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Cummins B6.7, ISL Doser DEF Pump 2021-2024: OEM 5509448RX

CUMMINS B6.7, ISL DOSER DEF PUMP 2021-2024: OEM 5509448RX

Shipping ICON

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY ICON

WARRANTY
1M MILES OR 1 YEAR

$1,895.00

AVAILABILITY IN STOCK
OEM NUMBER 5509448RX
PART TYPE Doser DEF Pump
BRAND Tamerx Diesel Products
ENGINE MAKE Cummins
ENGINE TYPE B6.7, ISL
YEAR 2021-2024
PART NUMBER 5509448RM
ADDITIONAL NOTES 24 Volt System

PRODUCT DESCRIPTION

This is a New, Tamerx Doser DEF Pump, Tamerx part number 5509448RM ( OEM Part Number 5509448RX ).This part is primarily made for a Cummins B6.7, ISL, production years 2021-2024, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here

Additional Notes: 24 Volt System

OEM NUMBERS

Primary OEM5509448RX
Additional OEM5509448, 5509448RX

ADDITIONAL DETAILS

CONDITIONNew
UPC / Barcode00840490542280
WEIGHT2.00 LBS

SHIPPING OPTIONS

Ship Weight : 2.00 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.

"This Product Doesn't Have a Core"


Drive your emissions system with confidence using the Cummins B6.7 / ISL Doser DEF Pump (2021–2024) – OEM 5509448RX — engineered to deliver consistent, high-precision DEF flow under all conditions. Built for seamless integration into your SCR system, this rugged pump ensures your dosing sequence stays on point, helping prevent derates and keep your engine running clean and compliant. Reliable, tough, and performance-tuned — it’s the upgrade your Cummins needs to thrive.

FITMENT CHART

YEARMAKEENGINE(S)
2021Cummins B6.7 ISL
2022Cummins B6.7 ISL
2023Cummins B6.7 ISL
2024Cummins B6.7 ISL

PEOPLE ALSO ASKS | BLOG(S)

In the intricate dance of modern diesel aftertreatment systems, the DEF (Diesel Exhaust Fluid) dosing circuit is a linchpin. For Cummins B6.7 and ISL engines (2021–2024), the OEM 5509448RX DEF Doser Pump supplies the pressure and flow control needed to deliver urea precisely where the SCR (Selective Catalytic Reduction) system needs it. Without a properly functioning doser pump, downstream injectors and sensors may struggle to maintain emissions compliance, leading to errors or forced derates.

  • Pressurizes the DEF supply line to the correct levels so the dosing system can operate effectively

  • Maintains steady, consistent flow even under varying demands and operating conditions

  • Helps protect against fault codes, emissions warnings, or derate events caused by weak or fluctuating pump pressure

  • Built to Cummins’ factory specifications (5509448RX) for reliable performance and drop-in compatibility

  • Engineered to resist corrosion, thermal stress, and chemical exposure from urea and exhaust components

  • Supports accurate dosing by ensuring injectors always see stable inlet pressure

A failing or underperforming doser pump is one of the common behind-the-scenes causes of emissions trouble. By replacing it with the correct OEM 5509448RX DEF Doser Pump, you restore the pressure baseline your dosing circuit depends on, stabilize downstream control, and help keep your engine running clean and compliant. In modern emission control systems, pressure is king—and this pump is royalty.

The DEF (Diesel Exhaust Fluid) doser pump is responsible for supplying the correct amount of DEF to the injector, ensuring emissions are reduced effectively. When this pump begins to fail, the system cannot maintain proper dosing, which can trigger fault codes, warning lights, and reduced vehicle performance. Recognizing the symptoms early can help avoid costly repairs and downtime.

Common Symptoms of a Failing DEF Doser Pump

  • Warning Lights on the Dashboard
    The check engine light or DEF system warning may appear when the pump cannot deliver fluid properly.

  • Recurring Fault Codes
    Codes such as P20E8 (low DEF pressure) or related dosing system errors often indicate pump problems.

  • Poor DEF Pressure
    A weak or failing pump may struggle to build and maintain the correct pressure for injection.

  • Engine Derate Mode
    If the engine control module (ECM) cannot verify proper DEF delivery, it may reduce power or speed to stay emissions-compliant.

  • Unusual Noises
    A failing pump may produce whining, buzzing, or grinding sounds during operation.

  • Reduced Fuel Efficiency or Emission Issues
    Inconsistent dosing can affect combustion efficiency, sometimes leading to higher fuel consumption or increased emissions.

A failing DEF doser pump often shows itself through dashboard warnings, poor DEF pressure, or derate conditions. Addressing the issue early—through inspection, repair, or replacement—keeps your emissions system functioning properly and prevents unnecessary downtime. Staying proactive ensures your vehicle remains reliable and compliant on the road.

Inspect and clean filters, ensure no blockage in lines, check electrical connections, and replace it if flow weakens.

Contaminants and crystals can clog the pump internals, damage seals, or wear internal components unevenly.

Measure the volume output under known conditions or log commanded vs actual dosing from diagnostics.

Yes — mechanical shock or excessive vibration can damage internal parts, loosen electrical connections, or degrade seals.

Cummins Doser DEF Pumps

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