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Eldorado Cummins DEF Head Unit

ELDORADO CUMMINS DEF HEAD UNIT

Shipping ICON

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY ICON

WARRANTY
1M MILES OR 1 YEAR

$1,295.00

CORE CHARGE:

$250.00
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 NUMBER840175
PART TYPEDEF Head Unit
BRANDTamerx Diesel Products
ENGINE MAKECummins
ENGINE TYPE
YEAR
PART NUMBER5410-22-FC01-4
APPLICATION NOTESEldorado
ADDITIONAL NOTESDEF Header, 40 MICRON, 22"

PRODUCT DESCRIPTION

This is a Remanufactured, Tamerx DEF Head Unit, Tamerx part number 5410-22-FC01-4 ( OEM Part Number 840175 ). This part is primarily made for a Cummins , and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here

Additional Notes: DEF Header, 40 MICRON, 22"

OEM NUMBERS

Primary OEM840175
Additional OEM840173, 840175, 10324221, 10773127

ADDITIONAL DETAILS

CONDITIONRemanufactured
UPC / Barcode00840490540675
WEIGHT8.00 LBS

SHIPPING OPTIONS

Ship Weight : 8.00 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.


Unleash peak emissions control with the Eldorado Cummins DEF Head Unit — precision-engineered for Eldorado chassis and Cummins engines (OEM 840175). This rugged, remanufactured unit integrates flawlessly with your SCR system, delivering real-time monitoring of DEF level, temperature, and quality to help eliminate derates and maximize uptime. With reliable performance and backed by Tamerx’s industry-leading warranty, it’s the smart choice for keeping your engine clean, compliant, and ready to roll.

PEOPLE ALSO ASKS | BLOG(S)

In fire trucks and emergency vehicles, downtime is not an option—and emissions compliance is a must. The Eldorado Cummins DEF Head Unit, built to OEM 840175 specs (Tamerx part 5410-22-FC01-4), acts as the pivotal control unit in your DEF (Diesel Exhaust Fluid) circuit. A failing DEF head can quickly escalate from a nuisance fault to derated engine operation when you least expect it.

  • Monitors fluid temperature, level, and urea concentration and relays real-time data to the ECU

  • Enables precise dosing of DEF into the exhaust stream, supporting the SCR (Selective Catalytic Reduction) system’s NOx conversion

  • Designed for drop-in compatibility with Eldorado / Cummins platforms thanks to OEM 840175 engineering

  • Reduces risk of fault codes, emissions warnings, and derate events due to inaccurate sensor signals

  • Built to withstand harsh environments: vibration, thermal cycling, and DEF’s corrosive nature

  • Replacing it restores system integrity and helps your vehicle maintain regulatory compliance

Emergency vehicle operators can’t afford surprises—especially ones tied to emissions systems. Installing the OEM 840175 Eldorado Cummins DEF Head Unit ensures your DEF circuit remains accurate, reliable, and ready for mission-critical duty. Keep your rig compliant and ready, so you’re never sidelined when you can’t afford to be.

The DEF (Diesel Exhaust Fluid) head unit is a small but critical component in modern diesel engines, ensuring proper monitoring of DEF level, quality, and temperature. Like all parts of the emissions system, it has a limited service life. Knowing how long a DEF head unit typically lasts—and the factors that affect its durability—can help operators plan ahead and minimize unexpected downtime.

Typical Lifespan and Key Factors

  • Average Service Life
    Most DEF head units last 5 to 7 years under normal operating conditions before needing replacement.

  • Vehicle Usage
    Heavy-duty trucks with high mileage and long operating hours may see a shorter lifespan compared to vehicles with lighter use.

  • Environmental Conditions
    Exposure to extreme heat, freezing temperatures, or constant outdoor storage can accelerate wear.

  • Quality of DEF Fluid
    Using certified, uncontaminated DEF helps protect sensors and extend the life of the head unit.

  • Maintenance Practices
    Regular inspections, tank cleaning, and careful handling during service all contribute to longer component life.

  • Early Warning Signs
    Frequent fault codes, inaccurate fluid readings, or false alerts may indicate the unit is nearing the end of its service life.

While a DEF head unit can typically last several years, its actual lifespan depends on operating conditions, maintenance habits, and fluid quality. By following preventive care practices and addressing early warning signs, operators can maximize the life of the unit and keep their vehicles running reliably.

Drain or isolate the DEF, disconnect wiring and fluid lines, remove the old unit, install the new one, prime, and run calibration diagnostics.

The engine may derate power, trigger emissions faults, or enter a safe mode until the issue is resolved.

It sends sensor signals (level, temperature, quality) to the engine control module for dosing decisions.

It should be inspected and tested during regular engine service intervals for sensor accuracy, cleanliness, and integrity.

Cummins DEF Head Units

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