If you raise the vehicle, remove the rear wheel speed sensor put the vehicle in neutral and slowly rotate the back wheel with some fine sandpaper on a popsicle stick rubbing gently against the pick up surface, you may clean off the surface and solve the problem. We do a lot of fabrication and grinding in our driveway and when I had the same problem, I had picked up some metal filings on the speed sensor and pick up surface. Welcome to the rust belt. You can also get corrosion in there and get an interrupted signal. I chased this for an annoying length of time until I cleaned it.

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2001 x5 3.0 (sold with broken motor), 1990 e30 M3, 1991 318is, 2002 325i, 2008 335i Dinan stage 3 6 speed,