Four wire O2 sensor

[Ed Mellinger]

Land Shark wrote:
> 
>         EGO Sensors in a nutshell..
> 
[snip]

... I'm still tryin' to figure out why ANYBODY would use the car body
for the common side of a fairly low-level signal that you need to read a
couple dozen times a second???  I mean, if you're going to go to three
wires, why not give two of them to the sensor and make the HEATER return
thru the body?  

Anyone know the rationale for this?

Ed