white wire is O2 Voltage (0-1V+), the 2 blacks need seperate grounds to most accurate, green need to be a swtiched 12V+ for the O2 heater
That's only 1/4 of the way right. As my diagram shows you are correct in that the white is the reference output but the green is actually the ground for the entire sensor (ties into the TPS, ECT, IAT gnd.), while one of the blacks is a IGN 12V+ input for the oxygen sensor heater and the other is the ground trigger for the heater which is activated by the ECU.
thats a great diagram, but i need it for the 4-wire oxygen sensor. i looked at my friends car yesterday on a lift and i saw that the top right is white the top left is green and the bottom two are black. which one is supposed to have the +12v? the bottom left or the bottom right? how can you check that the wires are properly connected? what will not having an oxygen sensor do besides making your car run richer?
As Qfactor said, polarity for the oxygen sensor heater really doesn't matter but if you want to wire it up the way the factory does, and the way I always do. The black wire on the left (of your diagram) is the IGN 12V+ and the one to the right is the ground trigger which traces back to the ECU (A6).
Yea, you're diagram is fine and the one on the LEFT is a IGN 12V+ but the one on the RIGHT is not just any old ground, it has to trace back to pin A6 at the ECU (this way the ECU can regulate the heater). If you were to just ground the wire on the right to any old point your oxygen sensor heater would always be on (do NOT do this). Like we've said there really isn't any polarity so even if they are backwards it should still work but just to keep things organized I always do how I listed above. Good Luck
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