Check Washer Fluid alert won't turn off after adding Mercedes approved Summer Fit
 

My Check Washer Fluid alert message came on in my multifuction display, 2014 E350.

I did it by the book, used Mercedes SummerFit, mixed it 100:1 just like the recipe says, mixed it with a bottle of Zephyr Hills water from our local store.

This is not de-ionized water, and this is not distilled water, which Mercedes tells you not to use.

I did not use any Rain-X window washer fluid, as Mercedes and several others tell you not to us either.

So I filled the washer reservoir up to the top with the official mixture I made from Mercedes own Summer Fit product, and still the Check Washer Fluid message will not go away.

What can be done, I did everything text book?

Probably a bad sensor. I replaced mine on my 2011 not too long ago. It was around $10 or so. You do have to kind of get to it through the wheel well and take off a bunch of panels. But it popped off quite easily and the new one popped in. Even got the gasket for it, but the old one was fine and didn't leak. The old and new one looked identical, the probe basically looked fine, I was expecting to see it gunked up from maybe the previous owner who may have used rainx or whatever, but I guess it's just one of those electrical items which can just fail for no reason.

Drain fluid then add some water and soap detergent into the container drive car on bumpy road so container is shaken. use sprayer on windshield then drain again and put normal fluid in. The detergent may free up sensor otherwise you need to do what the above post suggests for $10

When i just bought the car i had the same thing , turned out to be wire problem at the sensor

A wire problem? what did you do to resolve the wire problem?

Is it really that critical to use the Benz fluid? I used a high detergent washer fluid in our E320 for years and never had a problem. With the new E350 , I don't need any aggravation.

Not really. The sensor measures some kind of resistance so it needs to be the right ph in order for it not to think that it's out. Usually the regular blue stuff from Walmart is fine. Pure water might be neutral enough for it to think it's out.

I have read other forum posts where people ran into trouble buying the super cheap stuff, so the recommendations was to buy higher quality gallons of it, or simply buy the Mercedes SummerFit and WinterFit and mix them 100:1 according to the instructions. But most car makers say to stay away from RainX Brand which is odd, there must be something in their formula that causes problems with the sensor. I'll have to look more closely at my sensor and see if there's an issue with it.

Yes, RainX has been the source of several problems. Don't ever use that stuff.

bad contact or connector. I can look for a record , if needed.
but looks like it was easy and only took them a few minutes to fix.