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 4310-11-19 ( OEM Part Number 726853 ). 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 | 726853 |
| Additional OEM | 717558, 726853 |
ADDITIONAL DETAILS
| CONDITION | Remanufactured |
| UPC / Barcode | 00840490540965 |
| 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.
The E-ONE Cummins ISL DEF Head Unit: OEM 726853 provides accurate monitoring and reliable function for the diesel exhaust fluid system in compatible E-ONE emergency vehicles. Built to OEM specifications, this unit measures DEF level, temperature, and quality to maintain emissions compliance and consistent aftertreatment performance. Its rugged construction ensures dependable service in demanding environments, protecting both the exhaust system and engine efficiency. Choosing an OEM DEF head unit minimizes compatibility issues and supports long-term reliability. This component is a trusted solution for keeping E-ONE Cummins-powered apparatus operating smoothly and without interruption.
PEOPLE ALSO ASKS | BLOG(S)
The DEF Head Unit, part number 726853, is a multifunctional component installed on the DEF (Diesel Exhaust Fluid) tank in E-ONE vehicles powered by Cummins ISL engines. It plays a vital role in the emissions system, ensuring proper operation of the Selective Catalytic Reduction (SCR) system by managing DEF fluid monitoring and delivery.
Core Functions of the 726853 DEF Head Unit
- Monitors DEF Fluid Level
- The unit includes sensors that detect how much DEF remains in the tank. This information is sent to the vehicle's control system to alert operators before levels become critically low.
- Measures DEF Temperature
- Since DEF can freeze in cold conditions, the head unit keeps track of fluid temperature to help the system activate heating or adjust operations as needed.
- Filters the DEF Fluid
- An internal filter, typically around 40 microns, removes particulates and impurities from the fluid. This protects sensitive downstream components such as the DEF pump and dosing module.
- Manages Fluid Flow
- The unit handles both suction (drawing DEF from the tank) and return lines (sending unused fluid back to the tank), ensuring a consistent and clean flow throughout the system.
A properly functioning DEF head unit ensures that the SCR system receives clean, temperature-appropriate DEF at the right flow rate. If this unit fails, it can trigger warning lights, engine derate, or lead to non-compliance with emissions standards. Regular inspection and timely replacement of the DEF head unit can help avoid costly downtime and maintain system reliability.
This component is essential for ensuring emissions efficiency, protecting your equipment, and keeping your vehicle on the road without interruptions.
The DEF (Diesel Exhaust Fluid) head unit is a sensitive component responsible for reading fluid level, quality, and temperature inside the DEF tank. If you're experiencing false warnings or erratic readings, you may wonder if cleaning the unit is a safe and effective solution.
Can You Clean a DEF Head Unit?
Surface-level cleaning is generally safe when done carefully. However, the internal parts of the DEF head unit—like sensors and heating elements—should not be disassembled or aggressively cleaned unless handled by a trained technician.
Safe Cleaning Tips
If you choose to clean around the DEF head unit:
- Use only distilled water
- Avoid tap water or chemicals that could leave residue
- Remove crystal buildup gently
- Use a soft brush or cloth around ports and connectors
- Keep electrical areas dry
- Never spray water directly onto connectors
- Avoid pressure washing
- High-pressure water can force moisture into sealed components
- Do not open the unit
- Internal damage may occur if tampered with
Cleaning may help with minor surface buildup, but if issues persist, diagnostic testing is recommended. Replacing the unit is often the safest long-term fix.
Inaccurate DEF levels, warning lights, or derates are common indicators of failure.
It provides precise DEF data to prevent unexpected derates and downtime.
Yes, a bad unit can reduce engine power and reliability during critical use.
Match your current DEF head unit’s part number with OEM 726853 before ordering.
Cummins DEF Head Units
