More on ALT-LIN here: https://mbworld.org/forums/e-class-w...tire-life.html
and here: https://mbworld.org/forums/mercedes-...s-voltage.html

Thanks, but, I think the shutting off so early may be a symptom of the underlying problem, which is, if the radio is on when I shut the car off, it should come on by itself when I turn the car back on again. As it is, every time I start the car I have to turn the radio on.

I see, so all fuses good? I forgot if you mentioned already but also checked the aux battery?

Is there a fuse related to retaining configuration information?

I haven't checked the aux battery because I thought there was a warning message if it was not performing correctly, and I've never gotten one.

Sorry about that, I actually don't have the information on which fuse it might cause these issues. Yes do check aux, it doesn't always throw an error code when failing for some reason.