Subaru Legacy 2004 Service Manual page 562

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK SENSOR OUTPUT.
1) Turn the ignition switch to ON.
2) Read the data of sub throttle sensor signal
using Subaru Select Monitor.
2 CHECK POOR CONTACT.
Check poor contact in connector between
ECM and electronic throttle control.
3 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connectors from electronic
throttle control.
4) Measure the resistance between ECM con-
nector and electronic throttle control connector.
Connector & terminals
(B137) No. 24 — (E78) No. 2:
(B136) No. 17 — (E78) No. 4:
4 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
Measure the resistance between ECM connec-
tor and chassis ground.
Connector & terminal
(B137) No. 24 — Chassis ground:
(B136) No. 17 — Chassis ground:
5 CHECK SENSOR POWER SUPPLY.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E78) No. 4 (+) — Engine ground (
6 CHECK SHORT CIRCUIT INSIDE THE ECM.
1) Turn the ignition switch to OFF.
2) Measure the resistance between electronic
throttle control connector and engine ground.
Connector & terminal
(E78) No. 2 — Engine ground:
Check
Is the voltage more than 0.8 V? Go to step 2.
Is there poor contact?
Is the resistance less than 1
&?
Is the resistance more than 1
M&?
Is the voltage 4.5 — 5.5 V?
"
):
Is the resistance more than 10
&?
EN(H4SO 2.0)(diag)-130
Yes
Go to step 3.
Repair the poor Temporary poor
contact. contact occurred,
but it is normal at
present.
Go to step 4. Repair the open
circuit of harness
connector.
Go to step 5. Repair the chas-
sis short circuit of
harness.
Go to step 6. Repair the poor
contact in ECM
connector.
Replace the ECM
if defective. <Ref.
to FU(H4SO 2.0)-
34, Engine Con-
trol Module
(ECM).>
Repair the poor Repair the poor
contact of elec- contact in ECM
tronic throttle con- connector.
trol connector. Replace the ECM
Replace the elec- if defective. <Ref.
tronic throttle con- to FU(H4SO 2.0)-
trol if defective. 34, Engine Con-
trol Module
(ECM).>
No