Just want to ask if anyone has had this happen to them before... A few months ago my key remote just stopped working properly.. By that I mean it would only work by facing the key and standing directly in front of the door sensor to operate when normally u can face the key in any direction and even be a few metres away from the car and can still operate the keys functions.. It's really a pain because I have to stand directly in front of the door with the sensor to open/lock my car or open the boot when normally you should be able to do it while being metres away from the car. So I thought maybe it's the batteries or the key was playing up so I got my spare key and exact same problem.

I asked my dealer and they said might be the key but I believe it can't be the case as I had tried the spare key within that day and it wouldnt work properly.
Any ideas on what this could be guys? I thnk it has something to do with the car because I don't thnk that both keys can just "stuff up" at the same time..

 

It's a sensor that is in your rear windshield. Same thing happened to me, and it may also be that your door sensors are going bad too. It's around $1600 for the sensor plus installation at the dealer. I Havnt replaced mine yet

 

Oh that just brought a tear to my eye I can only imagine what the price is gonna be for here in australia probably double that as we get raped for Mercedes parts here