Holland Bus Cummins ISB 6.7L DEF Head Unit
HOLLAND BUS CUMMINS ISB 6.7L 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 5410-18-FA01-10 ( OEM Part Number 5011806 ). 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 OEM | 5011806 |
| Additional OEM | 5011806 |
ADDITIONAL DETAILS
| CONDITION | Remanufactured |
| UPC / Barcode | 00840490540262 |
| 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.
Consistent emissions control is maintained with the Holland Bus Cummins ISB 6.7L DEF Head Unit: OEM 5011806, a direct-fit solution for compatible Holland Bus vehicles. Built to OEM standards, this unit monitors diesel exhaust fluid level, temperature, and quality to support reliable aftertreatment performance and compliance with emissions regulations. Its durable design withstands demanding operating conditions, helping protect both the exhaust system and overall engine efficiency. By choosing an OEM DEF head unit, you reduce compatibility concerns and ensure dependable long-term service. This component is a trusted option for keeping Holland Bus Cummins-powered vehicles running smoothly and without interruption.
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The DEF Head Unit number 5011806 is a multifunction sensor‑module mounted on the DEF (Diesel Exhaust Fluid) tank in Holland Bus vehicles with the Cummins ISB 6.7L engine. It handles multiple tasks related to monitoring, circulating, and conditioning the DEF used for emissions control.
The primary role of the 5011806 DEF Head Unit is to ensure the proper operation of the DEF system so that the Selective Catalytic Reduction (SCR) aftertreatment system can reduce harmful NOₓ emissions according to regulatory standards.
To do this, it:
- Senses how much DEF fluid is in the tank and alerts when levels are low.
- Measures DEF fluid temperature—important because DEF can freeze or behave poorly outside certain temperatures.
- Filters the fluid to remove contaminants before it's used downstream.
- Provides the fluid suction and return flow paths for correct DEF delivery to the dosing or injection system.
A well‑functioning 5011806 head unit is essential to avoid warning codes, engine derate, or failure to meet emissions standards. It protects the SCR system, helps maintain fuel‑economy, and ensures your bus operates cleanly and reliably.
The DEF (Diesel Exhaust Fluid) head unit is a critical part of the aftertreatment system. It monitors fluid level, quality, and temperature. If it starts to fail, your vehicle may enter derate mode or show inaccurate alerts, even if the tank is full and the fluid is clean.
Step-by-Step Diagnosis Guide
To accurately diagnose a failing DEF head unit, follow these steps:
- Run a scan tool
- Retrieve trouble codes related to DEF level, temperature, or fluid quality (e.g., SPN 1761, 3031).
- Check actual DEF level
- Visually inspect the DEF tank. If the gauge says “empty” but the tank is full, sensor readings may be incorrect.
- Inspect wiring and connectors
- Look for damaged pins, corrosion, or loose harnesses on the DEF tank and head unit.
- Review freeze history
- If the system was exposed to extreme cold without proper heating, internal sensors may have failed.
- Monitor DEF usage
- Unusual consumption patterns or rapid drops in fluid level could point to signal problems.
If readings remain inaccurate after confirming fluid levels and wiring, the DEF head unit is likely the root cause and should be replaced.
It measures DEF tank level, temperature, and quality in Cummins ISB 6.7L engines.
It is designed for Holland Bus models equipped with Cummins ISB 6.7L engines.
It ensures accurate DEF monitoring so the SCR system meets emissions standards.
It is mounted inside the DEF tank to provide real-time fluid readings.
Cummins DEF Head Units
