The last couple of times I have driven my 2004 Bentley GT, Ive noticed a noise during the first 30 min of driving the car that when I come to a stop or I am taking off I notice a 2-3 second tone inside the car. This sound sounds like the tone on a tv station when its off air. I don't recall seeing any lights on the dash. I also believe this has happen right after I washed my car so I'm thinking its something to do with the parking distance sensors. Can anyone help?

 

To test your theory, turn off the parking sensors and see if the sound goes away.