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Freightliner Cummins ISX15, ISL, ISB 6.7 DEF Head Unit

FREIGHTLINER CUMMINS ISX15, ISL, ISB 6.7 DEF HEAD UNIT

Shipping ICON

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY ICON

WARRANTY
1M MILES OR 1 YEAR

$795.00

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 04-31353-006
PART TYPE DEF Head Unit
BRAND Tamerx Diesel Products
ENGINE MAKE Cummins
ENGINE TYPE ISX15, ISL, ISB 6.7
YEAR 2017
PART NUMBER 2323-20-1
APPLICATION NOTES Freightliner
ADDITIONAL NOTES DEF Header, Conc, SAE, Cummins, 20"

PRODUCT DESCRIPTION

This is a Remanufactured, Tamerx DEF Head Unit, Tamerx part number 2323-20-1 ( OEM Part Number 04-31353-006 ).This part is primarily made for a Cummins ISX15, ISL, ISB 6.7, production years 2017, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here

Additional Notes: DEF Header, Conc, SAE, Cummins, 20"

OEM NUMBERS

Primary OEM04-31353-006
Additional OEM04-31353-000, 04-31353-003, 04-31353-006

ADDITIONAL DETAILS

CONDITIONRemanufactured
UPC / Barcode00840490541597
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.


Rev up your emissions control with the Freightliner Cummins ISX15 / ISL / ISB 6.7 DEF Head Unit — a high-precision powerhouse built for compatibility across multiple engine platforms. Offering real-time monitoring of DEF level, temperature, and quality, this rugged unit ensures your SCR system stays optimized and derates stay away. Built tough for long hauls, backed by Tamerx’s trusted warranty, it’s the clean-running upgrade your rig deserves.

FITMENT CHART

YEARMAKEENGINE(S)
2017Cummins ISX15 ISL ISB 6.7

PEOPLE ALSO ASKS | BLOG(S)

Whether you’re hauling cross-country or doing local runs, your emissions system is not optional—it must function flawlessly. At the heart of that system is the DEF (Diesel Exhaust Fluid) head unit. For Freightliner trucks with Cummins ISX15, ISL, or ISB 6.7 engines, the OEM 04-31677-001 DEF head ensures accurate sensing and dosing. When it fails, you may face warning codes, forced derates, or even system lockouts—none of which are ideal on the highway.

  • Monitors DEF fluid level, temperature, and urea concentration, sending clean data to the ECU

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

  • Built to OEM 04-31677-001 tolerances for drop-in compatibility with Freightliner / Cummins setups

  • Helps avoid fault codes, emission warnings, and engine derates triggered by sensor drift or incorrect readings

  • Designed to withstand vibration, temperature swings, and exposure to DEF’s corrosive nature

  • Straightforward replacement minimizes downtime and restores emissions integrity

Don’t wait until your engine derates or your check engine light illuminates. Installing the correct OEM 04-31677-001 Freightliner DEF Head Unit restores the integrity of your emissions feedback loop, protects your SCR system, and keeps your truck running clean, compliant, and reliable. When your operation depends on uptime, this truly is one component you can’t afford to treat as optional.

The DEF (Diesel Exhaust Fluid) head unit measures fluid level, quality, and temperature, ensuring your emissions system works correctly. If it malfunctions, your vehicle may still run, but the risk of escalating issues is high. Driving with a faulty DEF head unit can lead to warnings, reduced power, or even shutdown if the problem isn’t resolved quickly.

What to Expect If You Keep Driving

  • Dashboard Alerts
    Check engine lights or DEF system warnings may appear almost immediately.

  • False or Inaccurate Readings
    The system may display empty, low, or poor-quality DEF even when the tank is properly filled.

  • Diagnostic Trouble Codes (DTCs)
    Fault codes such as P203F, P205B, or P207F may be triggered by inaccurate sensor data.

  • Risk of Derate Mode
    If the ECM (engine control module) cannot confirm DEF information, it may cut power or limit speed.

  • Possible Shutdown
    Ignoring the issue too long may result in stricter limits or even full vehicle shutdown.

Yes, you can technically drive with a malfunctioning DEF head unit, but it’s not recommended. What begins as a warning light can escalate to derate or shutdown, leaving you stranded and facing costly repairs. The safest move is to address the issue right away to keep your vehicle reliable and emissions-compliant.

A built-in temperature sensor monitors the DEF’s temperature and relays that information to the control system.

Inconsistent level or temperature readings, DEF system fault codes, or the engine entering derate mode.

Issues include clogged filters, sensor failure, freezing conditions, or wiring and connector corrosion.

During routine maintenance, especially when DEF or SCR system warnings appear.

Cummins DEF Head Units

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