Subaru Legacy 2004 Service Manual page 634

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK ELECTRONIC THROTTLE CON-
TROL RELAY.
1) Turn the ignition switch to OFF.
2) Remove the electronic throttle control relay.
3) Connect the battery to electronic throttle
control relay terminals No. 5 and No. 6.
4) Measure the resistance between electronic
throttle control relay terminals.
Terminals
No. 7 — No. 8:
2 CHECK POWER SUPPLY OF ELECTRONIC
THROTTLE CONTROL RELAY.
Measure the voltage between electronic throt-
tle control relay connector and chassis ground.
Connector & terminal
(B362) No. 7 (+) — Chassis ground (
(B362) No. 5 (+) — Chassis ground (
3 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY.
1) Disconnect the connector from ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control relay connector and chassis
ground.
Connector & terminal
(B362) No. 6 (+) — Chassis ground (
4 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY.
1) Turn the ignition switch to OFF.
2) Measure the resistance between electronic
throttle control relay connector and chassis
ground.
Connector & terminal
(B362) No. 6 — Chassis ground:
(B362) No. 8 — Chassis ground:
5 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY.
Measure the resistance between ECM connec-
tor and electronic throttle control relay connec-
tor.
Connector & terminal
(B137) No. 9 — (B362) No. 6:
(B137) No. 6 — (B362) No. 8:
(B137) No. 7 — (B362) No. 8:
Check
Is the resistance less than 1
&?
Is the voltage more than 5 V?
"
):
"
):
Is the voltage less than 5 V?
"
):
Is the resistance more than 1
M&?
Is the resistance less than 1
&?
EN(H4SO 2.0)(diag)-202
Yes
Go to step 2. Replace the elec-
tronic throttle con-
trol relay.
Go to step 3. Repair the open or
ground short cir-
cuit of power sup-
ply circuit.
Go to step 4. Repair the power
supply short cir-
cuit in harness
between ECM and
electronic throttle
control relay.
Go to step 5. Repair the ground
short circuit in har-
ness between
ECM and elec-
tronic throttle con-
trol relay.
Repair the poor Repair the open
contact in ECM circuit in harness
connector. between ECM and
Replace the ECM electronic throttle
if defective. <Ref. control relay.
to FU(H4SO 2.0)-
34, Engine Con-
trol Module
(ECM).>
No