I had exactly the same thing happen.

It seemed like the selector switch was the problem and I was plsnning it's replacement.

Then somebody from xo mentioned he had similar problem and it was water in the transmission connector.

Pulled the connector abs poured out an ounce of rusty water. Cleaned out the pins one by one with deoxit pro gold and problem solved.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)