I had same problems today - started car - Galaxy TDCI Ghia (away from obstructions), put it in reverse and parking sensors went loopy. Constant police style two tone warning. Cleaned sensors but no luck. Sensors also checked out OK. I then removed all the plugs from the control modual, cleaned an reconnected - It now works fine (fingers crossed). I do depend on the sensors quite allot as I am on call out in a busy town and forever parking in very small, busy streets.