Permanent Check Coolant Level message?

[Clutch]

Hi guys – I have the Check Coolant Level (CCL) message and I can’t get rid of it. Background – replaced seam-split expansion tank and sensor. Topped off system with correct coolant. Bled system. Float is positioned correctly. I expected the CCL message to clear at this point, but it did not. I have driven the car for several weeks now under various temperature conditions and drive durations. I am 100% convinced the system is full and has no leaks. I have no dried residuals anywhere, no puddles, no drips, no white smoke, no odors, nothing. Temp gauge behavior normal. Wire harness to the sensor looks undamaged. I am stumped even after reading the forum search results. The only thing I have not tried is disconnecting the battery to see if it will clear the error message. Any thoughts on if that will work? Any other theories or ideas? Thanks in advance for your wisdom.