Mercedes™

Hey guys, I have a problem with my S550. Whenever I try to use the key to lock, unlock, or open the trunk, it doesn't work at all. It doesn't matter if I'm a couple feet away from the car or if I'm next to the car. It won't work. Luckily the car still detects the key and Keyless-Go still works fine, but the key just won't work.

Does anyone know what could possibly be wrong?

Thanks,
Mercedes™

Mercedes™

P.S... When you press a button on the key, the red light flashes immediately... so the batteries aren't the problem.

MB Fanatic

take it to the dealer. does the second key work? You could have a bad key.

Mercedes™

Its both keys that don't work.

RajwanyS550

did it just started happening or never worked. probably needs programing or reprogramming. the dealer is your best bet.

Mercedes™

It started happening recently.

RajwanyS550

then its probably a simple reprogramming. not to worry

Diesel Benz

You mention the red light flashes immediately, do you actually press the button long enough? The trunk would not open from a short key press.

I guess you must know this if you managed to open the trunk earlier.

Mercedes™

Yeah, I do know how it works. It used to work flawlessly, but not anymore.

And RajwanyS550, thanks.

NJBoy115

My good friend has a 2007 S600 and he said that it happened to him too...He would always use the keyless go so he said when that problem would occur he would use the actual key to start the vehicle to let it reprogram itself...If the problem keeps occuring then it will need the dealers attention to be fixed.....Hope this helps!

Mercedes™

So what you're saying is try starting the car with the key instead of Keyless Go?

NJBoy115

Yes, use the actual key to start the car..For some reason if you always use the keyless go your key will loose its "memory" after awhile and will not function the locks/trunk. Once this occurs then you need to use the actual key itself in the ignition so it will recognize the vehicle to reprogram itself. If for some reason it doesn't, then you will need to consult your dealer.

MB Fanatic

This is not the case. I use keyless every single time and do not have this issue.

//AMG55lover

Maybe the battery of the car was low, so you have to go back to the dealer to reprogram the car with the keys!

NJBoy115

I use my Keyless Go all the time as well on my CLS55 and had NEVER had an issue of any kind. But apparently, my local dealer says that it does happen and its a common issue with some MB vehicles.

Mercedes™

Actually, the battery does get low often-ish. I don't drive the car too often. Could this be the problem?