Subaru Legacy 2004 Service Manual page 1355

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
5 CHECK REAR OXYGEN SENSOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between rear oxy-
gen sensor connector terminals.
Terminals
No. 1 — No. 2:
Check
Is the resistance less than 30
'?
EN(H4DOTC)(diag)-66
Yes
Repair the har- Replace the rear
ness and connec- oxygen sensor.
tor. <Ref. to
FU(H4DOTC)-34,
NOTE:
Rear Oxygen Sen-
In this case, repair
sor.>
the following:
• Open circuit in
harness between
rear oxygen sen-
sor and ECM con-
nector
• Poor contact in
rear oxygen sen-
sor connector
• Poor contact in
ECM connector
• Poor contact in
coupling connector
No