Loading...

Perkins Engines Perkins DEF Head Unit

PERKINS ENGINES PERKINS DEF HEAD UNIT

Shipping ICON

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY ICON

WARRANTY
1M MILES OR 1 YEAR

$585.00

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 T434814
PART TYPE DEF Head Unit
BRAND Tamerx Diesel Products
ENGINE MAKE Perkins
ENGINE TYPE
YEAR
PART NUMBER 1795-11-2
APPLICATION NOTES Perkins Engines
ADDITIONAL NOTES DEF Header, 40 MICRON, 11"

PRODUCT DESCRIPTION

This is a Remanufactured, Tamerx DEF Head Unit, Tamerx part number 1795-11-2 ( OEM Part Number T434814 ). This part is primarily made for a Perkins , 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 OEMT434814
Additional OEMT432585, T434814

ADDITIONAL DETAILS

CONDITIONRemanufactured
UPC / Barcode00840490541320
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.


Power your Perkins engine’s clean-air performance with the Perkins DEF Head Unit — precision-built for real-time monitoring of DEF level, temperature, and quality. Rugged and OEM-matched, it integrates flawlessly into your SCR system to help prevent derates, maintain compliance, and keep your equipment running strong under any conditions.

PEOPLE ALSO ASKS | BLOG(S)

In modern diesel engines, the aftertreatment system hinges on trustworthy feedback loops—and the DEF (Diesel Exhaust Fluid) head unit is a core piece of that puzzle. For Perkins engines, the DEF Head Unit (OEM T434814) is responsible for relaying fluid status and controlling DEF dosing. When it malfunctions or drifts from calibration, the results show up as error codes, emissions failures, or unplanned downtime.

  • Tracks DEF fluid level, temperature, and urea concentration and sends those readings to the ECU

  • Manages precise dosing of DEF into the exhaust stream to allow the SCR (Selective Catalytic Reduction) system to reduce NOx emissions correctly

  • Built to meet OEM T434814 specifications to ensure correct fit, calibration, and system integration

  • Helps prevent system warnings, error codes, or engine derates that stem from faulty or drifting sensor signals

  • Designed to resist vibration, temperature swings, and the harsh chemistry of DEF fluid

  • Replacement is simplified when you use a certified OEM-matched unit, minimizing downtime

Because the DEF head unit is often one of the first components to fail in the emissions circuit, it pays to treat it as a critical maintenance item rather than an afterthought. Installing the OEM T434814 Perkins DEF Head Unit brings your emissions feedback back into alignment, protects your SCR system, and reduces the risk of surprises down the road.

 
 

The DEF (Diesel Exhaust Fluid) head unit is a sensitive component of the emissions system, monitoring DEF level, temperature, and quality. When it fails, operators often ask if repair is possible, or if full replacement is the only solution. While some minor issues can be addressed, most failures require replacement due to the complexity of the unit’s sensors and electronics.

When Repair May Be Possible

  • Crystallization Build-Up
    Cleaning away DEF crystals around the sensors may restore accuracy in mild cases.

  • Connector or Wiring Issues
    Corroded or loose electrical connections can sometimes be repaired without replacing the entire unit.

  • Debris or Contamination
    Flushing and cleaning the DEF tank may resolve performance issues caused by dirt or fluid contamination.

When Replacement Is Necessary

  • Failed Internal Sensors
    The quality, level, and temperature sensors are sealed and cannot be repaired once damaged.

  • Electronic Circuit Failures
    Malfunctions inside the head unit’s circuitry require a full replacement to restore reliability.

  • Recurring Fault Codes
    If diagnostic trouble codes persist after cleaning or minor repairs, replacement is usually the only fix.

While minor cleaning or connector repairs may temporarily improve DEF head unit performance, most failures cannot be permanently repaired. Because the sensors and electronics are sealed, replacement is typically the most reliable long-term solution. Addressing issues quickly helps avoid costly downtime and ensures your vehicle stays emissions-compliant.

Excessive DEF can lead to ammonia slip, inefficiency, or trigger downstream faults in the aftertreatment system.

Depressurize the DEF system, disconnect wiring, unbolt the head unit carefully, and seal appropriately upon reinstallation.

With proper care and clean fluid, it often lasts several years in line with the exhaust aftertreatment module’s lifespan.

Excessive vibration or impact can damage sensors or connections, lead to leaks, or cause internal failure.

PRODUCT VIDEOS