{"id":472,"date":"2022-04-28T01:27:13","date_gmt":"2022-04-28T01:27:13","guid":{"rendered":"https:\/\/www.auto-eco.net\/?p=472"},"modified":"2022-04-28T01:45:55","modified_gmt":"2022-04-28T01:45:55","slug":"nox-sensor-failure-symptoms-an-inclusive-guide-reprinted-from-rxmechanic-com","status":"publish","type":"post","link":"https:\/\/www.auto-eco.net\/?p=472","title":{"rendered":"Nox Sensor Failure Symptoms \u2013 An Inclusive Guide (Reprinted from rxmechanic.com)"},"content":{"rendered":"

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Nox Sensor Failure Symptoms \u2013 An Inclusive Guide<\/h2>\n
Written by\u00a0Osuagwu Solomon<\/a><\/span><\/span>\u00a0in\u00a0Mechanic Talk<\/a><\/span>Last Updated April 26, 2022<\/span><\/div>\n
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Atmospheric pollution caused by several forms of gases like methane, carbon dioxide, and nitrogen oxide was once the order of the day. Some gases even cause ozone depletion. As a result, the authorities keep setting stricter emission regulations, and diesel vehicles\u2019 purchase cost keeps scaling through the roof.<\/p>\n

Automakers now design a few Nox sensors in cars that notify the driver when emissions are not as clean as they should be. That brings us to this mind-boggling question, \u2018what happens when a Nox sensor fails?\u2019<\/p>\n

Here, we\u2019ll discuss Nox sensor failure symptoms, causes, diagnoses, and fixes. But first, let\u2019s look at what it is.<\/p>\n

\"Nox<\/p>\n

What Are Nox Sensors?<\/span><\/h2>\n

As the name implies, Nox sensors are components used in measuring and calculating the amount of nitrogen oxides in the exhaust gas. The amount of nitrogen oxides in the exhaust gas shows whether there is adequate oxygen during the combustion process. This aids the catalytic converter is functioning properly.<\/p>\n

Their primary function is to reduce harmful exhaust byproducts and ensure a safe environment. You may wonder, \u2018what happens if a Nox sensor fails\u2019? This sensor will cause the powertrain control module to display the check engine light on the dashboard. You may also experience low engine power output, poor acceleration, and bad gas mileage.<\/p>\n

Nox sensors come in various designs, and it varies from vehicle to vehicle. Old vehicles may include DFP, turbocharger, SCR catalyst, and upstream Nox sensor from the exhaust catalyst.<\/p>\n

Modern vehicles come with upstream and downstream Nox sensors. They measure the exhaust emissions and send the data to the engine control module. The ECM calculates how much fuel to send into the combustion chamber.<\/p>\n

Both the upstream and downstream Nox sensors are mounted on the exhaust pipes. They perform differently and offer varying benefits. The upstream sensor measures the engine-output Nox, and the downstream sensor calculates the Nox emissions from the SCR catalyst.<\/p>\n

How Does A NOx Sensor Work?<\/span><\/h2>\n

By answering the question, \u2018what does a Nox sensor do in diesel\u2019 vehicles, we\u2019ll have a clear picture of how it works.<\/p>\n

A Nox sensor is an SCR system component that measures the amount of Nox in an exhaust system. This helps the SCR to know the right level of ammonia or urea to provide better fuel economy and less harmful emissions to the atmosphere.<\/p>\n

Aside from measuring the amount of nitrogen oxides in the exhaust gas, some Nox sensors also monitor the mass of exhaust flow.<\/p>\n

A high-end Nox sensor on modern cars features some compounds that react to nitrogen oxides. These compounds are known as catalysts and are usually manufactured with activated carbon, titanium oxide, and other base metals.<\/p>\n

These compounds send a voltage correlated to the level of nitrogen oxide. The higher the nitrogen in the exhaust gas, the stronger the voltage.<\/p>\n

Nox sensors with less sophisticated compounds work monitoring the exhaust gas and erasing oxygen, and judging the Nox concentration. So, how do I know if my Nox sensor is bad?<\/p>\n

NOx Sensor Failure Symptoms\u00a0<\/span><\/h2>\n

Like other\u00a0car sensors,<\/a>\u00a0Nox sensors can fail. Whether you\u2019re searching for Nox sensor failure symptoms on DD15 engines or BMW Nox sensor failure symptoms, here are the key signs you should watch out for.<\/p>\n

