code po 431-warm up catallyst efficiency below treshold

[vivallddi]

Hi everybody, need a bit of a help there,week ago i had on my ride engine light went and i thought another coilpack gone,so i call the aa man to see which one this time,but it was code po 431,did enyone had similar problem and whats the soliution?reseted after foults and it didnt came back yet
thanks