Which item is commonly inspected as part of an HVAC system check?

• A. Cabin air filter condition
• B. Tire tread depth
• C. Engine oil viscosity
• D. Brake rotor temperature

Answer: (A)

The item most commonly inspected in an HVAC system check is the cabin air filter condition. The HVAC system pulls outside air through this filter before it reaches the cabin, so a dirty or clogged filter can restrict airflow, reduce heating or cooling efficiency, and degrade interior air quality. Regular checks ensure the filter is clean or replaced as needed, keeping the system running smoothly and the air inside comfortable and clean. The other items listed—tire tread depth, engine oil viscosity, and brake rotor temperature—pertain to tires, engine lubrication, and braking, not the HVAC system.