Any normal wear, deterioration, or unintentional disturbance that will affect the operation of an emission control component or system.

• A. Defective
• B. Modified
• C. Tampered
• D. Not Applicable

Answer: (A)

The main idea is to recognize how wear or damage that changes how an emission control part works is described. When a component has normal wear, deterioration, or an unintentional disturbance that affects its operation, it’s considered defective. That term covers any degradation that compromises the component’s ability to control emissions, even if the problem isn’t caused on purpose. It isn’t about intentional changes (that would be modified) or deliberate interference (that would be tampered), and it isn’t any issue at all (not applicable). For example, a worn exhaust gas recirculation valve or cracked vacuum line that alters emissions performance would be labeled defective because it impairs the system’s function.