Hello, I hope someone can assist with an S Max parking sensor query. My parking sensors have very occasionally changed tone sound but have always reverted to the normal tone relatively quickly. For the past 4 or 5 days, the tone sound has been different (both the way it sounds and volume). Any idea why this is happening and how I can get them back to normal? Thanks!  

Mines has done that once, sounded like the speaker was blown. It’s never done it again. 

Thank you. It's done it before and reverted which is why I'm hoping it's something that can easily be fixed 😬

This is probably the fallback to instrument cluster "speaker" rather than the better audio quality provided by the chimes and beeps played through the stereo. A low battery may be the cause.

When the battery voltage is lower it doesn't use the speakers. 

This happens to mine if its sat on the drive for awhile.