Subaru Legacy 2002 Service Manual page 862

DIAGNOSTICS FOR ENGINE STARTING FAILURE
No.
2 CHECK GROUND CIRCUIT OF ECM.
1) Disconnect connector from ECM.
2) Measure resistance of harness between
ECM and chassis ground.
Connector & terminal
(B136) No. 21 — Chassis ground:
(B136) No. 22 — Chassis ground:
(B134) No. 27 — Chassis ground:
(B134) No. 8 — Chassis ground:
(B134) No. 7 — Chassis ground:
3 CHECK INPUT VOLTAGE OF ECM.
Measure voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 9 (+) — Chassis ground (–):
4 CHECK INPUT VOLTAGE OF ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 7 (+) — Chassis ground (–):
5 CHECK HARNESS BETWEEN ECM AND
MAIN RELAY CONNECTOR.
1) Turn ignition switch to OFF.
2) Measure resistance between ECM and
chassis ground.
Connector & terminal
(B135) No. 19 — Chassis ground:
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
(–):
7 CHECK INPUT VOLTAGE OF MAIN RELAY.
Check voltage between main relay connector
and chassis ground.
Connector & terminal
(B47) No. 2 (+) — Chassis ground (–):
8 CHECK GROUND CIRCUIT OF MAIN
RELAY.
1) Turn ignition switch to OFF.
2) Measure resistance between main relay
connector and chassis ground.
Connector & terminal
(B47) No. 1 — Chassis ground:
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 (−):
Step
Is the resistance less than
5 Ω?
Is the voltage more than 10
V?
Is the voltage more than 10
V?
Is the resistance more than
1 MΩ?
Is the voltage more than 10
V?
Is the voltage more than 10
V?
Is the resistance less than
5 Ω?
Is the voltage more than 10
V?
EN(w/oOBD)-51
Check Yes
Go to step 3.
Go to step 4.
Go to step 5.
Go to step 6.
Go to step 7.
Go to step 8.
Go to step 9.
Go to step 10.
Engine (Diagnostics)
No
Repair open cir-
cuit in harness
between ECM
connector and
engine grounding
terminal.
Repair open or
ground short cir-
cuit of power sup-
ply circuit.
Repair open or
ground short cir-
cuit of power sup-
ply circuit.
Repair ground
short circuit in
harness between
ECM connector
and main relay
connector, then
replace ECM.
Replace ECM.
Repair open cir-
cuit in harness
between ECM
connector and
main relay con-
nector.
Repair open cir-
cuit between main
relay and chassis
ground.
Repair open or
ground short cir-
cuit in harness of
power supply cir-
cuit.