E-ONE Cummins ISL DEF Head Unit
E-ONE CUMMINS ISL DEF HEAD UNIT
ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY
WARRANTY
1M MILES OR 1 YEAR
PRODUCT DESCRIPTION
This is a Remanufactured, Tamerx DEF Head Unit, Tamerx part number 5410-11-FA01-1 ( OEM Part Number 716838 ). This part is primarily made for a Cummins ISL, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here
Additional Notes: DEF Header, 40 MICRON, 11"
OEM NUMBERS
| Primary OEM | 716838 |
| Additional OEM | 716838 |
ADDITIONAL DETAILS
| CONDITION | Remanufactured |
| UPC / Barcode | 00840490540170 |
| WEIGHT | 8.00 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.
Ensure your emergency vehicle stays mission-ready with the DEF Head Unit for E-ONE on Cummins ISL, engineered to exact factory specs and deliver reliable control of your DEF system when it matters most. Built for durability, precision, and seamless integration, this unit ensures accurate dosing and emissions compliance so you can focus on getting the job done—without compromise.
PEOPLE ALSO ASKS | BLOG(S)
When you’re behind the wheel of an E-ONE apparatus powered by a Cummins ISL engine, you need every system to perform flawlessly—especially your emissions control components. The DEF (Diesel Exhaust Fluid) head unit is a pivotal but often overlooked link in that chain. The correct head unit built to OEM 724135 specifications ensures your DEF system sees accurate feedback and executes proper urea dosing. A compromised unit can trigger warning codes, reduce system efficacy, or lead to unexpected downtime when you can least afford it.
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Continuously monitors DEF fluid level, temperature, and urea concentration, delivering precise data to the engine control module
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Controls the exact dosing of DEF into the exhaust stream so the SCR (Selective Catalytic Reduction) system can properly convert NOx emissions
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Engineered to match OEM 724135 tolerances to ensure plug-and-play fit and calibration integrity with E-ONE ISL platforms
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Helps prevent emissions fault codes, check engine lights, and engine derates that stem from sensor drift or incorrect readings
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Built robustly to handle vibration, temperature fluctuations, and exposure to diesel exhaust fluid chemistry
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Supports faster servicing with fewer learning curve issues, reducing downtime for apparatus in critical service
In the high-stakes environment of emergency vehicles, emissions systems must be dependable—not just compliant. Installing the correct OEM 724135 DEF head unit restores precision to your feedback loop, supports SCR effectiveness, and helps ensure that your E-ONE unit remains ready for action without surprises. Don’t let a small sensor become your biggest liability.
The DEF (Diesel Exhaust Fluid) head unit is an essential component of a diesel engine’s emissions system. It monitors the DEF tank’s fluid level, quality, and temperature to ensure proper dosing and compliance with emission standards. When it starts to fail, it can trigger performance issues, fault codes, and even engine derate conditions. Recognizing the symptoms early helps prevent costly repairs and downtime.
Common Symptoms of a Failing DEF Head Unit
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Dashboard Warning Lights
The check engine or DEF system light may illuminate due to inaccurate or missing data from the head unit. -
Incorrect DEF Readings
The system may show the DEF tank as full, empty, or low even when the actual level is different. -
False DEF Quality Alerts
You might receive “poor DEF quality” messages despite using clean, ISO-certified fluid. -
Recurring Fault Codes
Codes such as P203F (DEF level), P205B (temperature sensor fault), or P207F (quality sensor issue) are common indicators of a bad head unit. -
Engine Derate Mode
If the ECM (Engine Control Module) can’t confirm DEF data, it may reduce power or limit speed to comply with emissions rules. -
Inconsistent System Behavior
The readings on your dashboard may fluctuate or reset unexpectedly, signaling internal sensor or wiring issues.
A failing DEF head unit can quickly escalate from simple warning lights to severe engine restrictions. If you notice false readings, repeated fault codes, or derate conditions, have the unit inspected immediately. Prompt maintenance and the use of clean, certified DEF fluid will help ensure your emissions system stays reliable and compliant.
Neglect may lead to failed emission tests, increased exhaust temperatures, excessive corrosion, or costly after-treatment damage.
Check gasket or seal surfaces, verify wiring harness connectors, ensure correct sensor calibration, and confirm the unit is properly mounted.
By ensuring correct DEF injection the unit supports optimized SCR operation, reducing thermal stress and excess exhaust heat build-up.
With proper treatment fluid and maintenance it can last for many miles of service, though operating environment and contamination can affect longevity.
Cummins DEF Head Units
