Cummins QSB 6.7L SCR Outlet Catalyst Module 2014-2021: OEM 4328918

Steady NOx Control for Cummins QSB 6.7L Engines (2014–2021)

What is it?
The Cummins QSB 6.7L SCR Outlet Catalyst Module, identified by OEM 4328918, is a key component of the Selective Catalytic Reduction (SCR) aftertreatment system. It works with Diesel Exhaust Fluid (DEF) to help convert nitrogen oxide (NOx) emissions into nitrogen and water vapor before treated exhaust exits the system. This process supports proper emissions treatment and consistent operation of the complete aftertreatment system.

Why choose this SCR Outlet Catalyst Module?
The SCR system depends on accurate DEF dosing, controlled exhaust flow, and effective catalyst operation. The OEM 4328918 SCR Outlet Catalyst Module is designed for Cummins QSB 6.7L applications from 2014 through 2021, helping maintain compatibility with surrounding factory aftertreatment components.

Continuous exposure to high exhaust temperatures, contaminants, and DEF-related deposits can gradually affect catalyst efficiency. When the module becomes restricted, damaged, or less effective, operators may encounter emissions warning lights, diagnostic fault codes, elevated NOx readings, or derate conditions.

Choosing the correct OEM-matched catalyst module helps restore proper exhaust treatment while maintaining the fit and connections required by the existing SCR system.

Key Benefits
✅ OEM-matched SCR Outlet Catalyst Module for Cummins QSB 6.7L engines (2014–2021)
✅ Supports effective nitrogen oxide (NOx) reduction
✅ Works with the DEF system to support proper SCR operation
✅ Helps maintain consistent exhaust treatment
✅ Supports dependable aftertreatment system function
✅ Direct-fit design for straightforward installation

Applications
This SCR Outlet Catalyst Module is designed for Cummins QSB 6.7L diesel engine applications from 2014 through 2021. These engines are commonly used in construction machinery, agricultural equipment, industrial equipment, generators, and other off-highway applications equipped with SCR emissions systems. Confirm the OEM number and equipment-specific fitment information before installation.

Installation Notes
Allow the exhaust system to cool completely before beginning installation. Inspect the DEF injector, NOx sensors, temperature sensors, exhaust connections, clamps, seals, and mounting hardware for contamination, wear, or damage. Install the replacement catalyst module using the correct seals and hardware to ensure proper alignment and secure connections. After installation, inspect for exhaust leaks, clear applicable diagnostic codes, and verify SCR system operation using appropriate diagnostic equipment.

Final Thoughts
Effective NOx treatment depends on reliable operation throughout the SCR system. The Cummins QSB 6.7L SCR Outlet Catalyst Module (OEM 4328918) helps maintain consistent exhaust processing, dependable emissions treatment, and reliable aftertreatment system operation for 2014–2021 applications.