Subaru Forester 2004 Service Manual page 59

ENGINE (DIAGNOSTIC)
Step
1 CHECK MAIN RELAY.
1) Turn the ignition switch to OFF.
2) Remove the main relay.
3) Connect the battery to main relay terminals
No. 1 and No. 2.
4) Measure the resistance between main relay
terminals.
Terminals
No. 3 — No. 5:
No. 4 — No. 6:
2 CHECK GROUND CIRCUIT FOR ECM.
1) Disconnect the connector from ECM.
2) Measure the resistance of harness
between ECM and chassis ground.
Connector & terminal
(B134) No. 6 — Chassis ground:
(B134) No. 7 — Chassis ground:
(B134) No. 34 — Chassis ground:
(B135) No. 1 — Chassis ground:
(B135) No. 4 — Chassis ground:
(B135) No. 12 — Chassis ground:
(B137) No. 1 — Chassis ground:
(B137) No. 2 — Chassis ground:
(B137) No. 7 — Chassis ground:
3 CHECK INPUT VOLTAGE OF ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 19 (+) — Chassis ground (
(B137) No. 14 (+) — Chassis ground (
4 CHECK INPUT VOLTAGE OF MAIN RELAY.
Measure the voltage between main relay con-
nector and chassis ground.
Connector & terminal
(B47) No. 1 (+) — Chassis ground (
(B47) No. 5 (+) — Chassis ground (
(B47) No. 6 (+) — Chassis ground (
5 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
(B135) No. 5 (+) — Chassis ground (
(B135) No. 6 (+) — Chassis ground (
(B137) No. 16 (+) — Chassis ground (
Diagnostics for Engine Starting Failure
Is the resistance less than 10
Ω?
Is the resistance less than 5
Ω?
Is the voltage more than 10 V? Go to step 4.
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Is the voltage more than 10 V? Go to step 5.
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):
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Is the voltage more than 10 V? Check ignition
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EN(H4DOTC 2.5)-58
Check
Go to step 2.
Go to step 3.
control system.
<Ref. to
EN(H4DOTC 2.5)-
59, IGNITION
CONTROL SYS-
TEM, Diagnostics
for Engine Start-
ing Failure.>
Yes No
Replace the main
relay.
Repair open circuit
in harness
between ECM con-
nector and engine
ground terminal.
Repair open or
ground short cir-
cuit of power sup-
ply circuit.
Repair open or
ground short circuit
in harness of power
supply circuit.
Repair open or
ground short circuit
in harness
between ECM con-
nector and main
relay connector.