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Capacity Cummins ISB 6.7L DEF Head Unit

CAPACITY CUMMINS ISB 6.7L 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 NUMBER 909934
PART TYPE DEF Head Unit
BRAND Tamerx Diesel Products
ENGINE MAKE Cummins
ENGINE TYPE ISB 6.7L
YEAR
PART NUMBER 5410-18-FA01-1
APPLICATION NOTES Capacity
ADDITIONAL NOTES DEF Header, 40 MICRON, 18"

PRODUCT DESCRIPTION

This is a Remanufactured, Tamerx DEF Head Unit, Tamerx part number 5410-18-FA01-1 ( OEM Part Number 909934 ). This part is primarily made for a Cummins ISB 6.7L, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here

Additional Notes: DEF Header, 40 MICRON, 18"

OEM NUMBERS

Primary OEM909934
Additional OEM909934

ADDITIONAL DETAILS

CONDITIONRemanufactured
UPC / Barcode00840490539938
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.


Boost your emissions control with the Capacity Cummins ISB 6.7L DEF Head Unit — engineered for precision, durability, and seamless integration. This rugged module delivers real-time monitoring of DEF level, temperature, and quality to help your SCR system run optimized, prevent derates, and ensure compliance. Built tough for heavy use and backed by Tamerx’s trusted warranty, it’s the emissions upgrade your operation demands.

PEOPLE ALSO ASKS | BLOG(S)

If your vehicle or machine is built on a Capacity chassis with a Cummins ISB 6.7L engine, your emissions system depends heavily on accurate feedback and dosing. The Capacity Cummins ISB 6.7L DEF Head Unit (OEM 911181, Tamerx part 4310-18-1) is a linchpin component that monitors fluid level, temperature, and urea concentration, while controlling flow into the SCR system. When that head is off—even slightly—you risk warning codes, emissions faults, or even system derates.

  • Monitors DEF fluid parameters — level, temperature, and urea concentration — sending reliable signals to the engine control unit

  • Regulates precise dosing of DEF into the exhaust stream so the SCR (Selective Catalytic Reduction) system can reduce NOx emissions effectively

  • Built to meet the OEM 911181 standard for plug-and-play integration with Capacity / Cummins ISB 6.7L systems

  • Helps prevent fault codes, warning lights, and engine derates triggered by sensor drift or inaccurate readings

  • Constructed to withstand real-world stress: vibration, thermal cycling, and exposure to DEF chemistry

  • Includes filtration (approx. 40 microns) to protect downstream injectors and components from contamination

A failing or mis-calibrated DEF head unit is often the silent culprit behind emission system errors. Installing the correct OEM 911181 Capacity Cummins ISB 6.7L DEF Head Unit restores sensor integrity, stabilizes your SCR circuit, and helps keep your machine emission-compliant and dependable. In the emissions chain, this small component plays an outsized role—don’t let it become your weak link.

The DEF (Diesel Exhaust Fluid) head unit plays a vital role in monitoring fluid level, temperature, and quality. When it starts to fail, it can trigger fault codes, warning lights, or even cause your vehicle to enter derate mode. Regularly testing your DEF head unit can help you confirm whether it’s working correctly and catch problems early.

Ways to Test a DEF Head Unit

  • Check Dashboard Alerts
    Look for check engine lights or DEF system warnings. Inconsistent or recurring alerts may indicate head unit issues.

  • Scan for Diagnostic Trouble Codes (DTCs)
    Use a diagnostic tool to look for codes like P203F (DEF level issue), P205B (temperature sensor fault), or P207F (quality sensor fault).

  • Monitor DEF Readings
    Compare the displayed DEF level to the actual fluid level in the tank to verify accuracy.

  • Inspect for Crystallization or Contamination
    Check the unit and surrounding area for DEF crystal buildup or debris, which can interfere with sensors.

  • Test Electrical Connections
    Ensure wiring and connectors are clean, secure, and free of corrosion to maintain proper communication with the ECM.

  • Confirm Consistency
    If readings fluctuate or reset frequently, it’s a sign the head unit may be failing.

Testing a DEF head unit involves checking warning lights, scanning for codes, verifying fluid level accuracy, and inspecting for physical issues. A healthy unit should provide consistent, accurate data. If you notice recurring errors or unreliable readings, it may be time for service or replacement to keep your vehicle compliant and running smoothly.

Sensor failure, clogged filters, freezing fluid, or erratic readings are typical issues.

You might see DEF error codes, inconsistent level or temperature readings, or the engine entering derate.

It should be checked during routine DEF or emissions system maintenance or when warning lights appear.

Flush the DEF pickup path with clean, ISO-compliant fluid and gently clean or replace its internal strainer.

 

Cummins DEF Head Units

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