NOx Sensors | Nitrogen Oxide Sensor Replacement

Replacement NOx sensors (nitrogen oxide sensors) for BMW, Mercedes-Benz, Jaguar, Land Rover, Ford and VW. Used on diesel engines with SCR/AdBlue and on some lean-burn petrol engines, a NOx sensor tells the engine computer how much nitrogen oxide is in the exhaust. Match your OE number below, or let our team check fitment for you.

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Read more about NOx sensors: symptoms, fitment and FAQs

What Does a NOx Sensor Do?

A NOx sensor sits in the exhaust and measures the level of nitrogen oxides (NOx) leaving the engine. The engine control unit uses this reading to manage the emissions system:

Diesel engines with SCR: the reading controls how much AdBlue is injected and checks that the SCR catalyst is working.
Lean-burn petrol engines (for example some BMW N43 and N53 models): the reading manages the NOx storage catalyst.

Most NOx sensors come as a probe with an attached control module (the small electronic box on the wiring). Many vehicles have two: an upstream sensor before the catalyst or SCR, and a downstream sensor after it. They are usually different part numbers and are not interchangeable.

Signs of a Faulty NOx Sensor

Engine warning lightFault codes for the NOx sensor circuit, often in the P2200–P2214 range.

AdBlue / emissions warningSCR or emissions system messages on the dashboard, sometimes with a countdown on AdBlue vehicles.

Reduced powerThe engine may go into limp mode to protect the emissions system.

Higher AdBlue or fuel useWrong readings can upset AdBlue dosing and engine running.

A NOx fault code does not always mean the sensor has failed. Exhaust leaks, poor-quality AdBlue, a blocked DPF or a failing SCR catalyst can trigger similar codes, so diagnose first. Our NOx sensor guide explains the common causes in more detail.

How to Choose the Right NOx Sensor

Find the OE number printed on your old sensor or its control module, and compare it with the OE numbers on our product pages.
Confirm the position: upstream (front) or downstream (rear). The two are not the same part.
Check engine code, chassis and year with the "Check By Make, Model and Year" tool above.
Still not sure? Send your registration or VIN to our team and we will check it for you, free of charge.

After fitting: on many vehicles the new NOx sensor must be registered or the adaptation values reset with a suitable diagnostic tool. Clear the fault codes and complete a test drive so the system can re-check the sensor.

NOx Sensors by Vehicle Make

Make	Examples of models covered in this collection
BMW	1 Series (E81, E82, E87, E88), 3 Series (E90, E91, E92, E93) including N43 and N53 petrol
Mercedes-Benz	A-Class, C-Class, E-Class, CLS, GLC, GLE, GLK, M-Class, S-Class, SLK/SLC, V-Class, Vito
Jaguar	E-Pace, F-Pace, XE, XF
Land Rover	Discovery, Discovery Sport, Range Rover Evoque, Range Rover Sport, Range Rover Velar
Ford	Transit, Transit Custom, Tourneo Custom
VW	Caddy, Caddy Alltrack, Sharan

Model lists are examples only. Fitment depends on engine, year and sensor position, so always check the individual product page.

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Related Guides & Parts

NOx Sensor Guide Oxygen (Lambda) Sensors Exhaust Gas Temperature Sensors EGR Valves Exhaust Parts

NOx Sensor FAQs

Is a NOx sensor the same as an oxygen (lambda) sensor?

No. An oxygen sensor measures oxygen in the exhaust to control the fuel mixture. A NOx sensor measures nitrogen oxides to control the SCR/AdBlue system or a NOx storage catalyst. They have different part numbers and cannot replace each other.

Can I drive with a faulty NOx sensor?

Usually for a short time, but the car may go into reduced power, and on some AdBlue vehicles a countdown can stop the engine restarting. Get it diagnosed and fixed as soon as possible.

How do I know if I need the front or rear NOx sensor?

The fault code normally tells you which one (for example "sensor 1" for upstream, "sensor 2" for downstream). You can also compare the OE number on the old sensor. If you are unsure, send us your reg or VIN and the fault code.

Does a new NOx sensor need coding or a reset?

On many vehicles, yes. The new sensor may need registering or the adaptation values resetting with a diagnostic tool after fitting. Your garage can do this as part of the job.

Will a new NOx sensor clear my AdBlue warning?

Only if the sensor is the cause. Check the AdBlue quality, the SCR catalyst and the exhaust for leaks first, because these can show the same warning.

Need help choosing? Contact our parts team with your registration, VIN or old part number.