Many owners of compact hatchbacks Škoda Fabia are faced with incomprehensible markings on the climate control panel. Often in conversations or when reading forums you can hear the question: “What is this button?” or “Why do I need a car?” In fact, we are talking about a typo or phonetic perception of marking CLO (Close), which means closing the air damper.
This function plays a critical role in the operation of the heating and ventilation system, especially in urban environments with heavy traffic. Understanding the principle of its operation will help you not only save fuel, but also ensure a comfortable microclimate in the cabin, avoiding fogging of windows and the entry of foreign odors.
Explanation of markings and principle of operation
The word you hear as "tso" is actually an abbreviation CLO from the English verb to close - to close. On the dashboard Škoda Fabia this button is often indicated by a car icon with an arrow inside pointing to a closed loop, or by text. When you press it, the system switches to internal air recirculation mode.
During normal operation of the air conditioner or heater, the car takes air from the street, filters it and supplies it to the cabin. When you activate CLO mode, the external damper closes, and the climate system begins to circulate only the air that is already inside the cabin. This allows you to heat or cool a space faster without wasting energy processing cold winter or hot summer air from outside.
However, it is important to understand that endless operation in this mode is impossible. If you leave the system in position CLO for a long time, the level of carbon dioxide inside the cabin will begin to rise, which will lead to drowsiness of the driver and fogging of the windows. Therefore, modern climate control systems Škoda automatically turn off this mode after a certain time or when a certain humidity is reached.
Main scenarios for using the recirculation mode
Knowing exactly when to enable a feature CLO, makes driving more comfortable and safe. There are several situations when activating this mode is not just useful, but necessary. For example, when driving in dense city traffic behind trucks or buses, the exhaust gases of which can penetrate into the cabin through the air intake system.
Also, the internal circulation mode is indispensable in winter at extremely low temperatures. If it is -25°C outside, starting the heating system in normal mode will require considerable time to warm up the engine and the air itself. Turning on CLO, you force the stove to work only with warm air from the cabin, which speeds up the process of creating a comfortable temperature several times.
Using the mode is also important when entering tunnels or when following cars with thick smoke coming from the exhaust pipes. In such cases, it is necessary to quickly shut off the access to outside air to avoid inhalation of harmful substances by passengers. Just press a button and the system instantly isolates the interior from the outside environment.
- 🌬️ Driving in traffic jams behind vehicles with bad emissions
- ❄️ Quickly warms up the interior in winter with severe frost
- 🚇 Entering contaminated tunnels or garage complexes
- 🚫 Driving behind a car with black smoke coming out of it
- Auto mode (A/C)
- Internal recirculation (CLO)
- Air intake from the street
- I don't use climate control
Effect on air conditioner operation and glass fogging
Many drivers mistakenly believe that turning on CLO mode always useful for air conditioner operation. In fact, when actively using the air conditioner in internal circulation mode, the cooling efficiency may decrease if the interior is already heated. It is easier for an air conditioner to cool the flow of cold air from the street than to constantly move warm air inside a closed volume if the temperature inside is already high.
However, if the interior is already cool, and you want to maintain this temperature, then the mode CLO will be a great helper. It prevents the entry of hot air from the street, allowing the air conditioning compressor to operate in a gentle mode. This also helps reduce fuel consumption, as the engine spends less energy driving the compressor.
The biggest problem with long-term use of the recirculation mode is the fogging of the windows. As passengers breathe, the humidity in the cabin increases. If the air is not renewed, moisture condenses on the cold glass surfaces, impairing visibility. In modern models Škoda Fabia the system itself detects an increase in humidity and briefly switches to air intake from the street to dry the glass.
⚠️ Warning: Never leave the CLO mode on for a long period of time when driving in rainy weather or when carrying a large number of passengers, as this is guaranteed to cause all windows to fog up and reduce visibility.
Why do windows fog up in CLO mode?
When the damper is closed, moisture from the passengers' breath does not escape outside. It settles on cold glass, forming condensation. Moisture accumulates faster than it evaporates, creating a film that obstructs your view.
Technical features of the damper
A special function is responsible for switching between modes. recirculation flap, the drive of which can be mechanical or electric, depending on the year of manufacture and configuration of your Škoda Fabia. In early models it was a simple lever connected by a cable to the damper, while in new generations the control is carried out through an electric motor integrated into the climate control unit.
If you hear strange clicking or squeaking noises when you press a button CLO, this may indicate a malfunction of the drive or jamming of the damper itself. In this case, the system may not completely block the air flow, which reduces the efficiency of operation in recirculation mode. The opposite scenario is also possible, when the damper gets stuck in the closed position and does not open to take in fresh air.
