So i have had my 2005 CTT for over 4 months now and parking sensors have worked perfectly to date... over Christmas, it snowed for the first time and all of a sudden the front parking sensors started going a bit haywire whenever I come to a stop. They just start screaming at me and it will look like it's coming from the left, then right, then both... then it will stop. I checked to make sure there wasn't a build up of snow on the bumper, but nothing.
The next day everything seemed fine again, and has been for the last 2 weeks, but then it snowed again quite heavy today and the same thing happened, except I got the red lights only coming on, which I understand means there is a fault? Funny thing is, once I got in my underground parking, they starting working perfectly well again. Any idea what's going on?

 

Sounds like snow is sticking to them. There is an overhead switch to turn them off when it snows

 

I've seen sensors go whacky, but I think it would be best to scan it and see which sensors are acting up and what their readings are.

 

It only takes a couple of snow flakes (or some heavy rain) on one of the sensors and the system can go a little crazy. After a while, the twin red lights may come on if the system gets too confused. I do what Cole suggested and just hit the overhead console switch to turn them off when it happens. After the snow flake or rain drops clear, I turn them back on.

 

Thanks for the help everyone, much appreciated!