I searched in Rambam [hilchot Korban Pessach][1] and if I don't miss something, no Kappara (atonement) is mentioned. 

Thanks to the answer of mevaqesh you can see [here][02] who is astonished by the Tosfot Yom Tov comparison between Pessach and taanit about  Kappara. The astonishing of Tif'eret Israel is perhaps also due to the lack of sources. 



[1]:  http://www.mechon-mamre.org/i/9100.htm  
[02]: http://beta.hebrewbooks.org/pdfpager.aspx?req=40744&st=&pgnum=392&hilite=