I have a 2008 and have had it for 8 months. I have a dog with me all the time and always use the 2X on the Key. Never have had a problem so I don't think it has anything to do with the 2X thing. However I have never done it more than once ( 2X ) so doing it several times in a row might do something.

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2008 E-70 4.8 Titanium Silver Met/Black/Bamboo