When Should A Lambda Sensor Be Replaced?

When should a lambda sensor be replacedThe lambda sensor, or oxygen sensor, is a component that measures the oxygen level in the exhaust gases coming out of the car’s engine. It helps the engine to fine-tune the air and fuel mix going into the engine, ensuring the engine can run smoothly. It also helps to keep fuel consumption down. The part does not need regular maintenance, but over time can deteriorate.

Symptoms For A Faulty Lambda Sensor

Eventually the lambda sensor will inevitably fail. As the sensor is fitted to your exhaust it is exposed to all the exhaust emissions flowing past. In the process, it can get clogged up or get affected by the constant temperature changes in the exhaust. Symptoms are often as follows:

  1. Exhaust emissions failure
    Often a faulty lambda sensor will be found during an exhaust emissions test. If the emissions are too high, it is often due to too much fuel being burned in the engine. As the sensor helps regulate how much fuel goes into the engine, it follows that a faulty lambda sensor is often the cause of emissions that are too high.

  2. Poor fuel consumption
    An increase in fuel consumption of your car can often point to a faulty lambda sensor. After all, if the sensor doesn’t work properly it may allow too much fuel to flow to engine.

  3. Check Engine Light
    A failed lambda sensor is actually one of the most common reasons for the ‘Check Engine‘ light coming on. It’s worth getting your car checked with a plug-in diagnostic tool.


How To Find Out If Your Lambda Sensor Needs Replacing

Sometimes it may not be immediately obvious if your lambda sensor really needs replacing. There is a number steps to take, though, that can help find out if it needs replacing.

The quickest way to find out if there may be something wrong with the sensor is by getting a computer read-out of the car’s computer and fault codes. If there is a fault then a fault code will be listed. A mechanic will be able to check this during a plug-in diagnostic inspection. Often it doesn’t end with plugging in a diagnostic scanner, as some cars have more than one lambda sensor. Only a physical inspection will then be able to show which one is actually needed.

Apart from a check, a faulty lambda sensor is often flagged up during an MOT test. The current MOT test includes an emissions check, any problems with the emissions will be reported on, and an advisory will be given on what to replace.

Remember, it is advisable to periodically check the sensor, to ensure it functions well. It could save your car from failing an MOT, and bring your car’s fuel consumption down.

About Kurt Schleier

Resident classic car enthusiast and blogger at Clickmechanic.