I have driven the car around the block with no issue. Drove it for a 30 mile trip and no issue. Inspected the car from underneath and could not find any immediate visual sign of an issue with the shift cable or any electrical connection to the transmission ecu.
Battery is holding at 12.5V. Battery is less than 1 year old. Nappa Gold. I checked all battery connections, all tight.
I kept the VB (voltage) readout on during my drive to work. The alternator is holding 13.8 V (a/c is on but it is cool outside, headlights are on, but no other electrical draw) and it dips down to 12.8 when I come to a stop (autotrans downshifting). I also notice that when I shift from drive to park the voltage readout dips down to 12.8V. Is this normal?
Signs of the ignition switch going out haven't cropped up, such as the passenger sun visor, but I am not marking that off.
My only thought now is a bad connection at the TCM or the gear selector switch.
2003 BMW 540i A M-Sport with factory Navigation and CD changer; winter package
1997 Toyota Landcruiser 40th anniversary edition