mbtech208

Okay, this has caused some confusion. Lets see if I can clear things up. Not every single non-221 key has problems. Your 112 key may work just fine. But, some non-221 keys have had problems. In fact, many of them have had problems with the remote locking not working, key not turning in ignition, car not starting, etc. Mercedes introduced an updated key with some internal mods, and these keys are identified with the numbers "221" on the key.

This is NOT to say that if your key doesn't have 221 on it, that you should rush to your dealer and cry to your service writer that you demand a new key. Thousands of non-221 keys will have no problems whatsoever throughout the entire life of the car. If a key malfunctions, THEN you need a new key. You know the old saying "If it ain't broke, don't fix it"? Same thing applies here.

Also, you may take delivery of a brand-new car that doesn't have a 221 key. There are still thousands and thousands of non-221 keys in the parts stock. 221 keys are being phased in. Eventually all keys will be the updated version.

karl k

Thanks for clearing this up.

QUESTION:

Does the smartkey start the engine if the battery in the smartkey is dead?

(I realize the remote door opening function won't work.)

mbtech208

Yes, it will still start the car. The batteries only serve to power the buttons on the key. When the key is inserted into the ignition, the EIS inductively powers up the key.

rp430

I wonder why my key wasn't replaced when the EIS was replaced. Should I be concerned??