Subaru Impreza 2003, Service Manual

Page: 816 / 3610

EN(H4SOw/oOBD)-40
ENGINE (DIAGNOSTICS)
DIAGNOSTICS FOR ENGINE STARTING FAILURE
3 CHECK INPUT SIGNAL FOR STARTER MO-
TOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from starter motor.
3)Turn the ignition switch to START.
4)Measure the power supply voltage between
starter motor connector terminal and engine
ground.
Connector & terminal
(B14) No. 1 (+) — Engine ground (
−−−−
):
NOTE:
On AT model, place the selector lever in the “P”
or “N” position.
Is the voltage more than 10 V? Go to step 4. Go to step 5.
4 CHECK GROUND CIRCUIT OF STARTER
MOTOR.
1)Turn the ignition switch to OFF.
2)Disconnect the terminal from starter motor.
3)Measure the resistance of ground cable
between ground cable terminal and engine
ground.
Is the resistance less than 5
Ω
?
Check the starter
motor. <Ref. to
SC(H4SO)-10,
INSPECTION,
Starter.> Repair the open
circuit of ground
cable.
5 CHECK HARNESS BETWEEN ECM AND
STARTER MOTOR CIRCUIT.
1)Turn the ignition switch to OFF.
2)Measure the resistance between starter
motor and ECM.
Connector & terminal
(B14) No. 1 — Engine ground:
Is the resistance less than 1
Ω
?
Repair the ground
short circuit. Go to step 6.
6 CHECK HARNESS BETWEEN ECM AND
STARTER MOTOR CIRCUIT.
1)Turn the ignition switch to START.
2)Measure the resistance of fuse.
Connector & terminal
(B14) No. 1 — Engine ground:
Is the resistance less than 1
Ω
?
Go to step 7. Repair the ground
short circuit.
7 CHECK HARNESS BETWEEN BATTERY
AND IGNITION SWITCH CONNECTOR.
1)Ignition the switch to OFF.
2)Disconnect the connector from ignition
switch.
3)Measure the power supply voltage between
ignition switch connector and chassis ground.
Connector & terminal
(B72) No. 1 (+) — Chassis ground (
−−−−
):
Is the voltage more than 10 V? Go to step 8. Repair the open
circuit in harness
between ignition
switch and battery.
8 CHECK HARNESS BETWEEN BATTERY
AND IGNITION SWITCH CONNECTOR.
1)Connect the connector to ignition switch.
2)Turn the ignition switch to START.
3)Measure the voltage between ignition switch
and chassis ground.
Connector & terminal
(B72) No. 3 (+) — Chassis ground (
−−−−
):
Is the voltage more than 10 V? Go to step 9. Replace the igni-
tion switch.
9 CHECK TRANSMISSION TYPE. Is the vehicle AT? Go to step 10. Repair the open
circuit between
ignition switch and
starter motor cir-
cuit.
Step Check Yes No