IN THE BAY Why fleets should bypass the urge to bypass aftertreatment systems Aftertreatment systems have come a long way in 14 years. With the right training, tools, and understanding of diagnostic procedures, fleets can relieve many of their common pain points without running the risk of illegal tampering. By Gregg Wartgow [ EMISSIONS & EFFICIENCY ] »Some OEs have taken steps to guard against active aftertreatment tampering. 991205326 | RomoloTavani | Getty Images 18 Fleet Maintenance | May 2021