have you tried this?

Program and Reprogram Your Car Remote Key Fob Control Transponder - Program Your Keys Free Instructions - BMW X5 Key Remote Control Fob Programming

both my keys stopped working to open and lock my x5 I tried to get it fixed with the website program and at first it didn't work then a few days later I tried it and it worked

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2014 Jeep Rubicon unlimited 3.6
2005 X5 4.4i
2002 Jeep TJ 4.0 SOLD
1997 328I 4 door 2.8 SOLD