What are the possible statuses of emissions monitors during a test?

The statuses of emissions monitors during a test indicate the operational state of the vehicle’s emissions control system and reflect whether the system is functioning properly to meet regulatory requirements. The correct answer outlines key conditions that help to determine if a vehicle can be tested for emissions compliance.

"Ready" signifies that all emissions monitors are functioning correctly, and the vehicle is prepared for testing. "Not ready” indicates that one or more monitors have not completed their tests, which can often occur if the vehicle has recently had its battery disconnected or if it hasn't been driven enough since repairs. "Pending" shows that the monitor’s status is not yet fully determined and typically means additional driving cycles are needed for completion. "Incomplete" suggests that testing has not reached a stage where all the necessary emissions monitors have been completed successfully.

This combination of terms is essential for operators to assess whether a vehicle can undergo emissions testing, as vehicle monitors must be in the "Ready" status to ensure compliance and accurate readings. Other combinations of statuses in the alternatives do not comprehensively capture these critical aspects or use terminology more commonly associated with diagnostic trouble codes (DTCs) rather than the operational status of emissions monitors.