Cummins QSB 4.5L Dosing Module 2018-2024: OEM 4394644
CUMMINS QSB 4.5L DOSING MODULE 2018-2024: OEM 4394644
ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY
WARRANTY
1M MILES OR 1 YEAR
PRODUCT DESCRIPTION
This is a Genuine New, Cummins Dosing Module, Cummins part number 4394644OE ( OEM Part Number 4394644 ).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 | 4394644 |
| Additional OEM | 0 444 025 092, 4394644, A05502 |
ADDITIONAL DETAILS
| CONDITION | Genuine New |
| UPC / Barcode | 00840490552791 |
| WEIGHT | 3.00 LBS |
SHIPPING OPTIONS
Ship Weight : 3.00 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 Dosing Module with OEM 4394644 is a key part of the SCR (Selective Catalytic Reduction) emissions aftertreatment system. This dosing module is engineered to work with factory DEF (diesel exhaust fluid) delivery and exhaust configurations specific to the QSB 4.5L platform, ensuring proper integration with emissions sensors and control systems. Its function is to accurately meter DEF into the exhaust stream to help reduce nitrogen oxide (NOₓ) emissions, supporting compliance with applicable emissions standards throughout these model years. Reliable dosing module performance helps maintain proper DEF flow and supports the stable operation of downstream aftertreatment components. This page provides application-focused information to assist with identifying the Cummins QSB 4.5L Dosing Module 2018–2024 (OEM 4394644) 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)
The Cummins QSB 4.5L Dosing Module, OEM 4394644, plays a key role in the engine’s SCR (Selective Catalytic Reduction) aftertreatment system for 2018–2024 applications. Its main role is to deliver the correct amount of Diesel Exhaust Fluid (DEF) into the exhaust stream so the SCR system can properly reduce emissions.
In simple terms, the dosing module is responsible for controlled DEF injection. It ensures DEF is sprayed at the right time and in the right quantity based on engine operating conditions.
What the dosing module does
- Supplies and controls DEF delivery to the doser/injector
- Helps convert DEF into ammonia for the SCR reaction
- Supports NOx reduction inside the SCR catalyst
- Works with sensors (NOx and temperature) to regulate dosing accuracy
- Helps prevent emissions fault codes and derate conditions
OEM 4394644 is essential because it enables proper DEF dosing, allowing the Cummins QSB 4.5L SCR system to reduce NOx emissions and maintain emissions compliance.
The main cause of dosing module failure is DEF crystallization and contamination, which clog internal passages and damage the dosing components over time.
A dosing module (DEF dosing system) is responsible for delivering the correct amount of DEF into the exhaust stream. When DEF dries or becomes contaminated, it forms deposits that restrict flow and cause inaccurate dosing—eventually leading to module failure.
The most common causes of dosing module failure include:
- DEF crystallization (most common)
- DEF dries inside the module, injector, or lines and forms hard crystals that clog valves and passages.
- Contaminated or poor-quality DEF
- Dirt, minerals, water dilution, or DEF mixed with other fluids can damage the system and cause internal corrosion or blockage.
- Leaking or dripping doser/injector
- DEF dripping when it shouldn’t leads to rapid crystal buildup and restriction.
- Faulty heaters or frozen DEF
- If DEF freezes and the heating system fails, it can stress the pump/module and create dosing errors.
- Electrical issues
- Damaged wiring, corrosion in connectors, or voltage problems can cause module communication and dosing failures.
- Exhaust temperature problems
- Low exhaust temps can prevent proper DEF atomization, leading to deposits and buildup near the injection point.
Dosing modules fail mainly because DEF crystallizes or becomes contaminated, which leads to clogging, corrosion, and incorrect DEF delivery.
Yes, the DEF dosing module can typically be replaced without changing other aftertreatment components.
It helps target nitrogen oxides (NOx) in the exhaust stream by delivering DEF for chemical reactions.
A failed or restricted dosing module can lead to aftertreatment restriction warnings and reduced NOx conversion.
Yes, proper DEF quality supports accurate dosing and correct SCR chemical reactions.
Cummins Dosing Modules
