I would guess that oxygen sensor is emission related...
however, after digging through the manual(s), which detailed
little on what's covered, sending me to the HondaCar site,
(which may be one of the least user friendly sites I've ever
been "on"/caught up in log-in hell), I finally was able to
get the list of what emission stuff is "covered" and for how
long:

On our 2003 pos CR-V, registered in NC, all the Fed emission
parts are only covered for 3 yrs/36,000 miles, except for
the cats which are covered for 80K miles. What a product
warranty...

I leave the keys in it regularly, hoping someone will steal this
3rd world piece of crap. Can hardly wait for the Honda Stlr
to rip me for the repairs...