Kia 2004.5 Spectra Service Technical Training page 139

2004.5 Spectra Technology
Typical H02S
Wide Range H02S
Driveability
Let's compare the operation of the two HO2S. The
key element of the down stream Zirconia oxygen
sensor is a ceramic body that is coated on both sides,
creating a Nernst Cell. This coating takes over the
function of electrodes, where one electrode layer
comes into contact with external air and the other with
the exhaust. A voltage difference is established
between the electrodes by differing concentrations of
oxygen in the external air and the exhaust. Low mV is
high in oxygen (lean) while closer to 1V is low in
oxygen (rich). The PCM evaluates this 0-1V signal to
determine the oxygen content of the exhaust.
The Wide Range sensor also produces a voltage
difference with the help of two electrodes, which are
in contact with external air and the exhaust gases.
This sensor differs in that it requires an ECM to function
and keep the voltage of the electrodes constant.
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