While driving home during a moderate rainstorm in my 2015 S550 I experienced a complete failure of basically all vehicle safety systems: Pre-Safe Functions Limited, Active Lane Keep Assist Unavailable, Blind Spot Assist Unavailable... Needless to say, I found this to be somewhat alarming! I never experienced this in my W221 and have trouble believing that the "world's best" automobile can only make this claim during perfect weather conditions. Is it really true that these features do not work in the rain??? Has anyone else run into this issue? I will definitely be scheduling a service appointment to have everything checked, but am curious to hear if/when any of you may have had this happen.

On a side note, anyone have to have their windshield wipers replaced? Mine literally seem to drag across the windshield while making a horrible noise...

Thanks in advance!!!

I've gone through lots of rain situations and all those functions you mention above work just fine. I'm not sure about a torrential downpour, however.

I have also been having a problem with the wipers. I had them replaced once, but there is no improvement. I am going to talk to the dealer about it again in the near future.

problem with the windsheild wiper is common across many MB's. My 08 Gl had it and now same thing on the 13 GL. Replacing is not the issue, they have to do an adjustment.

Earlier this week I was driving (2014 S550) @ 40 MPH through heavy rain in town and those systems did fail. A few days later we got caught in very heavy rain on the interstate @70 MPH , this time the system remained functional. I had less than 500 miles on the clock.

it is normal for those safety functions to shut down in severe inclement weather - heavy rain and snow. happens frequently. all the cars that i have had equipped with dap, etc have shut down intermittently but have reset themselves and operated normally again in short order. your owners guide will discuss this im sure. nothing to be worried about in terms of malfunctioning systems.

The only time that I have experienced a safety feature not work was when the painted lines on the road were very worn and almost missing.

Do you know what sort of adjustmeant is needed?

Happened to me during a heavy thunderstorm in Germany after European delivery.

Thanks to all that have shared their experiences, and my apologies for the late return to this thread. Although I remain somewhat disappointed that these systems are so temperamental in inclement weather, I suppose I cannot expect perfection 100% of the time. Hopefully it won't become a regular occurrence as the rain in GA has been unusually frequent/heavy over this past year.

As for the windshield wiper adjustment, my car is currently at the dealership now; I will report back when I learn what exactly was corrected.

FYI, I was given a brand new GLA as my loaner. Much like the CLA, the exterior is actually quite nice, but once inside, a huge letdown. Black plastic EVERYWHERE! I'm guessing the GLA and CLA will take over the loaner fleets as the 2015 C-Class appears to be in a completely different class, as reflected by its considerably higher price-point. Definitely looking forward to seeing the new C in person...

terrible! bring in your S and go home with a GLK.......I got one as a loaner once when I had my E.......and have gotten a loaner since having my S as well; but it was another S at least

I would very much be interested to hear what they say because I'm not happy with the noise my wipers make.

I would guess that these systems are designed to shut off during bad weather. There is only so much electronics can do in such a situation. I would think the driver should be paying attention even more so during such conditions.

M

So does the pre-safe function solve??

The day we lost our SL in a flash flood I experienced the same earlier when driving on the highway during a torrential downpour.
I think this was normal in this type of situation and cleared upon restarting the car...