Speedometer repair

The speedo is not something you can fix as a layman, it is probably the DSC control module as that is where the road speed signal is generated. You probably have a brake/DSC warning lamp lit too, yes?

It is possible the Dynamic Stability control module has sustained internal circuit or software degradation. The cost of the repair may be quite high depending on what method of repair you have chosen. If you want to try to repair it yourself, you might start with a call to my associates at Autobahn BMW/Porsche dismantling for a good used unit, the number is (619)444-2290. If you have the vehicle at a shop, the cost of the replacement module is approx $700 and it will require coding to the car at additional cost to you. 34516756289 is the part number (model and VIN dependent) and Realoem. Com is a site I use for folks to go to see the part and to see the retail part price. Having said that, I recommend having your friendly neighborhood BMW repair facility scan the car for faults and as a second opinion, you may have other issues. Repost with concerns/comments. Let me know what you are doing so that I can guide you through this repair. Dr. Hagerty?