High fuel consumption\u00a0<\/span><\/h3>\n

If the Nox sensor goes bad and cannot deliver accurate information to the engine management software regarding the air-fuel mixture ratio, the car computer may not know the proper amount of air fuel to mix.<\/p>\n

In some scenarios, this will cause the\u00a0powertrain control module<\/a>\u00a0to compensate by mixing more fuel to ensure optimal engine performance. This is known as a rich fuel mixture.<\/p>\n

If you have\u00a0bad gas mileage<\/a> on your Cummins, this could be a Cummins Nox sensor problem. It\u2019s important to note that other factors can lead to bad gas mileage.<\/p>\n

Rough idling\u00a0<\/span><\/h3>\n

One common Nox sensor failure on Mercedes and other vehicles is rough or erratic idling. The\u00a0fuel injectors<\/a>\u00a0inject a pre-defined amount of gas into the combustion chamber when the engine is running. The DME oversees and electronically manages this task. But when the Nox sensor malfunctions, it causes unstable, rough, or erratic idling.<\/p>\n

Erratic acceleration\u00a0<\/span><\/h3>\n

Uneven or erratic acceleration is a common sign of a lousy Nox sensor. Here\u2019s why; the engine control unit will compensate for the inappropriate reading by the sensor by using more fuel. In return, this will cause the vehicle to jerk when you depress the\u00a0gas pedal.<\/a><\/p>\n

Engine misfire and soot buildup\u00a0<\/span><\/h3>\n

Several factors can cause an engine to misfire. However, a sudden\u00a0engine misfire<\/a>\u00a0may mean the Nox sensor is malfunctioning. This happens when there\u2019s little oxygen during the combustion process.<\/p>\n

Nox sensors are one of the most costly exhaust system components because they contain platinum, which helps to reduce toxic nitrogen from the exhaust byproducts.<\/p>\n

A lousy Nox sensor will cause higher emissions, affecting the catalytic converter. It\u00a0damages the catalyst<\/a>, making it unable to manage emissions. This can also lead to soot buildup. Of course, you know what this means. It\u2019ll lead to a\u00a0failed emission test.<\/a><\/p>\n

Check engine light\u00a0<\/span><\/h3>\n

While the Nox sensor is not on under the hood, it can trigger an engine check light when it goes bad. However, several reasons can cause the car computer to trigger a check engine light. Therefore, do not conclude that an engine warning light shows a lousy Nox sensor.<\/p>\n

Diagnose the vehicle with a diagnostics scan tool to track the actual cause of the light. If you don\u2019t have this tool, drive down to a mechanic garage for a professional inspection.<\/p>\n

Having seen the symptoms, what can cause a NOx sensor to fail?<\/p>\n

What Causes NOx Sensors To Fail?<\/span><\/h2>\n

Some factors can cause a Nox sensor to fail. Here are the probable causes of Nox sensor failures.<\/p>\n

Soot buildup:<\/strong>\u00a0From the location of these sensors, it is no surprise that soot buildup can damage them. While soot buildup is a sign of a lousy Nox sensor, it is also a common cause.<\/p>\n

Burnt or damaged cables:<\/strong>\u00a0A burnt or damaged wiring harness can be the root cause of Nox sensor malfunction. In such a case, a virtual inspection will pinpoint the culprit.<\/p>\n

It may not mean the Nox sensor itself is bad. It could be that internal connectors that read the Nox level are defective.<\/p>\n

There may be other causes, but these are the common ones you should note. A visual inspection could be all you need to track the cause of the Nox sensor failure.<\/p>\n

How Do You Fix NOx Sensors?<\/span><\/h2>\n

If you notice two or more bad Nox signs outlined above, diagnose the vehicle with a diagnostics scan tool. This will help you determine if the sensor is bad or the symptoms project other system malfunction.<\/p>\n

You may have a bad probe or a broken\/damaged sensor. First, locate the sensor on the exhaust pipe and carry out a visual inspection. If the probe is the cause, follow these steps to fix it.<\/p>\n

Uninstall the Nox sensor:<\/strong>\u00a0Unscrew the Nox sensor from the exhaust pipes. You may visit your owner\u2019s booklet for a clear picture of the sensor location on your specific model. The booklet will also explain how to remove the Nox sensor.<\/p>\n

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Get your necessary tools<\/strong><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

You\u2019ll need some common tools to carry out this repair job. Here are the tools you\u2019ll need.<\/p>\n