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OEM Price: USD 924

USD 426

Save: $498

Roadwarrior Part #


Engine Manufacturer

OEM Part Number:


In stock

Direct Fit Replacement NOx Sensor for Cummins

OEM Price: USD 924

USD 426

Save: $498

Free ground shipping
Brand new! No core charge
In stock and ready to ship
OEM direct fit
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Need to Replace a Cummins NOx Sensor 4326873, 4326874 or 4326872?

Roadwarrior’s NOX-CXX-003 is a plug-and play replacement for Cummins outlet NOx sensors with part numbers 4326874 or 4326872! It’s also a perfect-fit replacement for your Cummins inlet sensor 4326873. The Roadwarrior aftermarket catalogue includes high-performance equivalents for 8 Cummins NOx sensor models! Our NOx sensors are rigorously tested before being released to ensure they’re compatible with Cummins ISX engines! Our testing also ensures that our parts meet the reliability and performance standards of the inlet or outlet Cummins NOx sensor they’re replacing! Find our full range of Cummins NOx sensor replacements here.

What is a NOx Sensor?

Most Cummins engines have two NOx sensors, one on either side of the SCR, to measure NOx in the exhaust! The inlet/ upstream sensor monitors NOx levels before the SCR, so the ECU knows how much DEF to inject. The outlet/ downstream NOx sensor then checks the NOx levels post-SCR. The ECU uses this combined data to make sure the SCR is working and establish whether it needs more DEF. This helps the SCR reduce toxic nitrogen oxide particles in your exhaust!

Why Choose Roadwarrior NOx Sensors?

Many drivers hesitate before trying aftermarket Cummins NOx sensors. This can be because of their own experiences or unflattering stories they’ve heard from other OTR drivers. The aftermarket experience varies a lot between suppliers, so we can understand this approach! That’s why we believe it’s so important to show our customers that they can trust us. Roadwarrior parts give drivers the lower prices and shorter delivery times of an aftermarket part, with the accountability of an OEM. You can order a Roadwarrior replacement for your inlet or outlet Cummins NOx sensor (4326873, 4326874 or 4326872) from your local dealer. You can also order, or browse our other Cummins NOx sensor replacements, on our website!

As a Canadian company with 13 warehouses across North America, we’re easy to contact! We keep our most ordered parts always in stock, so a Roadwarrior part means less downtime. Many of our most popular parts even come with next-day delivery or same-day pick-up! If you’d like to talk to a Roadwarrior representative, you can order parts straight through our sales team on 1-877-897-9759! If you’d rather start by learning what to look for in an aftermarket replacement for a Cummins NOx sensor, we recommend reading our blog.

What Are the Most Common Cummins NOx Sensor Problems?

Cummins NOx sensors are an extremely sensitive part that measures fluctuations in microscopic NOx particles in your exhaust stream. However, as with all delicate sensors, a small amount of damage or contamination can cause NOx sensors to malfunction. A benefit of a highly interconnected combustion and aftertreatment system is that the ECU can pick up data inconsistencies between parts and trigger a DTC. The downside is that soot contamination from other emissions-related parts is a leading cause of Cummins NOx sensor problems. If soot from the exhaust clogs up the nitrogen oxide sensor, it can also give inaccurate readings! This can then cause too much or too little DEF to be injected before the SCR.

Your 4326873, 4326874 or 4326872 Cummins NOx sensor is also highly susceptible to moisture contamination! The sensor can be exposed to moisture during installation or through your semitruck’s exhaust. The risk of contamination is one reason we recommend having your NOx sensor professionally installed, rather than installing it yourself. If you have any issues, this also makes it easier to prove that the part was faulty and didn’t become contaminated during installation.


Weight 2 kg
Part Type

Part type

NOx Sensor

RW Part Number


RW Part Number



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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.