The Complete Guide To Lambda Sensors

A lambda sensor is used to measure the oxygen in your exhaust fumes and ensure the engine is running smoothly with the correct air-to-fuel ratio. However, they can become problematic and within this article, we explain everything that you need to know.

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What Is Lambda Sensor
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What Is Lambda Sensor?

Often referred to as an oxygen sensor, the lambda sensor is a small probe that’s designed to measure the amount of oxygen in the exhaust. If the sensor reads unexpected oxygen values, it will send signals to the engine management system to automatically adjust the air-to-fuel mixture. The perfect mixture is called “Lambda” and this is where the name of the sensor comes from but due to the nature of its functionality, many call it an oxygen sensor.

Where Is The Lambda Sensor Located?

The majority of lambda sensors are located in the exhaust system between the manifold and catalytic converter. However, due to stricter emission standards, most modern cars are now equipped with two lambda sensors. The additional sensor is located behind the catalytic converter, which means modern cars now read the exhaust gases leaving the engine and the catalytic converter.

How To Remove It?

If you need to remove a lambda sensor to clean or replace it, you can do so fairly easily. We would highly recommend getting hold of a mechanics socket set because the size of the sensor varies between different manufacturers. Many are a common spark plug thread (M18 x 1.5) but you may want to do some research on the size beforehand.

Before you attempt to pull the lambda sensor away from the exhaust, ensure you disconnect the electrical connection. When it comes to installing the new sensor, ensure you reconnect the connection and use a torque wrench to tighten the sensor back to the exhaust at the correct torque.

How To Tell If It’s Faulty?

Apart from the usual engine warning light on the dashboard, a faulty lambda sensor may provide other symptoms. These can include unusually high fuel consumption, reduced performance, poor engine starts and high exhaust emissions. If the warning light appears, you can confirm that it’s the lambda sensor at fault by using a car diagnostic tool. It’s important to note that if you know your lambda sensor is faulty, you shouldn’t ignore it. Failing to replace it can eventually lead to clogging of the catalytic converter, which can be very expensive to replace.

When Should You Replace It?

The lifetime of a lambda sensor is relatively long (between 80,000 to 100,000 miles) but if you notice any of the above symptoms, you should get it replaced. However, if the main issue is due to an engine malfunction, the replacement lambda sensor may not solve the issues that you are facing.

How To Clean A Lambda Sensor?

If you are on a very tight budget and don’t want to have to pay for a new sensor, you may be able to clean it. In terms of cleaning it, there is a number of methods to clean a lambda sensor that includes:

  • Spraying it with brake cleaner or carb cleaner
  • Using a blow torch to burn away any dirt
  • Leaving the sensors in a bucket of petrol overnight
  • Brushing any dirt off with a wire brush
  • Take the car for a long and spirited drive (an Italian tune-up)

Although it’s possible to clean a lambda sensor, a replacement is the best solution that doesn’t involve getting your hands dirty. In terms of the replacements available, if you are willing to pay the premium price, you can get an OEM part from the dealership. However, at a fraction of the price, we would recommend a lambda sensor by the NGK or Bosch brand.

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