O2 Sensor Voltages.

[Trumanbuckley1]

Hello all, I purchased an ebay plug and play wiring harness and am having trouble getting my 02 sensors hooked up. I ordered sensors for an 01 silverado 1500 4.8l which is the engine I have and the PCM is a P01. The wiring harness didn't have connectors on it and I am having trouble deciding which wire actually does what since the wires aren't OEM. When I run my volt meter to ground and poke each wire from the harness with key on I have one wire with 12v, one with 4.5v, and one with 5.0v. At the time of writing this I don't remember exactly what the other wire has but I will check tomorrow. I know the 12v wire goes to the heater but which wire goes where for the other three? any help would be great, thanks

[blindsquirrel]

Sensors (and wiring diagrams/pinouts) need to match the year/make/model of the tune file in the PCM, not the engine. All O2 sensors screw into the same kind of M18x1.5 threaded hole.