Contour Enthusiasts Group Archives Forums Modifications Duratec Maintenance Many codes found, now where to start ?

Well I have had the MIL on for a while now and decided to get the codes scanned. Here's what was found:

-HO2S signal circuit malfunction: P0156.

-HO2S heater circuit malfunction: P0135, P0141, P0155 and P0161.

I find it very hard to believe all these HO2S's have gone for a crap all at once. Is it possible a fuse is blown somewhere to cause this or am I looking at multiple O2 sensor replacement ? Car seems to be running fine without any significant mileage change ...