October 12, 2026 · 1 min read
The prevalence of diesel aftertreatment systems (ATS), including Diesel Particulate Filters (DPF), Selective Catalytic Reduction (SCR), and Diesel Exhaust Fluid (DEF), in commercial buses manufactured from 2007 onwards presents unique maintenance and cost considerations for used vehicle buyers in 2026.
- Proactive understanding and management of these systems are crucial to avoid significant operational expenses and downtime, ensuring the longevity and compliance of your used coach fleet.
- Since 2007, and particularly with the 2010 EPA emissions standards, commercial bus manufacturers have integrated sophisticated diesel aftertreatment systems to reduce harmful emissions.
- These systems are designed to capture particulate matter (soot) and convert nitrogen oxides (NOx) into harmless nitrogen and water vapor.
The prevalence of diesel aftertreatment systems (ATS), including Diesel Particulate Filters (DPF), Selective Catalytic Reduction (SCR), and Diesel Exhaust Fluid (DEF), in commercial buses manufactured from 2007 onwards presents unique maintenance and cost considerations for used vehicle buyers in 2026. Proactive understanding and management of these systems are crucial to avoid significant operational expenses and downtime, ensuring the longevity and compliance of your used coach fleet.
The Evolution of Diesel Aftertreatment
Since 2007, and particularly with the 2010 EPA emissions standards, commercial bus manufacturers have integrated sophisticated diesel aftertreatment systems to reduce harmful emissions. These systems are designed to capture particulate matter (soot) and convert nitrogen oxides (NOx) into harmless nitrogen and water vapor. While effective in meeting environmental regulations, their complexity adds a new layer of consideration for fleet owners, charter operators, schools, churches, and other bus buyers. For those acquiring used coaches, understanding the history and maintenance of these systems is paramount to predicting future operational costs and ensuring regulatory compliance.
Common Diesel Aftertreatment System Problems
Several common issues plague DPF, SCR, and DEF systems in used commercial buses. These often stem from improper maintenance, fuel quality, or simply the natural wear and tear of components over time. DPFs can become clogged if regeneration cycles are not completed properly or frequently enough, leading to reduced engine power and increased fuel consumption. SCR systems, which use DEF, can suffer from sensor failures, DEF quality issues, or DEF crystallisation in the dosing unit or exhaust. These problems can trigger
This article was contributed by All Bus Sales Editorial Team, an independent seller on the All Bus Sales marketplace. Opinions are the author's own. All Bus Sales does not inspect, certify or warranty third-party vehicles or services referenced here.