So, cars with oxygen sensors (O2) have a minimum, of one sensor, in front of the catalytic converter.

In addition, one in each, of the car’s exhaust manifolds.

But, the actual number of oxygen sensors (O2) in a car; really depends on the year, make, model and engine size.

However, most of the later model vehicles, on the road today, have four oxygen sensors.

So, when a gasoline-powered engine burns gasoline, there has to be oxygen present.

The amount oxygen in an engine, is the result of a number of factors including:

  • Air temperature.
  • Altitude.
  • Engine temperature.
  • Load on the engine.
  • Barometric pressure.

The ideal ratio for oxygen and gasoline is 14.7:1; which slightly varies, depending on different types of gas. In the instance that there is less oxygen present, some fuel will remain, after combustion. Consequently, this is referred to as, a rich mixture.

Both, rich and lean mixtures, are bad for your car, as well as for the environment. A rich mixture results in, a fuel that is not burned. However, a lean mixture, generates nitrogen-oxide pollutants. As a result, leading to, decreased vehicle performance and engine damage.

Firstly, an (O2) sensor, creates a voltage, due to a chemical reaction. As a result, of an off-balanced, gasoline to oxygen ratio. So, most car engines can determine, how much fuel to expel into the engine. As a result, of the voltage of the (O2) sensor.

Consequently, if your oxygen sensor fails to function properly; your engine management computer, cannot determine the air to fuel ratio. As a result, the engine is forced, to guess how much gasoline to use. Therefore, resulting in a polluted engine and a, poorly functioning vehicle.

Symptoms of a Bad O2 Sensor

So, when an (02) sensor fails, there are a variety of diagnostic trouble codes (DTCs) that can pop up. Most of the time, a faulty (O2) sensor will result in, a check engine light accompanied with a fault code; that you can read with an OBD-2 scanner. Based on this fault code, it will point to how it failed and then; you can move forward with the diagnosis.


Choose Your Oxygen Sensors (O2) Help Topic Below

(O2) Oxygen Sensor – Function – Failure Symptoms – Testing

Oxygen Sensor (O2) – What Else Could Cause Rich Or Lean Codes

(O2) Oxygen Sensors – Function, Failure Symptoms, Testing Procedures


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