Seattleslew, you should try to find an indy with a GT1 to read the BMW codes.
It is possible that you will see errors related to CAN bus (communication bus between modules).

If a module goes bad, or there is corrosion / oxydation on the connector of one 'main' module, the CAN bus can be affected and problems like the one you have can happen.

In the meantime, you could try to disconnect the battery, and spray some contact cleaner in the DME, ABS/DSC, yaw sensor, and the steering angle sensor connectors. Spray and insert/remove many times to rub the oxydation, then make sure to remove all excess cleaner.

I had a similar problem in my E46. The DME connector had contact problems, and I had the tree light intermittently.
Not expensive to try, it may help.

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