I have a 2001 Chrysler Town and Country Limited (3.8 L) with 122K
miles on it. A few months ago the check engine light came on and
there where three codes 1684 (battery disconnect) , 1491 (radiator fan
relay) and 0135 (O2 sensor). Two weeks ago I replaced both O2
sensors. After driving the car for a few miles the check engine light
went off. A couple of days ago it came back on and the same three
codes are back.

Are the O2 sensor I put in bad or is something else wrong?

Thanks in advance,

Derek