Replacing the lambda sensor: Where to find the lambda sensor ?

Many motorists learn about the lambda sensor when it breaks down... Located on the exhaust line, the lambda sensor plays an essential role in the smooth running of a petrol or diesel engine. Let's find out more about the role of this sensor, which unfortunately deteriorates over the years and miles. We also look at the symptoms that should alert you to the need to replace a lambda sensor... Or clean it?

What is a lambda sensor?

Before going any further, I think it's a good idea to understand the role of the lambda sensor. As the name suggests, it's a small sensor found on the exhaust line, just before the catalytic converter. Wondering what the lambda sensor does? Its purpose is to measure the oxygen content at the engine outlet. From there, the lambda sensor adjusts the ratio between air and fuel. Generally speaking, there should be one volume of petrol to fourteen of air - the ideal ratio! Otherwise, the engine runs either too rich or too lean. Either way, it's not good for your car or the environment. On some car models, a second lambda sensor is installed after the catalytic converter, to check that the information transmitted by the first has been taken into account and carried out.

The lambda sensor is therefore particularly important, as it conditions the operation of the fuel injection system. A faulty lambda sensor can send the wrong information to the ECU, affecting your car's operation.

What causes lambda sensor wear?

Over time, the lambda sensor can become clogged. As a result, the information gathered may no longer be sufficiently accurate... Or even incorrect. Fortunately, there are a number of signals that can warn you if the sensor is malfunctioning. If the lambda sensor wears out, this can be due to a number of factors: clogging of the sensor, oil contaminating the sensor, damage to the sensor or failure to transmit signals to the ECU. When this happens, it's a good idea to clean the lambda sensor and, if necessary, replace it. But before that, there's diagnosis... How can I tell if this sensor has a problem?

How can I tell if the lambda sensor is worn?

• The engine light comes on;
• Fuel consumption increases;
• Pollution can increase drastically, leading to an adjustment at the roadworthiness test;
• Idling becomes unstable;
• Performance decreases.

Of course, these phenomena may or may not occur in combination. It all depends on the cause of the lambda sensor failure, but also on the mechanical architecture of your car. If your car has two lambda sensors, for example, the symptoms are more subtle. The key is to know how to test a lambda sensor. In many cases, it's during the technical inspection that pollution in excess of standards is detected...

How do you test a lambda sensor? Can it be cleaned?

To test a lambda sensor, you need to go through the test case. All garages and the vast majority of dealerships are able to perform this operation. It involves connecting an electronic suitcase to your car's OBD socket. This makes it possible to read the ECU's information and thus analyze any error that may have been reported by the lambda sensor. While some mobile applications can perform this operation, the risk of error is sometimes considerable. So it's best to leave it to a professional.

Lambda probe cleaning is a really good idea... But for do-it-yourselfers first! Accessing the lambda sensor can be more or less complicated, depending on the car model. Especially if the engine bay is quite full! But generally speaking, it does require the removal of a few components. So having the right tools and knowledge is a prerequisite. But it's important to remember that cleaning is a troubleshooting solution... The sensor will certainly work again, but it will still have a few thousand kilometers behind it. Cleaning can save a few thousand kilometers, but don't expect to start out again for 150,000 kilometers, which is generally the lifetime of a lambda sensor. So it's not worth asking a garage to clean the sensor, since the labor involved in dismantling it is far greater than the value of the sensor itself. But what is the price of a lambda sensor?

How much does it cost to replace a lambda sensor?

The lambda sensor is a relatively simple, standardized part. Depending on the brand, it generally costs between €15 and €50. However, to this price must be added the cost of labor. Depending on the car, the disassembly and reassembly stages can be more or less tedious. As a result, the cost of the operation generally fluctuates between €70 and €400. Note that for certain models with two sensors, accessibility is sometimes less...

Of course, since savings are always worthwhile, it may be tempting to put off replacing the lambda sensor. But, like the catalytic converter, it's not advisable to drive with a faulty part. In addition to higher fuel consumption and reduced performance, you run the risk of damaging many of your car's components. Ultimately, the risk of breakdown is greatly increased.

Image source:
Karolina Osinska / Author: ckstockphoto / License ID: BU98KHVSFD - elements.envato.com