Hmmmm.... looks like a new problem as of this AM. Started up the car and the readout on the OBC temperature setting read -535 F. Now, given this >is< a 535i model, I had to think this was some sort of secret message from Herr BMW himself.
But, alas, it was not to be. The reading later changed to -749 and then to -294 and so on.
Bottom line - something's whack with the temp sensor. Everything else on the OBC seems to work fine. Archive search suggests one of two solutions. Check the wiring for frays/shorts or replace the temp sensor.
Anyone have any additional insight? Hints on locations of the wiring? My understanding is that the temp sensor is located near the left foglight, under teh front bumper.
Gee...maybe my car's haunted...if this had happened on Halloween...hmmmm. :)