Thats a code for:

"Basically this means that the oxygen sensor downstream of the catalytic converter on bank 1 is detecting that the converter is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system."

I found a cheap fix that works on a 3g Eclipse, and may work for you at this site.

Also check for leaks in the exhaust system ahead of the final ohtwo sensor on bank 1. May be a bad ohtwo sensor too...

Not responsible for advice not taken...