Subaru Legacy 2002 Service Manual page 1304

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
No.
8 CHECK POWER SUPPLY TO FRONT OXY-
GEN (A/F) SENSOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from front oxygen
(A/F) sensor.
3) Turn ignition switch to ON.
4) Measure voltage between front oxygen
(A/F) sensor connector and engine ground.
Connector & terminal
(E47) No. 2 (+) — Engine ground (−):
9 CHECK FRONT OXYGEN (A/F) SENSOR.
1) Turn ignition switch to OFF.
2) Measure resistance between front oxygen
(A/F) sensor connector terminals.
Terminals
(E47) No. 2 — No. 1:
Step
Is the voltage more than 10
V?
Is the resistance less than
10 Ω?
EN(H6)-97
Check Yes
Go to step 9.
Repair harness
and connector.
NOTE:
In this case,
repair the follow-
ing:
¼ Open or ground
short circuit in
harness between
front oxygen (A/F)
sensor and ECM
connector
¼ Poor contact in
front oxygen (A/F)
sensor connector
¼ Poor contact in
ECM connector
Engine (DIAGNOSTICS)
No
Repair power sup-
ply line.
NOTE:
In this case,
repair the follow-
ing:
¼ Open circuit in
harness between
main relay and
front oxygen (A/F)
sensor connector
¼ Poor contact in
front oxygen (A/F)
sensor connector
¼ Poor contact in
main relay con-
nector
Replace front oxy-
gen (A/F) sensor.
<Ref. to FU(H6)-
43, Front Oxygen
(A/F) Sensor.>