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Product Details
Your modern Mercedes-Benz BlueTEC diesel utilizes a sophisticated Selective Catalytic Reduction (SCR) system to deliver massive torque while keeping nitrogen oxide (NOx) emissions incredibly low. At the heart of this system is the Diesel Exhaust Fluid (DEF) Injection Nozzle—often referred to as the dosing valve.
Mounted directly to the exhaust pipe ahead of the SCR catalyst, this highly advanced nozzle is responsible for injecting a microscopic, precisely timed mist of DEF (AdBlue) into the blazing hot exhaust stream. A chemical reaction then converts harmful smog-producing NOx into harmless nitrogen and water vapor. However, because this nozzle lives in an environment of extreme exhaust heat and constantly handles highly corrosive urea fluid, it is a common failure point. Over time, the internal solenoid can fail, or the nozzle tip can become completely clogged with rock-hard, crystallized DEF.
Common Signs of a Failing DEF Injection Nozzle:
The Dreaded "Start Countdown": Federal emissions regulations require the Engine Control Unit (ECU) to prevent the vehicle from running if the SCR system is compromised. A failed nozzle will trigger a dashboard message warning you of a limited number of engine restarts (e.g., "10 Starts Remaining") before the vehicle is completely immobilized.
Check Engine Light & SCR Codes: The ECU will quickly detect a pressure drop, circuit failure, or dosing inaccuracy and trigger a CEL, accompanied by specific OBD-II codes related to the reductant injection valve.
Visible White Buildup: If the internal seals of the nozzle fail, you may see massive amounts of chalky, white, crystallized DEF building up on the outside of your exhaust pipe around the dosing valve.
ECS Tuning Recommends for BlueTEC Owners: Do not ignore a DEF warning light—once the start countdown reaches zero, your vehicle will need to be towed! Replacing this DEF injection nozzle is a relatively straightforward DIY, but fitment is incredibly specific.
CRITICAL FITMENT NOTE: Mercedes-Benz updated these emissions systems frequently. This specific Bosch nozzle (Part # 0444025005) is specifically designed for ML350, GL350, and ML250 models with Build Codes U77, 806, or 807, and E250 models with Build Code U42. Please verify your vehicle's data card/build sheet before ordering.
Tech Tip: DEF crystallizes rapidly when exposed to air. When you remove the old nozzle, you will likely find heavy white crust built up inside the exhaust port. Do not scrape this into the exhaust! A well-known mechanic's secret is to use hot, distilled water to instantly dissolve and wipe away crystallized DEF. Ensure the mounting port is perfectly clean before installing the new nozzle to guarantee a leak-proof seal.
Essential Supplies for the Job
Replacing your DEF dosing nozzle usually requires topping off your fluid system and ensuring the mounting hardware is removed carefully. We highly recommend adding these to your cart before starting the repair:
Genuine Mercedes-Benz Diesel Exhaust Fluid (DEF): If you are servicing the SCR system, it is the perfect time to top off your AdBlue tank with fresh, high-quality reductant fluid to prevent future crystallization issues.
Schwaben 11-Piece External Torx (E-Torx) Socket Set (ECS Part #: ES#2777804): The clamps and brackets securing the exhaust and emissions components on your Mercedes-Benz rely almost entirely on E-Torx hardware. You cannot use standard hex sockets on these without stripping the heads.
