Hi I appreciate there are quite a few topics on this, however I'm having an issue which is intermittent. All of the sensors seem to be working (they are clicking when reverse is engaged) but when I start to move backwards the beeps go from be spaced out to a solid tone even though I'm no where near an object. I have had the bumper off, cleaned the sensors and even bought and new sensor unit, but the issue remains on and intermittent basis. Any suggestions 
