How an o2 sensor works ââ?¬Å?The oxygen sensor is positioned in the exhaust pipe and can detect rich and lean mixtures. The mechanism in most sensors involves a chemical reaction that generates a voltage (see the patents below for details). The engine's computer looks at the voltage to determine if the mixture is rich or lean, and adjusts the amount of fuel entering the engine accordingly. ââ?¬Å?
By not allowing the exhaust gases to pass over the nozzle of the o2 sensor it will not be able to send a signal voltage to the computer and the check engine light should remain on even with the mil eliminators.