You have to use MSC mode (on the player) for your car stereo to be able to read it. The same thing can be done with a memory card in a card reader or a flash drive. Note, your music must also be loaded to the player in MSC mode for it to work.
Note also, that your stereo will not be able to see more than one externally connected memory system, so it will not see (or play from) any micro SD card in the slot; only the internal memory of the player will be seen.
Don’t know if this is the correct place for this post, but here goes…
I have an old Sansa PMP and can’t seem to find any info on it here.
On the rear it says Connect-4GB
Right board, but your question really has nothing to do with this thread.
Not much info still exists on this long-discontinued model; even in the SanDisk KnowledgeBase. I know for a fact wi-fi support was dropped a number of years ago, but you’ll just have to google around for any info on it. Here is the AnythingbutiPod forum board on the Connect; you might be able to glean some tips or knowledge about it there, or use the Search function here on this forum; however when I tried I got a lot of results with the word “connect” in the posts but very few regarding the Connect model player.
If it works for what you want and/or need, I say leave well enough alone and enjoy it, but it’s an orphaned child at this point.