Get the correct wheel sensor for you model year X. BMW did change the design of the wheel sensor from the earlier X to the later X. A later X wheel sensor will not work on an older X.

I got the trifecta and it turned out to be.......
 

.........the ABS fuse.
Last year I was coming to a low speed stop at a red light and braking felt weird as if the ABS was engaging. When the light turned green my X5 ('01 4.4i 135,000 mi.) would barely move and jerked all over the place. I thought I broke a drive shaft or something.
I limped to the side of the road and looked under the vehicle, everything seemed fine.
I restarted and got the trifecta warning lights on the dash. I knew this would be ABS module or sensors, so I pulled the fuse to the ABS and it drove fine.
I noticed the speedo/odometer wasn’t working (since it uses and ABS sensor) and figured that was a clue to which sensor was bad.
But after a little while of driving without the odometer I was getting all sorts of warnings. So I plugged the fuse back in when I got home.
All warning lights went out, speedo was working and haven't had an issue since.

I don’t know if pulling the fuse reset something in the module or as I suspect, there was some minor corrosion on the fuse connections causing the ABS module to freak out and removing/replacing it made a clean connection.

May have just been a coincidence, but it's worth a shot to try clean those connections first.