Diesel Emissions Scandal: Global Mercedes NOx Sensor Recall

Recalls in the automotive industry are nothing new, but the recent Mercedes NOx sensor recall is one of the largest in history. The recall affects 670,000 vehicles worldwide and is related to the Diesel Emissions Scandal that has plagued the European automotive industry for years.

A global recall by Mercedes-Benz has been ordered after an engine management software issue was discovered on some models in 2018. This issue caused the vehicles to emit more nitrogen oxide (NOx) than allowed by law.

The issue is related to a faulty NOx sensor installed in these vehicles. The faulty sensors can cause the engine to produce higher levels of NOx than allowed by law, resulting in higher emissions.

The recall affects vehicles from the 2017-2019 model years and includes models such as Vito 1.6-liter diesel (OM 622), C-Class 1.6-liter diesel (OM 626), ML/GLE/GL/GLS 3.0-liter diesel (OM 642), V-Class 2.2-liter diesel (OM 651) and GLC 2.2-liter diesel (OM 651).

If you have these vehicles, you should contact your local Mercedes-Benz dealer to arrange for the NOx sensor to be replaced. Read below to learn more about the recall and how it will affect current users.

What Are NOx Sensors?

NOx sensors are an essential part of a vehicle’s emissions control system. They measure the amount of nitrogen oxide (NOx) in a vehicle’s exhaust. NOx is a pollutant that can cause smog and other air quality issues. The sensor measures the amount of NOx in the exhaust and sends this information to the engine management system, which adjusts the fuel-air mixture to reduce emissions.

Most modern vehicles include an onboard computer called the Engine Control Module (ECM). It measures the vehicle’s exhaust gas flow and sends the data to the engine management system as an emissions test. The engine management system then determines how much air and gasoline to inject into each cylinder. That's why it's important to have a functioning NOx sensor for the engine management system to work correctly.

Mercedes NOx Sensor Recall

As previously stated, Mercedes-Benz will vehiclery out a necessary recall for Mercedes-Benz vehicles equipped with diesel engines per an administrative order issued by the German Federal Motor Transport Authority (KBA). In Europe, there are about 670,000 automobiles included in the recall. About 280,000 of them are in Germany.

Affected diesel vehicles will be fixed by Mercedes-Benz dealership technicians using a software upgrade to the vehicle's electronic control system. This call will not affect fuel economy and will update the emissions control systems.

The recall was expected to take several months to complete, and Mercedes-Benz said it would cover the cost of the update. 

What Will The Update Include

The recall will affect your vehicle in the following ways

• First, the emission modification may change the frequency you need to refill your DEF tank. For example, if your previous refill rate coincided with your oil change interval, that might change with this modification. This means that you may need to refill your DEF tank more often.
• The update will also change how your vehicle runs, adjusting the fuel-air mixture to reduce emissions. This could initially lead to a slight decrease in performance, but it should improve immediately.
• Your vehicle’s OBD system will be modified based on the agreement with EPA and CARB. However, Mercedes-Benz said they do not anticipate the modification will affect the OBD system, at least not in a manner that would make identification and repair of any components difficult, compromise warranty coverage, or compromise the vehicle’s ability to comply with the vehicle's inspection and maintenance (Smog Check) test
• Finally, the recall will also include an update to the engine control module (ECM) software that will improve its ability to detect and respond to NOx emissions. This will enable the ECM to regulate the fuel-air mixture better and reduce NOx emissions.

Is My Vehicle Affected?

There were seven affected models spanning the 2009-2016 vehicle years. All vehicles had either standard or optional turbo-diesel motors. Almost all were marketed as Bluettac. Some of the affected models are:

• Vito 1.6-liter diesel (OM 622)
• C-Class 1.6-liter diesel (OM 626)
• ML/GLE/GL/GLS 3.0-liter diesel (OM 642)
• V-Class 2.2-liter diesel (OM 651)
• GLC 2.2-liter diesel (OM 651)

If you want to know more about the recall's specifics and how it will affect your vehicle, click here.

Frequently Asked Questions:

What happens if the NOx sensor goes bad?

Suppose the O2 sensor fails and cannot provide accurate information to the ECU (electronic control unit) about the oxygen content in the exhaust gas. In that case, the ECU may not be able to determine the correct proportion of fuel and oxidizer for combustion.

Also, the ECU may not be able to detect the presence of NOx in the exhaust gas, which can lead to higher emissions. You must take the vehicle to the manufacturer's dealership for repair if this happens.

What is a rich fuel mixture?

A rich fuel mixture is one in which there is an excess of fuel compared to the amount of air present. This can occur when the air-fuel ratio is higher than 14.7 parts air to 1 part fuel or when the engine is running too hot and needs more fuel to cool it down. A rich fuel mixture can lead to increased emissions, decreased performance, and poor fuel economy.

What are the environmental concerns?

Methane, vehiclebon, and nitrogen oxides were once the norm for our atmosphere. vehiclebon monoxide (CO), nitrogen oxides (NOx), and sulfur dioxides (SO2) are the main culprits behind smog, acid rain, and global warming that are being caused due to higher vehicle emissions.

Diesel engines also produce particulate matter (PM), which can cause respiratory problems in humans. The NOx sensor recall is an effort to reduce the amount of these pollutants released into the atmosphere.

What is the emissions software recall?

The emissions software recall is a mandatory recall issued by the German Federal Motor Traffic Authority (KBA) for certain Mercedes-Benz vehicles. This recall has been implemented in response to new testing procedures, which have exposed irregularities in emissions from some models of diesel engines.

The cause of the irregularities has been traced back to the suspected manipulation of onboard computer software controlling emissions output. Authorities also investigated Mercedes-Benz outside Germany for allegations of emission issues in select countries.

Can I get a software update?

Yes, you can get a software update for your affected Mercedes-Benz vehicle. A software update for the vehicle's engine management will be carried out, which will take about an hour to process.

How does Heavy Duty Pros ensure their sensors are compliant?

NOx sensors should comply with legal requirements, and these may vary on their specific applications and jurisdiction. Generally, they have to be accurate and precise, calibrated on a regular basis, have reasonable response time, and safe for general automotive use. To ensure that these legal requirements are met, Heavy Duty Pros take steps to ensure that the NOx sensors they provide meet these standards. This may involve using high-quality components, conducting rigorous testing and calibration procedures, and adhering to relevant safety standards and regulations.

Know all about your sensors with Heavy Duty Pros

Diesel Emissions Scandal has resulted in a global Mercedes NOx Sensor Recall for specific models, which implied a sour taste to its patrons. Therefore, as a recovery method, Mercedez-Benz took action and issued a recall, which included an engine control module software update and a new NOx sensor to help reduce emissions.

Vehicle owners must stay updated with automotive updates to ensure their vehicles run safely and efficiently. If you need to stay up to date on your parts or need an excellent resource for new parts, make sure you check out Heavy Duty Pros!