So how do they measure O2 then?

 

I dont think our O2's have the EGT sensor built in.

 

Agreed.

 

How deep into it do you want to get? google is your friend

Briefly, there are 2 main types of O2s: the older (non-linear) type (used for all the O2s on the 1999 S-Type and downstreams on the redesigned 2002/3-on S-Type) and the linear (aka AFR aka wideband, sometimes confusingly called "universal") type (used as upstreams on the redesigned S-Type).

Both essentially react to the amount of O2 by producing a small voltage and even smaller current.

BTW, that they measure O2 is why misfires commonly result in extra fuel being added. It's to compensate for the extra O2. (If they measured temperature I can't see why a misfire would cause that.)

 

I looked through the data sheets for the bocsh and denso sensors, and there nothing about temps.

 

i think 02 sensors have to be at a certain temperature to get a correct reading of o2. The sensors have a heating element in them so they get to optimal temperature quicker so a check engine light isn't triggered.

 

aka HO2S - heated O2 sensor

 

Left the heating circuit out because I thought that was a gimme lol