My 2014 E350 prompted me to replace the key battery. I did it. But it still asks me to replace it. I changed to another new battery, it keeps saying to replace it. Any thought?

 

make sure your usuing the correct battery. CR2025 I think it is

 

 

My 2012 E350 was doing the same thing. The dealer suggested that it was the off-brand Amazon batteries that I was using. I took it in for the airbag recall and they looked for a cause of the key issue. They found one stored fault for a "keyless go antenna" but found the system is operating properly. They put in a fresh "Mercedes recommended" battery and we haven't had any problem since then (11 Feb). I don't know if the battery was the issue or if they corrected some software issue during their diagnostics.

I would make sure you put a fresh, high quality battery in the key and see if that improves the situation.

Good luck!

Edit: The fresh battery did not solve the problem. I am chasing another electrical problem with the driver side headlight and the two may be related...