuel injector. <Ref.
to FU(H4DOTC)-
41, Fuel Injector.>
Tighten the cam-
shaft position sen-
sor or crankshaft
position sensor.
Replace the crank
sprocket. <Ref. to
ME(H4DOTC)-60,
Crank Sprocket.>
Repair the installa-
tion condition of
timing belt. <Ref. to
ME(H4DOTC)-50,
Timing Belt.>
Go to step 22.
Repair the short
circuit to power in
the harness
between ECM and
electronic throttle
control relay con-
nector.
No
Go to step 16.
Go to step 17.
Go to step 18.
Go to step 19.
Go to step 20.
Replace the elec-
tronic throttle con-
trol relay. <Ref. to
FU(H4DOTC)-57,
Electronic Throttle
Control Relay.>
Repair the open or
ground short circuit
of power supply
circuit.
Go to step 23.