
Cummins QSB 4.5L NOx Sensor 2018-2024: OEM 4384394
CUMMINS QSB 4.5L NOX SENSOR 2018-2024: OEM 4384394

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY
1M MILES OR 1 YEAR
PRODUCT DESCRIPTION
This is a Genuine New, Cummins NOx Sensor, Cummins part number 4384394OE ( OEM Part Number 4384394 ).This part is primarily made for a Cummins QSB 4.5L, production years 2018-2024, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here
OEM NUMBERS
| Primary OEM | 4384394 |
| Additional OEM | 4384394 |
ADDITIONAL DETAILS
| CONDITION | Genuine New |
| UPC / Barcode | 00840490552838 |
| WEIGHT | 1.00 LBS |
SHIPPING OPTIONS
Ship Weight : 1.00 LBS
UPS Ground, 2nd Day Air, Next Day Air
SHIPPING POLICY
Tamerx Diesel Products ships via UPS Ground. Next day air shipping can be arranged for a reasonable price of anywhere from $50.00 - $100.00 depending on the weight of the product and your location. We will do everything we can to make sure that you get the service you need. We understand how important it is to receive your order as quickly as possible.
In most cases Tamerx Diesel Products only needs one address, as long as your product is shipping to the same location as your billing information. In order to eliminate credit card fraud, your billing information must match the credit card you provide.
The terms, conditions, and details of our warranty vary from product to product. Specific warranty details can be found below.
Tamerx Diesel Products provides a replacement warranty on all of our parts. The duration and mileage limitations of the warranty vary by product and are specified on the product's detail page/item listing.
Please note that the warranty covers replacement of the part and the cost of shipping the replacement part to you only. It does not cover any shop, labor, towing, or any similar or related costs. This is not a "money back guarantee".
If you experience a problem with your part or it is not functioning properly, the correct warranty procedure is to call us at (510) 257-1777 (8:00 AM - 5:00 PM ET Monday through Friday). Be sure to have your order number and/or other relevant order information ready so we can easily locate your order and resolve your issue as quickly as possible. From that point, we will review with you any troubleshooting steps that may need to be taken and other areas or systems that can be checked to rule out external problems contributing to your part's issue. If a replacement is determined to be necessary, we will then arrange for your replacement part to ship out ASAP and issue any necessary return shipping labels and/or documents.
As is the case for the majority of the diesel products sold on Tamerx Diesel Products, your part's warranty is active as soon as you install it. In some other cases, warranty activation is contingent upon you sending us your core (i.e., your old part). Tamerx Diesel Products will provide you a return shipping label for parts that have a warranty with a core return condition. When we have received your core return, the part's warranty coverage begins. We reserve the right to void the product warranty if your core is not received within the allotted time, or if it isn't received at all. If the warranty for the diesel part you are purchasing has a core return requirement, it will be clearly noted on the product detail page/item listing.
What is a Core Charge?
A core charge (also called "core deposit") is similar to the deposit you might pay for a can or bottle of soda and is a standard requirement in the auto parts industry. For example, in many states, to promote recycling, you pay a deposit when you purchase a can of soda and receive your deposit back when you return the empty can. Many automotive parts have a core charge, or core price, that works in essentially the same way as a soda can deposit.
30 Day Core Charge Hold
You authorize Tamerx Diesel Products, to hold your credit card for the specified core charge amount and that you agree to return your core with 30 days of receiving the purchased part. When we have received your core return, the hold is released and the core charge payment is canceled.
The customer, or parts buyer, is responsible for any shipping costs associated with core returns unless otherwise specified in the product listing/detail page. Tamerx Diesel Products offers prepaid UPS shipping labels (SKU numbers UPS-CR1 and UPS-CR2) for use in returning your core that are available for purchase on our website during your shopping/order process.
The shipping label you will need to use for the core return is dependent upon what part you are purchasing. UPS-CR1 is good for cores weighing up to 20 pounds. UPS-CR2 is appropriate for shipping cores weighing 21 pounds or more. You must include enough information with the core return that clearly identifies it as a.) a Core Return, and b.) contains enough information we can use to clearly associate the core return with your order. Including a copy of the invoice or packing slip that came with the original shipment, clearly marked "Core Return", is ideal. Alternately, you can include a note marked as "Core Return" that includes your order number, full name and address, and phone number or other contact information. Failure to include this information with your returned core will most likely delay any due core credit being issued and/or delay any applicable warranty activation. Core returns need to be for the exact part purchased and cannot be damaged. Substituting another part in place of the part you have purchased is not acceptable.
All fluids must be drained.
If you have purchased a set or a parts package, you will need to return cores for all components of the set. For example, if you have purchaed a high pressure oil pump with an IPR valve, you will need to return both HPOP and IPR valve cores to receive proper credit. If you have purchased an EGR cooler/EGR valve package, your core return must consist of an EGR cooler core and an EGR valve core, or core credit will not be given.
