Since posting this, I have exclusively used the new key. Now the doors unlock and lock as they should.

But every once in a while, the esp/bas will fault with a yellow light and the center display ordering me to go to get serviced. If I turn the engine off and restart it, everything is fine. I bought a second new key as well (the Chrome new key looks nice, eh?), and it does the same thing.

Any clues? I just hate to bring this to a dealer - I can imaginespending thousands in electronic modules and never getting it fixed competely anyway.

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Thank You!
Fred
2009 ML350
2004 SL600
2004 SL500
1996 SL600
2002 SLK32
2005 CLK320 cabrio
2003 ML350
1997 C280 Sport