Why does the Mercedes-Benz still display 'Please add washer fluid' when it's already full?
2 Answers
The reasons why a Mercedes-Benz still displays 'Please add washer fluid' when the reservoir is full are: 1. The washer fluid level sensor or related hardware circuits are damaged, preventing accurate monitoring of the fluid level in the reservoir; 2. The washer fluid concentration is too high. Some washer fluids have poor conductivity due to excessive concentration. Although the fluid level has been replenished, the sensor cannot accurately measure the level status due to insufficient conductivity. Functions of washer fluid: 1. Cleaning performance - windshield washer fluid is formulated with various surfactants and additives. Surfactants typically have wetting, penetrating, and solubilizing properties, thereby achieving cleaning and stain removal effects; 2. Antifreeze performance - the presence of alcohol and ethylene glycol lowers the freezing point of the liquid, providing antifreeze protection and enabling quick dissolution of frost.
This is quite common in Mercedes-Benz vehicles. I've driven several Mercedes models myself and encountered similar issues. Even when the windshield washer fluid is fully topped up, the dashboard still displays a warning to add more. The main cause is often a faulty fluid level sensor. The sensor may have poor contact at the bottom of the reservoir, be aged, or covered with deposits causing misreading; another possibility is loose sensor wiring that disconnects when the car vibrates. Additionally, Mercedes' onboard computer systems are quite sophisticated, and sometimes software bugs can trigger false error codes. I recommend first confirming that the washer fluid is filled to the correct level (don't get it wrong), then wait a few minutes to see if the system resets itself. If that doesn't work, it's best to take the car to an authorized dealership for professional diagnostic equipment to check for circuit shorts or corrosion. Remember: regularly cleaning the sensor area can prevent such issues – otherwise, having no washer fluid during rain could compromise driving safety.
