POST UPDATED IN January, 2021
What is the O2 Sensor?
The Oxygen Sensors, also known as Lambda sensors, are included in the sensitive and important components of the car, and are located at the exhaust outlet. It is usually made of a ceramic zirconium tube, which is covered on both sides by a platinum layer.
The O2 (Oxygen Sensor) measures the concentration of oxygen in the exhaust smoke. Oxygen Sensors have 3 variants, which goes on the number of interconnection cables that goes to and from the ECM (Engine control module). There are Lambda sensors that have two, three and four terminals, but it should be mentioned that regardless of the number of terminals the function does not change, it is the same function in all.
How does the O2 Sensor work?
The O2 sensor (Oxygen Sensor) converts the oxygen amount of the gases produced by the car into an electrical signal, and then the Engine Control Unit (ECU) reads that signal to compare and see if the air-fuel mixture is the ideal or adequate. If not, take the necessary measures to correct it. If there is a lot of oxygen in the exhaust gases, the injection time increases and, in this way, the optimum engine power is obtained, in order to obtain a stoichiometric ratio of 14.1 parts of air, for one part of fuel.
For example, if 14.7 grams of air enter the ECU (Engine Control Unit) injects 1.0 grams of fuel into the combustion chambers, so that the air-fuel ratio is the most efficient.
If, on the other hand, the O2 Oxygen Sensor detects that the oxygen level is very low, it adjusts the amount of fuel it delivers, because the mixture is very rich, which means that there is a lot of gasoline and thus the fuel efficiency is reduced and the atmosphere becomes contaminated by emitting unburned gasoline residues.