Tunze 3155 Osmolator sensor not stopping pump

[Wg6]

I have had the 3155 Osmolator for about a year now, and the sensor has stopped sensing that the water level has reached it and it continues to pump until the second float sensor stops it.

When I turn on the controller all 4 lights turn on shortly with a beep, then the green light is on for about 1-2 seconds and then the yellow light turns on and the pump starts. About halfway through the 15-20 second run time that it normally goes through when it's turned on the green light flashes shortly and the sensor never picks up the water, and the light stays yellow until the float sensor stops it. I have tried testing it at several different run times, up to a minute and the sensor never picks up the water.

The green light is suppose to show that the sensor is running correctly so is this a problem with the controller?

Thanks