This Part Fits the Following Vehicles
| Make | Model | Submodel | Engine | Year | Chasis | Special Fitment Notes |
|---|---|---|---|---|---|---|
| Mercedes Benz | E250 | Bluetec | I4 2.1L 651.924 | 2014 | 212.004 | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | Bluetec 4Matic | I4 2.1L 651.924 | 2014 | 212.097 | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | All | I4 2.1L 651.924 | 2014 | 212.004 | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | All | I4 2.1L 651.924 | 2014 | 212.097 | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | Bluetec | I4 2.1L 651.924 | 2014 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | Bluetec 4Matic | I4 2.1L 651.924 | 2014 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | All | I4 2.1L 651.924 | 2014 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | Bluetec | L4 2.1L | 2015 | 212.004 | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | Bluetec 4Matic | L4 2.1L | 2015 | 212.097 | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | All | L4 2.1L | 2015 | 212.004 | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | All | L4 2.1L | 2015 | 212.097 | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | Bluetec | L4 2.1L | 2015 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | Bluetec 4Matic | L4 2.1L | 2015 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | All | L4 2.1L | 2015 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | Bluetec | L4 2.1L | 2016 | 212.004 | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | Bluetec 4Matic | L4 2.1L | 2016 | 212.097 | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | All | L4 2.1L | 2016 | 212.004 | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | All | L4 2.1L | 2016 | 212.097 | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | Bluetec | L4 2.1L | 2016 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | Bluetec 4Matic | L4 2.1L | 2016 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | E250 | All | L4 2.1L | 2016 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec 4Matic | V6 3.0L | 2015 | 166.824 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L | 2015 | 166.824 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec 4Matic | V6 3.0L | 2015 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L | 2015 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec 4Matic | V6 3.0L | 2016 | 166.824 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L | 2016 | 166.824 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec 4Matic | V6 3.0L | 2016 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L | 2016 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec 4Matic | V6 3.0L 642.820 | 2010 | 164.825 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L 642.820 | 2010 | 164.825 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec 4Matic | V6 3.0L 642.820 | 2010 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L 642.820 | 2010 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec 4Matic | V6 3.0L 642.820 | 2011 | 164.825 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L 642.820 | 2011 | 164.825 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec 4Matic | V6 3.0L 642.820 | 2011 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L 642.820 | 2011 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec | V6 3.0L 642.820 | 2012 | 164.825 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L 642.820 | 2012 | 164.825 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec | V6 3.0L 642.820 | 2012 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L 642.820 | 2012 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec 4Matic | V6 3.0L 642.826 | 2013 | 166.824 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L 642.826 | 2013 | 166.824 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec 4Matic | V6 3.0L 642.826 | 2013 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L 642.826 | 2013 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec 4Matic | V6 3.0L 642.826 | 2014 | 166.824 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L 642.826 | 2014 | 166.824 | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | Bluetec 4Matic | V6 3.0L 642.826 | 2014 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GL350 | All | V6 3.0L 642.826 | 2014 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | GLE300d | 4Matic | L4 2.1L | 2016 | 166.004 | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML250 | Bluetec 4Matic | L4 2.1L | 2015 | 166.004 | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | Bluetec 4Matic | V6 3.0L 642.820 | 2010 | 164.125 | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | All | V6 3.0L 642.820 | 2010 | 164.125 | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | Bluetec 4Matic | V6 3.0L 642.820 | 2010 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | All | V6 3.0L 642.820 | 2010 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | Bluetec 4Matic | V6 3.0L 642.820 | 2011 | 164.125 | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | All | V6 3.0L 642.820 | 2011 | 164.125 | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | Bluetec 4Matic | V6 3.0L 642.820 | 2011 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | All | V6 3.0L 642.820 | 2011 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | Bluetec 4Matic | V6 3.0L 642.826 | 2012 | 166.024 | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | All | V6 3.0L 642.826 | 2012 | 166.024 | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | Bluetec 4Matic | V6 3.0L 642.826 | 2012 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | All | V6 3.0L 642.826 | 2012 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | Bluetec 4Matic | V6 3.0L 642.826 | 2013 | 166.024 | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | All | V6 3.0L 642.826 | 2013 | 166.024 | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | Bluetec 4Matic | V6 3.0L 642.826 | 2013 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | All | V6 3.0L 642.826 | 2013 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | Bluetec 4Matic | V6 3.0L 642.826 | 2014 | 166.024 | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | All | V6 3.0L 642.826 | 2014 | 166.024 | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | Bluetec 4Matic | V6 3.0L 642.826 | 2014 | All | Use vehicle selector to confirm fitment |
| Mercedes Benz | ML350 | All | V6 3.0L 642.826 | 2014 | All | Use vehicle selector to confirm fitment |
This Product Is Covered By Our Lifetime Replacement Program
Products protected by our Lifetime Replacement Program are covered for as long as you own the product, no need to worry about an expiration date. Purchase your products and enjoy some worry-free motoring, knowing we've got you covered.
