I've mentioned this in other threads, but now I've made video of it so you can hear the beeps and see how they relate to the position of the key.
I am driving along at speed, kill the engine for EOC and turn the key immediately back to "On", and then I hear three long beeps unlike the seatbelt or other chimes the car normally makes. I wonder what they are about?
my car makes three longish beeps when I turn the ignition off. Not quite as long as those in the video. In my case I don't think it's an error--but I'm not sure why it does it? Maybe one of the 432 VX owners on this site might know.... Dunno why it might being doing that in your case.