Mine was doing the same. Is your transducer in the hull for this unit? If so, the transducer needs to be replaced. My 2011 P II had both the front and rear transducers mounted in the hull. Both units did this. My friend, former product engineer with Humminbird, said the WRONG epoxy was used when my boat was rigged. Thus, causing air bubbles and moisture to develop where the transducers are mounted. I got Bobby ( CS at BassCat ) to send two new ducers…….. Not a problem since. Bobby is the best in the business. I cant remember the name of the epoxy he used. He had HB send him some.