OKey Dokey. The ecm supplies a voltage to the O2 but it's veryyyy current limited. using a DVM it measured .395v, and then tried reading the voltage with a second DVM while the first one was still attached, and the reading was just a few millivolts. Diacom, reports the O2 voltage (key on engine off) in this application as .5. This is all the "valid" data I have about that Grumpy