Why must the cabin air filter be inspected during vehicle inspections?

The inspection of the cabin air filter during vehicle inspections is crucial primarily to ensure it does not impede airflow from the ventilation system. A clogged or obstructed cabin air filter can significantly affect the performance of the heating, ventilation, and air conditioning (HVAC) system in a vehicle. If the airflow is restricted, it can lead to poor cabin air quality, reduced efficiency of the HVAC system, and increased strain on the system, potentially leading to mechanical issues.

While maintaining a clean filter, free of dust and debris, is important, the fundamental reason for inspection focuses on how it affects the overall airflow through the vehicle's ventilation. If the filter is dirty or damaged, it compromises the system's ability to circulate air effectively, which can make passenger comfort and climate control challenging. Therefore, ensuring that the cabin air filter functions properly enhances both performance and safety within the vehicle.