sosh

While driving along the turnpike yesterday at 70MPH in my 2010 E350 4M the MFD in front of me went red and said "key not recognized". An alert chime sounded but the car continued to run just fine. The only thing I noticed was that I could not raise or lower radio volume nor could I clear the message on the MFD or shut off the chime. . Ran like that for maybe a half hour. After pulling into my drive I shut the car off in the normal manner with the start/stop button. Started it up again and everything was normal with no warnings. Worked fine on a couple of short trips this morning.
Anyone seen this before in their W212? This is the first glitch I have seen in over 2 years of driving this W212.

ttoE550

low key fob battery? radio interference? Did you pass a tollbooth or anything?

There are some on this board who think the car should stop running when the key cannot be detected by the car. This suggests it's a good thing it doesn't!

dfordham

Sure sounds like the key fob battery is right on the edge. I don't have keyless go, but from what I read here, it seems that the battery doesn't last long compared to the normal key fob.

Regards,
Don

sosh

The key fob battery is a month old. Have no low bat warning when using this key. As far as interference is concerned hard to tell but I was not in any area near a toll booth. Only thing that was unusual when it happened my wife was ending a call with her blackberry that was hooked up to the bluetooth and instead of using the hang up key on the dash she opted to use the hangup key on the Blackberry itself.

Daniel Cordova

I bought mine new in mid 2010, by summer of 11 I had both batteries replaced. Dealer did it at no cost since it was so soon. So yeah, not unheard of.

mnje350

You might have the answer with the cell phone. It should be easy to duplicate if that is the culprit.

Arrie

I had this happen a few times with my 2011 E350 and it has happened on my current 2010 E550 a couple of times. I keep my key in my left front pocket and I think it just sometimes doesn't see the key. When I move a little bit or take the key out of the pocket it sees it no problem.

If it is a low battery it will give you a message to replace the battery. This has also happened to me and I did replace the battery. No message after that.

sosh

Actually took the key from my pocket and put it in a cup holder. Made no difference. I change the key battery every year and I am familiar with the low key bat warning that appears with a low key battery.
At this point I am attributing this to either the Cell phone end call being pressed on my wife's phone or some strange interference. Been using the car every day this week since it happened and have not seen it happen again.

acr2001

I doubt his battery was low as he would have had the warning (as said).

One of the reasons the Keyless Go battery discharges so much faster is because of the fact that it isn't powered by the car while you're driving. When you insert the actual key into the ignition module an inductance coil provides all power to the key (which is why your key will start your car even without a battery installed). The coil may even apply a small charging current to the lithium battery in the key while driving in order to extend its life further (haven't read that in the documentation though, just an assumption). This is the same technology your electric toothbrush takes advantage of in order to recharge.

sosh

Well a week has gone by without another occurance. Last evening i drove the same route that I experienced the issue. No problem what so ever. I am going to write this off as a one time abnormality and continue to drive and enjoy my W212 without futher investigation.