2004 Grand Chrerokee P0135 and P0155..?

I feel its sort of odd to have these codes at once. so I looked at the infamous fuse 16. Not blown. Unplugged bank 1 sensor and tested incoming voltage at all 4 terminals with key on. No voltage..Went backl and Checked voltage at fuse terminal. no voltage So, leads me to question. Is there always voltage there? or could the PCM not be sending juice there if the sensors are already warm enough?. Is there also a relay That could be bad?