the three wire has two wires for heater loop.  this helps the sensor come
up to temp quicker thus allowing the computer to use its data.  this is to
reduce emissions.  i don't know how the computer knows that the sensor is
ready provide data.  i would guess either a timer or input from the
coolant temp II sensor or perhaps both.

jonathan

On Sat, 21 Jan 2006, John Rodgers wrote:

> Can the one wire version be used on a 2.1L engine?
> If not, why not??
> If so, what is lost without the other two wires.
>
> My newly installed  3-wire O2 sensor apparently has an internal fault.
>
> I have a brand-new-in-the-box 1-wire O2 sensor.
>
> Thanks,
>
> John Rodgers
> 88 GL Driver
>
>
>