On some diesel-powered vehicles, where is a second emission control label commonly affixed?

• A. Engine
• B. Transmission
• C. Exhaust system
• D. Fuel filler door

Answer: (A)

Emission control labels tell you what aftertreatment systems are installed and how they need to be serviced. In diesel-powered vehicles, the major aftertreatment devices—such as the diesel particulate filter, SCR components, and related EGR/DEF systems—are part of the engine assembly and sit in the engine bay. Placing a second emission control label on the engine ensures the information stays with the components that require maintenance and is easy for technicians to reference when servicing or inspecting the exhaust aftertreatment system.

The other locations aren’t as appropriate because the transmission isn’t part of the emission control hardware, the exhaust system location would be less practical for referencing specifics about the installed systems, and the fuel filler door relates to fuel type rather than the emission controls.