C5 loud beeping from under dash

[Clogzz]

Hi all,

The C5 misbehaved today, by loudly beeping every second from under the dashboard.
It happened when I shut the driver’s door after getting in, and nothing would stop it.
I drove home like that, and it still beeped with the key out.
I fully opened the driver’s window and closed the door, then disconnected the battery for several minutes.
When I reconnected it, the noise was gone, and I didn’t touch anything for several more minutes.
When I started, everything worked normally.

Before the beeping, I fiddled with the display while on the move, to try to reset the consumption indicator, but got nowhere for lack of remembering how to.

Over the recent days, I also had derangement in the offside rear power window, with the rear window’s button on the driver’s door often working backwards, while the button on the rear door always worked normally.

Any inspiration welcome, and thanks for your troubles.

[wheeler]

Have you set the overspeed warning by mistake ? it's done using the button on the end of the wiper stalk, you mave have set it to alert you at 0 mph.

[mooseshaver]

Handbrake? It only needs to be a little bit up (not even on) for it to complain in some C5s. If you push down on the hand brake does the beep stop?
a door thinking its open can cause this also.

[Clogzz]

Thank you both for the ideas.
I did fiddle with the overspeed and other settings while driving, and the noise started when I next returned to the car and closed the door.

The noise wasn’t the usual soft warning beep from open doors or handbrake left on.
It was a very loud sort of emergency warning, that could be heard from next door even with the car doors and windows closed.
It even continued with the car parked with the key out.
Disconnecting the battery was the only way to stop it.

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Editing on 15-08-2012
Apparently, the very loud sound could have been the radio thinking that it was getting stolen.