To delete your favorite songs/artists, you have setup a listener account. I also had to do this just to add favorites, as they would disappear after the truck was shut off until I setup a listener account.
Details on how to setup a listener account are on page 30 of the UConnect 12 manual. Here's the Canadian version I found online quickly, but it should be the same for USA.
After you do that, these next steps should show you how to delete a favorite...
Step 1: Tap the "Notify" button.
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Step 2: Tap the "Manage Alerts" button.
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Step 3: Press and hold (keep pressing) the song/artist you want to delete from your favorites.
After two or three seconds, the icon will change, as shown in step 4.
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Step 4: After holding your finger on the song/artist long enough, a "Remove" button appears. Tap the "Remove" button.
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Step 5: A confirmation box pops up. Press the "Delete" button to delete the favorite.
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