What does code CEL74 MEAN IN FREIGHTLINER CASCADIA 2016?

The code CEL74 in a 2016 Freightliner Cascadia typically indicates an issue related to the vehicle's exhaust system, specifically the Diesel Exhaust Fluid (DEF) system or the selective catalytic reduction (SCR) system. It may signal problems such as low DEF levels, a malfunctioning DEF pump, or issues with the SCR catalyst. It's essential to diagnose the specific cause using a compatible diagnostic tool to ensure proper repairs and compliance with emissions standards.