P0141 Ford - expedition

Question

I am getting a low voltage fault code for all four of my o2 sensors and I have checked the fuse,(providing the info was correct) the PO0155 comes up immediaely then the others follow after a short time po0141,0161 and po (forgot) 2 questions...1) can you tell me where the fuse for this circuit is located and 2)can you tell me what else to check...there hasn't been any major work done, i thought maybe a ground came loose but it all appears intact

Any help would be appreciated

Thank You,
Stan Nelson
[email protected]
559-284-0160