I recently traded in my 2008 Audi TT Roadster for an A3 2.0T because my son didn’t really appreciate his car seat going in the trunk with him in it. In all seriousness, I did a great write up (at least I think so) of putting in a Pioneer AVH-4300DVD in my TT and thought I would recreate it for the A3 as I installed everything this weekend, including the XM unit. Here’s how it all went down.

Tools Required:

• Audi Headunit Removal Keys (x4)
• Crimper
• Spade and Socket Connectors or Barrel Connectors for Wiring
• Screwdriver (Phillips)
• Allen Wrench
• Electrical Tape

Parts Required:

• Enfig RMK4-A3DD Double-Din Fascia Kit
• Connects2 CTSAD002 Electronic Stalk Interface for Audi A3
• Connects2 CTPIONEERLEAD Lead Cable
• Connects2 CT27AA56 Antenna Adapter (Dual to Single)
• Pioneer AVH-P4300DVD
• Pioneer IU50V iPod Interface Cable
• Absolute RLS125 12-VCD Automotive Relay SPDT 30/40A
• Transcend 16GB SDHC Card
• Pioneer GEX-P920 XM Tuner

The first and most time consuming thing is to wire the CTSAD002 and the Pioneer Harness together with the Absolute RLS125 relay to serve as my bypass for watching DVDs while the parking brake is not on.

I cut the two ends off of the Connects2 where it interacts with the aftermarket Head Unit (HU) so I could do the crimping. Luckily I work for a company that has a full electrical panel and wiring shop, but you need some basic crimpers and connectors. I went with connections that could be separated if needed, but you can use barrel connectors as well.

The one special thing you want to do here is, off of the HU harness, Y-off the amp turn on wire (blue), and double Y-off the ground. You’ll need these later. On the Absolute you want to connect the “30″ terminal to the parking break from the HU harness, “86″ and “87″ are both grounded (using two of the three connections we created from the ground wire, the third goes to the Connects2 harness to connect to the car’s wiring) and “85″ goes to one of the Y connections off the blue amp-turn on wire.

Why do it this way?

From my research it appears as though the Pioneer knows if you have just grounded the parking break wire, so what you do is utilize the amp-turn on wire (blue) which initializes a few seconds after the HU turns on, this grounds the unit after it powers on thereby allowing the bypass to work. You could do this with a manual switch, but I thought this way was better. There’s a great video on YouTube that explains it all and I found all the info on TundraSolutions.com.

Once you have the bypass in place, continue matching up all of the wires from the Connects2 to the Pioneer Harness. One mistake I made was that I didn’t initially Y-cable off the amp-turn on wire as I figured my pitiful audio system in the car didn’t have an amp, this was wrong, and the wire does need to be connected to the Connects2.

Once you have all of the wiring hooked up, you can connect the Lead wire and complete the wiring harness.

Now you can pull the existing radio out of the car and get to the OEM wiring. Place it in the Enfig Fascia. The Enfig fascia comes in two pieces, a back piece which goes behind the cage and a front piece which you put on afterwards.

Attach the brackets to the side of the Pioneer HU and the copper colored removal keys as well, be sure to measure the depth of the dash opening to get the HU lined up where you want it. The AVH-P4300DVD has a motorized face so I gave it a little bit of room just in case.

The tricky part here is that the Pioneer head unit is about 1mm too big to fit into the A3′s dash opening, go figure. What I had to do was remove the Pioneer from the cage, put the cage into the first half of the fascia, and ‘force’ that into the dash. Once those were in, pull all of the cables through the cage and connect to the Pioneer unit. Then, and you have to be careful, you need to push everything you can into the dash and down to make room for the double din Pioneer and gently force it into the dash until it locks into the cage. Its really, really tight but it will go in.

Now on this particular headunit there’s a small lip around it and isn’t considered with the Enfig fascia, so you need to grind that off. I took a Dremel and a grinding head and got all of the lip off after about 20 minutes worth of work, the front piece would then snap on, and the look was completed.

As an added step I made a small hole between the dash opening and the glove box to hide my iPod out of sight. The AZ heat won’t let me keep it in there in the summer, but there’s a great little cubby hole for it. In the location for the factory iPod connector I placed the iPod (an 5G iPod Video) and the Pioneer GEX-P920XM Tuner which fits perfectly, and allows for all of the cables to be hidden inside the dash. All you need to do then is ground it and route the antenna to your desired location.

It should be said that you should disconnect the Negative Terminal on your battery before proceeding. This is very easy as its located in the trunk and very easy to get to.

Now connect all the wires!

Do the smart thing, reconnect the battery and give the unit a dry run before putting everything in the dash, otherwise you’re going to have a frustrating time figuring out what you did wrong as you completely disassemble the dash, again.

All of the wiring that you see easily fit in the dash and was all taped up with electrical tape to preserve the connections and prevent any shorts, as well as hold the connections together in a very vibratory environment.

If you did everything right you should be able to watch movies, control your iPod, play music and pictures off of the SD card, have radio.

Now play with the head unit, have some fun and realize the stock speakers sound like poop through such a nice unit.

That should do it, it works great, looks great, and if I ever want nav (outside of my very reliable Galaxy Nexus phone) it would be easy to add as well.