What does the two modes of the Passat's internal circulation A mean?
3 Answers
The A button for the internal circulation in the new Passat means automatic internal and external circulation. It determines whether to turn on the internal circulation or external circulation based on the air quality sensor outside the vehicle. Introduction to internal circulation: The function of internal circulation is to prevent dust and odors from being sucked into the car through external circulation. Therefore, a control system is set up to close this external circulation air duct and block the dirty air outside the car. Introduction to external circulation: Since the interior of the car forms a relatively sealed indoor environment, people can easily suffer from oxygen deprivation in this environment for a long time. Therefore, the air conditioning system adds an air duct to draw fresh air from outside the car, which then passes through the air conditioning evaporator or heater core to blow out cold air and warm air respectively.
The two modes of the Passat's air recirculation refer to manual mode and automatic mode. Manual mode means pressing the button to completely close the external air intake and only circulate the air inside the car, which is suitable for avoiding exhaust fumes in heavy traffic or heavily polluted areas. I often use this trick when driving in the city. Automatic mode is much smarter—the air conditioning system automatically switches the recirculation status based on the temperature inside and outside the car and the dust sensor. For example, it activates quick cooling when it's hot, prevents fogging when it's cold, and operates more efficiently on highways. I find automatic mode the most hassle-free because it maintains air circulation, avoids carbon dioxide buildup from prolonged recirculation, and significantly reduces window fogging issues. The Passat's design is practical, and I recommend using automatic mode more often in daily driving while regularly cleaning the air filter to ensure air quality. For safety, remember to manually activate it for short periods in poorly ventilated areas.
When I first drove the Passat, I was quite confused about the two modes of the recirculation system. In manual mode, the button lights up after activation, completely blocking outside air. I use this to block dust near construction sites or on dusty roads. Automatic mode lets the system control itself, combining temperature sensors to activate circulation at the right time, maintaining comfort—like on long drives when it automatically turns off to save energy. While learning to drive, I found that manual mode is suitable for emergency situations, but automatic is safer, preventing dizziness caused by stuffy air. Practical tip: The recirculation button is on the AC panel for one-touch switching; related benefits include reducing AC energy consumption and improving fuel economy—beginners should use automatic mode more often. For maintenance, check the air filter every six months to prevent odors from affecting air quality.
