<font face="Verdana, Arial" size="2">You are also supposed to know what can be done with the sensor, and what can not. A basic EGO sensor cannot measure true oxygen content in automotive environment, nor does it tell you the exact lambda value. If you're looking for an accurate exhaust gas analyzer, you won't find it here. There might be better ways to use a zirconium dioxide sensor to measure oxygen content, but we don't use them here.

The LED colors give only an approximate information of what can be happening with the A/F-mixture. You cannot connect any unambiguous mixture ratio values to different sensor voltage levels.

This is usually enough for the purposes I, and many others use these sensors. An EGO sensor can quickly detect grossly incorrect situations, like a way too lean or too rich mixture under hard acceleration, transient mixture spikes that can't be captured otherwise, and other weird situations affecting driveability.</font>