input/recieve wires are giving off voltage

[slow6]

everything (egr, a/c, post-cat o2) on the input voltage wire reads .001 on my multimeter.
How come everyone of the wires that should be recieveing voltage, is giveing .001 voltage??
My multimeter is set at the 20 v DC setting.

Whenever I hook up a 0-5v to these input wires it wont work.
probably because these input wires are giving off voltage instead of recieveing voltage.

[S2H]

please wxplain what you are trying to do and how you have it wired...
not all things can use a 0~5volt input...
like the rear o2..only uses a 0~1.5 volt input...our stock o2's are a 0~1.1v roughly...
explain in as much detail as possible