Subaru Legacy 2003 Service Manual page 864

DIAGNOSTICS FOR ENGINE STARTING FAILURE
Step
6 CHECK OUTPUT VOLTAGE FROM ECM.
1) Connect connector to ECM.
2) Turn ignition switch to ON.
3) Measure voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 19 (+) — Chassis ground (–):
Does the measured value exceed the spec-
ified value?
7 CHECK INPUT VOLTAGE OF MAIN RELAY.
Check voltage between main relay connector
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 ignition switch to OFF.
2) Measure 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 voltage between main relay connec-
tor 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 main relay connector.
2) Turn ignition switch to ON.
3) Measure voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 1 (+) — Chassis ground (–):
(B136) No. 2 (+) — Chassis ground (–):
Does the measured value exceed the spec-
ified value?
Value
10 V
10 V
5 Ω
10 V
10 V
EN(H4SOw/oOBD)-45
ENGINE (DIAGNOSTICS)
Yes
Go to step 7. Replace ECM.
Go to step 8. Repair open circuit
in harness
between ECM
connector and
main relay con-
nector.
Go to step 9. Repair open circuit
between main
relay and chassis
ground.
Go to step 10. Repair open or
ground short cir-
cuit in harness of
power supply cir-
cuit.
Check ignition Repair open or
control system. ground short cir-
<Ref. to cuit in harness
EN(H4SOw/ between ECM
oOBD)-46, IGNI- connector and
TION CONTROL main relay con-
SYSTEM, Diag- nector.
nostics for Engine
Starting Failure.>
No