The reversing sensors on one side of my Octavia estate "beep" erroneously in wet weather, presumably due to water ingress.

Has anyone had any success, please, in repairing these by drying them out and sealing them in some way?  Or is the only cure to replace them?  How difficult / expensive is that?  

Edited 11 April, 201412 yr by Stuarted

Hi there I had same problem on my hatchback few weeks ago all I did was wash the area and used a hair dryer to dry it never had any problems since water must build up in it

Its water getting in....but it soon dries out and back to normal again

All factory fit ones do it

Yes. After a little driving, the water is blown out of the sensor housing.

Which means that whenever it rains, I have no effective reversing sensor!

Is there no way of sealing these things a bit better, using wax polish / grease / bath sealer?

I never used to have an issue with it.. but now one of my sensors is starting to fail and if its damp out it will disable the whole lot :\

 

get someone with VCDS to scan the controller and tell you which sensor it is and swap it out, i know mid right on mine needs swapping.. 

you dont need VCDS to tell if a parking sensor is faulty just put the car in reverse with ignition on and put your ear right up to each sensor in turn - if working the sensor will emit a clicking sound

I had a similar water-related problem with a Nissan Micra's parking sensors. I put a tiny amount of WD-40 into the circular foam bit. The problem disappeared and hasn't returned in the last 3 years. I'd guess the ultrasound beam is distorted if the foam is too wet.

 

FWIW, when I replaced the factory-fit rear sensor in my old Superb that I had some years ago, it was £100 for the part. That one was made in Italy and used a unique fit plastic engagement making it very hard to substitute a non-oem one, even if it had been electrically compatible.

 

After replacing it, I sawed the old one in half, just to see what was in there. There isn't much. The small electronic module is entirely potted in black silicone rubber, so repair is impossible.

 

As per raincloud's suggestion, the sensor can also be felt to be pulsing, especially if you rest your finger nail on the middle bit, but your 'wet' one will still be pulsing I'm sure.

 

HTH