Parking sensor on the blink

[Monday]

The front o/s parking sensor on my CLS is on the blink ie beeping at random regardless of where the car is. It seems to be clean and physically undamaged. Is there any solution other than simply replacing it?
NB Timing is impeccable, 2 months out of warranty!

 

[Monday]

Feeling a bit less lazy, I searched the problem and found an old post recommending spraying with WD40 (theory: to displace any damp/water inside the sensor). Seemed unlikely but I tried it - it seems to have worked, at least short term.