Parking sensors

[Forrester123]

My parking sensors have suddenly stopped working on my C5 57 estate.
Where do I look first?

[GiveMeABreak]

Are you getting a parking assistance faulty warning message when engaging reverse gear?

If so, likely causes are:

1) One or more sensors are faulty - a proper diagnostic with Lexia / Diagbox will tell you what the fault is and which sensor (s) are faulty.
2) A spillage in the boot of some liquid from a container that has penetrated into the spare wheel area and got into the parking assistance ECU.
3) An electrical short or water ingress into one of the sensors (usually the cause of item (1)

[Forrester123]

No indication of fault in sensors on display.
Presume your comments still apply, so will have to get Lexia diagnostic.

[GiveMeABreak]

So what happens when you engage reverse gear?

Do you get the beep that signifies rear parking assistance has been activated?

[Forrester123]

They started working again today on their own accord!
Thanks for the advice which has been noted.