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

Purpose-Built Emissions Catalyst for Cummins B6.7 & L9 Engines (2018–2021)

What is it?
The Cummins B6.7/L9 SCR (Selective Catalytic Reduction) assembly, designated by OEM part number 5418529, is an emissions aftertreatment unit designed for Cummins B6.7 and L9 diesel engines produced from 2018 to 2021. It works with Diesel Exhaust Fluid (DEF) to support a chemical reaction that converts nitrogen oxides (NOx) in the exhaust into benign nitrogen and water before the gases exit the system, helping keep emissions in check.

Why choose this SCR Assembly?
This SCR unit is manufactured to match Cummins’ original design criteria for both B6.7 and L9 engine applications, ensuring correct fitment and dependable operation with DEF metering components, exhaust sensors, and control modules. When SCR components deteriorate or lose efficiency, NOx conversion effectiveness can drop, which may trigger emissions alerts or irregular aftertreatment behavior. Installing the correct OEM-specified module helps maintain coordinated emissions control and smoother exhaust system performance.

Key Benefits
✅ Designed for use with Cummins B6.7 and L9 aftertreatment systems (2018–2021)
✅ Helps sustain dependable NOx conversion with DEF chemistry
✅ Supports coordinated function with other exhaust treatment elements
✅ Direct-fit replacement — no modifications required
✅ Built to handle heavy-duty exhaust environments

Applications
This SCR assembly is suitable for medium- and heavy-duty trucks and commercial vehicles equipped with either Cummins B6.7 or L9 engines manufactured between 2018 and 2021. Its typical applications include delivery fleet vehicles, vocational trucks, regional transport rigs, and other commercial platforms where emissions control and consistent aftertreatment are part of everyday operation.

Installation Notes
Before servicing, make sure the exhaust and aftertreatment system has fully cooled. Remove the existing SCR module and inspect adjacent DEF lines, sensors, and mounting hardware for wear, soot buildup, or damage. Install the replacement SCR assembly with proper seals and fasteners to secure a tight, leak-free connection. After installation, clear any stored emissions system codes and confirm correct SCR performance with diagnostic tools.

Final Thoughts
When emissions system warnings or inconsistent NOx behavior appear, replacing the SCR unit with an OEM-specified component can help restore dependable aftertreatment coordination. The Cummins B6.7/L9 SCR (OEM 5418529) plays a key role in managing regulated exhaust chemistry and supporting reliable vehicle operation under demanding duty cycles.