Core Charges are often mandated by state legislature, and, as such, the actual core charge and taxes on the charge may vary depending on the state in which you buy your part. The Tamerx Diesel Products core charge presented to you online today with your item is representative of the most common core charge.
Designed for 2018–2024 Cummins QSB 4.5L applications, the NOx Sensor (OEM 4384394) is an essential part of the emissions aftertreatment system. This sensor monitors nitrogen oxide (NOₓ) levels in the exhaust stream and sends accurate data to the engine control module (ECM) to support proper SCR system operation. Reliable NOx readings help manage diesel exhaust fluid (DEF) dosing and maintain compliance with applicable emissions standards across these model years. Proper sensor operation can also help reduce the likelihood of emissions-related warning lights and diagnostic fault codes. This page provides application-specific details to assist with accurate identification of the Cummins QSB 4.5L NOx Sensor OEM 4384394 for service and replacement needs.
FITMENT CHART
| YEAR | MAKE | ENGINE(S) | ||||
|---|---|---|---|---|---|---|
| 2018 | Cummins | QSB 4.5L | ||||
| 2019 | Cummins | QSB 4.5L | ||||
| 2020 | Cummins | QSB 4.5L | ||||
| 2021 | Cummins | QSB 4.5L | ||||
| 2022 | Cummins | QSB 4.5L | ||||
| 2023 | Cummins | QSB 4.5L | ||||
| 2024 | Cummins | QSB 4.5L | ||||
PEOPLE ALSO ASKS | BLOG(S)
Here are the main components of a Cummins QSB 4.5L NOx Sensor (2018–2024), OEM 4384394. While it’s often called a “sensor,” it’s really a small electronic assembly built to survive extreme exhaust heat and provide accurate emissions feedback.
Components of the Cummins NOx Sensor (OEM 4384394)
- 1) NOx Sensing Element (Sensor Probe)
- The part that sits in the exhaust stream and detects nitrogen oxide levels. This is the core measuring element.
- 2) Protective Sensor Housing
- A high-temperature metal body that protects the sensing element from heat, vibration, and exhaust flow impact.
- 3) Integrated Control Module (Electronics Unit)
- Many NOx sensors include a built-in control unit that:
- processes the raw sensor signal
- converts it into readable data
- communicates with the ECM
- Many NOx sensors include a built-in control unit that:
- 4) Wiring Harness / Lead Cable
- The heavy-duty cable connecting the sensor to the engine wiring system. It’s designed to handle heat exposure and movement.
- 5) Electrical Connector Plug
- The connector end that locks into the engine harness, allowing power supply and signal communication.
- 6) Mounting Threads
- Threaded section that allows the sensor to be securely installed into the exhaust pipe or aftertreatment component.
- 7) Sealing Surface / Washer
- Helps ensure a tight seal at the mounting point to prevent exhaust leaks.
- 8) Internal Temperature Monitoring (Common Feature)
- Most NOx sensors include internal temperature compensation so readings remain accurate under changing exhaust conditions.
OEM 4384394 combines a sensing probe, protective hardware, and signal-processing electronics to provide reliable NOx feedback for Cummins QSB 4.5L engines from 2018–2024.
You can prolong the lifespan of a NOx sensor by protecting it from contamination, moisture, excessive heat, and electrical issues. Since NOx sensors are precision emissions components, small problems in the exhaust or DEF system can shorten their life quickly.
Best ways to extend NOx sensor lifespan
- Use high-quality DEF only
- Poor-quality or contaminated DEF can cause SCR issues that lead to abnormal exhaust conditions, which can damage NOx sensors over time.
- Prevent DEF crystallization
- Crystals and deposits in the SCR system can create incorrect readings and stress the sensor. Fix leaking dosers/injectors and ensure heaters function properly.
- Keep the SCR system healthy
- Faulty DEF pumps, dosing modules, or injectors can cause under/over dosing, leading to high NOx levels and repeated sensor strain.
- Fix exhaust leaks immediately
- Exhaust leaks near the sensor allow outside air in, which can cause false readings and lead to sensor failure.
- Avoid excessive heat exposure
- Overheating from repeated faults, failed regen events, or abnormal exhaust temperatures can damage sensor elements.
- Inspect wiring and connectors
- NOx sensors are sensitive to voltage and communication issues. Corrosion, loose connectors, and damaged wiring can cause failures that look like sensor defects.
- Address warning lights early
- Driving too long with SCR/DPF faults can cause abnormal exhaust conditions that shorten sensor life.
A NOx sensor lasts longest when the DEF/SCR system is operating correctly, contamination is avoided, exhaust leaks are repaired quickly, and electrical connections stay clean and secure.
Yes, NOx sensor problems can lead to broader aftertreatment system diagnostic codes.
Technicians should inspect wiring, connections, and the sensor’s condition.
Yes, it contains electronic elements that generate signals based on NOx concentration.
Yes, soot contamination, heat, and exhaust conditions can impact sensor longevity.

































