Congrats on the new Equus! If I'm not mistaken, this model does not support bluetooth audio. If that's the case, you can add a bluetooth adapter that will give you this feature. This Tunai Firefly adapter, suggested by others on this group, works well and is rated well. They make several versions, with and without calling features, starting around $35.
If the audio system is the same as the older ones used in the original Genesis models, you can go wired but you'll need a different adapter (or two). While searching for what used to be two separate adapters, it looks like someone finally made one that does both for only $16. This should resolve the error message you get when plugging your iPhone directly in to the USB jack.
This cable allows you to listen your iPhone 5 6 /iPod to car audio system and Charge your iPhone5 6 /iPod when the car turns on.This cable only interfaces the audio all other controls must be made on the iPhone it's self. (i.e change song on the iPhone itself).Easy to use, just plug and...
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Perhaps an actual 2013 owner could confirm this first. I have a 2016 which has an entirely different audio system. Good luck and enjoy the ride. And SOUND!