The antenna for the E requires a power connection. It is not just a regular antenna it is "amplified". If you were thinking I was saying it is a power antenna that is retractable or something - that's not what I meant, but it does require hook-up of the power antenna lead off the harness which would be used for that purpose in other cars.
I have an old Pioneer DEH-P5200 and the power antenna wire is blue/white with a female spade clip end. I think Pioneer have changed the harnesses a little since then but you should have no problems locating your power antenna wire. Good luck!