Subaru Legacy 2005 Service Manual page 1795

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
6 CHECK OUTPUT SIGNAL FROM ECM.
1) Disconnect the connector from rear oxygen
sensor.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B135) No. 3 (+) — Chassis ground (
7 CHECK REAR OXYGEN SENSOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between rear oxy-
gen sensor connector terminals.
Terminal
No. 1 — No. 2:
Check
Is the voltage less than 1 V?
−
):
Is the resistance less than 30
Ω?
EN(H6DO)(diag)-99
ENGINE (DIAGNOSTICS)
Yes
Replace the ECM. Repair the battery
<Ref. to short circuit of har-
FU(H6DO)-34, ness between
Engine Control ECM and rear oxy-
Module (ECM).> gen sensor con-
nector. After
repair, replace the
ECM. <Ref. to
FU(H6DO)-34,
Engine Control
Module (ECM).>
Repair the har- Replace the rear
ness and connec- oxygen sensor.
tor. <Ref. to
FU(H6DO)-32,
NOTE:
Rear Oxygen Sen-
In this case, repair
sor.>
the following:
• Open circuit of
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