"dirty radar sensors" error (during heavy rain)
 

got this error (loosely translated from french) yesterday.

it was raining heavily, so suspect this has something to do with it
cos the car was clean.

1st time it happened was when I stopped at a gas station on the highway;
the message popped up the moment I came to a complete halt.
left the car & when I came back all was well again.

2nd time was maybe an hour later on the highway: message popped
up again and for about 10 minutes the system/radar was inoperative.
(couldn't even use "traditional" cruise control anymore.)
and then, just like that all went back to normal again.

Any thoughts?

Rain will block high frequency signals. I have the same issues with sat radio & tv at home.

The anti-skid system is smart enough to detect the differing tire rotation speeds.

guess i'm lucky it "only" happened twice while driving for about 5hrs through heavy rain..?

I have also seen this before in rain. No worries. After a few minutes, it went away.

Yes, just means there's excessive external interference and the system can't continue to trust the sensor. I have one in the shop right now where that error pops up after a few min of driving, and it's because the radar sensor mounting is bent from something hitting the grille, which is usually what happens.

cheers all

had this issue on my GLK at first thought it was rain related as it can be but we ended up having to have one or two replaced done under warranty but I know that corner of the car had been bumped by another car whilst left in a railway station car park for 3 days - I had to clean the scuff marks off but no paint damage. think that had damaged the sensors. Replacement was a few months later though.
So I would keep an eye on it. I know that the autobahn get seriously wet at times not sure if it is to do with the camber or lack of on the road but you are feel almost submerged sometimes in the amount of water.....so it is very possible they just overwhelmed in the wetness of it all.

I often get this error message and I'm unsure why. More so because I just cleaned the car the day prior.

We are talking about Distronic ( DST ) here. During heavy rain, snowfall, dense fog, the radarsignal ( high frequency ) is blocked, due to low power output from the radar. The car can't determine whatever it's a dirty grill, rain, or other vise blockage of signal.
Since Distronic ( if fitted ) is an integrated part of the Cruise control, it will not allow the use og Cruise control, during malfunction.