Subaru Legacy 2003 Service Manual page 542

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
1) Turn ignition switch to OFF.
2) Disconnect connectors from ECM and front
oxygen (A/F) sensor connector.
3) Measure resistance of harness between
ECM and front oxygen (A/F) sensor con-
nector.
Connector & terminal
(B136) No. 13 — Chassis ground:
(B136) No. 22 — Chassis ground:
Does the measured value exceed the spec-
ified value?
Value
1 MΩ
EN(H4SO)-145
ENGINE (DIAGNOSTICS)
Yes
Replace front oxy- Repair short circuit
gen (A/F) sensor. between ECM and
<Ref. to front oxygen (A/F)
FU(H4SO)-41, sensor connector.
Front Oxygen (A/
F) Sensor.>
No