Proven Aftertreatment Filter for Cummins B6.7 & L9 (2018–2021)
What is it?
The Cummins B6.7, L9 DOC Filter OEM 4394859 is a key emissions control component installed within the Diesel Oxidation Catalyst (DOC) of your engine’s aftertreatment system. Its role is to help oxidize harmful exhaust pollutants—like hydrocarbons and carbon monoxide—into less harmful compounds before they continue through the rest of the emissions system, contributing to cleaner exhaust and improved engine efficiency.
Why choose OEM 4394859?
This DOC filter is specifically engineered for Cummins B6.7 and L9 engines manufactured from 2018 through 2021. Its exact-fit design ensures seamless integration with your vehicle’s original emissions components, helping lower the risk of system faults and maintain dependable performance. With genuine OEM-grade construction, you’re choosing durability and long-term reliability.
Key Benefits
✅ Built for 2018–2021 Cummins B6.7 & L9 engines
✅ Helps reduce hydrocarbons and carbon monoxide in exhaust
✅ Supports efficient aftertreatment system performance
✅ Designed to withstand high-temperature exhaust conditions
✅ Direct-fit replacement for easier installation
Applications
This DOC filter is ideal for Cummins-powered commercial trucks, vocational vehicles, delivery fleets, and other diesel machinery built from 2018 through 2021 that rely on effective and compliant emissions control systems.
Installation Notes
Before installation, make sure the exhaust and aftertreatment system are completely cool. Inspect nearby sensors, gaskets, and connectors for wear or contamination. Follow Cummins-recommended installation procedures and torque specifications to ensure proper sealing and system performance. After installation, verify that the emissions system is functioning correctly.
Final Thoughts
If your Cummins B6.7 or L9 engine is showing emissions-related alerts or diminished aftertreatment effectiveness, the OEM 4394859 DOC filter delivers a reliable, OE-grade replacement solution. Designed for accurate fit and consistent emissions control, it helps keep your engine compliant and operating efficiently. Tamerx has this DOC filter in stock and ready to ship.