The P light on shifter stays on

[214000724]

I have a 1997 528I and I just notice that the P light on the shifter stays eluminated.
I also hear a low frequecy hum. What could that be?

Thank

[TD]

P light? WTF is that?

[M.Wong]

P light stays on 16 minutes.

Is the hum in the dash for just a few seconds?