An air injection system is present but the belt is missing. How should this be recorded during inspection?

In the context of smog check inspections, an air injection system is critical for controlling emissions by introducing air into the exhaust stream, which helps ensure complete combustion of hydrocarbons. If the air injection system is present but the belt is missing, it indicates that the system cannot function properly, as the belt is typically required to drive the air pumps or components that allow it to operate.

Recording this as "defective" is appropriate because the missing belt prevents the system from performing its intended function. The term "defective" accurately reflects that the air injection system is not functioning as designed due to a critical component's absence. It's essential for inspectors to document such deficiencies so that they can be addressed either through repairs or replacements.

Other terms like "operational," "functional," and "inspected" would imply that the system is working or has been checked for proper operation, which is not the case when a significant component is missing. Therefore, labeling the situation as defective provides a clear indication of the system's inability to contribute to emissions control effectively.