Subaru Legacy 2004 Service Manual page 845

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK OPTION CODE.
2 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B134) No. 2 (+) — Chassis ground (
(B134) No. 3 (+) — Chassis ground (
3 CHECK FRONT OXYGEN (A/F) SENSOR
HEATER CURRENT.
1) Turn the ignition switch to OFF.
2) Repair the battery short circuit in harness
between ECM and front oxygen (A/F) sensor
connector.
3) Turn the ignition switch to ON.
4) Read the data of front oxygen (A/F) sensor
heater current using Subaru Select Monitor.
NOTE:
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H4SO 2.5)(diag)-26, Subaru Select Mon-
itor.>
4 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 2 (+) — Chassis ground (
(B134) No. 3 (+) — Chassis ground (
Check
Is the option code EC, EK or
K4?
Is the voltage more than 8 V?
"
):
"
):
Is the current more than 2.3 A? Replace the ECM.
Does the voltage change by
shaking the ECM harness and
connector?
"
):
"
):
EN(H4SO 2.5)(diag)-86
Yes
Go to step 2. Refer to EN(H4SO
2.0) section. <Ref.
to EN(H4SO
2.0)(diag)-66, List
of Diagnostic Trou-
ble Code (DTC).>
NOTE:
Fuel injection sys-
tem for KA and KS
model is the same
as 2.0 L model.
Go to step 3. Go to step 4.
END.
<Ref. to FU(H4SO
2.5)-36, Engine
Control Module
(ECM).>
Repair the battery END.
short circuit in har-
ness between
ECM and front
oxygen (A/F) sen-
sor connector.
No