Cummins B6.7, L9 SCR 2018-2021: OEM 5418529

Unified NOx Reduction Module for Cummins B6.7 & L9 Engines (2018–2021)

What is it?
The Cummins B6.7/L9 SCR (Selective Catalytic Reduction) assembly, referenced by OEM part number 5418529, is a shared emissions aftertreatment module designed for use on both Cummins B6.7 and L9 diesel engines built between 2018 and 2021. Working with Diesel Exhaust Fluid (DEF), this SCR unit helps facilitate a chemical reaction that changes nitrogen oxides (NOx) in the exhaust into nitrogen and water before the gases exit the system, supporting controlled emissions behavior.

Why choose this SCR Assembly?
This SCR unit is engineered to match Cummins’ original specifications for both the B6.7 and L9 engine families, ensuring accurate fitment and seamless interaction with DEF dosing hardware, exhaust sensors, and control systems. When SCR components age or lose efficiency, NOx conversion effectiveness can decline and trigger warning indicators or uneven aftertreatment performance. Choosing the correct OEM-specified module helps maintain dependable emissions control and coordinated system responses.

Key Benefits
✅ Designed for both Cummins B6.7 and L9 aftertreatment systems (2018–2021)
✅ Supports consistent NOx conversion via DEF chemistry
✅ Helps sustain coordinated operation with related exhaust treatment components
✅ Direct-fit replacement — no modifications required
✅ Built to withstand heavy-duty exhaust conditions and duty cycles

Applications
This SCR assembly is suitable for medium- and heavy-duty trucks and commercial vehicles powered by either Cummins B6.7 or L9 engines manufactured between 2018 and 2021. Typical applications include delivery and vocational fleets, regional transport rigs, municipal vehicles, and other platforms where regulated emissions control and consistent exhaust behavior are essential.

Installation Notes
Before beginning service, ensure the exhaust and aftertreatment system has fully cooled. Remove the existing SCR module and inspect adjacent DEF lines, sensors, and mounting hardware for wear, contamination, or damage. Install the replacement SCR assembly using the correct seals and fasteners to ensure a secure, leak-free fit. After installation, clear any stored fault codes and verify correct SCR performance using proper diagnostic tools.

Final Thoughts
If your Cummins B6.7 or L9-equipped vehicle is showing NOx-related alerts, inconsistent emissions behavior, or uneven aftertreatment responses, replacing the SCR unit with the correct OEM-specified component can help restore more reliable NOx handling and coordinated system performance. The Cummins B6.7/L9 SCR (OEM 5418529) plays an important role in managing regulated exhaust chemistry and supporting dependable vehicle operation.