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OEM Price: USD 1,049

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Roadwarrior Part #

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Direct Fit Replacement NOx Sensor for Volvo Mack

OEM Price: USD 1,049

Call For Price and Availability

Free ground shipping
Brand new! No core charge
OEM direct fit
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Having Trouble with Your Volvo Mack NOx Sensor?

We stock aftermarket replacements for Volvo Mack NOx sensors with part numbers 22303390, 22303384 and 22303391. We test our nitrogen oxide sensors for both OEM-quality performance and compatibility, so you can install our parts with confidence! Roadwarrior sensors work well with Mack MP7 and MP8 engines, and Volvo D11, D13 and D16 engines. We also stock aftermarket replacements for your Mack DPF, DOC and SCR, gaskets, DEF dosers, clamps, and even emissions combustion chambers!


Which Roadwarrior Part is Right for My Semitruck?

  • The Roadwarrior part NOX-VXX-002 is an exact-fit replacement for your inlet Volvo Mack NOx sensor 22303390.
  • The Roadwarrior outlet sensor NOX-VXX-008 is a plug-and-play replacement for your post-SCR Volvo Mack NOx sensor 22303384.
  • The Roadwarrior outlet NOx sensor NOX-VXX-001 is a precise-fit substitute for a post-SCR Mack sensor 22303391.


What is a NOx Sensor?

Your Mack engine comes with two nitrogen oxide sensors. The inlet sensor monitors NOx levels in the exhaust before the SCR and the outlet sensor measures them after the SCR. Based on this information, the ECU determines how much DEF (urea) to inject into the pre-SCR exhaust stream. The gas reacts with the SCR catalyst, splitting the NOx into nitrogen and oxygen, making your semitruck’s emissions less toxic! NOx sensors also tell the ECU how well the SCR is working and alert it to any issues.


Why Are Roadwarrior NOx Sensors the Right Choice?

In the OTR trucking community, there’s a conception that buying an aftermarket nitrogen oxide sensor is a gamble! At Roadwarrior, we’ve made it our mission to prove that our aftermarket parts are a safe bet! By creating parts that provide consistent, reliable performance over time, we build trust among OTR drivers. So, when our customers need to replace a Mack MP8 NOx sensor, they see our parts as a permanent fix, not just a band aid! Our parts are built to last, not just to be a cheap stand-in till your new OEM part arrives, so every part comes with a hassle-free warranty! This way, if there’s an issue with your part, it’s quick and easy to return it and get it replaced!


With 13 warehouses spread across the U.S.A. and Canada, we’re able to offer next-day delivery on our most popular parts. You can order your replacement Volvo Mack NOx sensor (22303390, 22303384 or 22303391) through your dealer or on our website. If you prefer, you can also order parts straight through our sales team on 1-877-897-9759! To browse our other NOx sensors, check out our catalogue. Otherwise, why not head to our blog to learn what to look out for in a reliable aftermarket nitrogen oxide sensor.


What Problems do Volvo Mack NOx Sensors Have?

A fully functioning NOx sensor helps the ECU figure out how much fuel to inject into the combustion chamber and how much DEF to inject before the SCR. When the NOx sensor malfunctions, the SCR can’t do its job properly and this can lead to excess smoke coming out of the exhaust pipe. You may also see increased fuel consumption and either an increase or a decrease in DEF use depending on the exact issue. If your Mack MP8 NOx sensor is playing up, for example, the most likely causes are moisture contamination from a leak, or because it’s clogged with soot!


Soot contamination is more common in the inlet sensor (22303390) before the SCR, than in the outlet sensor (22303384 or 22303391) after the SCR. Moisture contamination on the other hand can affect either sensor, especially if it occurs during installation. For this reason, you should be especially careful when replacing your Mack NOx sensor.


Part Type

part type

NOx Sensor

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RW Part Number


1 Customer Review

  1. Rusty
    19 June 2021
    Really fast shipping, the product works well
    0 0
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Better Coating, Better Performance.

Roadwarrior is the only manufacturer to use Metalcor® catalyst technology across its entire range of Diesel Oxidation Catalysts (DOCs) and Selective Catalytic Reduction catalysts (SCRs). Metalcor® catalysts feature high activity catalyst coatings fused to thinner, stronger, catalyst substrates to guarantee maximum performance under the harshest conditions.

Metalcor® catalyst coatings are designed and produced in our own labs. We then inspect each unit to ensure you get more fuel efficiency, lower consumption of DEF, and long term performance from your heavy duty engine!


Roadwarrior Has You Covered!

All Roadwarrior emissions parts carry a full value 12 month warranty.

LightningVolt lithium batteries carry a full value 30 month warranty.

To make the process hassle-free, our parts have a metal nameplate with the serial number, so even after 500,000 miles of service, it’s still easy to identify. This avoids the common problem of serial numbers printed on stickers that burn off after the first start-up, making them impossible to return. Our failsafe system allows us to work in your interests, honouring claims for on-road and off-road replacements, and giving you peace of mind.

And since Roadwarrior parts are designed to meet or exceed OEM specifications, you can rest easy knowing our direct fit parts will take the problems out of your aftertreatment without interfering with your OEM warranty.

Next Day Is Nice, Same Day is Better!​

A faulty emissions control system can cost you thousands in wasted man-hours as your heavy equipment sits in the shop awaiting a new part. Whether it’s a truck behind on orders, a bus that can’t take passengers, or heavy machinery delaying construction deadlines, Roadwarrior can get you moving again! 

Roadwarrior has twelve warehouses across the U.S.A. and Canada, which can deliver the most popular aftertreatment parts in 1-2 days. With over 1,000 DPFs, DOCs and SCRs on offer, Roadwarrior offers the largest aftertreatment catalogue.

*LightningVolt lithium batteries ship directly from Roadwarrior in Ontario, to ALL 50 states, including Alaska and Hawaii within 2-4 days.