Oxygen Sensor?

[fj40supraman]

I've been reading that all 4-wire oxygen (o2) sensors are the same, and that only the connector is what changes. Is there any truth to this. I hate to get the wrong one and find out they don't have equivalent resistance values. Does anyone know what the four wires are for too. One is prolly for the heater, another for (+) terminal, and one for (-) terminal, and what else? If I know I can Ebay one for about $25 as opposed to $75 AutoZone wants. Thanks for your help, and so will the Avalon as gas mileage currently blows.

[ShawnM]

what year is the car? what engine? If its 96 or newer where is the sensor located (before or after the converter)

[alltrac165]

They are not all the same. Values change in the signal between types. On a 4 wire, two wires are for the heater, one is reference, one is signal. Which is which change between manufacturers and types.