Cummins ISB, QSB 4.5L, QSB 6.7L SCR Outlet Catalyst Module 2013-2016: OEM 4376645

Supporting Reliable NOx Treatment in Cummins ISB & QSB Engines (2013–2016)

What is it?
The Cummins ISB, QSB 4.5L, and QSB 6.7L SCR Outlet Catalyst Module, identified by OEM 4376645, is an aftertreatment component designed to support the Selective Catalytic Reduction (SCR) process. After Diesel Exhaust Fluid (DEF) is introduced and prepared within the exhaust stream, the SCR catalyst provides the environment needed to convert nitrogen oxides (NOx) primarily into nitrogen and water vapor before treated exhaust leaves the system.

Why choose this SCR Outlet Catalyst Module?
Proper SCR operation depends on effective catalyst activity, controlled DEF delivery, and consistent exhaust flow. OEM 4376645 is intended for compatible Cummins ISB, QSB 4.5L, and QSB 6.7L applications from 2013 through 2016, helping maintain the correct configuration within the existing aftertreatment system.

High exhaust temperatures, DEF deposits, soot accumulation, oil contamination, and repeated thermal cycles can gradually affect catalyst condition. Problems with the DEF dosing system or upstream engine components may also contribute to premature deterioration.

Possible signs of a compromised SCR catalyst include emissions-related fault codes, elevated NOx readings, DEF system warnings, or irregular aftertreatment operation. Installing the correct application-matched module helps restore the intended exhaust treatment process.

Key Benefits
✅ Designed for compatible Cummins ISB, QSB 4.5L, and QSB 6.7L applications (2013–2016)
✅ Supports effective Selective Catalytic Reduction treatment
✅ Helps reduce nitrogen oxide (NOx) emissions
✅ Supports conversion of NOx into nitrogen and water vapor
✅ Maintains integration with compatible DEF and exhaust components
✅ Designed for demanding diesel exhaust temperatures and operating conditions

Applications
This SCR Outlet Catalyst Module is intended for compatible Cummins ISB, QSB 4.5L, and QSB 6.7L diesel engine applications from 2013 through 2016. These engine families may be used in commercial vehicles, buses, agricultural machinery, construction equipment, industrial equipment, and other diesel applications equipped with compatible SCR systems. Confirm OEM number 4376645 and engine-specific fitment before installation.

Installation Notes
Allow the exhaust system to cool completely before installation. Inspect the DEF injector, decomposition components, NOx sensors, temperature sensors, exhaust connections, clamps, seals, and nearby aftertreatment components for deposits, leaks, contamination, or damage. Correct any underlying engine, DEF dosing, or exhaust-system issue that may have contributed to catalyst deterioration. After installation, inspect for exhaust leaks, clear applicable diagnostic codes, and verify SCR operation using suitable diagnostic equipment.

Final Thoughts
Consistent SCR operation requires the outlet catalyst to process treated exhaust effectively throughout changing engine conditions. The Cummins ISB, QSB 4.5L, QSB 6.7L SCR Outlet Catalyst Module (OEM 4376645) helps maintain dependable NOx treatment for compatible 2013–2016 applications.