Hello Everyone,

This morning whilst reversing my 2001 X308 out of the car port, I heard a second (and new to me) alarm tone higher in pitch than the reversing tone and constant. It lasted a few seconds and has not happened again.

Any idea what this sound might be?

 

I really don't think there is any other speaker behind you then the reverse alarm and your radio.

Did a parking sensor go out?
You might want to check them one by one.

No other suggestions right now ...