If you have any questions, would like to learn more or are ready to place a replacement claim, click here!
Return and Exchanges
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All you need is your order number and email address.
New/Unused Product Returns
ECS Tuning will accept returns for unused products within 90 days of the ship date for a refund to the original payment method used. The customer is responsible for the return shipping costs and fees. If selecting to use a prepaid shipping label, the shipping cost will be deducted from the total refunded amount. All new/unused products must be new, unused and must be in the original packaging, including labeling, manuals, hardware, etc. Special order parts are non-refundable.
In the event that we find an error on our website or on behalf of an ECS Tuning Representative, we will provide a return shipping label from the original delivery location.
Refused Packages
Any domestic orders that are returned to ECS Tuning as refused by receiver or non-deliverable will be subject to a return handling fee and will be processed as a return in compliance with our standard return policy, including a 15% restocking fee.
Any international orders that are refused at the time of delivery will be subject to carrier abandonment of the package, at which time the ordered products would be discarded by the carrier. The customer will not be refunded for the value of the order and the discarded products are no longer retrievable.
Return Process
ECS Tuning now offers an online returns solution! To get started, simply log into your ECS Tuning account, Click the "View Orders" button on the My Account home page and select the order that you wish to make a return on to begin. If you have any questions, feel free to reach out to our Customer Service Team for assistance!
Please note: Refunds will be processed to the original payment method used on the order or to an in store credit, respective to the type of return that is made as well as any pre-existing arrangements with an ECS Tuning Customer Service Representative. In the event that multiple forms of payment were used, we will refund the value to an in store credit. In the event that a return label is provided, these charges may be deducted from the total refund you receive.
Original shipping costs are non-refundable and the buyer is responsible for return shipping charges. ECS Tuning will not accept COD deliveries.
All in store credit balances will expire after one year from the original purchase date.
Shipping Policy
Free Shipping On Orders $49 & Up
Items marked with a 'Free Shipping On Orders $49 and Up' logo may qualify for free standard economy ground shipping to the contiguous United States (48 states) for most orders with a value greater or equal to $49.00 USD. Oversized products and direct ship products are excluded from this offer unless otherwise noted.
Free Shipping
Items marked as 'Free Shipping' may qualify for free standard economy ground shipping to the contiguous United States (48 states). Oversized products and direct ship products are excluded from this offer unless otherwise noted.
The policies listed above are subject to change at any time without notice.
Lifetime Replacement
Want to know more about our Lifetime Replacement program?
Click here to learn more.
Why You Should Shop From ECS Tuning
ECS Tuning stands out as more than an automotive parts supplier-it's a vibrant community fueled by a shared passion for cars. Born from the enthusiasm of car lovers, we offer an unmatched understanding and commitment to the automotive world, providing high-quality parts and accessories sourced from our own experiences. Our selection is meticulously crafted to meet the highest standards of performance, quality, and design, catering to both the latest trends and classic styles.
Our distinct advantage lies in our passionate team and comprehensive support, offering expert advice and seamless service from selection to installation. Shopping with ECS brings exclusive perks, including our Lifetime Replacement Guarantee and free shipping on orders over $49, enhancing the value of every purchase. As a central hub for car enthusiasts, ECS Tuning fosters a rich community where ideas and experiences flourish, transforming us from a mere supplier into a platform where automotive dreams come to life.
Cancellation Policy
At ECS Tuning, we understand that plans can change. That's why we offer a flexible cancellation policy for our customers. You may cancel your order at any time before you receive the shipment confirmation. This policy is designed to provide you with peace of mind and the flexibility to make adjustments to your purchases as needed. Should you decide to cancel your order, simply reach out to our customer service team, and we will assist you with the process swiftly and efficiently.
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