Regularly checking the system's functionality is important for safety. If the button is pressed but the indicator does not light up or lights up but the effect does not occur, it is necessary to carry out diagnostics. Often the problem lies not in the button itself, but in the damper motor, which can burn out or fail due to moisture or gear wear.
☑️ Diagnostics of damper operation
Impact on fuel consumption and ecology
Using the mode CLO directly affects fuel consumption, but the nature of this effect depends on operating conditions. In winter, turning on recirculation reduces the load on the engine, since it does not need to warm up cold air from the street. This can lead to fuel savings of up to 5-10% in extreme cold and short trips.
In summer, when the air conditioner is running, the effect may be the opposite. If you're driving on the highway and turn on the internal circulation mode, the air conditioning has to work harder to cool the sun-heated cabin air, which increases the load on the compressor. In such conditions, it is better to use air intake from the street, especially if it is not too hot outside.
From an environmental point of view, the regime CLO does not have a direct effect on vehicle emissions, since it only redistributes the air inside the cabin. However, it indirectly helps reduce fuel consumption, which reduces the overall volume of harmful emissions. It is important to maintain a balance and use the regime only when really necessary.
| Operating Condition | Recommended mode | Impact on consumption | Efficiency |
|---|---|---|---|
| Severe frost (-20°C and below) | CLO (Internal) | Reduced consumption | High (fast warm-up) |
| City traffic jam with exhaust | CLO (Internal) | Neutral | Maximum (odor protection) |
| Summer heat (+30°C) | Fence from the street | Moderate | High (fresh cool air) |
| Rain or high humidity | Fence from the street | Neutral | Critical (prevention of fogging) |
If you notice that CLO mode has stopped working, try turning off the ignition, opening and closing all doors, then starting the engine again. Sometimes this helps the climate control system recalibrate the dampers.
Frequent malfunctions and ways to solve them
If the system stops responding to button presses CLO, the first thing you should do is check the fuse responsible for the air conditioning system. In the electrical diagram Škoda Fabia This fuse is usually located in a box under the steering column or in the passenger compartment on the passenger side. Its value may vary depending on the year of manufacture, so it is better to refer to the owner's manual.
Another common problem is the failure of the microswitch in the control button itself. Over time, the contacts oxidize or wear out, causing signal loss. In this case, the button can be visually pressed, but no electrical signal is sent to the control unit. Diagnostics requires a multimeter and access to the control panel connectors.
In more complex cases, the malfunction lies in the climate control unit itself or the damper servomotor. Repairing such units often requires professional equipment and skills. Do not attempt to disassemble the unit yourself unless you have experience working with vehicle electronics, as other components may be damaged.
⚠️ Attention: When replacing the damper servomotor, it is necessary to perform the adaptation procedure via a diagnostic scanner, otherwise the system will not work correctly or will not close the damper completely.
Proper use of CLO mode not only improves comfort, but also prolongs the life of the cabin filter, as less dust and dirt passes through it when driving on dusty roads.
Specificity of work in different generations Fabia
In the first generation Škoda Fabia (1Z) climate control was often mechanical, and the button was CLO It may not be available in the basics. In richer climate-controlled versions, it was present, but the principle of operation was simple mechanical flap switching without complex automatic logic.
In the second and third generations (5J and NJ), the system became significantly smarter. There's a button. CLO It is integrated into the general logic of microclimate management. Automation itself analyzes data from air quality and temperature sensors, periodically switching mode to prevent fogging and ensure the air is fresh, even if you hold the button pressed.
In the latest models with digital panels and touch screen control, the recycling function can be implemented software. This allows you to adjust the parameters of the valve more flexibly, including the ability to set the operating time in the internal circulation mode or geolocation binding (for example, automatic switching on when entering an urban area).
FAQ: Answers to frequently asked questions
What if the CLO light is on but the air is not blocked?
This indicates a malfunction of the valve drive or a break in the communication between the button and the control unit. Check the fuse and, if necessary, contact the service for the diagnosis of the servo drive.
Can I use CLO mode when driving on the road?
It's not recommended. On the highway, a constant influx of fresh air is needed to prevent the driver's drowsiness and fogging of the glass. Use the mode only in emergency situations, for example, when entering a tunnel.
Why does CLO mode smell of dampness in the cabin?
Perhaps in the air conditioning system accumulated moisture or fungus. When recycling, this smell is enhanced. It is necessary to clean the air conditioner evaporator and replace the cabin filter.
How long can I drive with CLO mode enabled?
The safe time is no more than 10-15 minutes. Long-term operation will lead to the accumulation of CO2 and fogging of the glass, which is dangerous for movement.
Does the CLO work differently in A/C and heating?
The physics of the process is the same - the valve is blocked. But in A/C mode, it helps to cool the cabin faster, and in heating mode, it helps to heat up faster. In both cases, the system can automatically switch to air intake at high humidity.