Subaru 2009 IMPREZA Service Manual page 973

FUEL INJECTION (FUEL SYSTEMS)
16.Front Oxygen (A/F) Sensor
A: REMOVAL
1) Set the vehicle on a lift.
2) Disconnect the ground cable from battery.
3) Remove the air intake duct and air cleaner case.
<Ref. to IN(H4DOTC)-11, REMOVAL, Air Intake
Duct.> <Ref. to IN(H4DOTC)-9, REMOVAL, Air
Cleaner Case.>
4) Disconnect the connector from front oxygen (A/
F) sensor.
5) Lift up the vehicle.
6) Remove the under cover.
7) Apply spray-type lubricant to the threaded por-
tion of front oxygen (A/F) sensor, and leave it for
one minute or more.
8) Remove the front oxygen (A/F) sensor.
CAUTION:
When removing the front oxygen (A/F) sensor,
wait until exhaust pipe cools, otherwise it will
damage the exhaust pipe.
Front Oxygen (A/F) Sensor
B: INSTALLATION
CAUTION:
If lubricant is spilt onto the exhaust pipe, wipe it
off completely with cloth to avoid emission of
smoke or causing a fire.
1) Before installing front oxygen (A/F) sensor, ap-
ply anti-seize compound only to the threaded por-
tion of front oxygen (A/F) sensor to make the next
removal easier.
CAUTION:
Never apply anti-seize compound to the protec-
tor of front oxygen (A/F) sensor.
Anti-seize compound:
IN-00203
2) Install the front oxygen (A/F) sensor.
Tightening torque:
3) Install the under cover.
FU-04078 4) Lower the vehicle.
5) Connect the connector of front oxygen (A/F)
sensor.
6) Install the air intake duct and air cleaner case.
<Ref. to IN(H4DOTC)-9, INSTALLATION, Air
Cleaner Case.> <Ref. to IN(H4DOTC)-11, IN-
STALLATION, Air Intake Duct.>
FU-03994
FU(H4DOTC)-48
NEVER-SEEZ NSN, JET LUBE SS-30 or
equivalent
30 N·m (3.1 kgf-m, 22.1 ft-lb)
FU-03994
FU-04078