When I put my 2008 galaxy into reverse the parking sensor tone is constant as if you are right next to something. You can turn it off with the dash button. I have removed each sensor and refitted but still doing it. Is there some way you can check which is faulty rather than buy all four new ones?

try removing one sensor and then trying reverse,do this with each sensor in turn if the constant tones stoppes you have found you dodgy sensor.