What are the symptoms of a faulty lambda probe?

Lambda probe - small play is mandatory for all vehicles, but is still relatively unknown. In this article, we will explain all about the symptoms indicating that it is time to change it, as well as about its maintenance and repair in general.

🚗 What is a lambda probe for?

The role of the lambda sensor (or oxygen sensor) is to reduce your vehicle's fuel consumption as well as reduce particulate matter and pollutant emissions. To do this, the lambda probe will send information through the engine control unit, which will allow you to adjust the air-fuel mixture and, therefore, optimize the performance of your engine. The lambda probe is located in the exhaust system of your vehicle, between the exhaust manifold and the catalytic converter. On the most recent cars, you will find a second lambda probe after the catalytic converter.

🔧 How do I know if I need to change the lambda probe?

If your lambda probe is faulty but you don't take care of it, it can have serious consequences for your engine as the air / fuel mixture will no longer be optimal. Your engine will consume much more fuel than usual, you will feel engine jerking and your pollutant emissions will increase.

Typically, you will have to change your lambda probe every 160 km. However, some symptoms indicate that it is time to change the lambda probe:

• The engine control indicator will light up when you are driving.
• Do you feel the jerks of the engine
• Your engine lacks power when accelerating
• Exhaust gases come out due to an incorrectly metered fuel mixture.

If the lambda probe is faulty, the message sent to the computer will be incorrect and the air-fuel mixture will no longer be optimal. The computer will then go into default mode, which will cause the symptoms described above to appear. To find out if your lambda probe is defective, you have no choice but to contact a professional who will carry out the necessary tests using the appropriate diagnostic tools.

Already at the first visual inspection of the probe, the cause of the probe failure can be determined. Here are the most common cases:

• If used the probe is distorted in that it was poorly mounted when it was installed
• Cables melted : the sensor cables have been in too close contact with your vehicle's exhaust gases
• Deposit in the amount of calamine the holes on the sensor are clogged: several factors can be the cause, the most common of which are engine wear and leaks in the exhaust system
• Contacts are rusty
• Cables stripped : The probe was worn out and the beam did not sag.
• White and gray deposits form: there are two main reasons. Either the engine oil has burned out, or there are additives in the fuel.

?? How to maintain a lambda probe?

To prevent your lambda probe from failing too quickly, remember to regularly service the spark plugs, air filter and, in general, the entire engine block. If you notice any signs of weakness and suspect that the lambda probe is faulty, you can check it with a multimeter.

⚙️ How to change the lambda probe?

If you notice that your lambda probe is faulty, there are 2 solutions: either it is clogged or easy cleaning enough or you will have to completely change the part. In this guide, we explain how to replace a lambda probe yourself if you have the necessary mechanical skills.

Required material:

• toolbox
• new lambda probe
• penetrating oil
• grease

Step 1. Identify the lambda probe to be modified.

Some vehicles are equipped with two lambda probes, so check which lambda probe needs to be replaced before starting the replacement.

Step 2: disconnect the battery

First, disconnect the battery and place the vehicle on a jack stand to gain access to the lambda sensor located on the exhaust line.

Step 3: Remove the lambda probe

To remove a defective lambda probe, first disconnect the probe connector, then unscrew the screws holding the probe. To make it easier for you, you can apply penetrating oil to the screws. Now we remove the lambda probe.

Step 4: Install a new lambda probe

Always check that the model you purchased is identical to the old one before installing a new sensor. Use grease to lubricate the threads of the probe and then place the probe in its designated location. Screw the probe back onto the exhaust line, then reconnect the probe connector.

Step 5: reconnect the battery

Remember to reconnect the battery before closing the hood. Your lambda probe has been replaced! Start the engine and make sure everything is working properly before you get back on the road.

?? How much does it cost to change a lambda probe?

If you just need cleaning, a professional will take between 60 and 75 euros. The cleaning of the lambda probe should be entrusted to a professional, because the products used are dangerous and harmful.

If you have no choice but to replace the lambda probe, you will need to calculate between € 100 and € 200 per part, to which you will have to add labor costs.

To find out the exact price of replacing a lambda probe for your car, you can consult our garage comparator and get a list of the best deals from garages near you in a few minutes. After that, you can make your choice based on the lowest price or the opinions of other motorists.