Subaru LEGACY 2006 Manual page 314

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Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
16 CHECK REAR OXYGEN SENSOR CONNEC-
TOR AND COUPLING CONNECTOR.
17 CHECK HARNESS BETWEEN ECM AND
REAR OXYGEN SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and
rear oxygen sensor.
3) Measure the resistance of harness
between ECM and rear oxygen sensor con-
nector.
Connector & terminal
(B135) No. 4 — (E23) No. 3:
(B134) No. 29 — (E23) No. 4:
18 CHECK HARNESS BETWEEN REAR OXY-
GEN SENSOR AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the rear
oxygen sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between rear oxygen
sensor harness connector and engine ground
or chassis ground.
Connector & terminal
(E23) No. 3 (+) — Engine ground (–):
19 CHECK REAR OXYGEN SENSOR DATA.
1) Warm-up the engine until engine coolant
temperature is above 70°C (158°F), and rap-
idly reduce the engine speed from 3,000 rpm.
2) Read the data of rear oxygen sensor signal
using Subaru Select Monitor or general scan
tool.
NOTE:
• For MT model, depress the clutch pedal.
• Subaru Select Monitor
For detailed operation procedure, refer to
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H4SO)(diag)-26, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Check
Does water enter the connec-
tor?
Is the resistance more than 3
Ω?
Is the voltage 0.2 — 0.5 V?
Is the voltage less than 250
mV?
EN(H4SO)(diag)-277
ENGINE (DIAGNOSTICS)
Yes No
Dry the water thor- Go to step 17.
oughly.
Repair the open Go to step 18.
circuit of harness
between ECM and
rear oxygen sen-
sor connector.
Replace the rear Repair the har-
oxygen sensor. ness and connec-
<Ref. to tor.
FU(H4SO)-34,
NOTE:
Rear Oxygen Sen-
In this case, repair
sor.>
the following item:
• Open circuit of
harness between
rear oxygen sen-
sor and ECM con-
nector
• Poor contact of
the rear oxygen
sensor connector
• Poor contact in
ECM connector
Go to step 20. Go to step 16.