Cummins ECO-FIT Cummins ISB 6.7L, B6.7 DEF Head Unit
CUMMINS ECO-FIT CUMMINS ISB 6.7L, B6.7 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 2317-22-1 ( OEM Part Number 5511561 ). This part is primarily made for a Cummins ISB 6.7L, B6.7, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here
Additional Notes: DEF Header, 564mm
OEM NUMBERS
| Primary OEM | 5511561 |
| Additional OEM | 4378044, 4378046, 5511559, 5511561 |
ADDITIONAL DETAILS
| CONDITION | Remanufactured |
| UPC / Barcode | 00840490540996 |
| 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.
DEF system reliability is supported by the Cummins ECO-FIT ISB 6.7L, B6.7 DEF Head Unit: OEM 5511561, a direct-fit replacement for compatible Cummins-powered equipment. Built to OEM standards, this unit tracks diesel exhaust fluid level, temperature, and quality to help maintain emissions compliance and consistent aftertreatment function. Its durable construction provides long-term service in demanding operating conditions, protecting both the exhaust system and overall engine efficiency. By selecting an OEM DEF head unit, you reduce compatibility concerns and promote dependable performance. This component is a proven solution for keeping Cummins ECO-FIT ISB 6.7L and B6.7 engines operating smoothly and without interruption.
PEOPLE ALSO ASKS | BLOG(S)
The DEF Head Unit with part number 5511561 is a remanufactured or OEM module in the “ECO‑FIT” lineup—designed for Cummins ISB 6.7L (B6.7) engines. It serves as what’s often called a “header” or sensor‑head mounted on the DEF tank. This unit handles multiple tasks for the Diesel Exhaust Fluid (DEF) system in order to support emissions control via the SCR (Selective Catalytic Reduction) process. It comes with a warranty (often 1,000,000 miles or 1 year) when supplied remanufactured.
How It Works & Key Functions
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Fluid Level Sensing: It detects how much DEF is in the tank and provides that information to the engine’s control logic. Knowing fluid levels helps avoid towing or compliance issues if the DEF runs low.
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Fluid Temperature Monitoring: It tracks how warm or cold the DEF is. DEF can freeze or have reduced effectiveness when too cold, so this helps the system decide when heating is required or when accuracy might suffer.
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Filtration / Clean Fluid Passage: It includes filtering (often via internal screen/elements) to block particulates or contaminants from entering downstream parts such as the dosing module, injectors, or SCR catalyst. Clean fluid means less risk of clogs or damage.
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Fluid Routing (Suction & Return): The unit provides the plumbing to pull DEF fluid from the tank (“suction”) toward the dosing or injection point, and also sometimes provides a return or recirculation path for any unused fluid. Proper routing helps maintain steady flow, avoid air locks, and support efficient dosing.
This “5511561” DEF Head Unit is fundamental to making sure the SCR emissions system works properly. If it fails or provides inaccurate readings (level, temperature, cleanliness), you might see one or more of the following:
- Warning lights or error codes
- Engine derate (reduced power) or compliance interruption
- Increased emissions or failure to pass emissions checks
- Potential damage or reduced life of downstream components (injector, SCR catalyst, sensors)
Replacing a failing head unit with a properly remanufactured or OEM “ECO‑FIT” unit ensures reliability, lower risk of downtime, and helps keep your Cummins‑powered equipment compliant and efficient.\
The DEF (Diesel Exhaust Fluid) head unit monitors fluid level, temperature, and quality, making it essential to your vehicle’s emissions system. When it malfunctions, the vehicle may still run—but driving with a bad DEF head unit is not recommended for long periods.
Risks of Driving With a Faulty DEF Head Unit
While temporary operation may be possible, doing so comes with several risks:
- Unexpected derates
- The system may limit speed or engine output, often without warning.
- Incorrect DEF readings
- You could run low on fluid without knowing, or face false "empty tank" alerts.
- Frequent dashboard warnings
- "Service DEF System" and check engine lights may appear often.
- Failed emissions compliance
- A faulty sensor may prevent accurate DEF dosing, leading to inspection failures.
- Potential shutdowns
- After multiple faults, some systems will trigger shutdown procedures.
If you suspect your DEF head unit is bad, get a diagnostic scan immediately. In most cases, continued driving will only increase the risk of downtime and more costly repairs.
It should be checked during regular maintenance or when DEF-related warnings appear.
Yes, it can cause failed emissions tests and regulatory issues.
Persistent false low DEF readings even when the tank is full.
No, it is designed as a direct OEM replacement with standard tools.
Cummins DEF Head Units
