1 – The role of the Oxygen sensor

The o2 sensor (oxygen sensor) is located within the exhaust system, upstream of the catalytic converter.

Its role is to inform the ECU of the oxygen content of the burned gases that result from combustion. The o2 sensor helps to ensure that the amount of fuel injected into the cylinders for the air-fuel ratio is at an ideal level.

The o2 sensor ensures low fuel consumption as well as reduced pollutants emitted from the engine. It is therefore an important component to help pass vehicle inspection.

The latest standards of emissions require the presence of a second lambda probe, located after the catalytic converter in order to determine its effectiveness.

2 – Why replace a Oxygen Sensor?

A faulty oxygen sensor has the direct consequence of disrupting the engine air-fuel balance. This leads to an increase in pollutants emitted by the engine, as well as causing the engine to stutter and consequently fuel consumption to increase.

3 – When does the Oxygen Sensor need to be replaced ?

The lifespan of a Oxygen Sensor is 160,000 km on average, as long as it is not shortened by engine malfunction.

Unburned oil due to engine misfire may contaminate the probe irreversibly. Exhaust leaks also damage the Oxygen Sensor, leading to an intake of air which can cause a dangerous increase in temperature.

To ensure the maximum lifespan of the Oxygen Sensor, it is necessary to perform strict engine maintenance (spark plugs, air filter, et al.).

Several signs that your Oxygen Sensor needs to be replaced:

–       If the engine check light turns on while the vehicle is being driven.
–       The engine stutters and suffers from a lack of acceleration power.

Diagnosis of the Oxygen Sensor :

A defective oxygen sensor is detected only by a special diagnostic tool used by trained professionals. It is therefore necessary to have this service administered at a professional garage.

Condition of the Oxygen Sensor:

Dark brown saturation

Possible cause:

Unbalanced air/fuel mixture

Condition of the Oxygen Sensor:

Grainy green saturation

Possible cause:

Anti-freeze leak that has entered the combustion chamber

Condition of the Oxygen Sensor:

Reddish or white saturation

Possible cause:

Additives in the fuel

Condition of the Oxygen Sensor:

Blackish with oily saturation

Possible cause:

Too high oil consumption

How to clean the O2 Sensor

There are two ways to clean or replace the oxygen sensor, falling within a broad price range.

  • The most expensive option is the outright replacement of the part. This is what most mechanics will propose. The price of the component varies according to the brand and engine type.
  • The least expensive option, with no need for disassembly and entailing the shortest service time, and which is an alternative to part replacement, is hydrogen treatment via the Carbon Cleaning station. This service works as a preventative treatment, recommended every 15,000 miles, but can also resolve existing problems in the engine.