Why would engine code say coolant is below coolant sensor when coolant is full on a 2004 grand prix gt2?

If the engine code indicates that the coolant level is below the coolant sensor despite the reservoir being full, it could be due to a faulty coolant level sensor itself, which may need replacement. Additionally, there could be a wiring issue or a loose connection affecting the sensor's ability to accurately detect the coolant level. It's also possible that air pockets in the cooling system are preventing proper sensor readings. Lastly, the engine control module (ECM) could be experiencing a glitch that requires a reset or reprogramming.