HI there can you disconnect the ultra sonics control unit in the roof and see if it still happens if it dont work you will need to find the alarm unit ,sometimes in the engine bay on the n/s under the injection computer bracket ,the best way to find it is to set the alarm off and see where the noise is coming from ,then find it then disconnect it, then connect the ultra sonics back ,then check central locking .
mark
November 2008