Subaru Legacy 2003 Service Manual page 1897

DIAGNOSTICS FOR ENGINE STARTING FAILURE
ENGINE (DIAGNOSTICS)
6 CHECK OUTPUT VOLTAGE FROM ECM.
1) Connect the connector to ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B134) No. 2 (+) — Chassis ground (–):
Does the measured value exceed the spec-
ified value?
7 CHECK INPUT VOLTAGE OF MAIN RELAY.
Check the voltage between main relay connec-
tor and chassis ground.
Connector & terminal
(B47) No. 2 (+) — Chassis ground (–):
Does the measured value exceed the specified
value?
8 CHECK GROUND CIRCUIT OF MAIN RE-
LAY.
1) Turn the ignition switch to OFF.
2) Measure the resistance between main relay
connector and chassis ground.
Connector & terminal
(B47) No. 1 — Chassis ground:
Is the measured value less than the speci-
fied value?
9 CHECK INPUT VOLTAGE OF MAIN RELAY.
Measure the voltage between main relay con-
nector and chassis ground.
Connector & terminal
(B47) No. 5 (+) — Chassis ground ( − − − − ):
(B47) No. 6 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the specified
value?
10 CHECK INPUT VOLTAGE OF ECM.
1) Connect the main relay connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B137) No. 2 (+) — Chassis ground (–):
(B137) No. 3 (+) — Chassis ground (–):
Does the measured value exceed the spec-
ified value?
Step
EN(H4DOSTC)-58
Value
10 V
10 V
5 Ω
10 V
10 V
Yes
Go to step 7. Replace the ECM.
<Ref. to
FU(H4DOSTC)-
40, Engine Con-
trol Module.>
Go to step 8. Repair the open
circuit in harness
between ECM
connector and
main relay con-
nector.
Go to step 9. Repair the open
circuit between
main relay and
chassis ground.
Go to step 10. Repair the open or
ground short cir-
cuit in harness of
power supply cir-
cuit.
Check the fuel Repair the open or
pump circuit. <Ref. ground short cir-
to EN(H4DOSTC)- cuit in harness
60, FUEL PUMP between ECM
CIRCUIT, Diag- connector and
nostics for Engine main relay con-
Starting Failure.> nector.
No