What does 'Please add cleaning fluid' mean?

[OValentina]

Please add cleaning fluid means that the windshield washer fluid has been used up and needs to be refilled. Automotive windshield washer fluid is a consumable item in vehicle use. Some car models can detect the remaining level of the windshield washer fluid, and when it runs out, the system will alert the owner to add more in time to avoid affecting normal use. The functions of windshield washer fluid are: 1. Keeping the front windshield transparent while driving; 2. Extending the lifespan of the glass and wipers; 3. Preventing the windshield from icing up in winter; 4. Preventing static electricity on the windshield. The method for adding windshield washer fluid is: 1. Open the hood and locate the windshield washer fluid filler port; 2. Open the cap and pour the washer fluid into the container; 3. Observe the fluid level until it reaches the marked line.