Subaru Legacy 2003 Service Manual page 411

ENGINE (DIAGNOSTICS)
( 1 )
(1) Front oxygen (A/F) sensor
(2) Rear oxygen sensor
( 3 )
ELECTRICAL COMPONENTS LOCATION
( 3 )
( 2 )
(3) Front catalytic converter
(4) Rear catalytic converter
( 1 )
EN-00856
EN-00858
EN(H4SO)-14
( 4 )
( 4 )
EN-00685
( 2 )
EN-00857
EN-00859