baybombers

I went to start my car this evening and my brake pedal was hard and although the gauges lit up as they normally do, the car didn’t turnover. I then pushed the brake harder, pressed the keyless go button and it fired up normally. After a short trip I turned it off and when I restarted it, I got a message that the battery for my key needed to be replaced.
Is it possible my low fob battery could be related to the initial problem starting the car?

Thanks.

KEY08

No, the battery warning comes on well in advance of needing replacement.

thefisch

What you described has happened to me without a low key battery warning. With a very low battery in the keyfob, you would notice the car has a harder time recognizing the key when you touch door handles or press the start button to turn on. My warning just started popping up and I have not noticed a difference in responsiveness yet. As Key said, it comes on well in advance. Some time ago after getting the first key battery warning, I checked the battery voltage with a multimeter and it was at 2.99v on a 3v battery... so yeah the warnings can be very early.

djdirty76

Hi. I just picked up a 2014 e550 yesterday. With 60,000 km from local Mercedes Dealer.. Drove car back for about 2 hrs and when I paired my i-phone on a store parking lot I went to do grocery shopping. When I got back, I could not open the car with either keys, since I had them both with me. When inside keylessGo did not work, had to remove it and insert the key to start the car. Both key fob do not allow me to lock the car, trunk, panic, or anything. Had to use mechanical key to lock car overnight.. I bought brand new batteries for both key fobs last night at wallmart - no luck.. Any ideas? I found some forum post about the fuses, will check them now.. Dealer is closed today so I can't do much..