Cummins QSF3.8, ISF3.8 SCR Outlet Catalyst Module 2014-2022: OEM 4376878
Compact NOx Control for Cummins QSF3.8 & ISF3.8 Engines (2014–2022)
What is it?
The Cummins QSF3.8 / ISF3.8 SCR Filter, identified by OEM 4376878, is an emissions aftertreatment component designed for engines produced between 2014 and 2022. This filter is part of the Selective Catalytic Reduction (SCR) system, where Diesel Exhaust Fluid (DEF) is introduced into the exhaust stream. As DEF mixes with hot exhaust gases, it converts into ammonia, which reacts inside the SCR catalyst to reduce nitrogen oxide (NOx) emissions into nitrogen and water vapor.
Why choose this SCR Filter?
SCR systems are essential for meeting modern emissions standards, especially in compact and mid-range diesel engines. The OEM 4376878 filter is designed to match Cummins QSF3.8 and ISF3.8 platforms, helping maintain proper exhaust flow and chemical conversion. These engines often rely on SCR-based aftertreatment to achieve emissions compliance without additional filtration components.
When the SCR unit becomes restricted or less effective, it can impact NOx reduction and lead to emissions-related alerts or inconsistent system behavior. Replacing it with the correct component helps restore proper interaction between DEF dosing, exhaust flow, and catalyst performance.
Key Benefits
✅ OEM-matched SCR filter for Cummins QSF3.8 and ISF3.8 engines
✅ Supports NOx reduction through DEF and catalyst interaction
✅ Helps maintain smooth exhaust flow within the aftertreatment system
✅ Works alongside DEF dosing and sensor systems for balanced operation
✅ Direct-fit design for straightforward installation
Applications
This SCR filter is used on diesel engines equipped with Cummins QSF3.8 and ISF3.8 platforms manufactured from 2014 through 2022. These engines are commonly found in light- to medium-duty trucks, construction equipment, and industrial applications that rely on SCR-based emissions systems.
Installation Notes
Allow the exhaust system to cool completely before beginning service. Remove the existing SCR filter and inspect surrounding components such as DEF injectors, sensors, and mounting hardware for buildup or wear. Install the replacement unit using proper seals and fasteners to ensure correct alignment. After installation, clear any stored fault codes and verify proper system operation using diagnostic tools.
Final Thoughts
SCR technology plays a major role in reducing emissions in modern diesel engines. The Cummins QSF3.8 / ISF3.8 SCR Filter (OEM 4376878) supports proper exhaust treatment by enabling effective NOx conversion, helping maintain smooth system operation and compliance across Cummins diesel platforms.