
Cummins QSK SCR Outlet Catalyst Module 2018-2024: OEM 4353991
CUMMINS QSK SCR OUTLET CATALYST MODULE 2018-2024: OEM 4353991

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY
1M MILES OR 1 YEAR
PRODUCT DESCRIPTION
This is a Genuine New, Tamerx SCR Outlet Catalyst Module, Tamerx part number 4353991RM-SCR ( OEM Part Number 4353991 ).This part is primarily made for a Cummins QSK, production years 2018-2024, and comes with a One Million Miles or One Year Warranty.
Additional Notes: Outlet Catalyst Muffler, Type CES 4000 SCR
OEM NUMBERS
| Primary OEM | 4353991 |
| Additional OEM | 4353991, A049B949 |
ADDITIONAL DETAILS
| CONDITION | Genuine New |
| UPC / Barcode | 00840490558397 |
| WEIGHT | 300.00 LBS |
SHIPPING OPTIONS
Ship Weight : 300.00 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 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, 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 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.
Improve exhaust emissions treatment with this Cummins QSK SCR Outlet Catalyst Module for 2018–2024 applications. OEM 4353991 helps reduce nitrogen oxide emissions by facilitating chemical reactions within the SCR aftertreatment system. A dependable replacement for damaged, restricted, or failing catalyst modules in compatible Cummins QSK engines.
FITMENT CHART
| YEAR | MAKE | ENGINE(S) | ||||
|---|---|---|---|---|---|---|
| 2018 | Cummins | QSK | ||||
| 2019 | Cummins | QSK | ||||
| 2020 | Cummins | QSK | ||||
| 2021 | Cummins | QSK | ||||
| 2022 | Cummins | QSK | ||||
| 2023 | Cummins | QSK | ||||
| 2024 | Cummins | QSK | ||||
PEOPLE ALSO ASKS | BLOG(S)
Changing exhaust conditions can affect how efficiently nitrogen oxides are treated within a diesel aftertreatment system. The Cummins QSK SCR Outlet Catalyst Module 2018-2024: OEM 4353991 provides a dedicated catalyst section that supports NOx conversion as exhaust temperatures and gas composition vary during normal engine operation.
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OEM 4353991 is intended for compatible 2018-2024 Cummins QSK diesel applications.
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SCR catalyst functionality supports the conversion of nitrogen oxides (NOx) into nitrogen and water vapor.
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Temperature-dependent catalyst activity allows the module to promote chemical reactions when suitable exhaust temperatures are reached.
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Catalyst-coated internal surfaces provide reaction sites where ammonia and nitrogen oxides interact.
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Flow-through substrate construction guides exhaust through multiple channels while exposing gases to the catalyst coating.
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DEF-based treatment compatibility allows the module to work with ammonia produced from diesel exhaust fluid.
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Heat-resistant catalyst materials accommodate the elevated temperatures encountered during diesel exhaust treatment.
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Protective metal housing helps shield the internal substrate from vibration and external damage.
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Application-specific configuration helps maintain correct positioning within compatible Cummins QSK aftertreatment assemblies.
The Cummins QSK SCR Outlet Catalyst Module OEM 4353991 provides the catalyst structure needed to support NOx conversion under suitable exhaust operating conditions. Customers searching for a Cummins QSK SCR outlet catalyst, QSK SCR catalyst module, diesel SCR catalyst replacement, NOx reduction catalyst, or OEM 4353991 can find this application-specific component at TamerX Diesel Parts for compatible 2018-2024 applications.
A failing SCR Outlet Catalyst Module can affect the diesel aftertreatment system's ability to reduce nitrogen oxide (NOx) emissions and maintain proper exhaust treatment. Recognizing the warning signs of a damaged or deteriorating catalyst can help prevent recurring emissions faults, engine derate conditions, and additional exhaust system problems.
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Check engine light activation: Reduced SCR efficiency or abnormal emissions readings may trigger diagnostic trouble codes and illuminate the check engine light.
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Increased NOx emissions: A deteriorating SCR Outlet Catalyst Module may struggle to convert nitrogen oxides effectively, resulting in elevated downstream NOx readings.
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SCR system warning messages: The vehicle may display emissions-related warnings when the engine control module detects poor SCR performance.
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Reduced engine power: Persistent aftertreatment faults can activate engine derate strategies that limit power until the underlying problem is corrected.
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Abnormal exhaust backpressure: A physically damaged or internally restricted catalyst may interfere with exhaust flow and contribute to increased backpressure.
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Recurring aftertreatment fault codes: SCR efficiency codes that return after repairs may indicate an unresolved catalyst problem or a malfunctioning related component.
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Failed emissions testing: A catalyst with reduced NOx conversion efficiency may cause the vehicle to exceed applicable emissions limits during testing.
A bad SCR Outlet Catalyst Module can produce several warning signs, but similar symptoms may also result from faulty NOx sensors, incorrect DEF dosing, exhaust leaks, or wiring problems. Checking diagnostic codes, comparing NOx sensor readings, and inspecting the complete SCR system can help confirm the cause and determine whether catalyst replacement is necessary.
The lifespan of an SCR Outlet Catalyst Module depends on operating conditions, exhaust temperatures, DEF quality, and overall engine maintenance. Proper aftertreatment operation and timely repairs can help extend the catalyst's service life.
Yes. A deteriorating SCR catalyst may lose its ability to reduce nitrogen oxide (NOx) emissions without causing noticeable changes in engine operation. Emissions-related fault codes or abnormal NOx readings may be the first indications of a problem.
White deposits may form when Diesel Exhaust Fluid (DEF) does not properly evaporate or decompose within the exhaust system. Incorrect dosing, low exhaust temperatures, or poor DEF mixing can contribute to deposit formation.
The SCR catalyst is not responsible for directly burning soot during Diesel Particulate Filter (DPF) regeneration. However, related aftertreatment faults may interfere with system operation, so the DOC, DPF, temperature sensors, and DEF components should be evaluated when regeneration problems occur.




























