Check to see if the amps really are turned off.

If the amps are actually still on, but the player seems to be muted when it's paused, I know what this is. This is a known bug that was on the internal bug list, but they couldn't reproduce it and marked it as "works for me". It is bug number 1785 on the internal bug list.

What's happening is this: Normal expected behavior is that the DSP is supposed to get muted whenever the player software pauses playback of the MP3 file. There is something happening in the power-on-ignition sequence of events, in certain rare cases with certain cars, is confusing the software and causing the DSP to become "opposite toggled", muting when it's not supposed to be muted.

It was happening to me as well, but I haven't been able to reproduce it recently, so I can't offer much more help in diagnosing it.

One symptom of this is that when you pause and unpause a song, you will get a brief split-second "burst" of the sound of the song before it goes silent again.

One work around is to press the Pause button a bunch of times really fast and eventually it will opposite-toggle again and go back to where it was supposed to. If you are experiencing this, see if that fixes it then you'll know it's the same bug. If not, then it's something else and we should keep looking for causes.