Subaru Legacy 2004 Service Manual page 543

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and
front oxygen (A/F) sensor connector.
3) Measure the resistance of harness
between ECM and chassis ground.
Connector & terminal
(B136) No. 33 — Chassis ground:
(B136) No. 35 — Chassis ground:
Check
Is the resistance more than 1
M&?
EN(H4SO 2.0)(diag)-111
ENGINE (DIAGNOSTICS)
Yes
Replace the front Repair the ground
oxygen (A/F) sen- short circuit in har-
sor. <Ref. to ness between
FU(H4SO 2.0)-32, ECM and front
Front Oxygen (A/ oxygen (A/F) sen-
F) Sensor.> sor connector.
No