I understand your frustrations..... Happend to me when visiting downtown San Antonio, I was in class for a week and the parking lot I parked my X in for the week would not allow me to use my remote. At first I was pissed because the key I was using was only about 6 months old and I thought it had stopped working until I realized that it would only not work when I was downtown. I took my 740iL down to the same lot and it worked properly, just only had issues with the X.

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Robert

1994 740iL
2001 X5 4.4i Sport
2004 Kawasaki ZX-6R
2009 VW Jetta S