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Cummins L9 DOC Filter 2022-2024: OEM 4394879

CUMMINS L9 DOC FILTER 2022-2024: OEM 4394879

Shipping ICON

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY ICON

WARRANTY
1M MILES OR 1 YEAR

$3,995.00

CORE CHARGE:

$1,000.00
iCORE DISCLAIMER: The CORE charge is a 30 day hold and will not be processed as long as the CORE is returned within 30 days. If you do not have a CORE or fail to return the CORE within 30 days, the CORE charge hold amount will be processed at that time.

AVAILABILITY IN STOCK
OEM NUMBER4394879
PART TYPEDOC Filter
BRANDTamerx Diesel Products
ENGINE MAKECummins
ENGINE TYPEL9
YEAR2022-2024
PART NUMBER4394879RM-DOC-2
APPLICATION NOTESPACCAR, 260-350, EPA21
ADDITIONAL NOTESInlet Catalyst

PRODUCT DESCRIPTION

This is a Remanufactured Tamerx DOC Filter, Tamerx part number 4394879RM-DOC-2 ( OEM Part Number 4394879 ). All parts are proudly remanufactured in the U.S.A. to the highest of OEM standards, and improvements are often applied to the original design in the remanufacturing process. This part is primarily made for a Cummins L9, production years 2022-2024, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here

Additional Notes: Inlet Catalyst

OEM NUMBERS

Primary OEM4394879
Additional OEM4394879

ADDITIONAL DETAILS

CONDITIONRemanufactured
UPC / Barcode00840490550278
WEIGHT35.00 LBS

SHIPPING OPTIONS

Ship Weight : 35.00 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.


Covering 2022–2024 Cummins L9 engine applications, the OEM 4394879 DOC Filter is designed to support proper exhaust aftertreatment function and maintain emissions compliance. This Diesel Oxidation Catalyst (DOC) helps convert harmful exhaust gases into less harmful compounds before they continue through the downstream DPF and SCR system. Manufactured to original equipment specifications, it provides precise fitment and reliable compatibility with factory-installed sensors and mounting hardware. Its durable construction is engineered to withstand high exhaust temperatures and the demanding conditions of commercial truck operation. As a direct OEM replacement, this Cummins L9 DOC Filter helps maintain aftertreatment system integrity while reducing the likelihood of unexpected downtime. Tamerx Diesel Products LLC supplies dependable diesel emissions components that align with strict manufacturer standards.

FITMENT CHART

YEARMAKEENGINE(S)
2022Cummins L9
2023Cummins L9
2024Cummins L9

PEOPLE ALSO ASKS | BLOG(S)

The Cummins L9 DOC Filter 2022–2024 (OEM 4394879) is built with several engineered components that allow it to function effectively within the engine’s aftertreatment system. Often referred to as an inlet catalyst module, this Diesel Oxidation Catalyst (DOC) is installed near the front of the exhaust assembly where it begins the process of treating exhaust gases.

These components work together to manage exhaust flow, trigger oxidation reactions, and withstand the high temperatures produced by heavy-duty diesel engines.

Main Components of OEM 4394879

  • Catalyst substrate
    • A ceramic or metallic honeycomb structure that allows exhaust gases to pass through while providing a large surface area for chemical reactions.
  • Precious metal washcoat
    • Typically platinum and/or palladium applied to the substrate to initiate oxidation reactions that convert harmful gases.
  • Stainless steel outer housing
    • A durable shell designed to protect internal catalyst components from heat, vibration, and pressure changes.
  • Mounting flanges or connection points
    • Interfaces that secure the DOC module within the exhaust and aftertreatment system.
  • Insulation or support matting
    • Internal material that stabilizes the catalyst substrate and accommodates thermal expansion during operation.
  • Sensor ports
    • Openings for temperature or oxygen sensors that allow the engine control module to monitor exhaust conditions.

Together, these components allow the Cummins L9 DOC Filter (OEM 4394879) to process exhaust gases efficiently while supporting the operation of downstream emissions components in the aftertreatment system.

Prolonging the lifespan of your DOC (Diesel Oxidation Catalyst) filter begins with maintaining a clean and properly running engine. Because the DOC processes exhaust gases, contamination or poor combustion can shorten its service life.

Most DOC issues develop gradually due to soot buildup or fluid contamination. Taking preventative steps can help keep the catalyst functioning properly and reduce the likelihood of early failure.

To help extend the lifespan of your DOC filter:

  • Use high-quality diesel fuel to minimize residue and deposits
  • Follow manufacturer-recommended oil change intervals
  • Use approved engine oil and fluids
  • Repair faulty fuel injectors promptly
  • Fix oil or coolant leaks before they reach the exhaust system
  • Avoid excessive idling whenever possible
  • Address check engine or emissions warning lights quickly

Driving habits also play an important role. Frequent short trips that prevent the engine from reaching normal operating temperature can contribute to soot accumulation. Allowing the vehicle to reach proper exhaust temperatures helps maintain normal catalyst operation.

Routine inspections of sensors, exhaust connections, and related components can catch small issues early. Staying proactive with maintenance and addressing engine concerns promptly helps reduce the risk of DOC filter failure and unnecessary repairs.

The module is typically mounted near the beginning of the aftertreatment system where exhaust gases first enter emissions treatment.

It is a diesel oxidation catalyst designed for commercial diesel engine aftertreatment systems.

Exhaust gases pass through a catalyst-coated substrate that triggers chemical oxidation reactions.

The correct replacement can be confirmed by matching the OEM number on the existing catalyst module to 4394879.

Cummins DOC Filters