The tank level system is a notable feature when it works. We hear so many complaints that their lights show the tank is full and it is reporting empty. Somewhere along the line, your tank has been overfull, and waste has lodged and hardened onto the sensors in the tank. The tank may have been used during travel on a trip and not enough water was available to properly flush. The lack of water is not how the system was designed to work. When the toilet is used, the best operation is to fill the bowl over half full before flushing. This will help to end the famous “Pyramid.”